Abstract
In 2003, science is the midst of a molecular genetics revolution. Genomes of diverse biological systems ranging from C. elegans to Human are cloned, partly with the expectation of functional and organizational insight into the nervous system. Likewise, identifying genes that are regulated in the song control system of the zebra finch may increase our understanding of the mechanisms and constraints underlying the dynamic changes required by plastic phenotypes such as vocal learning. Zebra finch vocal learning is developmentally regulated and involves multiple cognitive processes. A candidate gene that could underlie this experience-dependent behavioral plasticity is ZENK. For example, two distinct patterns of ZENK expression emerge in the telencephalon of the zebra finch songbird during the perception and production of song. That is, hearing song can induce a rapid increase in ZENK expression (mRNA and protein) within auditory telencephalon. In contrast, singing in deafened and normal hearing birds induces ZENK mRNA throughout the song-control circuit. Although collectively these correlational data suggest a role for ZENK in learning and memory, no investigations have directly addressed this issue. Here a series of behavioral, anatomical, and pharmacological manipulations are used to question the hypothesis that ZENK expression (auditory and vocal-motor-induced) in the songbird brain is significant for learning and memory. The studies herein of the relationships and interactions between environment, behavior, and gene expression are considered part of a growing body of evidence that transcription factor expression in the central nervous system (CNS) can play an important role in learning and memory, and furthermore serve to better our understanding of the complex interplay between nature and nurture in the determination of behavior.
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