Habituation in a simple repetitive motor task: a study with movement-related cortical potentials

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Neuroscience

Background:

• Movement-related cortical potential (MRCP) typically attenuates over the right hemisphere during complex motor sequences.
• This attenuation has been previously attributed to motor learning processes.
• The role of the right hemisphere in simple, non-learning motor tasks remains less understood.

Purpose of the Study:

• To investigate if MRCP attenuation occurs during simple, repetitive motor tasks that do not require learning.
• To explore potential transfer effects of MRCP changes when switching between hands for motor tasks.

Main Methods:

• Recorded MRCPs in 33 right-handed healthy subjects using a counterbalanced crossover design.
• Subjects performed 100 self-paced unilateral button presses with either the left or right index finger, followed by 100 movements with the other hand.
• Task speed was kept constant throughout the experiment.

Main Results:

• MRCP amplitude consistently attenuated over the right hemisphere, regardless of the moving limb (left or right).
• MRCP amplitude decreased across the scalp during the initial sequence, reaching a minimum.
• Following a hand switch, MRCP amplitude slightly increased from its minimum during the subsequent sequence.

Conclusions:

• The right hemisphere appears to play a predominant role in motor activation, attention, or somatosensory processing, even in simple motor tasks.
• The observed decrease and subsequent increase in MRCP negativity may indicate shifts in subject arousal levels during the task sequences.