Histochemical study of organization of inferior colliculi (IC) in the pointed-eared bat, Myotis blithy, has demonstrated an area on the boundary of the central and pericentral nuclei that has an increased cytochrome oxidase reactivity, with no cytoarchitectonic analogy. Characteristics of neuronal responses in this area to ultrasonic stimuli differ significantly from responses reported for neurons of the IC central nucleus. Based on the data obtained data and the current concept of the role of the brainstem auditory sensory system in coding complex acoustic stimuli, it is suggested that the lateral IC area contains inhibitory interneurons that participate in coding parameters of amplitude-modulated stimuli in the IC. ?1999 MAEe Cyrillic signK "Hay?a/Interperiodica".