The Emergence, Persistence and Plasticity of Neural Codes for Self-Selected Goal-Directed Navigation

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PROJECT SUMMARY Goal-directed navigation often occurs in complex, large environments where the same goal can be reached from different starting point and through different routes which are often self-selected. The hippocampus is believed to play a central role in navigation yet it remains poorly understood how it supports the planning and execution of naturally emerging navigation patterns during goal-directed behaviors. The Egyptian fruit bat is a powerful model for bridging this gap due to specialization for spatial navigation and in particular, its natural desire to converge onto self-selected, stereotyped and highly structured navigation patterns. Here, we leverage the bat natural behavior and significantly extend the arsenal of tools and approaches to study how the hippocampus contributes to the planning, emergence and sustainment the goal-directed, structured navigation behavior. To do so, we develop novel fully automated environments aimed at engaging the bats in self-paced and self-selected, natural navigation under closely monitored laboratory conditions. In doing so, we find that the bats readily engage in goal directed foraging behavior which resembles that observed in the natural setting. To study the neural dynamics, computations and involvement of the hippocampus in this behavior we integrate a wide range of wireless neuro-technologies, many of which are entirely novel for the bat model system. These include, wireless electrophysiology, wireless cellular resolution calcium imaging and wireless optogenetics in freely flying bats. Our preliminary results provide a detailed account of the bat's navigational strategies during goal-directed behavior and are beginning to reveal the neural computations in the hippocampal formation that could facilitate this function. These includes functionally discrete set of neurons that are participating during discrete stages of the foraging behavior including, planning, execution and evaluation of goal-directed navigation as well as neuronal sequences that are specific to distinct navigational routes. Combined, we marry the development of the controlled, yet ethologically-relevant, behavioral setup with a wide range of cutting- edge neurophysiological methods to thoroughly examine the role and computations in the bat hippocampus that can subserve that bat's natural ability for structured goal-directed navigation behavior. In doing so, this research aims to provide a new model the hippocampal neural computations that can support self-selected and complex goal-directed navigation.