This laboratory conducts research aimed at advancing scientific understanding of the neurobiology underlying learning and memory. We employ both songbirds and rodents to elucidate the neurophysiological foundations of learning and memory by investigating phenomena of synaptic and intrinsic plasticity at molecular, cellular, and network levels in the nervous system. While synaptic plasticity has been considered the cellular correlate of learning, non-synaptic, cell-autonomous modulation of neuronal excitability had been shown to play a prominent role in encoding learning and memory. In our lab, we utilize an expanded approach in which we focus on both plasticity of synaptic connectivity as well as plasticity of intrinsic excitability as important mechanisms for engram integration.
Through our work, we are seeking to gain insights into how the brain generates and learns complex sequential behaviors. The neural mechanisms of these complex behaviors underlie motor sequencing, navigation, decision making, skilled movement and various cognitive tasks. Several brain regions have been assumed to execute precise interval timing mechanisms, such as the basal ganglia, the hippocampus, the prefrontal cortex, and the motor cortex. The ability of the brain to recognize and scrutinize sequential patterns within an intricate sensory system is a fundamental cognitive function, yet despite their fundamental importance, the underlying neural mechanisms are not well understood.
The songbird system is an excellent model system for studying the mechanisms underlying neural sequences responsible for stereotyped complex vocal behavior especially since they sing remarkably stereotyped songs. Songbirds represent one of the few species that learn vocalization akin to how humans acquire speech, thereby serving as a preeminent model for identifying neural mechanisms of vocal learning. The songbird proves ideal for this purpose owing to its well-documented ability to vocally imitate the songs of other birds, and because its brain comprises a constellation of discrete, interconnected regions that operate in the patterning, perception, acquisition and preservation of song.
The vocalizations of these birds are a great example of a learned sensorimotor skill: songbirds initially produce variable (immature) sounds and then through extensive rehearsal, this variability is reduced and a highly stereotyped and refined song emerges that’s dependent on auditory feedback throughout their lives. In the song system, there are specific neurons in areas spanning from the midbrain to the highest levels of the telencephalon and other auditory association areas that generate extremely precise temporal patterns of firing during singing. This is particularly true for the auditory-motor association area HVC where all of its neuronal classes exhibit some of the most temporally precise firing sequences known in nature to date.
In the Daou laboratory, we use a diverse array of methodologies to advance understanding of the brain’s processing of sensory inputs and adaptive behaviors. We employ in vitro intracellular and in vivo extracellular recordings to study identified neurons. Retrograde dye injections via surgical interventions to trace neural pathways. Microsimulation and targeted pharmaceutical applications experimentally to manipulate neuronal activity levels.
Computational modeling also features prominently in our work. Collectively, these techniques comprise a comprehensive technical framework for investigating how the central nervous system harvests sensory data and accordingly recalibrates behavior. The multidisciplinary nature of our approach aims to provide novel insights into this complex organ’s operational underpinnings and functional capacities.
