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Fast imaging reveals how experience modifies neural structure and function in an awake brain Dellazizzo Toth, Tristan

Abstract

During learning, neurons in the brain are remodelled in both their structure and function in ways that can dramatically shape how they process incoming information and compute an output. This is especially the case in early development when neurons are extremely plastic. The spatial arrangement of a neuron’s synapses determines how inputs interact to perform computations, such as through recruitment of nonlinear conductances by spatially clustered activity. However, it remains poorly understood how such functional arrangements arise. Here, I generate the capabilities that allow me to record and analyze sensory-evoked activity in an in vivo model system and to analyze how sensory inputs shape neural activity. I develop and validate the genetic and optical tools and protocols that allow me to record neural activity across the neuron, being able to capture both synaptic input across the dendritic arbor and the action potential output. Leveraging the albino Xenopus laevis visual system as an accessible vertebrate model of early brain circuit formation I then use these tools to image growing neurons during plasticity-inducing visual training while recording and manipulating neuronal firing, I show that dendrite growth and pruning are correlated to neurons’ evoked calcium responses. Lastly, I use the functional data from these experiments to build and validate a mathematical model to predict locations of synaptic input on dendritic arbors, using fluorescence-based calcium data.

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Attribution-NonCommercial-NoDerivatives 4.0 International