Increased stressor-evoked cardiovascular reactivity is associated with reduced amygdala and hippocampus volume

Exaggerated cardiovascular reactivity to acute psychological stress is associated with an increased risk of developing cardiovascular disease. The amygdala and hippocampus have been implicated in centrally mediating stressor-evoked cardiovascular reactivity. However, little is known about the associations of amygdala and hippocampus morphology with stressor-evoked cardiovascular reactivity. Forty (M [SD] age = 19.05 [0.22] years) healthy young women completed two separate testing sessions. Session one assessed multiple
parameters of cardiovascular physiology at rest and during a validated psychological stress task (Paced Auditory Serial Addition Test), using electrocardiography, Doppler echocardiography and blood pressure monitoring. In session two, one year later, structural MRI was conducted. Brain structural volumes were computed using automated segmentation methods. Regression analyses, following Bejamini-Hochberg correction, showed that greater heart rate and cardiac output reactivity were associated with reduced amygdala and
hippocampus grey matter volume. Systolic blood pressure reactivity was associated with reduced hippocampus volume. In contrast, no associations between diastolic blood pressure, mean arterial blood pressure, stroke volume, or total peripheral resistance reactivity with amygdala or hippocampus volumes were apparent. Comparison analyses examining insula volume found no significant associations. Some indicators of greater stressor-evoked
cardiovascular reactivity associate with reduced amygdala and hippocampus grey matter volume, but the mechanisms of this association warrant further study.