Early song-deprivation affects the expression of protein kinase C in the song control nuclei of the zebra finch during a sensitive period of song learning.

Male zebra finches learn to imitate a tutor's song through auditory and motor learning during a sensitive period. The molecular aspects of auditory-dependent learning was investigated using protein kinase C (PKC) as a molecular marker for synaptic plasticity. We found a transient increase in the expression of PKC in the robust nucleus of the archistriatum (RA) during a sensitive period. Furthermore, both early deafening by cochlea removal and song deprivation inhibited the increase of PKC enzyme activity. The results strongly suggest that PKC is an important enzyme related to the synaptic plasticity of RA neurons during a sensitive period of song learning in the zebra finch.