High frequency rTMS modulation of the sensorimotor networks: behavioral changes and fMRI correlates

Area of Science:

• Neuroscience
• Neuromodulation
• Motor Control

Background:

• Repetitive transcranial magnetic stimulation (rTMS) applied to the primary motor cortex (M1) can influence motor and sensory functions.
• Understanding the neurophysiological changes induced by rTMS is crucial for its therapeutic applications.

Purpose of the Study:

• To investigate the neurophysiological modulation of motor performance and sensory perception following 10 Hz rTMS over M1.
• To examine cortical activation patterns using functional magnetic resonance imaging (fMRI) and correlate them with behavioral changes.

Main Methods:

• 10 Hz rTMS was applied over the primary motor cortex (M1).
• Cortical activation was assessed using 3T fMRI during a sequential finger motor task and noxious mechanical stimulation.
• Motor performance was measured via the finger task, and sensory perception was assessed by current perception threshold.

Main Results:

• Real rTMS, compared to sham, showed significant activation in basal ganglia, superior frontal gyrus, pre-SMA, medial temporal lobe, inferior parietal lobe, and cerebellar hemisphere, correlating with enhanced motor performance.
• Conversely, rTMS was associated with significant deactivation in frontal gyri, postcentral and cingulate gyri, SMA, insula, basal ganglia, and cerebellum, linked to increased sensory threshold.
• These findings indicate rapid changes in sensorimotor networks following rTMS.

Conclusions:

• rTMS induces swift neurophysiological alterations within sensorimotor networks.
• The study highlights the complex impact of rTMS on both motor and sensory processing.
• These findings contribute to understanding the mechanisms underlying rTMS effects on brain function.