Podcasts about itds

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.08.04.551950v1?rss=1 Authors: Goupell, M. J., Stecker, G. C., Williams, B. T., Bilokon, A., Tollin, D. J. Abstract: The interaural time difference (ITD) is a primary horizontal-plane sound localization cue computed in the auditory brainstem. ITDs are accessible in the temporal fine structure of pure tones with a frequency of no higher than about 1400 Hz. Explaining how listeners' ITD sensitivity transitions from very best sensitivity near 700 Hz to impossible to detect within 1 octave currently lacks a clear physiological explanation. Here, it was hypothesized that the rapid decline in ITD sensitivity is dictated not to a central neural limitation but by initial peripheral sound encoding, specifically, the low-frequency edge of the cochlear excitation pattern produced by a pure tone. To test this hypothesis, ITD sensitivity was measured in 16 normal-hearing listeners as a joint function of frequency (900-1500 Hz) and level (10-50 dB sensation level). Performance decreased with increasing frequency and decreasing sound level. The slope of performance decline was 90 dB/octave, consistent with the low-frequency slope of the cochlear excitation pattern. Consequently, fine-structure ITD sensitivity near 1400 Hz may be conveyed primarily by "off-frequency" activation of neurons tuned to lower frequencies near 700 Hz. Physiologically, this could be realized by a single narrow channel near 700 Hz that conveys fine-structure ITDs. Such a model is a major simplification and departure from the classic formulation of the binaural display, which consists of a matrix of neurons tuned to a wide range of relevant frequencies and ITDs. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.08.04.551983v1?rss=1 Authors: Schnupp, J. W., Buchholz, S., Buck, A. N., Budig, H. K., Khurana, L., Rosskothen-Kuhl, N. Abstract: Cochlear implants (CIs) have restored enough of a sense of hearing to around one million severely hearing impaired patients to enable speech understanding in quiet. However, several aspects of hearing with CIs remain very poor. This includes a severely limited ability of CI patients to make use of interaural time difference (ITD) cues for spatial hearing and noise reduction. A major cause for this poor ITD sensitivity could be that current clinical devices fail to deliver ITD information in a manner that is accessible to the auditory pathway. CI processors measure the envelopes of incoming sounds and then stimulate the auditory nerve with electrical pulse trains which are amplitude modulated to reflect incoming sound envelopes. The timing of the pulses generated by the devices is largely or entirely independent of the incoming sounds. Consequently, bilateral CIs (biCIs) provide veridical envelope (ENV) ITDs but largely or entirely replace the "fine structure" ITDs that naturally occur in sounds with completely arbitrary electrical pulse timing (PT) ITDs. To assess the extent to which this matters, we devised experiments that measured the sensitivity of deafened rats to precisely and independently controlled PT and ENV ITDs for a variety of different CI pulse rates and envelope shapes. We observed that PT ITDs completely dominate ITD perception, while the sensitivity to ENV ITDs was almost negligible in comparison. This strongly suggests that the confusing yet powerful PT ITDs that contemporary clinical devices deliver to biCI patients may be a major cause of poor binaural hearing outcomes with biCIs. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.02.526884v1?rss=1 Authors: Carr, C. E., Wang, T., Kraemer, I., Kuokkanen, P. T., Capshaw, G., Ashida, G., Kempter, R., Koeppl, C. Abstract: Barn owls experience increasing interaural time differences (ITDs) during development, because their head width more than doubles in the month after hatching. We therefore hypothesized that their ITD detection circuit might be modified by experience. To test this, we raised owls with unilateral ear inserts that delayed and attenuated the acoustic signal, then used the binaural neurophonic to measure ITD representation in the brainstem nucleus laminaris (NL) when they were adult. The ITD circuit is composed of delay line inputs to coincidence detectors, and we predicted that plastic changes would lead to shorter delays in the axons from the manipulated ear, and complementary shifts in ITD representation on the two sides. In owls that received ear inserts around P16, the maps of ITD shifted in the predicted direction, but only on the ipsilateral side, and only in those regions that had not experienced auditory stimulation prior to insertion. The contralateral map did not change. Thus, experience-dependent plasticity of the ITD circuit occurs in NL, and our data suggest that ipsilateral and contralateral delays are independently regulated. Thus, altered auditory input prior to, and during, sensory experience leads to long lasting changes in the representation of ITD. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Wszyscy zgadzamy się ze stwierdzeniem, że skuteczny HR jest potrzebny w każdej firmie. Jak wygląda tworzenie takiego działu od podstaw? W którym momencie należy zacząć myśleć o tworzeniu struktury HR w firmie? Na co zwrócić uwagę będąc pierwszą odpowiedzialną za to osobą w firmie? Dowiecie się o tym w najnowszym odcinku naszego podcastu! Naszym gościem był Arkadiusz Czyżowski - HR Manager w ITDS, absolwent psychologii w biznesie i przedsiębiorczości, coach oraz trener kompetencji miękkich. Posiadający 4 letnie doświadczenie w procesach okołoludzkich z branży IT, takich jak rekrutacja, Employee Branding, komunikacja wewnętrzna, szkolenia i rozwój pracowników, wsparcie przywództwa czy Employee Journey. W swojej ścieżce zawodowej pracował także nad projektami dotyczącymi Customer Experience i Marketingu. W swojej pracy bazuje na filozofii Candidate/Employee Experience. Mówi o sobie: “Company Culture Freak" ;) Aby być na bieżąco sprawdzajcie również nasze IG i LinkedIn:@inhire.io

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.09.09.507313v1?rss=1 Authors: Camperos, M. J. G., Goncalves, T. C., Marin, B., Pavao, R. Abstract: Interaural Time Difference (ITD) is the main cue for azimuthal auditory perception in humans. ITDs at each frequency contribute differently to azimuth discrimination, which can be quantified by their azimuthal Fisher Information. Consistently, human ITD discrimination thresholds are predicted by the azimuthal information. However, this prediction is poor for frequencies below 500 Hz. Such poor prediction could be ascribed to the strategy of quantifying azimuthal information using HRTFs obtained in unnaturalistic anechoic chambers or by using a direct method which does not incorporate the delay lines proposed by the Jeffress-Colburn model. In the present study, we obtained ITD discrimination thresholds from extensive sampling across frequency and ITD, and applied multiple strategies for quantifying azimuthal information. These strategies employed HRTFs obtained in realistic and anechoic chambers, with and without considering delay lines. We found that ITD discriminability thresholds across the complete range of frequencies are better predicted by azimuthal information conveyed by ITD cues when (1) we use naturalistic high-noise HRTFs, and (2) ITD delay compensation is not applied. Our results support that auditory perception is shaped by natural environments, which include high reverberation in low frequencies. Moreover, we also suggest that delay lines are not a crucial feature for determining ITD discrimination thresholds in the human auditory system. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.27.358085v1?rss=1 Authors: Franken, T. P., Bondy, B. J., Haimes, D. B., Golding, N. L., Smith, P. H., Joris, P. X. Abstract: Locomotion generates adventitious sounds which enable detection and localization of predators and prey. Such sounds contain brisk changes or transients in amplitude. We investigated the hypothesis that ill-understood temporal specializations in binaural circuits subserve lateralization of such sound transients, based on different time of arrival at the ears (interaural time differences, ITDs). We find that Lateral Superior Olive (LSO) neurons show exquisite ITD-sensitivity, reflecting extreme precision and reliability of excitatory and inhibitory postsynaptic potentials, in contrast to Medial Superior Olive neurons, traditionally viewed as the ultimate ITD-detectors. In vivo, inhibition blocks LSO excitation over an extremely short window, which, in vitro, required synaptically-evoked inhibition. Light and electron microscopy revealed inhibitory synapses on the axon initial segment as the structural basis of this observation. These results reveal a neural vetoing mechanism with extreme temporal and spatial precision and establish the LSO as the primary nucleus for binaural processing of sound transients. Copy rights belong to original authors. Visit the link for more info

The ITDS Crew catches up after Juan and Michelle's trip to the UK. They went to Tales of the Cocktail and visited the Laphroaig Distillery. We talk about their experiences on their trip and about what's in store for the ITDS podcast. Take a listen! --- Support this podcast: https://anchor.fm/inside-the-drinkers-studio/support

Aside from recognizing and distinguishing sound patterns, the ability to localize sounds in the horizontal plane is an essential component of the mammalian auditory system. It facilitates approaching potential mating partners and allows avoiding predators. The superior olivary complex (SOC) within the auditory brainstem is the first site of binaural interaction and its major projections and inputs are well investigated. The adult input pattern, however, is not set from the beginning but changes over the period of development. Mammals including humans experience different stages and conditions of hearing during auditory development. The human brain for instance has to perform a transition after birth from the perception of sound waves transmitted in amniotic fluid to the perception of airborne sounds. Furthermore, small mammals like rodents, which are common model organisms for auditory research, perceive airborne sounds for the first time some days after birth, when their ear canals open. The basic neuronal projections and the intrinsic properties of neurons, such as the expression of specific ion channels, are already established and adjusted in the SOC during the perinatal period of partial deafness. An additional refinement of inputs and further adaptations of intrinsic characteristics occur with the onset of hearing in response to the new acoustic environment. It is likely that with ongoing maturation well-established inputs within the sound localization network need these adaptations to balance anatomical changes such as an increasing head size. In addition, short-term adjustments of synaptic inputs in the adult auditory system are equally necessary for a faithful representation of auditory space. A recent study suggests that these short-term adaptations are partially represented at the auditory brainstem level. The question of how intrinsic properties change during auditory development, to what extent auditory experience is involved in these changes and the functional implications of these changes on the sound localization circuitry is only partially answered. I used the hyperpolarization-activated and cyclic nucleotide-gated cation channels (HCN channels), which are a key determinant of the intrinsic properties of auditory brainstem neurons, as a target to study the influence of auditory experience on the intrinsic properties of neurons in the auditory brainstem. Another important question still under discussion is how neurons in the auditory brainstem might fine-tune their firing behavior to cope optimally with an altered acoustic environment. Recent data suggest that auditory processing is also affected by modulatory mechanisms at the brainstem level, which for instance change the input strength and thus alter the spike output of these neurons. One possible candidate is the metabotropic GABAB receptor (GABABR) which has been shown to be abundant in the adult auditory brainstem, although GABAergic projections are scarce in the mature auditory brainstem. These questions were investigated by performing whole-cell patch-clamp recordings of SOC neurons from Mongolian gerbils at different developmental stages in the acute brain slice preparation. Specific currents and receptors were isolated using pharmacological means. Immmunohistochemical results additionally supported physiological findings. In the first study, I investigated the developmental regulation of HCN channels in the SOC and their underlying depolarizing current Ih, which has been shown to regulate the excitability of neurons and to enhance the temporally precise analysis of binaural acoustic cues. I characterized the developmental changes of Ih in neurons of the lateral superior olive (LSO) and the medial nucleus of the trapezoid body (MNTB), which in the adult animals show different HCN subunit composition. I showed that right after hearing onset there was a strong increase of Ih in the LSO and just a minor increase in the MNTB. In addition, the open probability of HCN channels was shifted towards more positive voltages in both nuclei and the activation time constants accelerated during the first days of auditory experience. These results implicate that Ih is actively regulated by sensory input activity. I tested this hypothesis by inducing auditory deprivation which was achieved by surgically removing the cochlea in gerbils before hearing onset. The effect was opposite in neurons of the MNTB and the LSO. Whereas in LSO neurons auditory deprivation resulted in increased Ih amplitude, MNTB neurons displayed a moderate decrease in Ih. These results suggest that auditory experience differentially changes the amount of HCN channels dependent on the subunit composition or possibly alters intracellular cAMP levels, thereby shifting the voltage dependence of Ih. This regulatory mechanism might thus maintain adequate excitability levels within the SOC. A second study was carried out to investigate the role of GABABRs in the medial superior olive (MSO). Upon activation, these metabotropic receptors are known to decrease the release probability of neurotransmitters at the presynapse thereby altering excitatory and inhibitory currents at the postsynaptic site. Neurons in the MSO analyze interaural time differences (ITDs) by comparing the relative timing of the excitatory inputs from the two ears using a coincidence mechanism. In addition, these neurons receive a precisely timed inhibitory input from each ear which shifts ITDs in the physiological relevant range. Since the major inhibitory input changes its transmitter type from mixed GABA/glycinergic to only glycinergic after hearing onset it was now interesting to examine the mediated effects of GABABRs, which have been shown to be abundant in the prehearing and adult MSO of gerbils. Furthermore, revealing the precise expression pattern of GABABRs and their influence on excitatory and inhibitory currents in the MSO during auditory development should provide further evidence of their functional relevance. Performing pharmacological experiments I could now demonstrate that the activation of GABABRs before hearing onset decreases the current of excitatory inputs stronger than that of inhibitory inputs whereas a switch is performed after hearing onset and inhibitory currents are stronger decreasedcompared to excitatory currents. In a similar way, also the expression pattern of GABABRs changes before and after hearing onset as revealed by immunohistochemistry. Since the main inhibitory inputs to the adult MSO are purely glycinergic, it was commonly assumed that GABABRs occupy only a minor role in the mature auditory brainstem. Contradictory to this, it was possible to activate presynaptic GABABRs by synaptic stimulation even in adult animals and to observe a profound decrease of inhibitory current in MSO neurons. These results suggest GABAergic projections of yet unknown origin targeting the MSO. It is therefore quite likely that GABABRs modulate and possibly improve the localization of low frequency sounds even in adult mammals. Summarized, the outcome of this thesis contributes to a better understanding of the developmental adaptation in the auditory system and demonstrates that the orderly specification of intrinsic properties within the SOC is dependent on auditory experience. Moreover, I show that even in mature animals the synaptic strength of MSO inputs can be modulated by synaptic GABA release. This should emphasize the importance of modulatory mechanisms and could be the basis for future studies concerning the field of sound localization.

The ability to localize sounds in space is important to mammals in terms of awareness of the environment and social contact with each other. In many mammals, and particularly in humans, localization of sound sources in the horizontal plane is achieved by an extraordinary sensitivity to interaural time differences (ITDs). Auditory signals from sound sources, which are not centrally located in front of the listener travel different distances to the ears and thereby generate ITDs. These ITDs are first processed by binaural sensitive neurons of the superior olivary complex (SOC) in the brainstem. Despite decades of research on this topic, the underlying mechanisms of ITD processing are still an issue of strong controversy and the processing of concurrent sounds for example is not well understood. Here I used in vivo extra-cellular single cell recordings in the dorsal nucleus of the lateral lemniscus (DNLL) to pursue three novel approaches for the investigation of ITD processing in gerbils, a well-established animal model for sound localization. The first study focuses on the ITD processing of static pure tones in the DNLL. I found that the low frequency neurons of the DNLL express an ITD sensitivity that closely resembles the one seen in the SOC. Tracer injections into the DNLL confirmed the strong direct inputs of the SOC to the DNLL. These findings support the population of DNLL neurons as a suitable novel approach to study the general mechanism of ITD processing, especially given the technical difficulties in recording from neurons in the SOC. The discharge rate of the ITD-sensitive DNLL neurons was strongly modulated over the physiological relevant range of ITDs. However, for the majority of these neurons the maximal discharge rates were clearly outside this range. These findings contradict the possible encoding of physiological relevant ITDs by the maximal discharge of single neurons. In contrast, these data support the more recent hypothesis that the discharge rate averaged over a population of ITD-sensitive neurons encodes the location of low frequency sounds. In the second study, I investigated the ITD processing of two concurrent sound sources, extending the classical approach of using only a single sound source. As concurrent sound sources a pure tone and background noise were chosen. The data show that concurrent white noise has a high impact on the response to tones and vice versa. The discharge rate to tones was mostly suppressed by the noise. The discharge rate to the noise was suppressed or enhanced by the tone depending on the ITD of the tone. Investigating the responses to monaural stimulation and to tone stimulation with concurrent spectrally filtered noise, I found that the ITD sensitivity of DNLL neurons strongly depends on the spectral compositions, the ITDs, and the levels of the concurrent sound sources. Two different mechanisms that mediate these findings were identified: monaural across-frequency interactions and temporal interactions at the level of the coincidence detector. Simulations of simple coincidence detector models (in cooperation with Christian Leibold) suggested this interpretation. In the third study of my thesis, the temporal resolution of binaural motion was analyzed. Particularly, it was investigated how fast the neuronal system can follow changes of the ITD. Here, psychophysical experiments in humans and electrophysiological recordings in the gerbil DNLL were performed using identical acoustic stimulation. Although the binaural system has previously been described as sluggish, the binaural response of ITD-sensitive DNLL neurons was found to follow fast changes of ITDs. Furthermore, in psychophysical experiments in humans, the binaural performance was better than expected when using a novel plausible motion stimulus. These data suggest that the binaural system can follow changes of the binaural cues much faster than previously reported and almost as fast as the monaural system, given a physiological useful stimulus. In summary, the results presented here establish the ITD-sensitive DNLL neurons as a novel approach for the investigation of ITD processing. In addition, the usage of more complex and naturalistic stimuli is a promising and necessary approach for opening the field for further studies regarding a better understanding of the hearing process.

Activating mutations in the juxtamembrane domain of FLT3 (FLT3-internal tandem duplications, FLT3-ITDs) represent the most frequent genetic alterations in acute myeloid leukemia (AML). FLT3-internal tandem duplications (FLT3-ITDs) are a heterogenous group of mutations in patients with acute leukemias that are prognostically important. To characterize the mechanism of transformation by FLT3-ITDs, we sequenced the juxtamembrane region (JM) of FLT3 from 284 patients with acute leukemias. The length of FLT3-ITDs varied from 2 to 42 amino acids (AA) with a median of 17 AA. The analysis of duplicated AAs showed that in the majority of patients, the duplications localize between AA 591 to 599 (YVDFREYEY). Arginine 595 (R595) within this region is duplicated in 77% of patients. Single duplication of R595 in FLT3 conferred factor-independent growth to Ba/F3 cells and activated STAT5. Moreover, deletion or substitution of the duplicated R595 in two FLT3-ITD constructs as well as the deletion of wildtype-R595 in FLT3-ITD substantially reduced the transforming potential, pointing to a critical role of the positive charge of R595 in stabilizing the active confirmation of FLT3-ITDs. Deletion of R595 in the FLT3-WT inhibited the growth of cells upon FL stimulation and the STAT5 activation. In this study we could also show that the tyrosine residues 589 and 591 of the FLT3-ITDs could be important phosphorylation sites and are very crucial for the activation of FLT3- ITDs. Simultaneous substitution of these two tyrosine residues with phenyalanine showed complete inhibition of the transforming potential of FLT3-ITDs and STAT5 activation. The substitution of tyrosine residues 597 and 599 did not show any effect on the transforming potential of FLT3-ITDs, supporting the previous hypothesis that these tyrosines may be only important to maintain the integrity of FLT3-WT in its inactive state. Our data provide important insights into the role of the juxtamembrane domain in the mechanism of transformation by FLT3-ITDs.

Schalllokalisation ist eine der wichtigsten Aufgaben unseres Hörsystems. Die Position von tieffrequenten Schallquellen wird vor allem auf der Basis von interauralen Zeitdifferenzen (ITD) bestimmt. Die Verarbeitung solcher ITDs findet in der medialen oberen Olive (MSO), einer Struktur des auditorischen Hirnstamms statt (Goldberg and Brown, 1969; Yin and Chan, 1990; Spitzer and Semple, 1995), die zum ersten Mal in der aufsteigenden Hörbahn binaurale akustische Information verarbeitet. Die Zellen in der MSO bekommen von beiden Ohren erregende und hemmende Eingänge. Ein zeitlich präzise abgestimmtes Zusammenspiel dieser vier Eingänge sorgt für die richtige Einstellung der ITD-Empfindlichkeit in der Wüstenrennmaus (Brand et al., 2002). Die Koinzidenz der erregenden Eingängen alleine erzeugt eine ITD-Sensitivität, die bei ca. 0 ITD ihre maximale Antwort hat. Dadurch liegt die maximale Steigung der ITD-Funktion außerhalb des physiologisch relevanten Bereiches. Die Inhibition sorgt dafür, dass die maximale Antwort in den contralateralen Bereich verschoben und somit die maximale Steigung der ITD-Funktion auf den Bereich der physiologisch relevanten ITDs abgestimmt wird. Die glyzinergen inhibitorischen Projektionen zur MSO der Wüstenrennmaus sind vor Hörbeginn noch diffus verteilt und innervieren Somata und Dendriten gleichermaßen. Weniger als zwei Wochen nach Hörbeginn sind diese hemmenden Eingange jedoch auf die Somata der MSO-Neurone beschränkt (Seidl, 1999). Diese Beschränkung ist abhängig von binauraler Aktivität (Kapfer, 1999). In der vorliegenden Arbeit wird gezeigt, dass diese Eliminierung der dendritischen inhibitorischen Eingänge in der Wüstenrennmaus durch die Aufzucht in omnidirektionalem weißem Rauschen während einer kritischen Periode nach Hörbeginn unterdrückt werden kann. Für die normale Entwicklung der räumlichen Verteilung der glyzinergen Synapsen in der MSO ist also normale akustische Erfahrung notwendig. Bei Tieren, die ITDs nicht zur Schalllokalisation verwenden, kommt es zu keiner solchen Entwicklung. Vor Hörbeginn und auch im Erwachsenenstadium sind die inhibitorischen Eingänge auf den Zellen der MSO gleichmäßig über Soma und Dendriten verteilt. Als weiteres Ergebnis wird beschrieben, dass es eine Veränderung der ITD-Empfindlichkeit nach Hörbeginn gibt. Die Abstimmung der maximalen Steigungen der ITD-Funktionen auf den physiologischen Bereich nach Hörbeginn unterbleibt, wenn die räumlichen akustischen Signale durch weißes Rauschen während der kritischen Periode maskiert werden. Diese Entwicklung korreliert mit der Verteilung der glyzinergen Synapsen an MSO-Neuronen. Werden erwachsene Tiere weißem Rauschen ausgesetzt, so kommt es zu einer Änderung der ITD-Empfindlichkeit, die reversibel ist, aber nicht mit der unterdrückten Entwicklung nach Hörbeginn vergleichbar ist. Diese Arbeit zeigt, dass die korrekte strukturelle Entwicklung inhibitorischer Synapsen notwendig ist um die biophysikalische Grundlage für Schalllokalisationsmechanismen zu schaffen. Diese Entwicklung ist abhängig von der Erfahrung räumlicher akustischer Signale. Somit ist sie ein Beispiel für ein System, das sich direkt durch die Information die es später verarbeitet, selbst abstimmt und optimiert.

Sound localization and recognition are two important tasks of the auditory system. Both require accurate processing of temporal cues. Microsecond differences in the arrival time of a sound at the two ears (interaural time differences, ITDs) are the main cue for localizing low frequency sound sources in space. Traditionally, ITDs are thought to be encoded by an array of coincidence-detector neurons, receiving excitatory inputs from the two ears via axons of variable length (“delay lines”), aligned in a topographic map of azimuthal auditory space. Convincing evidence for the existence of such a map in the mammalian ITD detector, the medial superior olive (MSO) is, however, lacking. Equally undetermined is the role of a temporally glycinergic inhibitory input to MSO neurons. Using in vivo recordings from the MSO of the Mongolian gerbil, the present study showed that the responses of ITD-sensitive neurons are inconsistent with the idea of a topographic map of auditory space. Moreover, whereas the maxima of ITD functions were found to be outside, the steepest slope was positioned in the physiologically encountered range of ITDs. Local iontophoretic application of glycine and its antagonist strychnine revealed that precisely-timed glycinergic inhibition plays a critical role in determining the mechanism of ITD tuning, by shifting the slope into the physiological range of ITDs. Natural sounds are modulated in frequency and amplitude and their recognition depends on the analysis of, amongst others, temporal cues. The bat MSO has been shown to be involved in filtering of sinusoidally amplitude modulated (SAM) sounds. This observation led to the assumption that the MSO serves different functions in high and low frequency hearing mammals, namely filtering of temporal cues in high and sound localization in low frequency hearing animals. However, the response to temporally structured sounds has only rarely been investigated in low frequency hearing animals. This study showed that MSO neurons in the gerbil (a rodent that uses ITDs for sound localization) exhibit filter properties in response to the temporal structure of SAM sounds. These results provide evidence for the fact that the MSO in low frequency hearing animals cannot only be linked to temporal processing of spatial cues, but has additional temporal functions. Auditory information is processed in a number of parallel paths in the ascending auditory pathway. At the brainstem level, several structures are involved, which are known to serve different well-defined functions. However, the function of one prominent brainstem nucleus, the rodent superior paraolivary nucleus (SPN) is unknown. Two hypotheses have been tested using extracellular single cell physiology in the gerbil. The existence of binaural inputs indicates that the SPN might be involved in sound localization. Although almost half of the neurons exhibited binaural interactions (most of them excited from both ears), effects of ITDs and interaural intensity differences were weak and ambiguous. Thus, a straightforward function of SPN in sound localization appears to be unlikely. Inputs from octopus and multipolar/stellate cells of the cochlear nucleus, and from principal cells of the medial nucleus of the trapezoid body, could relate to precise temporal processing in the SPN. Based on discharge types, two subpopulations of SPN cells were observed: sustained discharges and phasic ON or OFF responses. The temporal precision of ON responders in response to pure tones and SAM was significantly higher than that in sustained responders. The existence of at least two subpopulations of neurons (ON and sustained responders) is in line with different subsets of SPN cells that can be distinguished morphologically and may point to them having different roles in the processing of temporal sound features.