Neurobiological and Epigenetic Substrates of Learning, Memory, and Behavioural Flexibility in Three Songbird Species: the Black-capped Chickadee (Poecile atricapillus), Zebra Finch (Taeniopygia castanotis), and European Starling (Sturnus vulgaris)

Abstract

Songbirds rely on learning, perceiving, and producing complex vocalizations to perform critical functions such as conspecific identification, mate selection, and territory defence These cognitive processes are influenced by a variety of natural and laboratory-induced factors, including sex, season, and social context. Along with changes in behaviour, songbirds have been extensively studied for the neurobiological mechanisms underlying their vocal behaviour, making them an ideal model to investigate both behavioural and neural plasticity. This thesis aims to explore the intricate relationship between neurogenesis, learning, and perception in songbirds, specifically examining the impact of acoustic discrimination, social isolation, and season on neurogenic and epigenetic processes. Employing a comparative cognitive approach, I generated and tested hypotheses regarding cognitive and behavioural adaptations in three songbird species: black-capped chickadees, zebra finches, and European starlings. In the first study, I examined DNA methylation levels in key vocal and auditory brain regions of all three species, thereby providing insights into the potential role of epigenetic processes in behavioural and neural plasticity in songbirds. In the second study, I examined the effects of social isolation and auditory discrimination on neurogenesis in auditory brain regions. In the third study, I explored seasonal changes in the rates of neurogenesis in European starlings, specifically regarding vocal behaviour, conspecific discrimination, and stress. Overall, results from the studies described in this thesis lend new insight into how epigenetic factors may mediate behavioural and neural plasticity while extending the literature examining how learning, perception, and an animal’s environment modulate neuroplasticity in specific brain regions.