Working memory (WM) is the cognitive ability that allows an organism to maintain recent information in order to guide behavior. Communication between the sensory areas that process visual information and prefrontal areas that prepare plans of action is pivotal to the information flow during WM tasks. Efficacy of this communication has been shown to depend on the content of WM. Moreover, coherence between prefrontal and posterior visual areas has been shown to correlate with success in WM tasks. We tested whether local oscillations within prefrontal cortex and coherent oscillations between this area and visual areas determine the efficacy of inputs arriving in prefrontal cortex. An anterograde viral vector expressing channelrhodopsin-2 was injected into rhesus macaque V4. After allowing viral expression in V4 axon terminals, we performed photostimulation of V4 axon terminals within the FEF during a memory guided saccade (MGS) task to induce excitation in axon terminals of V4 neurons within FEF while recording local field potentials and spiking activity within both regions. Optogenetic stimulation successfully evoked activity in FEF. We found that the efficacy of V4 axon terminal photostimulation to drive FEF spiking activity depends on oscillations within FEF. We present the analysis regarding the specificity of certain oscillations within FEF, as well as the relationship between FEF and V4 oscillations, in gating the efficacy of V4 inputs to FEF. This study aims to reveal whether and how the efficacy of inputs from V4 to FEF is dynamically gated by WM-induced oscillations, a mechanism for efficient communication of sensory information during WM.
Acknowledgements: This work is supported by National Eye Institute R01EY02694, National Institute of Neurological Disorders and Stroke R01NS113073, and an unrestricted grant from Research to Prevent Blindness, Inc to Moran Eye Center, University of Utah. Authors declare no competing financial interests.