Topic: sound localization

The auditory nerve encodes sound with spike-timing that is phase locked to the fine-grained temporal structure of sound. The precision of this coding substantially exceeds that of any other sensory modality, but its role in hearing remains controversial because physiological mechanisms for extracting information from the spike timing have proven elusive. We investigated the perceptual role of auditory nerve phase locking using deep artificial neural networks in the spirit of ideal observer analysis. Neural networks took input from a simulated cochlea and were optimized for natural tasks. We ex

Aims: SCA13 patients carrying the R420H mutation in Kv3.3 also have compromised sound localization based on inferior processing of interaural differences in time and intensity of sound. These patients show no pure-tone deficit in the audiogram and their peripheral auditory system seems unaffected. The Kv3.3 subunit of voltage-gated potassium channels is highly expressed in fast-firing neurons of the auditory pathway, including the medial nucleus of the trapezoid body (MNTB) and the lateral superior olive (LSO) and is often co-expressed with the Kv3.1 subunit. Here, we investigate how this Kv3.

Implementing bioinspired neural networks in silico is a powerful tool for studying brain processes. These networks grant access to the real-time behavior of individual neurons within a complex circuitry, such as the ones executing neurosensory functions. This study proposes a computational model to study how the mammalian brainstem implements sound localization: the ability to identify an acoustic source in the surrounding space. The main actors in sound localization are two brainstem nuclei: the medial and the lateral superior olive. We have reconstructed a model made of thousands of spiking

Early deafened patients with bilateral cochlear implants (biCI) often show impaired spatial hearing, particularly due to reduced sensitivity to interaural time differences (ITDs). Recent research of our groups has shown that neonatally deafened rats, supplied with biCI in young adulthood, can effectively learn to use ITDs for sound localization if the animals received informative pulse timing (pt) ITDs from the onset of stimulation. Here we investigate whether the hearing-inexperienced auditory system can develop good ITD sensitivity when ptITDs are jittered from onset of electric stimulation.

Synaptic integration is crucial for inter-neuronal communication, and excitatory-inhibitory integration is utterly important in lateral superior olive (LSO) neurons, enabling sound localization. For this purpose, LSO neurons integrate excitatory inputs from the ipsilateral cochlear nucleus (CN) with inhibitory inputs from the medial nucleus of the trapezoid body (MNTB). The strength and number of excitatory and inhibitory inputs show notable differences. The convergence of multiple excitatory input fibers (~10‑40) is a source for synaptic noise in the spike driving inputs. We focused on how sy

The giant synaptic terminals play an important role transmitting information with exquisite precision and speed. The thalamus, an important center for the integration and relay of sensory information, is the brain region innervated by more giant terminals. These giant terminals act like drivers, delivering primary sensory information from the somatosensory, visual and auditory pathways. In the auditory thalamus, the drivers arise from the inferior colliculus. Surprisingly, we have observed a population of giant synaptic terminals in the auditory thalamus arising from the medial superior olive

Binaural cues, such as interaural time difference (ITD), are pivotal for sound localization in the auditory system. However, contemporary cochlear implant (CI) processors convey only envelope ITD, neglecting pulse-timing ITD in the temporal fine structure, possibly contributing to CI users' spatial hearing challenges.To assess CI-implanted rats' sensitivity to envelope and pulse timing ITD, we utilized a stimulus involving a 900pps pulse train modulated by a 20 Hz sine envelope, allowing independent variation of PT_ITD and ENV_ITD {-0.1, 0, 0.1 ms}. Neural activity from the inferior colliculus

Spatial hearing, as a fundamental aspect of auditory perception, plays a central role in our daily interactions with the auditory environment. The ability to localize sound and navigate through our environment relies primarily on two binaural cues: interaural time differences (ITDs) and interaural level differences (ILDs). However, for patients with bilateral cochlear implants (biCI), sound localization is a major challenge and ITD sensitivity is particularly poor, with most biCI patients relying almost exclusively on ILDs. Nevertheless, our recent work demonstrates that neonatally deafened ra