| Relationships between cardiovascular and neural activities were explored in 11 patients with intractable epilepsy. Using depth electrodes, we examined the cardiovascular response to direct electrical stimulation, and monitored EEG activity during simple physical and mental challenges known to elicit a cardiovascular response. Stimulation was most commonly performed in four regions: the hippocampus, amygdala, and the supra- and sub-callosal anterior cingulate cortex (ACC). While increases in systolic blood pressure (SBP) in response to electrical stimulation of these brain regions were observed with equal frequency, a striking cardiovascular response was observed in one patient when stimulating the supracallosal ACC (an increase in SBP of almost 50 mmHg). Cross-correlation analysis revealed significant relationships between EEG power and SBP during physical but not mental challenges, and the pattern of these relationships was only observed for power of EEG data recorded from the ACC. The observed relative timing of the correlations was consistent in the three patients whose SBP increased upon ACC stimulation. These results support the role of the ACC in cardiovascular regulation, as revealed in previous studies in experimental animals. |
