Rehearsing biological motion in working memory: an EEG study

Area of Science:

• Cognitive Neuroscience
• Social Cognition
• Neuroscience

Background:

• Holding biological motion (BM) in working memory (WM) is crucial for social interaction.
• The neural mechanisms underlying BM maintenance in WM are not well understood.

Purpose of the Study:

• To investigate the role of the human mirror neuron system (MNS) in rehearsing biological motion within working memory.
• To test the hypothesis that MNS activity underlies the maintenance of BM in WM.

Main Methods:

• Utilized electroencephalography (EEG) to measure mu suppression (8-12 Hz), an index linked to MNS activity.
• Employed a change detection task with varying memory loads of BM stimuli across three experiments.
• Manipulated cognitive strategies by instructing participants to use verbal coding in one experiment.

Main Results:

• Mu suppression increased with memory load for BM up to four stimuli, then plateaued, indicating WM capacity limits.
• A negative correlation was observed between the number of BM stimuli and mu suppression.
• The modulation of mu suppression by memory load disappeared when participants used verbal coding, suggesting a specific role for MNS in non-verbal motion rehearsal.

Conclusions:

• The findings provide evidence that the human mirror neuron system is involved in the rehearsal of biological motion in working memory.
• This suggests a neural basis for how we internally represent and maintain observed movements, crucial for social understanding.