Brain lateralization of zebra finch courtship singing
Abstract
Previous studies have described lateralization of sensory and motor aspects of birdsong. We have begun to examine the possibility that communicative function of singing also is lateralized. As the optic nerves in birds decussate nearly completely, one way to show lateralization is to test the birds monocularly. An analysis of visual behavior showed that male birds had a preference for using the right eye (RE) during courtship singing. Birds sang significantly more when using their RE than when using their left eye (LE), and singing began more quickly when birds could use their RE than their LE. This suggests that processing by the left hemisphere is important in courtship singing, consistent with previous suggestions that it is involved in maintaining attention on stimuli to which a motor response is planned. In order to examine possible central results of such behavioral lateralization, we are comparing the levels of ZENK expression and singing-related neural activity from both hemispheres when birds sing while alone and to a female bird.