Low-frequency activity in the primate superior colliculus activates a head turning synergy: evidence using neck EMG recordings

High-frequency bursts within the deeper layers of the primate superior colliculus (dSC) encode desired eye-head gaze shifts. In addition, many dSC neurons emit earlier low-frequency activity. We hypothesized that low-frequency activity in dSC neurons contributes to priming and orienting the head in advance of eye-head gaze shifts. We simultaneously recorded dSC unit discharge and electromyographic (EMG) activity of dorsal neck muscles from three rhesus monkeys performing a gap-saccade paradigm with different levels of reward expectancy. As reward expectancy increased, low-frequency dSC activity increased and EMG activity from the contralateral obliquus capitis inferior (OCI) muscle also increased. These measures were positively correlated, with the optimal correlation occurring when EMG activity was delayed by 14 ms. These results support the hypothesis that low-frequency dSC activity constitutes a motor command, which functions in head control prior to upcoming gaze shifts.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Physiology

Year dc:date.issued

2007

Author dc:creator

• Rezvani, Sam

Advisors dc:contributor.advisor

• Corneil, Brian
• Hore, Jonathan
• Leung, Stan

• superior colliculus
• gaze shift
• head movements
• eye-head coordination
• single-unit recording
• electromyography
• obliquus capitis inferior
• neck muscles

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/20289

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/20289