It has been hypothesized that activation of the baroreceptor reflex arc, by its central nervous inhibitory effects, is involved in an operant learning mechanism of blood pressure elevation. The present study investigated the effects of mechanical stimulation of the baroreceptors in the carotid sinus on pain threshold and electrical brain activity in two groups of humans with different tonic blood pressure levels. In normotensives, baroreceptor stimulation lowered pain threshold as compared to a control condition, while borderline hypertensives tolerated more intense electric stimulation when baroreceptors were activated. A marked reduction of the contingent negative variation in anticipation of the aversive stimulation accompanied baroreceptor stimulation, probably a consequence of baroreceptor afferent impulses exerted via brainstem centers to cerebral cortex. The distribution of the potenial change across the scalp depended on the tonic blood pressure, indicating defferences in brain functioning between normotensives and borderline hypertensives. The present results suggest that the hypothesis of an operantly-conditoned blood pressure elevation under stress may be valid only in subjects with a predisposition for essential hypertension.
|Number of pages||5|
|Publication status||Published - 1988|
ASJC Scopus subject areas
- Physiology (medical)
- Experimental and Cognitive Psychology
- Neuropsychology and Physiological Psychology