Binaural fusion

[2] The binaural auditory system is highly dynamic and capable of rapidly adjusting tuning properties depending on the context in which sounds are heard.

[4] In vertebrate mammals, as sound waves travel via the eardrum, through the cochlea in the inner ear, they stimulate the hair cells that line the basilar membrane.

The signal ascends to the medial geniculate body (MGC) of the thalamocortical system; sensory inputs to the MGB are then relayed to the primary auditory cortex.

This system contains many subcortical nuclei that collect, integrate, and analyze afferent signals from the ears, for extraction and analysis of the dimensions of sounds.

[4] The key mechanisms of the AN and CN are fast synapses that preserve the detail timings, or temporal fine structure, of sounds as transduced to action potentials, from the hair cells in the cochlea through to the olivary complex.

Precisely timed inhibitory inputs are received at the LSO from the MNTB, relayed from globular bushy cells of the contralateral cochlear nucleus.

[3] MSO neurons extract ITD information from binaural inputs and resolve small differences in the time of arrival of sounds at each ear.

The neurological disorder autism is associated with many symptoms of impaired brain function, including the degradation of hearing, both unilateral and bilateral.

[16] Individuals with autism who experience hearing loss maintain symptoms such as difficulty listening to background noise and impairments in sound localization.

Both the ability to distinguish particular speakers from background noise and the process of sound localization are key products of binaural fusion.

[18] Data also suggests that neurons of the LSO and MNTB contain distinct dysmorphology in autistic individuals, such as irregular stellate and fusiform shapes and a smaller than normal size.

All of these structures play a crucial role in the proper functioning of binaural fusion, so their dysmorphology may be at least partially responsible for the incidence of these auditory symptoms in autistic patients.

Transmissions from the SOC , in the pons of the brainstem , travel along the lateral lemniscus to the IC , located in the midbrain . Signals are then relayed to the thalamus and further ascending auditory pathway.