Functional connectivity
How does premotor cortex prepare the hand for different grips?
Open access · cc by · source: Europe PMC
A pulse to ventral premotor cortex just before a pulse to motor cortex selectively boosted the hand muscle that the person was about to use, depending on whether they were preparing a pinch or a whole-hand grasp.
Study at a glance
- Design
- Human experiment — Within-subject dual-coil conditioning-test TMS (ventral premotor to M1, M1 to M1 control, and M1 paired-pulse) delivered 800 ms after a pen or disc appeared, while people prepared to grasp it.
- N
- N=11 · 11 right-handed volunteers aged 20 to 30, all tested in every condition.
- Population
- Healthy right-handed young adults in London
- Outcome
- Motor evoked potential amplitude in the first dorsal interosseous and abductor digiti minimi hand muscles, relative to test pulse alone
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Conditioning PMv 6 or 8 ms before the M1 pulse strongly facilitated the index muscle only when a precision grip was being prepared and the little-finger muscle only when a whole-hand grasp was being prepared. Across people, the size of this grasp-specific boost tracked how differently the muscles were later used in the two grasps (r of about .78 to .79). Conditioning over M1 itself produced the usual inhibition and facilitation regardless of grasp, arguing against current spread, and paired pulses over M1 gave a smaller grasp-specific facilitation than the PMv route.
Methodology
Eleven healthy right-handers saw either a pen (to be picked up with a thumb-index precision grip) or a disc (to be grasped with the whole hand) and, 800 ms later, a TMS pulse over primary motor cortex (M1) cued them to reach. On many trials a weaker conditioning pulse was first given over ventral premotor cortex (PMv) at intervals from 1 to 15 ms, and muscle responses (motor evoked potentials) were recorded from an index-finger muscle and a little-finger muscle. Two control conditions stimulated M1 twice, to check for current spread and to probe other inputs to M1.
Limitations
The sample was only 11 young adults and the paper has no dedicated limitations section. Only two objects, two muscles and a single preparation time (800 ms) were tested, so the timing and generality of the effect are unknown. TMS reveals a net influence of PMv on M1 but cannot tell whether it is direct or relayed, and interpretations about grasp-specific neuron populations rest on monkey data rather than measurements in these participants.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Not yet placed on a claim. This paper has study layers, but no concept page yet cites it as support, challenge, or qualifier.
Related papers in this topic
Same topic cluster — not a recommendation engine.