Distinct cortical networks for hand movement initiation and directional processing: An EEG study

Area of Science:

• Neuroscience
• Motor Control
• Brain Networks

Background:

• Movement preparation and initiation involve large-scale brain networks.
• These processes are increasingly understood to be represented in functionally distinct cortical networks.
• Movement initiation is marked by the movement-related cortical potential (MRCP), while preparation involves directional processing.

Purpose of the Study:

• To investigate the distinct cortical network representations of movement initiation and preparation.
• To compare the encoding of movement direction in sensorimotor (SM) and parieto-occipital (PO) cortex during visuomotor and oculomotor tasks.
• To determine if delta band EEG activity carries information about movement direction and initiation.

Main Methods:

• Analyzed delta band electroencephalographic (EEG) activity during center-out reaching movements in 15 healthy participants.
• Recorded EEG during visuomotor and oculomotor tasks with four movement directions.
• Utilized a classification approach to decode movement directions from EEG data.

Main Results:

• Movement direction was consistently represented in the parieto-occipital cortex 300-400 ms after the direction cue, regardless of task.
• Sensorimotor areas, despite generating the MRCP, encoded less movement direction information than the PO cortex.
• Encoded directional information in SM areas was less consistent across participants and task-specific.
• Classification accuracies for inferring movement direction reached up to 55.9%, with higher accuracy for cue-aligned than movement onset-aligned data.

Conclusions:

• EEG delta band amplitude modulations carry information about both arm movement initiation and direction.
• Movement direction and initiation are represented in distinct cortical networks, with PO cortex showing stronger directional encoding.
• Movement direction is more strongly represented during the preparation phase (cue-aligned) than during movement initiation (onset-aligned).