Working memory load modulates sensorimotor cortical oscillations underlying anticipatory postural adjustments during...

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Psychology

Background:

• Anticipatory postural adjustments (APAs) are crucial for stable weight transfer during locomotion.
• Working memory (WM) load, especially under visual interference, can impair APA execution.
• The neural basis for WM load-induced APA errors remains poorly understood.

Purpose of the Study:

• To investigate the cortical activity associated with increased erroneous APAs under working memory load.
• To elucidate the neural mechanisms linking cognitive demands to motor control deficits during gait initiation.

Main Methods:

• Sixteen healthy young men performed a visual stimulus-cued stepping task.
• Participants experienced two working memory load conditions (LOW: 1 digit, HIGH: 6 digits) combined with congruent and incongruent Flanker task stimuli.
• Electroencephalography (EEG) recorded cortical oscillatory activity during step initiation.

Main Results:

• APA error rates were significantly higher in the incongruent condition under HIGH WM load compared to LOW WM load.
• Theta-band synchronization in the sensorimotor area was significantly enhanced under HIGH WM load versus LOW WM load.
• Increased cognitive demand correlated with greater recruitment of sensorimotor areas.

Conclusions:

• Elevated working memory load necessitates greater sensorimotor area engagement to manage cognitive demands during step initiation.
• Inefficient activation of the sensorimotor area under high cognitive load may contribute to faulty weight shifting and APA errors.
• This study highlights the interplay between cognitive load and motor control in gait initiation.