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The Bereitschaftspotential in preparation to mental activities.
G Freude1, P Ullsperger, H Krüger
1Central Institute of Occupational Medicine of the G.D.R., Department of Psychophysiology, Berlin.
Summary
The Bereitschaftspotential (Bp) increases with higher mental load during tasks. This suggests Bp reflects self-activation for cognitive challenges, not just motor preparation.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Human Motor Control
Background:
- The Bereitschaftspotential (Bp) is a well-studied electrophysiological signal linked to motor preparation.
- Previous research has explored the Bp in relation to various muscular activities.
- The influence of cognitive factors, such as mental load, on the Bp remains less understood.
Purpose of the Study:
- To investigate whether the degree of mental load affects the Bereitschaftspotential (Bp).
- To examine the Bp while keeping motor activity constant.
- To differentiate between motor preparation and cognitive activation in Bp generation.
Main Methods:
- 14 healthy male subjects performed arithmetic tasks under varying time pressure.
- Subjects selected task difficulty by pressing one of three keys.
- Electroencephalogram (EEG) signals were recorded and averaged, time-locked to key press onset.
- Artefact rejection and specific EEG filtering (5s time constant, 15Hz cut-off) were employed.
Main Results:
- The Bereitschaftspotential (Bp) was significantly larger under conditions of higher time pressure.
- This increase in Bp amplitude correlated with increased mental load.
- No significant differences in motor preparation were indicated as the primary cause.
Conclusions:
- The findings suggest that the Bereitschaftspotential (Bp) is modulated by the level of mental load.
- The elevated Bp under high time pressure may represent increased self-activation for demanding cognitive tasks.
- This challenges a purely motor preparation interpretation of the Bp in certain contexts.