Neurobiology Faculty Candidate Talk: David Hildebrand: Studying face perception in marmoset monkeys using calcium imaging
Recognizing and representing socially relevant signals such as faces requires complex processing by many interconnected neurons. The computations and circuit architectures that support this capability have been challenging to study, partly because the underlying neurons are inaccessibly embedded within the large brains of most social primates. We know a great deal about the broad properties of face areas from fMRI and about individual 'face cell' tuning properties from single-cell electrophysiology. However, understanding how populations of neurons work together to collectively represent faces necessitates simultaneous activity measurements from many individual face cells. In this talk, I will present my approach for filling this gap. First, I will describe methods that I developed for recording calcium dynamics of cortical neurons using two-photon microscopy in awake marmoset monkeys. I will then show recordings of stimulus-evoked activity from large neuron populations in both the primary auditory cortex and the middle temporal visual area. I will also show early results from recordings of face cells in the posterior dorsal face area. Finally, I will discuss my future plans for directly measuring the connectivity architectures that support face representations and for studying interactions between different face areas.