JULIAN F. THAYER, PhD
Professor, Department of Psychology,
The Ohio State University, Columbus, OH
Mannheim Institute of Public Health, Social and Preventive Medicine,
Mannheim Medical Faculty, Heidelberg University,
Inhibition of sympathoexcitatory circuits is influenced by cerebral structures and mediated via vagal mechanisms. Studies of pharmacologic blockade of the prefrontal cortex together with neuroimaging studies support the role of the right hemisphere in parasympathetic control of the heart via its connection with the right vagus nerve. Neural mechanisms also regulate infl ammation; vagus nerve activity inhibits macrophage activation and the synthesis of tumor necrosis factor in the reticuloendothelial system through the release of acetylcholine. Data
suggest an association between heart rate variability and infl ammation that may support the concept of a cholinergic anti-infl ammatory pathway.
The neurovisceral integration model of cardiac vagal tone integrates autonomic, attentional,
and affective systems into a functional and structural network. This neural network can be indexed by heart rate variability (HRV). High HRV is associated with greater prefrontal inhibitory
tone. A lack of inhibition leads to undifferentiated threat responses to environmental challenges.