Project: The Evolution and Function of Ancestral Brain States
Abstract: One of the oldest enigmas in neuroscience is the function of brain states. During these states, dramatic transitions occur in the firing patterns of neurons in the cerebral cortex. These transitions are correlated with behavior during wakefulness but, strikingly, are even more prominent during sleep, when interaction with the environment is limited. The similarities between sleep and awake patterns remains unexplained, thus complicating our understanding of the global function of brain states. Additionally, state transitions are prominent in both the cortex and hippocampus, but the interplay between these areas during different states remains ambiguous. Why is the function of brain states so elusive? A likely explanation is that state transitions are inextricably intertwined with many other processes, rendering their dissection difficult.
This project is motivated by the notion that to understand brain states we need to: a) examine them in a simpler model system, b) understand how they evolved, c) identify which state properties are fundamental and which are species specific.
Studying brain states in the cerebral cortex of reptiles offers a unique opportunity for achieving all three goals:
We utilize the simpler and highly structured state organization in Pogona Vitticeps, to expose the full repertoire of brain states in a naturally behaving animal. We take advantage of the limited diversity of motor movements in Pogona, to expose the link between population patterns and defined behaviors. We furthermore exploit the unique evolutionary positions of reptiles as closest to stem amniotes, in which the layered cortex and hippocampus first emerged, to reveal the forces that pushed the emergence of brain states in evolution. Finally, through a comparative analysis of brain state properties between different lizards and mammals we can extract the fundamental properties and functions of brain states and the network that supports them.