Cortical neurons have complex dendritic trees that extend in multiple directions and span multiple layers. There are theories for why this is the case, but they have not been tested causally. Recent work in our collaboration has perfected an optical method to test these theories: cutting one or more of a neuron’s dendrites (dendrotomy) under 2-photon imaging and comparing the activity of the neuron before and after the procedure. In this project, we will apply this technique to understand what apical dendrites do, testing the longstanding hypothesis that they carry top-down signals from higher visual areas and other brain regions.
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