Grant: Discovery Grants Program - Individual

The brain has a limited information processing capacity, therefore it must from the multitude of signals entering the senses select a subset that is relevant for behavior. The long-term goal of my research program is to understand how the primate brain select behavioral relevant sensory signals through the mechanisms of attention and gaze. Diurnal primates have evolved a sophisticated visual system with a specialized fovea that enables high resolution color vision and a gaze control system for moving the eyes and aligning the fovea with objects of interest. Gaze shifts are movements of the eyes in space, composed of combined head and/or eye (saccades) rotations that are guided by selection of targets through the mechanism of attention. Several brain areas have been implicated in the process of selecting targets for gaze shifts. Prominent amongst them is the Frontal Eye Fields (FEF) in the prefrontal cortex. It is currently thought that ensembles of FEF neurons functionally organized in columns encode the allocation of attention in space sending signals towards visual areas that increase the sensitivity of neurons with receptive fields at attended locations to sensory inputs. The FEF also sends commands to the brainstem centers that ultimately activate the eyes and neck muscles to execute coordinate eye-head gaze shifts. It has been proposed that two codes for attention and gaze allocation co-exist within the FEF. The microcircuit dynamics supporting such codes remains poorly known. The general objective of this proposal is investigating the microcircuit level mechanisms of spatial attention and gaze with cell type resolution within the FEF of a non-human primate, the common marmoset (Callithrix jacchus). The common marmoset is a small new world primate native from central Brazil that has gained popularity as an animal model in neuroscience. Marmosets have a fovea and gaze control system that resembles the one of macaque monkeys and humans (Mitchell et al. 2014). Importantly, marmosets are lissencephalic. Thus, areas such as the FEF, located deep in the knee of the arcuate sulcus in old world primates such as macaques are in the dorsal cortical surface of the marmoset frontal lobe. This feature makes it accessible to methods that allow mapping of the area columnar microcircuit such as electrophysiological recordings using high density probes, and methods that explore the area surface topography such as Calcium imaging 2-photon microscopy. Our results will reveal the specific operations and cell types underlying the allocation of attention and gaze in the FEF of primates. They will ultimately serve computational neuroscientists and engineers to build biologically informed computational models of attention and gaze control in visual primates.