Cerebral Cortex Advance Access originally published online on September 26, 2008
Cerebral Cortex 2009 19(5):1186-1197; doi:10.1093/cercor/bhn166
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Smooth Pursuit–Related Information Processing in Frontal Eye Field Neurons that Project to the NRTP
Division of Sensory-Motor Systems, Yerkes National Primate Research Center, and Department of Neurology, Emory University, 954 Gatewood Road Northeast, Atlanta, GA 30329, USA
Address correspondence to email: mjmustar{at}rmy.emory.edu.
The cortical pursuit system begins the process of transforming visual signals into commands for smooth pursuit (SP) eye movements. The frontal eye field (FEF), located in the fundus of arcuate sulcus, is known to play a role in SP and gaze pursuit movements. This role is supported, at least in part, by FEF projections to the rostral nucleus reticularis tegmenti pontis (rNRTP), which in turn projects heavily to the cerebellar vermis. However, the functional characteristics of SP-related FEF neurons that project to rNRTP have never been described. Therefore, we used microelectrical stimulation (ES) to deliver single pulses (50–200 µA, 200-µs duration) in rNRTP to antidromically activate FEF neurons. We estimated the eye or retinal error motion sensitivity (position, velocity, and acceleration) of FEF neurons during SP using multiple linear regression modeling. FEF neurons that projected to rNRTP were most sensitive to eye acceleration. In contrast, FEF neurons not activated following ES of rNRTP were often most sensitive to eye velocity. In similar modeling studies, we found that rNRTP neurons were also biased toward eye acceleration. Therefore, our results suggest that neurons in the FEF–rNRTP pathway carry signals that could play a primary role in initiation of SP.
Key Words: cerebral cortex • eye movements • macaque • pontine nucleus