Functional MRI cerebral activation and deactivation during finger movement

Area of Science:

• Neuroscience
• Motor Control
• Brain Imaging

Background:

• Previous studies on interhemispheric inhibition used animal models, clinical data, and transcranial magnetic stimulation (TMS).
• Functional MRI (fMRI) had not been utilized to investigate activation and deactivation patterns during unilateral motor tasks.
• Standard fMRI analysis compares motor task activation to a resting state; this study also examined resting state changes relative to motor activity.

Purpose of the Study:

• To investigate interhemispheric interactions during motor processes using functional MRI (fMRI).
• To explore brain activation and deactivation patterns associated with unilateral hand movements.

Main Methods:

• Thirteen healthy participants performed sequential finger/thumb tapping with each hand.
• fMRI data were acquired across four epochs, each including rest, right-hand activity, and left-hand activity phases.
• Functional MRI images underwent spatial normalization and smoothing.

Main Results:

• Unilateral hand movements elicited activation in the contralateral sensorimotor cortex and ipsilateral cerebellum.
• Significant deactivation (reduced blood flow) was observed in the ipsilateral sensorimotor cortex and contralateral cerebellum.
• Conjunction analysis identified brain regions activated by one hand and deactivated by the other.

Conclusions:

• Unilateral hand movements are linked to contralateral cerebral activation and ipsilateral cerebral deactivation.
• These findings support the hypothesis that transcallosal inhibition underlies these observed interhemispheric interactions.