Distributed representations of the "preparatory set" in the frontal oculomotor system: a TMS study
M Nagel1, A Sprenger, R Lencer
1Department of Psychiatry and Psychotherapy, University of Luebeck, Ratzeburger Allee 160, Luebeck, Germany. matthias.nagel@psychiatrie.uk-sh.de
BMC Neuroscience
|September 20, 2008
Summary
Transcranial magnetic stimulation (TMS) of key brain areas like the dorsolateral prefrontal cortex (DLPFC), frontal eye field (FEF), and supplementary eye field (SEF) delays saccade initiation, confirming their role in preparatory set activity for eye movements.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Oculomotor Research
Background:
- Saccade generation relies on preparatory activity in cortical oculomotor areas.
- The gap paradigm assesses this activity by introducing a delay between target disappearance and appearance.
Purpose of the Study:
- To investigate the role of the dorsolateral prefrontal cortex (DLPFC), frontal eye field (FEF), and supplementary eye field (SEF) in saccade preparation.
- To examine how transcranial magnetic stimulation (TMS) affects saccade latencies during a gap period.
Main Methods:
- Ten healthy subjects performed pro- and antisaccades with a 200 ms gap.
- Single-pulse TMS was applied to DLPFC, FEF, or SEF at specific intervals.
- Saccade latencies were measured; sham TMS was used as a control.
Main Results:
- TMS applied to DLPFC, FEF, or SEF significantly increased saccade latencies.
- This delay was more pronounced with higher preparatory set activity, particularly for prosaccades.
- Sham TMS shortened anti-saccade latencies, indicating specific effects of real TMS.
Conclusions:
- The preparatory set for contraversive saccades involves a distributed network including the contralateral DLPFC, FEF, and SEF.
- These findings support the role of these cortical areas in planning and executing eye movements.
