Hemispheric differences of motor execution: a near-infrared spectroscopy study
Ingo Helmich1, Robert Rein2, Nico Niermann2
1Department of Neurology, Psychosomatic Medicine and Psychiatry, Institute of Health Promotion and Clinical Movement Science, German Sport University, Cologne, Germany. in.helmich@gmail.com.
Advances in Experimental Medicine and Biology
|July 16, 2013
Summary
Simple hand movements activate both brain hemispheres equally, challenging the idea of specialized control. This study used functional near-infrared spectroscopy to investigate brain activity during thumb movements, finding bilateral engagement.
Area of Science:
- Neuroscience
- Motor Control
- Brain Imaging
Background:
- Limb movements are typically controlled by the opposite brain hemisphere.
- Functional neuroimaging studies show conflicting results regarding cerebral activation lateralization during hand movements.
- Previous studies suggest either contralateral dominance or symmetrical bihemispheric activation.
Purpose of the Study:
- To investigate cerebral activation patterns in both hemispheres during simple motor tasks of the right and left hands.
- To clarify divergent findings in previous functional neuroimaging studies on hand movement lateralization.
- To examine brain activity using functional near-infrared spectroscopy (fNIRS).
Main Methods:
- Twenty participants performed thumb flexion/extension tasks with either their right or left hand.
- Cerebral oxygenation changes were measured using fNIRS across 48 channels.
- fNIRS data covered primary motor, pre-motor, supplementary motor, somatosensory cortex, subcentral, and supramarginal areas in both hemispheres.
Main Results:
- A consistent increase in oxygenated and total hemoglobin was observed in the hemisphere contralateral to the moving hand.
- This contralateral activation pattern was consistent regardless of whether the right or left hand was used.
- Findings align with previous localization and brain imaging studies.
Conclusions:
- Simple distal motor tasks, like thumb movements, do not exhibit hemispheric specialization.
- Both brain hemispheres are equally activated during contralateral upper limb movements.
- The study supports a model of bilateral brain engagement for basic motor actions.
