Furest Cataldo, Basilio. Neurobiological mechanisms of memory formation in the auditory forebrain of adult male zebra finches. Retrieved from https://doi.org/doi:10.7282/t3-agmb-kj06
DescriptionSongbirds provide a powerful model for studying adult neuroplasticity in the auditory cortex as a function of recent auditory experience due to many parallels with the human auditory system, which is similarly tasked with processing complex conspecific vocalizations. As in human speech processing, lateralized auditory responses are evident in an area of the songbird’s higher auditory cortex, NCM (caudomedial nidopallium), that encodes specific auditory memories through a process of adaptation that leads to reduced responses to familiar sounds. The right NCM typically shows larger auditory responses than the left, suggesting lateral differences in auditory representations and memory. Furthermore, the songbird brain incorporates new neurons in adulthood, including in NCM. In this study, Zebra finches (Taeniopygia guttata) were continuously exposed to a novel heterospecific acoustic environment to confirm a previous report wherein NCM multi-unit activity undergoes dynamic shifts in lateralized activity and assess whether these transient shifts in activity are correlated with shifts in incorporation of new neurons. Bilateral NCM electrophysiology confirmed previous reports wherein left-hemisphere activity was elevated relative to the right after 9 days of exposure to a novel heterospecific acoustic environment, an effect that was not observed in a cohort exposed to the same environment for 30 days. A novel longitudinal measuring approach, via epidural recordings, revealed the timeline during which these transient shifts in lateralized activity occur. Finally, preliminary data suggests that there is an inverse relationship between the asymmetric electrophysiology and lateralized new neuron incorporation.