Podcasts about epsp

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.08.03.551788v1?rss=1 Authors: Eberhardt, F. Abstract: The cable equation is key for understanding the electrical potential along dendrites or axons, but its application to dendritic spines remains limited. Their volume is extremely small so that moderate ionic currents suffice to alter ionic concentrations. The resulting chemical-potential gradients between dendrite and spine head lead to measurable electrical currents. The cable equation, however, considers electrical currents only as result of gradients in the electrical potential. The Poisson-Nernst-Planck (PNP) equations allow a more accurate description, as they include both types of currents. Previous PNP simulations predict a considerable change of ionic concentrations in spines during an excitatory postsynaptic potential (EPSP). However, solving PNP-equations is computationally expensive, limiting their applicability for complex structures. Here, we present a system of equations that generalizes the cable equation and considers both, electrical potentials and time-dependent concentrations of ion species with individual diffusion constants. Still, basic numerical algorithms can be employed to solve such systems. Based on simulations, we confirm that ion concentrations in dendritic spines are changing significantly during current injections that are comparable to synaptic events. Electrical currents reflecting ion diffusion through the spine neck increase voltage depolarizations in the spine head. Based on this effect, we identify a mechanism that affects the influx of Ca2+ in sequences of pre- and postsynaptic action potentials. Taken together, the diffusion of individual ion species need to be taken into account to accurately model electrical currents in dendritic spines. In the future the presented equations can be used to accurately integrate dendritic spines into multicompartment models to study synatptic integration. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

In the final episode of this mini-series,  we talk about the impact of pesticides, herbicides, and artificial sweeteners and fats on our health. We explore how these substances have inadvertently wreaked havoc on our bodies.We delve into the ecosystem within our bodies, teeming with trillions of bacteria, mitochondria, and other organisms. Pesticides and herbicides, originally designed to eliminate pesky things like insects and weeds, have unintentionally harmed us by destroying this vital inner ecosystem we depend on. They are damaging our nervous system, hormones, and more.We also touch on the topic of water fluoridation and how it might be disrupting our microbiome, thereby throwing off various processes within our body. Once considered beneficial, fluoride in our water systems (and toothpastes) has now been linked to adverse effects. We talk a little about that and also how water systems vary across the globe.Next, we run through the world of artificial additives, focusing on artificial sweeteners and fats. These additives disrupt our body's natural processes, leading to overeating and weight gain. The divorce between appearances, like taste, and reality has confused and broken our bodies.We discuss strategies to reclaim vibrant health and free ourselves from our current troubles. Armed with empowering knowledge, and realigning ourselves with the way we evolved to be, we can navigate the modern world while safeguarding our health and vitality.RESOURCES - The End of Craving by Mark Schatzker (book) - Environmental Working Group (organization)      - Dirty Dozen     - Clean Fifteen - Silent Spring by Rachel Carson VOCABULARY, CONCEPTS, & THINGS - artificial fats: Olestra, Simplesse - artificial sugars: Ace K, aspartame,  saccharin, stevia, sucralose, xylitol - enzymes: acetylcholinesterase, EPSP synthase - herbicides:glyphosate (Roundup) - insect anatomy: ventral nerve cord - minerals: fluoride - nerve receptors: nicotinic acetylcholine receptors - neurotransmitters: acetylcholine  - pesticides: carbamates, DDT, organophosphates 

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.05.511027v1?rss=1 Authors: Walling, S. G., Harley, C. W., Martin, G. M., Dutton, D. O., Burke, A. T., Chirinos, E. A. Abstract: Network plasticity in the medial perforant path (MPP) of adult (5-9 mo) and aged (18-20 mo) urethane-anesthetized male and female Sprague-Dawley rats was characterized. Paired pulses probed recurrent networks before and after a moderate tetanic protocol. Adult females exhibited greater EPSP-spike coupling suggesting greater intrinsic excitability than adult males. Aged rats did not differ in EPSP-spike coupling but aged females had larger spikes at high currents than males. Paired pulses suggested lower GABA-B inhibition in females. Absolute population spike measures were larger post-tetani in female rats than male rats. Relative population spike increases were greatest in adult males relative to females and to aged males. EPSP slope potentiation was detected with normalization in some post-tetanic intervals for all groups except aged males. Tetani shortened spike latency across groups. Tetani-associated NMDA-mediated burst depolarizations were larger for the first two trains in each tetanus in adult males than other groups. EPSP slopes over 30 min post-tetani predicted spike size in female rats, but not in males. Replicating newer evidence MPP plasticity in adult males was mediated by increased intrinsic excitability. Female MPP plasticity was related to synaptic drive increases, not excitability increases. Aged male rats were deficient in MPP plasticity. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

不得不說，我們且走且行的這個節目，竟然就快要邁向60集了！在60集上線以前，簡尖剪了一些之前節目的小花絮，有很多垃圾話，很多閒聊，還有我們怎麼決定主題的一些內容，歡淫大家來聽喔！ 合作請寄：girldormforcabincrew@gmail.com 也歡迎大家到我們『空服女子宿舍』的ＩＧ來玩喔！！請點擊下列網址 空服女子宿舍 本集採用音效為「小森平的免費音效」https://taira-komori.jpn.org/freesoundtw.html 本集採用音樂為Kevin MacLeod創作的「Ecossaise in E-flat」並依據創用 CC (姓名標示) 4.0 授權使用。 https://creative commons.org/licenses/by/4.0/ 來源： http://incompetech.com/music/royalty-free/?keywords=ecossaise&Search=Search

Dr. Stephanie Seneff Researcher and Author of Toxic Legacy: How the Weedkiller Glyphosate Is Destroying Our Health and the Environment Dr. Stephanie Seneff is a Senior Research Scientist at MIT’s Computer Science and Artificial Intelligence Laboratory in Cambridge, Massachusetts, USA. She has a bachelor’s degree from MIT in biology, and a master’s degree, engineer’s degree, and PhD degree, all from MIT, in electrical engineering and computer science. Her recent interests have focused on the role of toxic chemicals and micronutrient deficiencies in health and disease, with a special emphasis on the pervasive herbicide, glyphosate, and the mineral, sulfur. Since 2008, she has authored over three dozen peer-reviewed journal papers on topics relating toxic chemical exposures to chronic disease. She is the author of a new book on glyphosate titled “Toxic Legacy: How the Weedkiller Glyphosate Is Destroying Our Health and the Environment” (Chelsea Green Publishing, June 2021). New website – stephanieseneff.net The book is available for pre-order on several bookseller websites: Amazon: https://bit.ly/ToxicLegacy_Amazon Barnes and Noble: http://bit.ly/ToxicLegacy_BN Dr.Stephanie Seneff discusses her latest book, “Toxic Legacy: How the Weedkiller Glyphosate Is Destroying Our Health and the Environment.” Her new book stands shoulder to shoulder with Rachel Carson’s 1962 book, “Silent Spring.” “Toxic Legacy” will be released in several months, but it can be preordered now. Patrick asks Dr. Seneff how she became interested in glyphosate. She gives a detailed backstory. “I’ve been studying glyphosate intensely for 9 years,” says Dr. Seneff. Why is there such a gluten and casein intolerance in the U.S.? How does autism relate to glyphosate? What do minerals in the gut have to do with autism and glyphosate? What part does the microbiome play in autism? What is EPSP synthase? What’s the difference between Dr. Seneff’s views on glyphosate versus those of Monsanto, the original patent holder? Is glyphosate sprayed on oranges? Is it sprayed on non-GMO foods? What exactly does non-GMO mean? A listener asks, “Do plumbers and boiler-makers still use glyphosate? They once used it extensively. Are large residues of glyphosate still in our reservoirs and water supplies?” Is it true that Vladimir Putin is “not a big glyphosate guy”? A listener asks, “Monsanto lost all three patents on glyphosate. Many companies are manufacturing it. China manufactures 30% of the world’s supply. Who are people suing nowadays?” Atom writes in, “Glyphosate is used extensively on oranges and all citrus fruit.” How does glyphosate affect the gut’s uptake of sulfate? Why is sulfate so important to the entire body? Manny asks about labs that test for glyphosate. He also asks about glyphosate in vaccines. Does gelatin contain glyphosate? Do Tampons contain glyphosate? How does glyphosate affect newborn human babies? What does it do to testosterone? How does it affect infertility? “We don’t need the government to tell us we don’t have to eat this stuff,” according to Dr. Seneff, addressing the fact that the U.S. government won’t do anything to protect us from companies like Monsanto/Bayer. How is Quanta Computers involved in research showing the toxicity of glyphosate?

Hier das SKRIPT. Frage: was passiert bei der Schreckkrankheit? Dazu müssen wir klären: 1) Was ist ein postsynaptisches Potential (IPSP vs. EPSP)? 2) Was hat es mit digitalen und analogen Umwandlungen auf sich? 3) Was ist zeitliche und räumliche Summation? Fachbegriffe: EPSP, IPSP, Depolarisation, Hyperpolarisation, exzitatorsich, inhibitorisch, Glycin, Acetylcholin, GABA, Axonhügel, präsynaptisch, postsynaptisch, zeitliche Summation, räumliche Summation, Integration, Schwellenwert, ... Feedback/Wünsche: biologopodcast@gmail.com oder @biologopodcast bei Instagram.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.09.289017v1?rss=1 Authors: Qiu, J., Stincic, T. L., Bosch, M. A., Connors, A. M., Petrie, S. K., Ronnekleiv, O. K., Kelly, M. J. Abstract: Kisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1ARH) co-express kisspeptin, neurokinin B, dynorphin and provide an episodic, excitatory drive to gonadotropin-releasing hormone (GnRH) neurons, which is critical for pubertal development and fertility. Previously, we showed that high frequency firing of Kiss1ARH neurons co-releases NKB and dynorphin onto neighboring Kiss1ARH neurons to generate a slow excitatory postsynaptic potential (EPSP) that entrains intermittent, synchronous firing of Kiss1ARH neurons (Qiu et al., 2016). Presently, we discovered that insulin significantly increased the amplitude of the slow EPSP, which we documented is mediated by TRPC5 channels, and augmented synchronous GCaMP6s ([Ca]i) oscillations in Kiss1ARH neurons. Deletion of the endoplasmic reticulum calcium-sensing protein stromal interaction molecule 1 in Kiss1ARH neurons amplified insulin's actions and protected ovariectomized female mice from developing obesity and glucose intolerance with high-fat dieting. Therefore, insulin appears to be critical for facilitating synchronous firing of Kiss1ARH neurons and coordinating energy homeostasis with fertility. Copy rights belong to original authors. Visit the link for more info

The Wisconsin Vegetable Gardener Radio Show from March – Oct weekly Heard on Joy 1340 AM & 98.7 FM Milwaukee, WI Saturday mornings 7-8 AM CST https://tunein.com/radio/Joy-1340-s30042/ Heard on WCRN 830 AM Westborough/Boston, MA Saturdays 8-9 AM EST https://tunein.com/radio/WCRN-AM-830-Full-Service-Radio-s1112/ Heard on KYAH 540 AM Delta/Salt Lake City, UT Saturdays 1-2 PM MST Reply Sundays 9-10 PM MST https://www.yahradio540.com/listen-live/ Heard on KDIZ 1570 AM Minneapolis, MN Saturdays 4-5 PM and replay Sundays 2-3 PM CST http://player.listenlive.co/57071 Heard on WAAM 1600 AM & 92.7 FM Ann Arbor, MI Sundays 7-8 AM EST https://tinyurl.com/p68cvft Heard on WOGO 680 AM & 103.1 FM Chippewa Falls, WI Sundays 9-10 AM CST https://www.christiannetcast.com/listen/player.asp?station=wogo-am Heard on KFEQ 680 AM & 107.9 FM St. Joseph/Kansas City, MO Sundays 10-11 AM CST http://www.680kfeq.com/live-stream/ Heard on WNAX 570 AM Yankton SD Sundays 10-11 AM CST https://tunein.com/radio/Radio-570-s36447/ Heard on WRMN 1410 AM & 96.7 FM Elgin/Chicago, IL Sundays Noon-1 PM CST https://www.wrmn1410.com/ Heard on KMET 1490 AM & 98.1 FM Banning, CA Tuesdays 9 - 10 AM PST https://www.kmet1490am.com/ Check out https://thewisconsinvegetablegardener.com/ Email your questions to Gardentalkradio@gmail.com Or call 24/7 leave your question at 1-800 927-SHOW In segment one Joey and Holly answer four questions about glyphosate What is glyphosate? glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. Glyphosate is a non-selective herbicide, meaning it will kill most plants. It prevents the plants from making certain proteins that are needed for plant growth. Glyphosate stops a specific enzyme pathway, the shikimic acid pathway. The shikimic acid pathway is necessary for plants and some microorganisms. What is it mainly used for ? When used precisely and according to label instructions, herbicides help to keep weeds from competing with crops for water, sunlight and nutrients. Glyphosate helps farmers and homeowners control weeds in many different kinds of plantings How does it work? Glyphosate-based herbicides all work on the same biochemical principle – they inhibit a specific enzyme called EPSP synthase [source: Funke et. al.]. Without that enzyme, plants are unable to produce other proteins essential to growth, so they yellow and die over the course of several days or weeks. A majority of plants use this same enzyme, so almost all plants succumb to glyphosate. Why do some feel it is unsafe? Although generally believed to be less toxic to humans than other herbicides, some experts have concerns about the possibility that it may disrupt endocrine activity in people [source: U.S. National Institutes of Health]. Other animals, including frogs and fish, may also suffer negative effects. Scientists continuing to study glyphosate have noted increases in Non-Hodgkin lymphoma, a type of cancer, in some people exposed to the chemical [source: Dixon]. The World Health Organization's International Agency for Research on Cancer stated in March 2015 that it believed glyphosate is "probably carcinogenic to humans." Check out the companies that make the show possible Power Planter of www.powerplanter.com Proplugger of www.proplugger.com World's coolest rain gauge www.worldscoolestraingauge.com Rootmaker of www.rootmaker.com Us coupon code TWVG at checkout and save 10% of your order Tomato snaps of www.tomatosnaps.com Chapin Manufacturing Inc. of www.chapinmfg.com Pomona pectin of www.pomonapectin.com Iv organics of www.ivorganics.com Dr. JimZ of www.drjimz.com Seed Savers Exchange of www.seedsavers.org Waterhoop of www.waterhoop.com Green Gobbler of www.greengobbler.com Nessalla koombucha of www.nessalla.com MI Green House LLC of www.migreenhouse.com Phyllom BioProducts of www.phyllombioproducts.com Happy leaf led of www.happyleafled.com Neptunes harvest of www.neptunesharvest.com Dripworks of www.dripworks.com We Grow Indoors of www.wegrowindoors.com Harvestmore of www.harvest-more.com Deer defeat www.deerdefeat.com Blue ribbon organics www.blueribbonorganics.com Bluemel's garden & landscape center www.bluemels.com Milwaukee,WI official garden center of the show Wisconsin Greenhouse company of https://wisconsingreenhousecompany.com/ Chip Drop of https://getchipdrop.com/?ref=wisconsinvegetable Tree-Ripe Fruit Co of https://www.tree-ripe.com/ Big elk Garlic farm https://www.bigelkgarlicfarm.com/#/

The Wisconsin Vegetable Gardener Radio Show from March – Oct weekly Heard on Joy 1340 AM & 98.7 FM Milwaukee, WI Saturday mornings 7-8 AM CST https://tunein.com/radio/Joy-1340-s30042/ Heard on WCRN 830 AM Westborough/Boston, MA Saturdays 8-9 AM EST https://tunein.com/radio/WCRN-AM-830-Full-Service-Radio-s1112/ Heard on KYAH 540 AM Delta/Salt Lake City, UT Saturdays 1-2 PM MST Reply Sundays 9-10 PM MST https://www.yahradio540.com/listen-live/ Heard on KDIZ 1570 AM Minneapolis, MN Saturdays 4-5 PM and replay Sundays 2-3 PM CST http://player.listenlive.co/57071 Heard on WAAM 1600 AM & 92.7 FM Ann Arbor, MI Sundays 7-8 AM EST https://tinyurl.com/p68cvft Heard on WOGO 680 AM & 103.1 FM Chippewa Falls, WI Sundays 9-10 AM CST https://www.christiannetcast.com/listen/player.asp?station=wogo-am Heard on KFEQ 680 AM & 107.9 FM St. Joseph/Kansas City, MO Sundays 10-11 AM CST http://www.680kfeq.com/live-stream/ Heard on WNAX 570 AM Yankton SD Sundays 10-11 AM CST https://tunein.com/radio/Radio-570-s36447/ Heard on WRMN 1410 AM & 96.7 FM Elgin/Chicago, IL Sundays Noon-1 PM CST https://www.wrmn1410.com/ Heard on KMET 1490 AM & 98.1 FM Banning, CA Tuesdays 9 - 10 AM PST https://www.kmet1490am.com/ Check out https://thewisconsinvegetablegardener.com/ Email your questions to Gardentalkradio@gmail.com Or call 24/7 leave your question at 1-800 927-SHOW In segment one Joey and Holly answer four questions about glyphosate What is glyphosate? glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. Glyphosate is a non-selective herbicide, meaning it will kill most plants. It prevents the plants from making certain proteins that are needed for plant growth. Glyphosate stops a specific enzyme pathway, the shikimic acid pathway. The shikimic acid pathway is necessary for plants and some microorganisms. What is it mainly used for ? When used precisely and according to label instructions, herbicides help to keep weeds from competing with crops for water, sunlight and nutrients. Glyphosate helps farmers and homeowners control weeds in many different kinds of plantings How does it work? Glyphosate-based herbicides all work on the same biochemical principle – they inhibit a specific enzyme called EPSP synthase [source: Funke et. al.]. Without that enzyme, plants are unable to produce other proteins essential to growth, so they yellow and die over the course of several days or weeks. A majority of plants use this same enzyme, so almost all plants succumb to glyphosate. Why do some feel it is unsafe? Although generally believed to be less toxic to humans than other herbicides, some experts have concerns about the possibility that it may disrupt endocrine activity in people [source: U.S. National Institutes of Health]. Other animals, including frogs and fish, may also suffer negative effects. Scientists continuing to study glyphosate have noted increases in Non-Hodgkin lymphoma, a type of cancer, in some people exposed to the chemical [source: Dixon]. The World Health Organization's International Agency for Research on Cancer stated in March 2015 that it believed glyphosate is "probably carcinogenic to humans." In segment two Joey and Holly go over lesser known facts about landfills There are fewer landfills today. In the 1980s, the United States was home to more than 7,600 dumps but that number was slashed by more than 75 percent – to 1,908 – by 2009. That’s partly because the average landfill grew substantially (approx. 4x) in size. It doesn’t mean we’re producing less waste. Trash production has actually tripled in the U.S. since 1960! And, contrary to popular belief, much of this waste isn’t decomposing quickly, if at all. Landfill excavators have found 40-year-old newspapers with print that’s still completely legible. We have room to grow, but at what price? Nine out of America’s 10 largest landfills will reach maximum capacity in less than 50 years. Is there room for new sites? Sure, though laws restricting the location of landfills means a longer haul for trash and increased emissions from trucking. Landfills can find new life. Once a landfill reaches capacity, it can be capped and the area repurposed into nature preserves, golf courses, resorts and more. But, that doesn’t change the fact that we’re sometimes just tossing away otherwise valuable materials – like yard clippings, food and other organic waste – which could be turned into renewable energy through anaerobic digestion. Landfills burn methane gas. A byproduct of trash in landfills is methane gas, which is vented or burned off via embedded pipes and released into the atmosphere. These harmful emissions are damaging the environment. Methane that comes from biomass can actually be turned into a power source! Here are a few reasons why we shouldn’t toss food into landfills. It increases greenhouse gas emissions. More food reaches landfills than any other single material in municipal solid waste. Food is a significant source of methane gas, which has 21x the global warming potential of CO2! If we diverted food waste from landfills, it would be like removing 2 million cars from the road. It’s a waste of resources. Nothing ever decomposes completely when it’s buried in the ground, not even organic waste like food scraps. It just sits there untreated and creates loads of nasty fumes. Instead, we could be turning organic waste into clean, renewable energy through anaerobic digestion. It’s a waste of money. Ten percent of the total U.S. energy budget goes toward food production and we waste between 30 to 40 percent of the food supply…that’s something like $165 billion each year that we’re basically just throwing away. Think about what you can do Reusing, striving to produce less waste, etc is the best. In segment three Joey and Holly welcome their guest founder of IV Organics https://ivorganics.com/ charles Malki https://www.amazon.com/Saving-World-Home-Garden-Gardening/dp/B0884KFBC6 Charles is a biologist, attorney, all American swimmer, inventor, entrepreneur, and author. He recently published a book called Saving the World with the Home Garden. He also is the founder of IV Organic with a popular YouTube channel. 1.Full disclosure, Charles’ company – IV Organic – has been a sponsor of TWVG radio show, but now that you have a book we wanted to have you on the show. Please tell us about your company, IV Organic? 2.We often advise people to use fertilizer properly for their garden, what is the vital importance of properly fertilizing and not over fertilizing? 3.You say it's good to have some pests in the garden – why? 4.In your book you talk about making free plants – how do you make free plants? What are the lesser known methods of making free plants? 5.Mycorrhizae are vital to plant life – what are they and why should the home gardener be aware of them? 6.How can we find out more about you? In segment four Joey and Holly answer gardeners questions Q Is there an organic method to keep cabbage worms off my kale and cabbage other than plucking them off every day? . A: Apply Diatomaceous Earth Get some food-grade diatomaceous earth and sprinkle it on plants where cabbage worms are spotted. The diatomaceous earth powder will kill cabbage worms by piercing their bodies. Set up a Netting Barrier Cabbage moths and butterflies may lay eggs a couple of times during the year. During these times, you should set up row barriers or netting barriers across your garden to prevent the adults from laying their eggs. No eggs, no cabbage worm problems. Dust Leaves with Cornmeal You could kill the cabbage worms by dusting the affected plants with cornmeal. The caterpillars with eat the cornmeal, swell up, and eventually die. Original all-purpose flour may also work. Apply Companion Planting Grow pest-repelling plants (e.g. thyme, mint) next to your susceptible plants. This could discourage the adult butterflies and moths from laying eggs on your valuable garden crop. Make a Natural Repellent Spray There are a number of natural ingredients, such as garlic and cayenne pepper, that may deter cabbage worms. Blend these ingredients with water to create the repellent then use a spray to apply it on the undersides of leaves. Introduce Beneficial Insects A sustainable approach to getting rid of cabbage worms is by introducing natural predators to the garden. This may include spiders, praying mantis, and ground beetles. In addition to these insects, you may also want to attract other natural predators such as birds and geckos. Q: my cucumber plants do not look healthy. The leaves have yellow spots on them. I am not noticing any pest on the plant. Again, anything I should be looking for as a cause/cure? A: You plants have a fungal and bacterial this can happen but in your pictures I do not see yellow or shrivel on the leaves that would be a fungal infection On your cucumbers you have Anthracnose this is a fungus that is most prevalent in wet and warm conditions. It can overwinter in fallen vines, leaves, and other plant debris, releasing spores in the spring to infect new plants. The spores (conidia) need moisture and mild temperatures to germinate. the first thing you can do is remove up to 25% of the leaves on the plant just remove the infected leaves and throw them in the trash this will mostly be the lower leaves on the plant Chlorothalonil (Bravo) and benomyl (Benlate) are popular fungicides used to treat anthracnose these are the active ingredients benomyl is a possible carcinogen. Chlorothalonil is a broad-spectrum agricultural fungicide that is often applied to crops in bloom when honeybees are present for pollination because it is currently deemed safe to bees If a large part of your plant is infected, you may need to remove the entire plant and start over with sanitized soil in a different part of the garden I would trime the affected leaves off the plant Q: I have hole being eaten in my bok choy what is doing this and how to I stop it A: That is caused by the Flea Beetle. No, they aren’t really fleas, and they only bite plants, not people. Try this homemade spray to control flea beetles: 2 cups rubbing alcohol, 5 cups water, and 1 tablespoon liquid soap. Test out the mixture on a leaf of the plant, let it sit overnight, then spray the rest of the plant if you don’t notice any adverse effects. Spray the mixture on the foliage of garden plants that are susceptible to these pests. Dusting your plants with plain talcum powder repels flea beetles on tomatoes, potatoes, peppers, and other plants. Use white sticky traps to capture flea beetles as they jump. Insecticides may be used early in the season, but are generally unnecessary in the control of flea beetles on adult plants. Be extra diligent if your soil has history of bacterial diseases. Please contact your local nursery or cooperative extension for further advice. Check out the companies that make the show possible Power Planter of www.powerplanter.com Proplugger of www.proplugger.com World's coolest rain gauge www.worldscoolestraingauge.com Rootmaker of www.rootmaker.com Us coupon code TWVG at checkout and save 10% of your order Tomato snaps of www.tomatosnaps.com Chapin Manufacturing Inc. of www.chapinmfg.com Pomona pectin of www.pomonapectin.com Iv organics of www.ivorganics.com Dr. JimZ of www.drjimz.com Seed Savers Exchange of www.seedsavers.org Waterhoop of www.waterhoop.com Green Gobbler of www.greengobbler.com Nessalla koombucha of www.nessalla.com MI Green House LLC of www.migreenhouse.com Phyllom BioProducts of www.phyllombioproducts.com Happy leaf led of www.happyleafled.com Neptunes harvest of www.neptunesharvest.com Dripworks of www.dripworks.com We Grow Indoors of www.wegrowindoors.com Harvestmore of www.harvest-more.com Deer defeat www.deerdefeat.com Blue ribbon organics www.blueribbonorganics.com Bluemel's garden & landscape center www.bluemels.com Milwaukee,WI official garden center of the show Wisconsin Greenhouse company of https://wisconsingreenhousecompany.com/ Chip Drop of https://getchipdrop.com/?ref=wisconsinvegetable Tree-Ripe Fruit Co of https://www.tree-ripe.com/ Big elk Garlic farm https://www.bigelkgarlicfarm.com/#/

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.04.186478v1?rss=1 Authors: Zhang, X., Schloegl, A., Vandael, D., Jonas, P. Abstract: To understand the mechanisms of information coding in single neurons, it is necessary to analyze subthreshold synaptic events, action potentials (APs), and the interrelation between these two forms of activity in different behavioral states. However, detecting excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) in awake, behaving animals remains challenging, because of unfavorable signal-to-noise ratio, high frequency, fluctuating amplitude, and variable time course of synaptic events. Here, we developed a new method for synaptic event detection, termed MOD (Machine-learning Optimal-filtering Detectionprocedure), which combines concepts of supervised machine learning and optimal Wiener filtering. First, experts were asked to manually score short epochs of data. Second, the algorithm was trained to obtain the optimal filter coefficients of a Wiener filter and the optimal detection threshold. Third, scored and unscored data were processed with the optimal filter, and events were detected as peaks above threshold. Finally, the area under the curve (AUC) of the receiver operating characteristics (ROC) curve was used to quantify accuracy and efficiency of detection. Additionally, cross-validation was performed to exclude overfitting of the scored data, a potential concern with machine-learning approaches. We then challenged the new detection method with EPSP traces in vivo in mice during spatial navigation and EPSC traces in vitro in slices under conditions of enhanced transmitter release. When benchmarked using a 1/(1-AUC) metric, MOD outperformed previous methods (template-fit and deconvolution) by a factor of up to 3. Thus, MOD may become an important tool for large-scale analysis of synaptic activity in vivo and in vitro. Copy rights belong to original authors. Visit the link for more info

Welcome back to episode 405 of the Whole View. (0:27) Today Stacy and Sarah are talking about a super interesting topic submitted a listener. Which, if you didn't know this already, we love it when you email us. Sarah shared some behind the scenes information on where listener questions come from. There are Stacy's requests, listener questions, and the really challenging listener questions. The question in discussion in this episode is one of those really hard ones that has been in the queue for a long time. Sarah was able to pull together the information for this show because she actually did a lot of research on this topic for her gut microbiome book. And of course, Sarah did extra research to address the many facets of this challenging question. Stacy is excited about this science rich show.   Listener Question Is the EWG's dirty dozen list based on strong science? (3:37) My husband listened to two episodes of the Skeptoid podcast on organic vs. conventional farming. Mr. Dunning said that we are being duped into paying extra for organic produce. It is sprayed with larger amounts of pesticides than those used in conventional farming and the organic pesticides have been shown to cause disease. My husband believes Mr. Dunning because he provides references and appears to be liberal and non-biased in other podcasts.   I have been purchasing organic produce according to the Environmental Working Group's dirty dozen list. It says on the Activist Facts website that "There’s really only one thing you need to know about the Environmental Working Group when it comes to its studies of toxins: 79 percent of members of the Society of Toxicology (scientists who know a little something about toxins) who rated the group say that the Environmental Working Group overstates the health risk of chemicals. I am walking around with holes in my shirts, and I haven't gotten the air conditioning fixed in my car, so that I can afford organic food. Am I wasting my money? I feel like I cannot trust anyone but you.   Preface Stacy wanted to refer listeners to listen back to previous episodes for information on how both Stacy and Sarah have evolved the way they purchase and prioritize their own foods within their budget. (5:06) Neither Stacy nor Sarah buys everything organically. Nothing that Stacy and Sarah are going to discuss in this episode is intended to be a judgment on you or your family or what you did in the past or what you are doing now. This is all education so that you can be empowered to make the choices that are best for your family at the correct time for you. Where Stacy's family is today, ten years later, is a lot different than where they were ten years ago. The goal of this episode is to help you so that you can walk away and ask questions. There is a larger philosophy that each family needs to adapt to what works best for them. No one is perfect. If you are starting in your journey, you don't need to forego the necessities to have organic food. There is a way to prioritize your budget in a way that is consistent with what your family believes in. Healthy living choices are so personal.   Foundational Choices & Next Level Choices Sarah wanted to emphasize that there are foundational health principles. Nutrient density diet, eating a lot of fruits and vegetables, getting enough sleep, managing stress, and living an active lifestyle. Then Sarah thinks of the next level steps like adding some biohacks, supplements, purchasing grass-fed beef, and organic fruits and vegetables. We need to first make sure that we are focusing on the foundational principles and adding in the next level choice if and when it makes sense. Eating organic is beyond the basic principles, but is overall a better choice. The EWG's overall approach is in many ways more rigorous than the American regulatory agencies. The EWG tends to align with the European Union, Health Canada, and these other regions of the world where the criterion for approving a chemical or pesticide is firmer. In America, the thought process is that chemicals are assumed fine unless proven bad. In Europe, a chemical is not ok until proven safe.   Conventional Evaluation of Pesticide Safety The FDA's safety assessment for chemicals in foods have a variety of criteria. (13:11) They look at acute chronic and subchronic toxicity, carcinogenicity, genotoxicity, reproductive and developmental toxicity, neurotoxicity, and immunotoxicity. Pesticides also go through additional impact evaluation on the environment and ecology. The vast majority of the studies evaluating the effects of pesticides show problems to human health only with occupational exposure, rather than the much lower exposure the majority of us would have simply by eating produce from crops treated with these chemicals. However, there are some challenges with this. We can see high exposure in rodents causing all kinds of problems. The assumption is that acute exposure is not the same as low dose chronic exposure.   Where the Standards Differ One of the challenges that we have in evaluating pesticides is that our exposure is already so vast. There are no humans that don't already have multiple points of exposure to pesticides. There are studies that are linking the chronic low dose exposure to pesticide residues that have correlated pesticide exposure in the food supply with a number of health issues. In the United States, there are 72 pesticides that are routinely used that are completely banned or are in the process of being completely phased out in Europe. Of the pesticides used in USA agriculture in 2016, 322 million pounds were of pesticides banned in the EU. Twenty-six million pounds were of pesticides banned in Brazil and 40 million pounds were of pesticides banned in China. Pesticides banned in the EU account for more than a quarter of all agricultural pesticide use in the USA. It is important to understand that the European Union is looking at the same science as the EPA. And they are making a different judgment based on the strength of the data. We have a challenge that our metric is, 'is it toxic' and 'does it cause cancer'. WHO Guidelines for Safety of Chemicals in Food are much more thorough, and add to the above. They include general system toxicity, allergy and hypersensitivity, and GI Tract Considerations (includes microbiome).   Pesticides and the Microbiome (Sarah’s Biggest Concern) Microbial diversity is generally considered to be the most important measurable criteria for a healthy microbiome. (24:31) The more different species you have, they tend to keep each other in balance. The bacteria basically control the growth of each other. We are also looking for the growth of these really important probiotic strains. In addition, we are looking for completely absent levels of pathogens. We are also looking at the balance between the two main phylum of bacteria in the gut. It is important to understand that rodent studies are actually really good studies for understanding the gut microbiome. We would want to eventually be able to do a similar study in humans. But what Sarah wants to emphasize is that these rodent studies are a really good model for understanding what is happening in humans. Let’s go through some of the most commonly-used pesticides in agriculture for food crops. Permethrin is a broad-spectrum chemical often used as an insecticide for cotton, corn, alfalfa, and wheat crops—unfortunately, it’s also lethal to bees. It’s also used to treat lice, ticks, and scabies.  For more on this, visit this link here. PEM has higher antibacterial activity against some beneficial bacteria, (including Lactobacillus paracasei and Bifidobacterium). Than against pathogens (such as Staphylococcus aureus and Escherichia coli, which only respond to higher concentrations of PEM). Carbendazim (CBZ) is a broad-spectrum benzimidazole fungicide, widely used in agriculture. In mice, 28 days of exposure to CBZ resulted in gut dysbiosis. It suppresses the growth of some of the most important probiotic families while increasing the growth of some problematic families of bacteria. And it decreases bacterial diversity. To learn more about this pesticide, see here. Epoxiconazole (EPO) is a broad-spectrum fungicide often used on grain crops, and that works by inhibiting the metabolism of fungal cells. It reduces the production of conidia—the asexual spores of a fungus that facilitate reproduction. In rats, EPO for 90 days decreased the relative abundance of Firmicutes and increased the abundance of Bacteroidetes and Proteobacteria, while also selectively enriching Lachnospiraceae and Enterobacteriaceae. To learn more about this pesticide, see here.   More Commonly Used Pesticides Imazalil (IMZ) is a systemic fungicide used to combat fungi on vegetables and fruit (especially citrus), as well as tubers during storage. (30:39) In mice, IMZ exposure (at doses of 100 mg per kg of body weight daily for up to 14 days) reduced the cecal relative abundance of Bacteroidetes, Firmicutes, and Actinobacteria, while also reducing microbiota richness and diversity. The IMZ-treated mice also exhibited colonic inflammation. In another study of mice, low-dose, environmentally relevant exposure to IMZ (0.1, 0.5, or 2.5 mg per kg of body weight daily) for 15 weeks resulted in gut microbiota changes. These changes included reduced mucus secretion, decreased the expression of genes related to cystic fibrosis transmembrane conductance regulator (CTFR) in the ileum and colon, and generally disturbed intestinal barrier function. Stacy shared her perspective on how she looks at this information. Think through the way how these pesticides are more heavily used on grains. Chlorphyrifos (CPF) is an extremely common organophosphate pesticide used to kill insects and worms, by interfering with acetylcholine signaling and disrupting their nerve processes. It’s commonly used on fruit and vegetable crops, as well as vineyards. This is one that was going to be banned in the USA, but Scott Pruitt reversed the planned ban. You can learn more about this here. Sarah shared on this study, this study, this study, and this study. This information should stimulate a reevaluation of the use of these chemicals in the food supply. Diazinon is an organophosphate insecticide used on a variety of crops—including fruit trees, rice, sugarcane, nuts, potatoes, and corn. You can learn more about this pesticide here. It causes different changes in male rodents versus female rodents. The researchers speculated that these differences—with male mice experiencing the most severe changes—were due to sex-dependent gut microbiota profiles present before treatment. You can read more about this study here.   Two More Commonly Used Pesticides Propamocarb (PMEP) is a systemic fungicide used to control root, leaf, and soil diseases caused by oomycetes (water molds) by interfering with fatty acid and phospholipid biosynthesis and therefore changing the membrane in fungi. (41:41) It can accumulate in fruit at high levels, thus reaching humans.  You can find more information on this pesticide here. In mice, 28 days of exposure to PMEP (at levels of 300 mg/L in drinking water) induced gut dysbiosis and changes in 20 fecal metabolites, including SCFAs, succinate, bile acids, and TMA. You can read more about this study here. Glyphosate is a broad-spectrum herbicide that can kill both grasses and leafy weeds. It works by inhibiting an enzyme (5-enolpyruvylshikimic acid-3-phosphate synthase, or EPSP synthase), which is used by bacteria, archaea, fungi, algae, some protozoans and plants to synthesize folates (vitamin B9), ubiquinone, menaquinones (vitamin K2), phenolic compounds, and the aromatic amino acids tyrosine, tryptophan, and phenylalanine. The pathway this affects doesn’t exist in animals, which is part of why glyphosate has historically been considered to have low toxicity in animals.  Now that we understand that we have at least as many bacterial cells living within our body as we do human cells and that those bacteria are essential to our health, the relevance of glyphosate exposure comes into focus. Many bacterially-derived compounds that benefit human health are produced via the shikimate pathway. One rat study evaluated the impact on the microbiome of two weeks of glyphosate consumption, and showed a dose-dependent increase in fecal pH attributable to a reduction in acetic acid production, implying the metabolomic impact of glyphosate exposure.   More on Glyphosate It's not that glyphosate is necessarily directly impacting our cells, but it is dramatically impacting the gut microbiome at levels that we are already being exposed to in the food supply. (48:50) In studies in poultry, cattle, and pigs, glyphosate exposure increases the ratio of pathogenic bacteria to probiotic microbes, reducing Bifidobacteria, Lactobacillus, and Enterococcus while increasing Salmonella and Clostridium. In a long-term rat study, the impact on the gut microbiome was evaluated following nearly two years of glyphosate exposure via drinking water at three different doses. Glyphosate caused a large increase in the Bacteroidetes family S24-7 (associated with obesity and inflammation) and a decrease in Lactobacillus species in females (more modest changes in males). It also altered the Firmicutes to Bacteroidetes ratio to one more closely associated with chronic disease. The authors concluded “our data suggests that the exposure to an environmental concentration of [Roundup] residues could have a role in the current epidemic of gut dysbiosis”. This occurs even at levels well below the US ADI of 1.75 mg/kg body weight /day.  There is no strong dose-response. Sarah wants to emphasize that our glyphosate exposure in food is quite high. It is definitely above the cusp for an impact on our gut microbiome composition. The FDA has a report where they have been mandated to measure glyphosate residue in the food supply. In their 2016 report they measured measurable levels of glyphosate residues in 63% of corn food crops and in 67% of soybean food crops. However, they did not say how much residue was there. The 2018 report goes to a dead link now. A Swiss study of foods purchased at a grocery store showed that legumes had the highest concentrations of glyphosate residues, up to 2.95 mg/kg. United Kingdom government testing of glyphosate residues in wholegrain bread showed levels up to 0.9 mg/kg. A study of foods purchased in Philadelphia, USA metropolitan area showed 59 percent of honey samples contained glyphosate residues, and 36 percent of soy sauce contained glyphosate residues. Third-party testing of popular breakfast cereals, crackers, and cookies by the Detox Project and Food Democracy Now! showed alarming levels of glyphosate residues in all products. Roundup Ready GMOs have the highest level of glyphosate residues. Studies prove that our current levels of exposure are sufficient for measurable amounts of glyphosate to get into our bodies.  One study showed that 44% of city dwellers in 18 countries in Europe had detectable glyphosate residues in their urine, despite Europe’s more aggressive campaign against GMO foods. A pilot study in the United States of America evaluating 131 urine samples from across the country detected glyphosate residues in the urine of 86.7% of them. The highest observed detection frequency in the Midwest was at 93.3% and the lowest in the South at 69.2%.   How to Look at this Science The EWG is looking at this much more broad group of criteria and they are taking a very similar standpoint to the European Union. (58:09) A small effect is still an effect and we need to be concerned about it. When Sarah does a deep dive look to look at the impact on the gut microbiome this is where Sarah sees the biggest area of concern. Sarah thinks it is especially important because it is not currently part of the criteria by the FDA and the EPA for whether or not these chemicals are going to be approved for use. This is the thing that Sarah really thinks needs to change. The good news is that a healthy gut microbiome and high fiber consumption can actually protect us from absorbing a lot of these pesticides.  There have been studies that showed that lactobacilli can help reduce how much pesticide on our food gets into our bodies.  There are also studies that show that higher fiber consumption can at least partially reverse the gut dysbiosis. As we get back to the heart of this question, there are studies that show that the answer is no. High vegetable consumption is still really important because it does support a healthy gut microbiome, to begin with. And a healthy gut microbiome is going to protect us in a lot of ways. For example, they can protect us against heavy metals. Even if we can't afford organic to not let that dissuade us from eating that high vegetable consumption because of this. Sarah sees this as an exciting two-way street. Even though pesticide residues are impacting the composition of our guts, the composition of our gut is influenced by more than just that. It is influenced by how many fruits and vegetables we eat, mushrooms, nuts and seeds, variety, how much fish, how quality the olive oil is that we are consuming, etc. All of these things help to determine the composition of our gut microbiome. Doing all of these foundational things becomes more important when we are not necessarily in a position to be able to seek out and afford the highest food quality. It is still really important to eat a vegetable-rich diet. That's why Sarah wants to classify all of this science as the next level. The foundational principle is still eating a lot of fruits and vegetables, even if our only access to that is conventional. Beyond that, yes the Dirty Dozen and Clean Fifteen lists from the EWG are a wonderful tool. Not that Sarah agrees with everything the EWG has said, Sarah thinks that these are spot on in the sense of trying to minimize our exposure to pesticide residues.   How to Limit Pesticide Exposure Stacy feels that the podcast referenced and the information they are sharing aren't so far apart. (1:02:10) Sarah and Stacy discussed a point shared in the documentary Food Inc. that really hit this information home. We do the best that we can with what we can, and become educated on what other things we can do to support healthy living. Nothing is ever perfect. Prioritize the foods you purchase and do the best you can. It is not good to stress about these things. The dirty dozen list includes strawberries, spinach, kale, nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery and potatoes The clean fifteen list includes avocados, sweet corn, pineapple, onions, papaya, sweet peas (frozen), eggplants, asparagus, cauliflower, cantaloupes, broccoli, mushrooms, cabbage, honeydew melon, and kiwifruit. If you are going to get something off the dirty dozen conventional, look at ways that you can wash that food very well or ways you can peel the food to remove the majority of the pesticide residue. USDA certification is very expensive, so a lot of small family farms are growing organically, but don't have the certification. Talk to farmers and find out how they are growing their food. Stacy can't handle the sight of bugs in her fresh vegetables. Eating fruits and vegetables is a good thing. Perfection is not the goal. Neither Stacy nor Stacy eats 100% organic, they both do the best that they can. Sarah has found that the prices at her local farmer's market are best. Develop relationships with your local farmers, and shop at the end of the market. Stacy subscribes to Hungry Harvest, which has a waiting list right now. Sarah prescribes to MisFit Market, there is also one called Imperfect Produce. One of the things that Sarah loves about her subscription is the surprise element of it, which forces her to get creative with her meal planning. At Stacy's house they meal plan when their box arrives, based on what they received. Stacy shared more information on their meal planning process as a family, and how focused they have become to make sure they are not wasting food. Building relationships with your local farmers is a point that Stacy echoed from Sarah. Buying things in season or frozen can also be a helpful way to save money. Stacy's organic box is at least 30% off had they purchased those items at a grocery store regularly. The thing that Stacy most loves about Hungry Harvest is that they give back to the community.   Closing Thoughts Stacy thanked Sarah for all the research she did for this show! (1:23:13) If you have any follow up questions on all of this, you are welcome to email Stacy and Sarah using the contact forms on their blogs. You can comment on social media posts as well. Stacy and Sarah are always happy to hear from you! If you have been loving this show, please help spread the word to others by sharing a link to an episode you enjoyed with a family or friend, or leave a review. Stacy and Sarah so greatly appreciate your support! Thank you again for tuning in! Next week is another science-heavy show that builds off of this week's episode. We will be back again next week! (1:25:57)

Folge 027 - Postsynaptisches Potential | Neurobiologie Teil 7 Show Notes: Bitte unterstützt den Biologie Passion Podcast finanziell ➤ paypal.me/biologiepassionpdcst Hier gehts zum zugehörigen Blogartikel auf meiner Webseite. Wenn dir die Podcastfolge gefallen hat, würde mich eine kurze Bewertung auf iTunes freuen. Trag dich in meinen Newsletter ein, wenn du über neue Podcastfolgen informiert werden willst. Vielen Dank fürs Zuhören!

Hallo Zusammen und herzlich willkommen zur zehnten Folge des AbiTour Podcast. Heute präsemtieren wir euch den drtitten Teil unser Neurobiologie Serie, dieses Mal mit dem Thema Synapsen. Des weiteren werden in dieser folge auch die Unterschiede zwischen IPSP's und EPSP's erklärt, und veranschaulicht wie diese entstehen. Des weiteren beihnaltet die Folge auch die Summation von PSP's, mit der Unterscheidung von zeitlicher und räumlicher Summation. Außerdem erklären wir euch den Codierungswechsel, welcher entlang der Erregungsbahn stattfindet und gehen dabei auf die digitale und analoge Codierung ein. Viel Spass! Olli & Sven

Bei Welsen der Spezies Schilbe mystis kommt es im elektrosensorischen System zur Konvergenz mehrerer (bis zu ca. 30) ampullärer Rezeptororgane eines sog. Clusters auf ein primäres afferentes Neuron. Es gibt zwei morphologische Grundtypen der Clusterinnervierung (stern- oder baumförmig); bei Clustern vom "Bäumchentyp" an der Analflossenbasis erstreckt sich das Konvergenzareal über bis zu ca. 2 mm. Die Dendriten weisen eine vollständige, aber untypische Myelinisierung mit u.a. sehr kurzen Internodienabständen auf und erreichen Längen bis zu ca. 3mm. Im Unterschied zu Physialia spec. sind bei Schilbe die Leitungslängen innerhalb eines Clusters vom Bäumchentyp zwischen Synapse und Axonstamm - und davon abhängig auch die elektrischen Eigenschaften der Dendriten - sehr unterschiedlich. Ampulläre Rezeptororgane sind spontanaktiv und generieren in der afferenten Faser Aktionspotentiale in sehr regelmäßiger Abfolge; die statistische Auswertung des Interspike-Intervalls zeigt eine eingipflige, schmale, symmetrische Verteilung (s = 7%). Zusammen mit den Ergebnissen zur Empfindlichkeitsaddition im Cluster (Peters & Mast 1983, van Dongen & Bretschneider 1984, Peters & van Ieperen 1989, Peters et al. 1997a) und Überlegungen zur Signalausbreitung lassen sich diese Ergebnisse nur mit monozentrischer Erregungsbildung im Axonstamm erklären (Bestätigung durch progressive TTX-Vergiftungsexperimente, s.u.) und sind mit der "Kollisionstheorie" (Murray & Capranica 1973, Pabst 1977, Holden 1976, Sanchez & Zakon 1990, Teunis et al. 1990b, Longtin & Racicot 1996) nicht vereinbar. Nach MS-222 Anästhesie oder Anwendung des Natriumkanal-Blockers TTX zeigt die Histogrammverteilung charakteristische Veränderungen und gibt so weitere Hinweise auf Funktionsmechanismen bei Erregungsbildung und Fortleitung. Der Vergleich der meßbaren Aktionspotentialamplituden im Cluster zeigt keine Abhängigkeit von der Fortleitungsdistanz innerhalb des Dendritenbaums. Die Ergebnisse sind nur mit einer aktiven Invadierung der Endarborisation vereinbar, was auch durch progressive TTX-Vergiftungsexperimente klar bestätigt wird (s.u.). Es gibt während "kathodischer Inhibition" mit starken Stimuli nach der zu erwartenden anfänglichen Unterdrückung der Nervenantwort eine Plateauphase, in der eine reduzierte, sehr regelmäßige Spontanaktivität bei fehlender Reizempfindlichkeit auftritt. Die Rückkehr der Empfindlichkeit nach dieser Phase erfolgt anisotrop. Dies legt die Existenz wenigstens zweier adaptiver Prozesse innerhalb der analogen Verarbeitung (vor der Generation von Aktionspotentialen) nahe. Nach den Ergebnissen der progressiven TTX-Vergiftung ist der schnellere dieser Mechanismen in den Dendriten lokalisiert und korreliert mit der Adaptation dendritischer Natriumkanäle. Es gibt eine positive, nichtlineare Korrelation zwischen Spikeamplitude und Interspike-Intervall: bei Stimulation des Systems tritt eine Amplitudenverminderung ein und umgekehrt. Ein Zusammenhang mit Refraktärphänomenen oder "Shuntingprozessen" in der Endarborisation kann ausgeschlossen werden. Das Ergebnis ist allein auf der Basis verminderter Aktivierbarkeit der dendritischen Natriumkanäle (potentialabhängige Inaktivation) aufgrund des EPSP-induzierten Anstiegs des intradendritischen Potentials zu erklären und gibt damit Hinweise auf die aktive Rolle der Natriumkanäle bei der Fortleitung graduierter Potentiale. Progressive TTX-Blockierungsexperimente der dendritischen Natriumkanäle zeigen bei Doppelableitungen von proximalen und distalen Organen innerhalb eines Clusters charakteristische, hochsignifikante Veränderungsmuster in Aktionspotentialamplituden, Reizempfindlichkeit und Erregungsmustern in Abhängigkeit von der Diffusionsrichtung des Kanalblockers. Die Ergebnisse liefern u.a. eindeutige Hinweise, daß: (1) in jedem Cluster nur ein Impulsentstehungsort für die Generierung der Aktionspotentiale verantwortlich ist, der sich im Axonstamm der gemeinsamen Afferenz befindet. (2) Die Ausbreitung der postsynaptischen Potentiale erfolgt mit aktiver Unterstützung dendritischer Natriumkanäle, die im unterschwelligen Bereich als spannungsgesteuerte Stromverstärker arbeiten und postsynaptische Signale stabil verstärken; damit schaffen sie erst die Voraussetzung für Konvergenz und Addition der Analoginformation im Axonstamm. (3) Die Endarborisation wird in ihrer gesamten Erstreckung von den Aktionspotentialen aktiv retrograd invadiert, was u.a. eine wichtige "Reset"-Funktion in der Endarborisation erfüllen dürfte. Die Endarborisation stellt damit ein - in dieser Form und Ausprägung aus der Literatur noch nicht bekanntes - effizientes peripheres mononeuronales Konvergenzsystem dar, das in komplexer Weise essentiell auf aktiven Funktionen dendritischer Natriumkanäle basiert. Konsequenzen daraus für den neuronalen Informationsverarbeitungsprozeß (analoge Vorverarbeitung) und den Rezeptormechanismus ampullärer Organcluster werden diskutiert.

In vitro-Experimente wurden am isolierten Hirnstamm von Fröschen durchgeführt. Die einzelnen Nervenäste der Bogengänge und der Lagena wurden auf jeder Seite des Gehirns getrennt elektrisch stimuliert. Afferente und kommissurale Antworten wurden intrazellulär in vestibulären Neuronen zweiter Ordnung (2°VN) gemessen. Das Projektionsmuster eines Teils dieser 2°VN wurde durch antidrome Stimulation der okulomotorischen Kerne und des zervikalen Rückenmarks bestimmt. Bei der Hälfte aller identifizierten 2°VN konnte ein monosynaptisches EPSP nach Stimulation des ipsilateralen Lagena-Nerven registriert werden. Etwa ein Viertel dieser Neurone erhielt einen monosynaptischen Eingang ausschließlich von der Lagena, die anderen drei Viertel der Neurone erhielten zusätzlich noch ein monosynaptisches EPSP von einem oder mehreren ipsilateralen Bogengängen. In den Neuronen mit einem konvergenten monosynaptischen Eingang von der Lagena und einem der drei Bogengänge stammte der Bogengangs-Eingang entweder vom anterioren vertikalen oder vom posterioren vertikalen Bogengang, aber nie vom horizontalen Bogengang. Kommissurale Eingänge nach Stimulation des kontralateralen Lagena-Nerven waren erregender Natur und wurden in vertikalen Bogengangs-Neuronen und in Lagena-Neuronen, nicht aber in horizontalen Bogengangs-Neuronen angetroffen. Diese bemerkenswerte Spezifität der monosynaptischen Konvergenz für Lagena- und vertikale Bogengangsinformationen stimmt mit der Koaktivierung der entsprechenden vestibulären Sinnesorgane bei natürlichen Bewegungen überein. Die andere Hälfte der registrierten 2°VN erhielt ein monosynaptisches EPSP ausschließlich nach Stimulation der ipsilateralen Bogengangs-Nerven. Die Mehrheit (91%) dieser 2°Bogengangs-Neurone erhielt einen monosynaptischen Eingang von nur einem der drei ipsilateralen Bogengänge, der Rest entweder von zwei (8%) oder von allen drei Bogengängen (1%). Die meisten 2°Bogengangs-Neurone (79%) mit einem monosynaptischen Eingang von nur einem Bogengang erhielten eine kommissurale Hemmung vom kontralateralen Bogengang der gleichen Drehebene (koplanar) und eine kommissurale Erregung von einem oder zwei der anderen beiden kontralateralen nicht-koplanaren Bogengänge. Die koplanaren hemmenden Signale wiesen disynaptische (78%) oder trisynaptische Latenzen auf. Im ersten Fall wurde die Hemmung direkt, also ohne weitere Verschaltung von einem 2°Bogengangs- Neuron im gegenüberliegenden vestibulären Kern vermittelt. Im zweiten Fall war ein zusätzliches Interneuron dazwischen geschaltet. Erregende kommissurale Eingänge nach Stimulation des gesamten VIII. Hirnnerven sind auf erregende Signale der kontralateralen nicht-koplanaren Bogengänge und einer daraus resultierenden Maskierung der kommissuralen bogengangs-spezifischen Hemmung zurückzuführen. Somit sind auch beim Frosch die funktionellen Strukturen vorhanden, die als neuronale Grundlage für eine „push-pull- Organisation“ bei Kopfbewegungen bei der Katze dienen. Axone von 2°Bogengangs-Neuronen projizierten absteigend zum Rückenmark, aufsteigend zu den okulomotorischen Kernen oder über Axonkollaterale ab- und aufsteigend. Axone von 2°Lagena-Neuronen projizierten ausnahmslos zum Rückenmark, nicht aber zu den okulomotorischen Kernen. Diese elektophysiologischen Untersuchungsergebnisse sind kompatibel mit in vivo-Studien, die zeigen dass Informationen über vertikale Linearbeschleunigung bei Vertebraten praktisch keine Bedeutung für den makulo-okulären Reflex haben.

The effects of the cholinoceptor agonist, carbachol (CCh), were examined in the rat hippocampal slice preparation. Intracellular recordings from CA1 pyramidal neurones revealed that CCh (1–3 μM) inhibited excitatory postsynaptic responses evoked by stimulation of the Schaffer collateral/commissural pathway while, at the same time, direct excitability was enhanced. Extracellularly, CCh produced a concentration-dependent reduction of the amplitude of the field excitatory postsynaptic potential (field EPSP) recorded in the CA1 apical dendritic region. The muscarinic receptor antagonist, pirenzepine, competitively antagonized the effects of CCh on the field EPSP with a pA2 of 7.4. These results confirm earlier reports of a presynaptic inhibitory action of CCh in the hippocampal CA1 region and provide strong evidence that this effect is mediated by muscarinic receptors of the M1 subtype.

1. Intracellular recordings were obtained from neurons in layer II/III of rat frontal cortex. Single-electrode current- and voltage-clamp techniques were employed to compare the sensitivity of excitatory postsynaptic potentials (EPSPs) and iontophoretically evoked responses to N-methyl-D-aspartate (NMDA) to the selective NMDA antagonist D-2-amino-5-phosphonovaleric acid (D-2-APV). The voltage dependence of the amplitudes of the EPSPs before and after pharmacologic changes in the neuron's current-voltage relationship was also examined. 2. NMDA depolarized the membrane potential, increased the neuron's apparent input resistance (RN), and evoked bursts of action potentials. The NMDA-induced membrane current (INMDA) gradually increased with depolarization from -80 to -40 mV. The relationship between INMDA and membrane potential displayed a region of negative slope conductance in the potential range between -70 and -40 mV which was sufficient to explain the apparent increase in RN and the burst discharges during the NMDA-induced depolarization. 3. Short-latency EPSPs (eEPSPs) were evoked by low-intensity electrical stimulation of cortical layer IV. Changes in the eEPSP waveform following membrane depolarization and hyperpolarization resembled those of NMDA-mediated responses. However, the eEPSP was insensitive to D-2-APV applied at concentrations (up to 20 microM) that blocked NMDA responses. 4. EPSPs with latencies between 10 and 40 ms [late EPSPs (lEPSPs)] were evoked by electrical stimulation using intensities just subthreshold to the activation of IPSPs. The amplitude of the lEPSP increased with hyperpolarization and decreased with depolarization. 5. The lidocaine derivative QX-314, injected intracellularly, suppressed sodium-dependent action potentials and depolarizing inward rectification. Simultaneously, the amplitude of the eEPSP significantly decreased with depolarization. Neither the amplitude of a long-latency EPSP nor the amplitude of inhibitory postsynaptic potentials (IPSPs) was significantly affected by QX-314. 6. Cesium ions (0.5-2.0 mM) added to the bathing solution reduced or blocked hyperpolarizing inward rectification. Under these conditions, the amplitude of the eEPSP increased with hyperpolarization. The amplitude of the lEPSP was unaltered or enhanced. 7. The lEPSP was reversibly blocked by D-2-APV (5-20 microM), although the voltage-dependence of its amplitude did not resemble the action of NMDA on neocortical neurons.

1. To investigate excitatory postsynaptic potentials (EPSPs), intracellular recordings were performed in layer II/III neurons of the rat medial frontal cortex. The average resting membrane potential of the neurons was more than -75 mV and their average input resistance was greater than 20 M omega. The amplitudes of the action potentials evoked by injection of depolarizing current pulses were greater than 100 mV. The electrophysiological properties of the neurons recorded were similar to those of regular-spiking pyramidal cells. 2. Current-voltage relationships, determined by injecting inward and outward current pulses, displayed considerable inward rectification in both the depolarizing and hyperpolarizing directions. The steady-state input resistance increased with depolarization and decreased with hyperpolarization, concomitant with increases and decreases, respectively, in the membrane time constant. 3. Postsynaptic potentials were evoked by electrical stimulation via a bipolar electrode positioned in layer IV of the neocortex. Stimulus-response relationships, determined by gradually increasing the stimulus intensity, were consistent among the population of neurons examined. A short-latency EPSP [early EPSP (eEPSP)] was the response with the lowest threshold. Amplitudes of the eEPSP ranged from 4 to 8 mV. Following a hyperpolarization of the membrane potential, the amplitude of the eEPSP decreased. Upon depolarization, a slight increase in amplitude and duration was observed, accompanied by a significant increase in time to peak. 4. The membrane current underlying the eEPSP (eEPSC) was measured using the single-electrode voltage-clamp method. The amplitude of the eEPSC was apparently independent of the membrane potential in 8 of 12 neurons tested. In the other 4 neurons, the amplitude of the eEPSC increased with hyperpolarization and decreased with depolarization. 5. Higher stimulus intensities evoked, in addition to the eEPSP, a delayed EPSP [late EPSP (lEPSP)] in greater than 90% of the neurons tested. The amplitude of the lEPSP ranged from 12 to 20 mV, and the latency varied between 20 and 60 ms. The amplitude of the lEPSP varied with membrane potential, decreasing with depolarization and increasing following hyperpolarization. The membrane current underlying the lEPSP (lEPSC) displayed a similar voltage dependence. 6. At stimulus intensities that led to the activation of inhibitory postsynaptic potentials (IPSPs), the lEPSP was no longer observed.

The present study examined the role of N-methyl-D-aspartic acid (NMDA) receptors in synaptic plasticity in regular-spiking cells of rat frontal cortex. Intracortical stimulation, at levels subthreshold for elicitation of action potentials, evoked a late excitatory postsynaptic potential (EPSP) in layer II III neurons that was sensitive to the selective NMDA antagonist -2-amino-5-phosphonovaleric acid (APV). This late EPSP showed marked short-term frequency-dependent depression, suggesting that it is polysynaptic in origin. Polysynaptic late EPSPs were selectively enhanced following high-frequency stimulation. This sustained increase in synaptic efficacy, or long-term potentiation, was expressed in regular spiking cells and appeared to result from activation of NMDA receptors on excitatory interneurons. These data demonstrate the existence of an NMDA-modulated polysynaptic circuit in the neocortex which displays several types of use-dependent plasticity.

Intracellular recordings were made from neocortical neurons in vitro. Application of D-Ala2-D-Leu5-enkephalin (DADL) by different methods produced a decrease in EPSP amplitude and in the amplitude of L-glutamate-induced depolarizations without changes in membrane potential or membrane input resistance. The DADL effects were blocked by naloxone and persisted when synaptic transmission was depressed, suggesting DADL acts on postsynaptically located opiate receptors. With dynorphin A (1–17), depolarizations, hyperpolarizations, decreases and increases in EPSP were observed, but never an anti-glutamate effect.