Evidence for an Active Handoff between Hemispheres during Target Tracking.

The brain has somewhat separate cognitive resources for the left and right sides of our visual field. Despite this lateralization, we have a smooth and unified perception of our environment. This raises the question of how the cerebral hemispheres are coordinated to transfer information between them. We recorded neural activity in the lateral prefrontal cortex, bilaterally, as two male nonhuman primates covertly tracked a target that moved from one visual hemifield (i.e., from one hemisphere) to the other. Beta (15-30 Hz) power, gamma (30-80 Hz) power, and spiking information reflected sensory processing of the target. In contrast, alpha (10-15 Hz) power, theta (4-10 Hz) power, and spiking information seemed to reflect an active handoff of attention as target information was transferred between hemispheres. Specifically, alpha power and spiking information ramped up in anticipation of the hemifield cross. Theta power peaked after the cross, signaling its completion. Our results support an active handoff of information between hemispheres. This "handshaking" operation may be critical for minimizing information loss, much like how mobile towers handshake when transferring calls between them.