Handedness and task demands modulate motor cortex lateralization: A cross-sectional fNIRS study
Abstract
It is generally accepted that the contralateral cerebral hemisphere is activated during motor control of an upper limb. Most studies exploring the cerebral mechanisms of motor control have focused on right-handed individuals, who represent around 90% of the general population. However, it appears that the lateralization of cortical activation is linked to various factors such as manual preference, the use of the dominant or non-dominant hand, and the type of task performed. The aim of this study was to compare cortical activation asymmetry during two different motor tasks as a function of manual laterality. We included 25 right-handed and 25 left-handed healthy individuals. They performed a distal and a manipulation task with each hand. Cortical activity in the premotor (PMC) and sensorimotor cortices (SMC) was measured using functional near-infrared spectroscopy (fNIRS). A Laterality Index was calculated to assess the degree of left-right hemisphere activation asymmetry for each region of interest. Irrespective of the hand used, cortical activation was predominantly contralateral for right-handers and more bilateral for left-handers. These results were more marked when using the right hand (non-domi- nant for left-handers) and seem to be modulated by the specific motor demands of the task. Thus, brain orga- nization was less asymmetrical in left-handers than in right-handers, probably because of enhanced interhemispheric connectivity. This organization might favor recovery mechanisms in pathologies such as stroke. These results underline the importance of considering manual laterality in both neurophysiological and clinical studies of central nervous system pathologies
Related
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BibTeX
@article{bonnal2026handedness,
title = {{Handedness and task demands modulate motor cortex lateralization: A cross-sectional fNIRS study}},
author = {Julien Bonnal and Ophélie Pila and Coraline Papin and Lucie Lebkowski and Mathilde Sarrazin and Raquel Bravo and Fabrice Prieur},
journal = {NeuroImage},
year = {2026},
month = sep,
doi = {10.1016/j.neuroimage.2025.121578},
url = {https://hal.science/hal-05743911v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Handedness and task demands modulate motor cortex lateralization: A cross-sectional fNIRS study
AU - Julien Bonnal
AU - Ophélie Pila
AU - Coraline Papin
AU - Lucie Lebkowski
AU - Mathilde Sarrazin
AU - Raquel Bravo
AU - Fabrice Prieur
PY - 2026
DA - 2026/09/09
JO - NeuroImage
DO - 10.1016/j.neuroimage.2025.121578
UR - https://hal.science/hal-05743911v1
AB - It is generally accepted that the contralateral cerebral hemisphere is activated during motor control of an upper limb. Most studies exploring the cerebral mechanisms of motor control have focused on right-handed individuals, who represent around 90% of the general population. However, it appears that the lateralization of cortical activation is linked to various factors such as manual preference, the use of the dominant or non-dominant hand, and the type of task performed. The aim of this study was to compare cortical activation asymmetry during two different motor tasks as a function of manual laterality. We included 25 right-handed and 25 left-handed healthy individuals. They performed a distal and a manipulation task with each hand. Cortical activity in the premotor (PMC) and sensorimotor cortices (SMC) was measured using functional near-infrared spectroscopy (fNIRS). A Laterality Index was calculated to assess the degree of left-right hemisphere activation asymmetry for each region of interest. Irrespective of the hand used, cortical activation was predominantly contralateral for right-handers and more bilateral for left-handers. These results were more marked when using the right hand (non-domi- nant for left-handers) and seem to be modulated by the specific motor demands of the task. Thus, brain orga- nization was less asymmetrical in left-handers than in right-handers, probably because of enhanced interhemispheric connectivity. This organization might favor recovery mechanisms in pathologies such as stroke. These results underline the importance of considering manual laterality in both neurophysiological and clinical studies of central nervous system pathologies
SN - 1053-8119
SN - 1095-9572
ER -