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The Bereitschaftspotential in preparation to mental activities

1988; Elsevier BV; Volume: 6; Issue: 4 Linguagem: Inglês

10.1016/0167-8760(88)90016-5

1872-7697

Gabriele Freude, Peter Ullsperger, Heidelind Krüger, Manfred Pietschmann,

EEG and Brain-Computer Interfaces

Earlier studies had investigated the Bereitschaftspotential (Bp) under different aspects of muscular activities. The present experiments were designed to test whether the Bp will be affected by the degree of mental load while motor activity is kept constant. Fourteen healthy male subjects had to solve arithmetical tasks under a graduated time pressure (3 categories of tasks). The subjects had to indicate by pressing one of three keys (trigger), which category of task they wanted to solve next. As soon as a key had been pressed, a task appeared on the computer display and disappeared after the time interval corresponding to the selected category. The results had to be entered into a computer via a keyboard. The EEG signals (5 s time constant, 15 Hz upper frequency cut-off) were averaged time-locked to the movement onset, starting 1.5 s before the pressing of the key. Trials with artefacts were rejected from averaging. The Bp was found to be significantly higher when the tasks were to be solved under higher time pressure. We assume that this might be rather an expression of an appropriate self-activation for the expected mental task than due to a different motor preparation.