Cortical modulation of the cardiovascular system.

Cortical modulation of central cardiovascular control mechanisms has been recognized for many decades. However, it is only recently that the mechanisms underlying cortical influences on circulatory function have been systematically examined. This review considers the view that certain regions of the cerebral cortex, including the medial prefrontal cortex (MPFC) and insular cortex (IC), participate in specific aspects of central circulatory control. Anatomical investigations indicate that these cortical areas are connected with hypothalamic, midbrain, pontine and medullary brain regions involved in cardiovascular control. Lesions of the MPFC and IC have demonstrated modulation of the activity of cardiovascular reflexes such as the baroreceptor heart rate reflex and involvement in conditioned cardiovascular responses. Electrophysiological studies have provided evidence that cortical regions are able to influence premotor sympathoexcitatory vasomotor neurons within the rostral ventrolateral medulla and subsequently alter sympathetic vasomotor tone. Cortical regions such as the IC receive visceral sensory information arising from baroreceptors and chemoreceptors within the cardiovascular system. In contrast, the MPFC receives afferents predominantly from limbic sources, although its outputs include structures associated with central sympathetic vasomotor control. Cortical modulation of circulatory function has been demonstrated in man and may underlie the cardiovascular components of a number of conditions. It is suggested that cortical areas involved in visceral sensory or visceral motor processes associated with circulatory function may be involved in generation of patterns of cardiovascular responses specific for certain behaviours.