Poster Z9 - Testing the Efficacy of Corticocortical Communication Using Optogenetics

Introduction: Cognitive flexibility is the mechanism by which the same neural resources are used in differing manners during differing cognitive loads. While neural circuitry is fixed in short-term operations, by varying the specific communication between neurons, the information conveyed can also change, without changing the physical wiring. An example of such a dynamic variance is in the case of working memory (WM), a process by which current information is held for short-term storage and manipulation. In the case of the communication of visual information into the prefrontal cortex, previous studies have reported that the efficacy of communication between extrastriate visual area V4 and the frontal eye field (FEF) part of prefrontal cortex increases when information held in WM aligns with the respective response fields of the neurons. The coherence of local field potential (LFP) oscillations between areas has been implicated in dynamic gating of information between brain areas. Our goal is to assess the efficacy of visual inputs into the prefrontal cortex using optogenetic stimulation and determine the role of coherent oscillations within these areas in dynamic gating of this efficacy.

Materials and

Methods: Here, we present data recorded from the FEF and V4 of an awake, behaving rhesus macaque monkey during the completion of a memory guided saccade task with periodic optogenetic stimulation of V4 projections in the FEF region. By targeting V4 neurons for viral transfection, V4 spiking inputs into the FEF during visual cognitive task performance can be induced and analyzed. Using the integration of the optogenetic system with the presentation of the task, we timed optogenetic stimulation to occur at specific times within the task in order to observe the changes in induced activity depending on the nature of communication between areas.

Results, Conclusions, and Discussions: Using our optogenetic stimulation system we determine whether patterns of oscillations alter the efficacy of V4 inputs to the FEF during cognitive processing. Our technique grants us the ability to more readily determine the influence of oscillatory coherence between areas on the efficacy of their communication, and would allow us to understand the mechanisms involved in dynamic gating of information, underlying cognitive flexibility.

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