Thomas Elbert, Larry E Roberts, Werner Lutzenberger, and Niels Birbaumer (1992)
Modulation of slow cortical potentials by instrumentally leaned blood pressure responses
The Society for Psychophysiological Research, 29(2):154-164.
We assessed whether instrumentally-learned pressor responses inhibit electrocortical activity, as predicted by learning theories of idiopathic hypertension. Subjects received beat-by-beat feedback for increases and decreases in mean arterial pressure measured from the finger (Penaz method). Slow potentials were recorded from the midsaggital line during the final training session. Also recorded at this time were heart rate, eye movements, respiration, and post-session verbal reports of the subject's control strategies. Thirteen of 14 subjects differentiated blood pressure increases and decreases at p < .05 or better during the final session (within-subject discriminative operant procedure). Slow potentials were less negative on blood pressure increase compared to decrease trials at all midsagittal sites (p> .02), indicating relative cortical inhibition by pressor responses. This effect occurred even though subjects reported tensing of muscles on increase trials (p< .01), a behavioral activity previously associated with augmented rather than diminished cortical negativity. On increase trials slow potentials shifted toward positivity just prior to heart rate deceleration (the latter effect confirming activation of the baroreceptors)>