Cortical negative motor network in comparison with sensorimotor network: a cortico-cortical evoked potential study

Area of Science:

• Neuroscience
• Motor Control Research
• Epilepsy Studies

Background:

• Understanding the neural basis of motor control is crucial.
• Negative motor phenomena, characterized by impaired movement organization, require further investigation.
• Existing research lacks detailed insights into the connectivity of negative motor areas.

Purpose of the Study:

• To investigate the connectivity originating from the negative motor area.
• To elucidate the underlying neural mechanisms of negative motor phenomena.
• To map cortico-cortical evoked potential (CCEP) responses following stimulation of motor and sensory areas.

Main Methods:

• Cortico-cortical evoked potentials (CCEPs) were recorded in eight epilepsy patients with intracranial electrodes.
• Electrical stimulation was applied to the primary motor area (MI), primary sensory area (SI), primary negative motor area (PNMA), and supplementary negative motor area (SNMA).
• Electrocorticograms were averaged time-locked to 1-Hz electrical stimuli.

Main Results:

• Stimulation of MI, SI, and PNMA elicited CCEP responses in the premotor area (PM), pre- and postcentral gyri, posterior parietal cortex, and temporo-parietal junction.
• SNMA stimulation resulted in CCEP responses in the prefrontal cortex, PM, pre- and postcentral gyri, supplementary motor area (SMA), and preSMA.
• PNMA stimulation demonstrated a broader CCEP distribution in the frontal and parietal association cortex compared to SI and MI stimulation, highlighting the fronto-parietal network's role.

Conclusions:

• The study identified significant cortico-cortical connections associated with motor control.
• The findings suggest that negative motor phenomena arise from disruptions in movement organization.
• The fronto-parietal network plays a critical role in higher-level motor control processes.