Role of the dorsal cochlear nucleus in the sound localization behavior of cats

• Published in: Hearing research Vol. 148; no. 1; pp. 74 - 87
• Main Author: May, Bradford J
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2000; Elsevier
• Subjects: Animals; Behavior, Animal - physiology; Biological and medical sciences; Cats; Cochlear Nucleus - physiology; Dorsal cochlear nucleus; Ear - physiology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Fundamental and applied biological sciences. Psychology; Male; Orientation - physiology; Orientation behavior; Sensory Deprivation - physiology; Sound localization; Sound Localization - physiology; Spatial acuity; Vertebrates: nervous system and sense organs; Sound localization; Spatial acuity; Dorsal cochlear nucleus; Orientation behavior; Fissipedia; Carnivora; Stimulus localization; Central nervous system; Cochlear nucleus; Sound source; Binaural hearing; Vertebrata; Mammalia; Acoustic stimulus; Cat; Auditory pathway; Auditory striae; Stimulus direction; Brain (vertebrata)
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/S0378-5955(00)00142-8

The role of the dorsal cochlear nucleus (DCN) in directional hearing was evaluated by measuring sound localization behaviors before and after cats received lesions of the dorsal and intermediate acoustic striae (DAS/IAS). These lesions are presumed to disrupt spectral processing in the DCN without affecting binaural time and level difference cues that exit the cochlear nucleus via the ventral acoustic stria. Prior to DAS/IAS lesions, cats made accurate head orientation responses toward sound sources in the frontal sound field. After a unilateral DAS/IAS lesion, subjects showed increased errors in the azimuth and elevation of their responses; in addition, the final orientation of head movements tended to be more variable. Largest deficits in response elevation were observed in the hemifield that was ipsilateral to the lesion. When a second lesion was placed in the opposite DAS/IAS, increased orientation errors were observed throughout the frontal field. Nonetheless, bilaterally lesioned cats showed normal discrimination of changes in sound source location when tested with a spatial acuity task. These findings support previous interpretations that the DCN contributes to sound orientation behavior, and further suggest that the identification of absolute sound source locations and the discrimination between spatial locations involve independent auditory processing mechanisms.