Effects of nicotine administration on spectral and temporal features of crystallized song in the adult male zebra finch.

INTRODUCTION The process through which the zebra finch (Taeniopygia guttata) acquires and produces crystallized song has long been thought of as highly analogous to the process through which humans acquire and produce speech. Nicotinic acetylcholine receptors are present in song nuclei that play important roles in song production and/or acquisition. We studied the effect of in vivo nicotine on temporal and spectral features of crystallized song. METHODS We used 16 adult male zebra finches that were exposed to an established 7-day nicotine or saline treatment. Song behavior was monitored for a 2-month period following the cessation of the nicotine/saline treatment. All animals served as their own control in order to determine whether any song characteristics changed over the observed time period compared to the baseline measurement. RESULTS Inter-syllable duration and Wiener entropy were significantly affected by the in vivo administration of nicotine. These observed changes persisted for a 2-month period following the cessation of nicotine exposure. Similar changes were not observed in the age-matching control group. CONCLUSIONS Nicotine significantly affected tempo and rhythm of the crystallized zebra finch song. We believe that this in vivo nicotine-exposed zebra finch model can not only provide a further understanding of the underlying behavioral mechanisms of the cognitive implications of nicotine dependence but also help in the development of therapeutics targeting cognitive deficits often observed during nicotine withdrawal.