Differences in spectral profiles between rostral and caudal premotor cortex when hand-eye actions are decoupled

Abstract

The aim of this research was to understand how the brain controls voluntary movement when not directly interacting with the object of interest. In the present study, we examined the role of premotor cortex in this behavior. The goal of this study was to characterize the oscillatory activity within the caudal and rostral subdivisions of dorsal premotor cortex (PMdc and PMdr) with a change from the most basic reaching movement to one that involves a simple dissociation between the actions of the eyes and hand. We were specifically interested in how PMdr and PMdc respond when the eyes and hand are decoupled by moving along different spatial planes. We recorded single-unit activity and local field potentials within PMdr and PMdc from two rhesus macaques during performance of two types of visually guided reaches. During the standard condition, a visually guided reach was performed whereby the visual stimulus guiding the movement was the target of the reach itself. During the nonstandard condition, the visual stimulus provided information about the direction of the required movement but was not the target of the motor output. We observed distinct task-related and topographical differences between PMdr and PMdc. Our results support functional differences between PMdr and PMdc during visually guided reaching. PMdr activity appears more involved in integrating the rule-based aspects of a visually guided reach, whereas PMdc is more involved in the online updating of the decoupled reach. More broadly, our results highlight the necessity of accounting for the nonstandard nature of a motor task when interpreting movement control research data.

Cognitive-motor integration deficits in young adult athletes following concussion

“…Further, recent anatomical studies have found altered white matter integrity in concussed adolescents, younger adults with concussion history, and older adults with concussion history that involved those pathways connecting frontal and parietal regions [ 34 – 37 ]. These data complement our group’s findings on the crucial role played by such fronto-parietal networks in integrating thought and action [ 10 , 14 , 19 , 20 , 38 ].…”

Decoupling the actions of the eyes from the hand alters beta and gamma synchrony within SPL

“…While some research suggests that a strong relationship exists (Ray and Maunsell 2011; Zanos et al 2011, 2012), others suggest a difference between spiking and high gamma activity (Flint et al 2012; Pesaran et al 2002). To remain consistent with our laboratory's previous work, we decided to only include data from below 60 Hz (Sayegh et al 2013).…”

“…Two rhesus monkeys (female Macaca mulatta, both 5.2 kg) were trained to perform a visually instructed delayed reaching task under coupled and decoupled eye-hand conditions, as described previously (Hawkins et al 2013;Sayegh et al 2013). All surgical and animal handling procedures were in accordance with Canadian Council on Animal Care guidelines on the use of laboratory animals, and preapproved by the York University Animal Care Committee.…”

“…A gaze-only control task, which has been described previously in detail (Hawkins et al 2013;Sayegh et al 2013), was also included to determine if the neural activity was affected solely by the overall shift in gaze angle. This condition was performed for every recording.…”

“…The average spectral value across each time-frequency bin was determined for each condition. A bootstrapping permutation test (Hawkins et al 2013;Sayegh et al 2013;Sergio and Kalaska 2003) was used to assess whether the difference in power between the two conditions was significant. According to the null hypothesis, power would be the same irrespective of condition (coupled/decoupled), and as such the observed difference in mean power would not exceed the 95% confidence limits of a distribution of differences in LFP power.…”