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Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation
Published on: February 23, 2020
Functional specificity of human premotor-motor cortical interactions during action selection
Jacinta O'Shea1, Catherine Sebastian, Erie D Boorman
1Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK. jacinta.oshea@psy.ox.ac.uk
The European Journal of Neuroscience
|September 18, 2007
Summary
Functional connections between the dorsal premotor cortex (PMd) and primary motor cortex (M1) are key for response selection. TMS revealed these PMd-M1 interactions are specific to selecting a response, not just executing it.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Motor Control
Background:
- Paired-pulse transcranial magnetic stimulation (TMS) has previously identified functional connections between the dorsal premotor cortex (PMd) and primary motor cortex (M1).
- Response selection is a cognitive process known to involve these motor circuits.
Purpose of the Study:
- To investigate if PMd-M1 functional connections are modulated during the cognitive process of response selection.
- To determine the temporal, anatomical, and functional specificity of PMd-M1 interactions during motor tasks.
Main Methods:
- Utilized paired-pulse TMS to probe functional connectivity between PMd and M1 during a response selection task.
- Measured motor-evoked potentials (MEPs) and choice reaction time (RT) to assess the impact of TMS.
- Compared TMS effects during response selection versus a control response execution task.
Main Results:
- PMd-M1 TMS at 75 ms post-cue facilitated MEPs, specifically during response selection, unlike during response execution (50 ms).
- PMd-M1 TMS at 100 ms delayed choice RT, with effects correlating with MEPs in a hand-specific manner.
- TMS confined to M1 did not yield similar effects, confirming the causal role of PMd inputs.
Conclusions:
- A response selection signal emerges in PMd early in the reaction period (75-100 ms).
- This PMd signal causally influences M1, impacting behavior and demonstrating temporal, anatomical, and functional specificity.
- These findings elucidate the neural mechanisms underlying movement selection.
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