<unk>  hearing Action potentials originate in the hair cells of the cochlea and propagate to the brainstem; both the timing of these action potentials and the signal they transmit provide information to the SOC about the orientation of sound in space. The processing and propagation of action potentials is rapid, and therefore, information about the timing of the sounds that were heard, which is crucial to<unk>  processing, is conserved. Each eardrum moves in one dimension, and the auditory brain analyzes and compares the movements of both eardrums in order to synthesize auditory objects. This integration of information from both ears is the essence of<unk> . The<unk>  system of hearing involves sound localization in the horizontal plane, contrasting with the monaural system of hearing, which involves sound localization in the vertical plane. Superior olivary complex The primary stage of<unk> , the processing of<unk>  signals, occurs at the SOC, where afferent fibers of the left and right auditory pathways first converge. This processing occurs because of the interaction of excitatory and inhibitory inputs in the LSO and MSO. The SOC processes and integrates<unk>  information, in the form of ITD and ILD, entering the brainstem from the cochleae. This initial processing of ILD and ITD is regulated by GABAB receptors. ITD and ILD The auditory space of<unk>  hearing is constructed based on the analysis of differences in two different<unk>  cues in the horizontal plane: sound level, or ILD, and arrival time at the two ears, or ITD, which allow for the comparison of the sound heard at each eardrum. ITD is processed in the MSO and results from sounds arriving earlier at one ear than the other; this occurs when the sound does not arise from directly in front or directly behind the hearer. ILD is processed in the LSO and results from the shadowing effect that is produced at the ear that is farther from the sound source. Outputs from the SOC are targeted to the dorsal nucleus of the lateral lemniscus as well as the IC. Lateral superior olive LSO neurons are excited by inputs from one ear and inhibited by inputs from the other, and are therefore referred to as IE neurons. Excitatory inputs are received at the LSO from spherical bushy cells of the ipsilateral cochlear nucleus, which combine inputs coming from several auditory nerve fibers. Inhibitory inputs are received at the LSO from globular bushy cells of the contralateral cochlear nucleus. Medial superior olive MSO neurons are excited bilaterally, meaning that they are excited by inputs from both ears, and they are therefore referred to as EE neurons. Fibers from the left cochlear nucleus terminate on the left of MSO neurons, and fibers from the right cochlear nucleus terminate on the right of MSO neurons. Excitatory inputs to the MSO from spherical bushy cells are mediated by glutamate, and inhibitory inputs to the MSO from globular bushy cells are mediated by glycine. MSO neurons extract ITD information from<unk>  inputs and resolve small differences in the time of arrival of sounds at each ear. Outputs from the MSO and LSO are sent via the lateral lemniscus to the IC, which integrates the spatial localization of sound. In the IC, acoustic cues have been processed and filtered into separate streams, forming the basis of auditory object recognition.
Binaural fusion
Disc protrusion
Tooth fusion
Labial fusion
Ankle fusion
Four corner fusion
Condylar resorption
Retrolisthesis