SONG PRESENTATION INDUCES GENE-EXPRESSION IN THE SONGBIRD FOREBRAIN

We investigated the participation of genomic regulatory events in the response of the songbird brain to a natural auditory stimulus of known physiological and behavioral relevance, birdsong. Using in situ hybridization, we detected a rapid increase in forebrain mRNA levels of an immediate-early gene encoding a transcriptional regulator (ZENK; also known as zif-268, egr-1, NGFI-A, or Krox-24) following presentation of tape-recorded songs to canaries (Serinus canaria) and zebra finches (Taeniopygia guttata). ZENK induction is most marked in a forebrain region believed to participate in auditory processing and is greatest when birds hear the song of their own species. A significantly lower level of induction occurs when birds hear the song of a different species and no induction is seen after exposure to tone bursts. Cellular analysis indicates that the level of induction reflects the proportion of neurons recruited to express the gene. These results suggest a role for genomic responses in neural processes linked to song pattern recognition, discrimination, or the formation of auditory associations.