STRESSED BODY, STRESSED BRAIN

RESEARCH, 2011

AINE KELLY & SHANE O'MARA

The diving reflex is a natural physiological response that occurs when your face is immersed in cold water and you hold your breath, for example when you dive headfirst into the sea or splash your face with cold water. It evolved in diving mammals like seals to enable prolonged underwater search for food. During the diving reflex, your heart rate slows down, your blood pressure increases and the blood supply is diverted from your arms and legs towards your brain and heart. This survival reflex was preserved during evolution and is retained in human beings. It is not under conscious control; it occurs because there are nerve endings in the face (cold trigeminocardiac reflex receptors) that, when stimulated by cold water, cause changes to the physiology of the heart and blood vessels. As such, this is a normal and natural physiological stress response.

Our mental and physical states are profoundly influenced by each other. Even mild physiological stress causes increased activity in brain regions associated with mental stress and anxiety, resulting in wide-ranging effects in the brain including impairments in learning and memory. In this experiment, we wish to see the specific effects of mild physiological stress evoked by the diving reflex on simple visual and verbal learning tasks.

Extreme psychological and physiological stress, when applied during interrogation, is a definition of torture. Our knowledge of the negative effects of even mild stress on the accuracy of memory calls into question the scientific, not to mention moral, validity of using extreme stress to extract accurate information from the human brain.

BIO:

Áine Kelly is Associate Professor and Head of Physiology in the School of Medicine at Trinity College Dublin. Her research expertise lies at the interface between neuroscience and exercise physiology. She investigates how lifestyle factors such as physical activity and cognitive stimulation enhance brain function and protect against age-related cognitive decline.

Shane O’Mara is Professor of Experimental Brain Research at Trinity College, Dublin, and Director of the Trinity College Institute of Neuroscience. He is author of Why Torture Doesn’t Work: The Neuroscience of Interrogation (Harvard University Press, 2015). He is also one of the the curators of TRAUMA: BUILT TO BREAK.