Conditional discrimination of electroencephalogram alpha amplitudes in humans

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychophysiology

Background:

• Conditional discrimination of human electroencephalogram (EEG) alpha amplitudes was first reported in the 1950s.
• Subsequent replication attempts yielded limited success, with accuracy only slightly above chance and potential methodological confounds.
• These confounds included temporal cues, unequal trial numbers, and short trial durations potentially creating carry-over effects.

Purpose of the Study:

• To investigate the replicability of human alpha amplitude discrimination.
• To eliminate potential confounds present in previous studies.
• To determine if alpha discrimination is a robust phenomenon under controlled conditions.

Main Methods:

• A modified procedure was employed to eliminate known confounds.
• Participants observed a bar's motion visually correlated with real-time alpha amplitude changes.
• Trials had constant durations, and participants discriminated between positive and negative correlations between bar motion and alpha amplitude.

Main Results:

• Three out of five evaluable participants (60%) successfully discriminated alpha amplitudes.
• The observed success rate is comparable to the original 1950s study.
• The results suggest successful discrimination was achieved without the previously identified confounds.

Conclusions:

• Human conditional discrimination of EEG alpha amplitudes is a replicable phenomenon.
• Careful control of experimental confounds is crucial for demonstrating alpha discrimination.
• This study provides further evidence for the reliability of alpha amplitude discrimination.