Eco de Geus: measuring the physiological substrate of human psychology
'We want to find ways to visualise the psychological events that happen inside the brain, without harming our test subjects. Be it by using MRI-scanners, by measuring the electrical activity of the brain or by counting heartbeats, we seek to exploit and improve the possibilities to objectively chart psychological states in humans.'
Eco de Geus, professor of Biological Psychology, leads one of the most productive groups in his field. Striving to measure physiological responses to psychological activity, his research has led to many successes, among others the development of a portable tool to measure the autonomic (or visceral) nervous system. This new tool has been applied to the genetics of disorders of the psyche, especially anxiety and depression, and their link to somatic disease.
‘We use three main classes of readouts: brain activity imaging by functional MRI, electrophysiological measurements using EEG and evoked potentials, and peripheral signals like heart frequency, skin conduction and thorax movements. That last category is especially useful to monitor emotions, as this type of psychological activity has a profound influence on many organs. An example is the fight or flight response to a threatening situation: central brain activity modulates the physiology of the whole body to prepare for action.’
In contrast to his colleagues in clinical psychology who work with patients, De Geus is interested in unravelling the psychology of all people, including healthy people. ‘That is one reason to strive to minimise the impact of tests on our test subjects. For our studies, we sometimes test hundreds of people, which forces us to invent clever measuring methods that are cost-effective and cause no major distress to the individual volunteers. Most of our studies are epidemiologically oriented, and eventually we try to draw conclusions about the psychology of the general population.’
Many of the studies are performed on a unique population: Dutch twins. ‘The Netherlands Twin Register was founded in 1987 by VU researchers. It gives us the opportunity to distinguish the influence of the genetic background of an individual from the influence of the environment on the psychological state and development. If we find a significant difference between genetically identical twins in, for example, an fMRI study, we know that in principle it must be caused by environmental factors, instead of the genes.’
Anxiety disorders and depression
Those genes are another big target in psychophysiological research, and in De Geus’ research. The department works closely together with the NESDA study of the Psychiatry department and the genetic lab of professor Heutink, trying to identify the genes that contribute to diseases of the mind. De Geus: ‘We already collaborate extensively with other neuroscientists, so for us the Neuroscience Campus is merely a continuation of this process of integration of research areas. Especially for anxiety disorders and depression, our existing collaborations have yielded many successes.’
Eventually, the identification of physiological and genetic markers of psychiatric disorders could be used in the clinic for faster diagnoses and tailored treatments. ‘We hope to find the genetic causes of conditions like attention disorders, anxiety disorders and depression, in order to develop tests. It will take some time before these tests will be routinely used on real patients, but I am confident we'll get there.’
