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Cortical activity in precision- versus power-grip tasks: an fMRI study.
H H Ehrsson1, A Fagergren, T Jonsson
1Motoriklab, Department of Woman and Child Health, MR Research Center, 171 76 Stockholm, Sweden.
Journal of Neurophysiology
|January 15, 2000
Summary
Brain activity differs between precision and power grips. Precision grips involve more bilateral brain activation, particularly in premotor and parietal areas, while power grips primarily engage contralateral motor cortex.
Area of Science:
- Neuroscience
- Human Motor Control
- Biomechanics
Background:
- Manual grips are broadly classified into precision and power grips based on phylogenetic and functional criteria.
- Understanding the neural underpinnings of different grip types is crucial for grasping complex motor control.
Purpose of the Study:
- To compare human brain activity during force production using precision versus power grips of the right hand.
- To investigate the differential involvement of brain regions in controlling fine fingertip forces versus whole-hand grasping.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was employed to measure brain activity.
- Participants performed two distinct tasks: a precision grip (index finger and thumb) and a power grip (cylindrical object).
Main Results:
- Higher activity in the primary sensory and motor cortex (contralateral) was observed during the power grip.
- Increased activity in the ipsilateral ventral premotor area, rostral cingulate motor area, posterior parietal, and prefrontal cortices occurred during the precision grip.
- Power grip showed predominantly contralateral (left-hemisphere) activity, whereas precision grip involved bilateral brain activation.
Conclusions:
- Precision grip control relies on extensive bilateral brain networks, including premotor and parietal areas, in addition to the primary motor cortex.
- The ipsilateral hemisphere plays a significant role in controlling precision grip tasks performed with the dominant hand.