Covert movements trigger repetition suppression of electroencephalography in sensorimotor cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Repetition suppression (RS) is typically observed as reduced neural responses to repeated external sensory stimuli.
• Internal brain processes, such as motor imagery, involve cortical activity without overt muscle movement.
• Understanding the neural mechanisms of adaptation in response to repetitive neural activation is crucial.

Purpose of the Study:

• To investigate whether repetition suppression can be elicited by internal cognitive processes alone.
• To examine the effect of repetitive covert movements (motor imagery) on neural oscillations in sensorimotor cortices.
• To compare the effects of covert movements with those of overt movements on repetition suppression.

Main Methods:

• Participants performed repetitive covert movements (motor imagery) while electroencephalography (EEG) was recorded.
• EEG data were analyzed to assess changes in alpha (α) and beta (β) oscillations over sensorimotor cortices.
• Neural responses were monitored during and after the task performance to quantify the degree of repetition suppression.

Main Results:

• Repetitive covert movements led to a significant recovery of electroencephalography oscillations in sensorimotor cortices towards baseline levels.
• After 58 seconds of motor imagery, only 20% of alpha and 5% of beta suppressions remained.
• Compared to overt movements, covert movements showed a more pronounced recovery of neural oscillations, suggesting a distinct form of repetition suppression.

Conclusions:

• Repetition suppression is not limited to external stimuli but can also be triggered by internal cognitive processes.
• Repetitive cerebral activations, including those during motor imagery, are associated with repetition suppression.
• This phenomenon likely reflects neural network adaptation to stereotyped activation patterns.