Neural sensitivity to interaural level differences determines virtual acoustic space minimum audible angles for single neurons in the lateral superior olive.

2011 ◽  
Vol 129 (4) ◽  
pp. 2621-2621
Author(s):  
Daniel J. Tollin
Keyword(s):  
Single Neurons ◽  
Lateral Superior Olive ◽  
Superior Olive ◽  
Acoustic Space ◽  
Interaural Level Differences

scholarly journals Evidence of a Functionally Segregated Pathway from Lateral Superior Olive to Inferior Colliculus

2019 ◽  
Author(s):  
Nathaniel T. Greene ◽  
Kevin A. Davis
Keyword(s):  
Inferior Colliculus ◽  
Excitatory Amino Acid ◽  
Excitatory Input ◽  
Central Nucleus ◽  
Type I ◽  
Lateral Superior Olive ◽  
Reversible Inactivation ◽  
Superior Olive ◽  
Receptive Field Organization ◽  
Interaural Level Differences

ABSTRACTNeurons in the central nucleus of the inferior colliculus (ICC) of decerebrate cats show three major response patterns when tones of different frequencies and levels are presented to the contralateral ear. The frequency response maps of type I units uniquely exhibit a narrowly tuned I-shaped area of excitation around best frequency (the most sensitive frequency) and flanking regions of inhibition at lower and higher frequencies. Type I units receive ipsilateral inhibition, and show binaural excitatory/inhibitory interactions. Lateral superior olive (LSO) principal cells display a similar receptive field organization and sensitivity to interaural level differences (ILDs) and project directly to the ICC, therefore are supposed to be the dominant source of excitatory input for type I units. To test this hypothesis, the responses of ICC units were compared before and after reversible inactivation of the LSO by injection of the non-specific excitatory amino-acid antagonist kynurenic acid. When excitatory activity within the LSO was blocked, many ICC type I units (~50%) were silenced or showed substantially decreased activitycomparable. By contrast, the responses of the other two ICC unit types were largely unaffected. With regard to the origins of unaffected ICC type I units, evidence indicates that the LSO was inactivated in an incomplete, anisotropic manner, and the monaural and binaural responses of such units are similar to those of affected type I units. Taken together, these results support the interpretation that most type I units are the midbrain components of a functionally segregated ILD processing pathway initiated by the LSO.

Lateral Superior Olive

2019 ◽  
pp. 328-394 ◽  
Author(s):  
Eckhard Friauf ◽  
Elisa G. Krächan ◽  
Nicolas I.C. Müller
Keyword(s):  
Neural Plasticity ◽  
Auditory Processing ◽  
Sound Intensity ◽  
Inhibitory Synapses ◽  
Superior Olivary Complex ◽  
Central Auditory Processing ◽  
Spatial Cues ◽  
Lateral Superior Olive ◽  
Superior Olive ◽  
Interaural Level Differences

Auditory neurons in the mammalian brainstem are involved in several basic computation processes essential for survival; for example, sound localization. Differences in sound intensity between the two ears, so-called interaural level differences (ILDs), provide important spatial cues for localizing sound in the horizontal plane, particularly for animals with high-frequency hearing. The earliest center of ILD detection is the lateral superior olive (LSO), a prominent component of the superior olivary complex (SOC) in the medulla oblongata. LSO neurons receive input from both ears of excitatory and inhibitory nature and perform a subtraction-like process. The LSO has become a model system for studies addressing inhibitory synapses, map formation, and neural plasticity. This review aims to provide an overview of several facets of the LSO, focusing on its functional and anatomical organization, including development and plasticity. Understanding this important ILD detector is fundamental in multiple ways—among others, to analyze central auditory processing disorders and central presbyacusis.

scholarly journals GABA is a modulator, rather than a classical transmitter, in the medial nucleus of the trapezoid body–lateral superior olive sound localization circuit

2019 ◽  
Vol 597 (8) ◽  
pp. 2269-2295 ◽  
Author(s):  
Alexander U. Fischer ◽  
Nicolas I. C. Müller ◽  
Thomas Deller ◽  
Domenico Del Turco ◽  
Jonas O. Fisch ◽  
...  
Keyword(s):  
Sound Localization ◽  
Lateral Superior Olive ◽  
Superior Olive ◽  
Medial Nucleus ◽  
Trapezoid Body

Glutamatergic Calcium Responses in the Developing Lateral Superior Olive: Receptor Types and Their Specific Activation by Synaptic Activity Patterns

2003 ◽  
Vol 90 (4) ◽  
pp. 2581-2591 ◽  
Author(s):  
F. Aura Ene ◽  
Paul H. M. Kullmann ◽  
Deda C. Gillespie ◽  
Karl Kandler
Keyword(s):  
Calcium Channels ◽  
Intracellular Calcium ◽  
Glutamate Receptors ◽  
Cochlear Nucleus ◽  
Metabotropic Glutamate Receptors ◽  
Lateral Superior Olive ◽  
Voltage Gated ◽  
Superior Olive ◽  
Metabotropic Glutamate ◽  
Voltage Gated Calcium Channels

The lateral superior olive (LSO) is a binaural auditory brain stem nucleus that plays a central role in sound localization. Survival and maturation of developing LSO neurons critically depend on intracellular calcium signaling. Here we investigated the mechanisms by which glutamatergic afferents from the cochlear nucleus increase intracellular calcium concentration in LSO neurons. Using fura-2 calcium imaging in slices prepared from neonatal mice, we found that cochlear nucleus afferents can activate all major classes of ionotropic and metabotropic glutamate receptors, each of which contributes to an increase in intracellular calcium. The specific activation of different glutamate receptor classes was dependent on response amplitudes and afferent stimulus patterns. Low-amplitude responses elicited by single stimuli were entirely mediated by calcium-impermeable AMPA/kainate receptors that activated voltage-gated calcium channels. Larger-amplitude responses elicited by either single stimuli or stimulus trains resulted in additional calcium influx through N-methyl-d-aspartate receptors. Finally, high-frequency stimulation also recruited group I and group II metabotropic glutamate receptors, both of which mobilized intracellular calcium. This calcium release in turn activated a strong influx of extracellular calcium through a membrane calcium channel that is distinct from voltage-gated calcium channels. Together, these results indicate that before hearing onset, distinct patterns of afferent activity generate qualitatively distinct types of calcium responses, which likely serve in guiding different aspects of LSO development.

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