Differential conditioning of alpha amplitude: a fresh look at an old phenomenon.

Objective To determine the latency and development of conditional suppression of alpha amplitude and its relationship to behaviour, alpha amplitude (8'13 Hz) was measured in a differential conditioning procedure. Methods The CS+/' were tones and the US was a photic checkerboard. Alpha amplitude, CNV, RT and verbal responses were recorded from 12 participants. Results The CS+/' difference in acquisition was greatest from 250 ms before the US. It was greatest from the trial where RT declined and participants could report the CS+/US relationship. There was an amplitude increase in lower band activity 230 ms after the US. This looked like a VEP but was produced by phase-locked activity starting before the US. Conclusions Predicting the US led to cortical priming. Amplitude change in acquisition is congruent with CNV, RT and verbal performance. Significance Prediction, expectancy and motor preparation are reflected in changes in alpha activity. These results provide converging evidence for the functional role of 8'10 Hz activity. They complement the emerging picture of the role of alpha activity in cognition, indicating that it extends to the acquisition of predictive knowledge.