Intrinsic Plasticity and Its Functional Role in the Developing Auditory Cortex of Zebra Finch

The brain’s ability to accurately process complex, structured sounds, such as speech or conspecific vocalizations, in noisy environments is vital for communication and survival across species. Speech perception in a noisy environment requires the brain to extract structured information from noisy environment. However, how the brain acquire this ability is not well understood. Numerous studies have tried to answer it by investigating the effect of early experience on the development of auditory perception. Songbirds are a well-established model for studying the neural basis of the development of auditory perception and vocal communication. This dissertation investigates how early acoustic environments shape intrinsic membrane plasticity in the developing caudal mesopallium (CM) of the zebra finch. The first study shows that during the onset of the song memorization sensitive period, CM neurons undergo rapid, activity-dependent plasticity of intrinsic dynamics. This process is mediated by upregulation and trafficking of the Kv1.1 potassium channel and requires exposure to acoustically complex environments. The second study extends these findings by exploring how acoustical complexity affects intrinsic plasticity, identifying the specific temporal and spectral features, exposure timing, and minimum duration of colony noise required to induce plasticity. Together, the data presented in the dissertation establish the mechanistic link between environmental acoustics and neuronal intrinsic dynamics that underlie experience-dependent auditory development in zebra finch.