Grant: Discovery Grants Program - Individual

The long-term goal of my research is to understand how interactions between neuronal populations affect brain function and behaviour. In this grant proposal, I will focus in particular on investigating the neuronal interactions involved in memory processes. Memory formation is one of the most important processes in the brain, yet the neuronal dynamics underlying this process are only beginning to be understood, partly due to the technical difficulty of recording from large neuronal populations in behaving animals. Recently, we reported that the hallmark of memory formation and memory replay - stimulus-induced sequential activity patterns that reactivate spontaneously - can also be observed in urethane-anesthetised rats after inducing an activated (awake-like) brain state induced by injection of amphetamine or through the infusion of carbachol in the hypothalamus (Bermudez et al. Neuron 2013). In this preparation, population recordings and other brain manipulations can be more easily performed than in behaving animals, thus providing a convenient model for electrophysiological study of mechanisms leading to formation of sequential patterns implicated in memory processes. In support of my long term goal, I have proposed 3 short-term objectives: (1) I would like to take a full advantage of this new experimental animal model which will allow us to record activity from a large number (>200) of single neurons across multiple hippocampal and neocortical areas during memory-like processes, and use optogenetic stimulations to switch on/off specific groups of neurons to define causal relations in memory circuits. (2) I will record neuronal populations in behaving animals during memory task to directly test the relevance of an anesthetized animal model for investigating neuronal dynamics involved in memory processes. And finally (3) I will apply powerful new algorithms recently developed for image analyses (e.g. currently used by Google) to analyse the complex interactions within large neuronal populations.*In summary, the strength of this proposal is to explore interactions among hundreds of neurons where most electrophysiological studies have concentrated only on the single neuron or small neuronal groups. This project will further our understanding about the neuronal population patterns involved in memory formation, and develop ready-to-use experimental and analytical tools to investigate neuronal population activity during learning and memory processes.*