Where did the feeling go?

Presents information on a research which attempts to predict the development of Huntington's disease before mental deterioration or uncontrollable movement sets in. Information on the basal ganglia part of the brain; How a related experiment was conducted; Behavioral theories supported by the finding.

By Annie Murphy Paul, published on May 01, 1998

Genetic testing can reveal who will develop Huntington's disease--beforemental deterioration or uncontrollable movement sets in. Now scientists have found that symptom-free carriers betray their vulnerability another way: they can't recognize others' expressions of disgust.

The ability to experience and identify disgust begins with the basal ganglia, located in the subcortex of the cerebral hemispheres. This is. where our visceral reactions to bad tastes and smells originate--and it's on these reactions that the more highly-evolved emotion of disgust is built. Since Huntington's disease attacks the basal ganglia first, the capacity to recognize disgust is affected very early on.

At the University of Newcastle-upon-Tyne in England, John Gray, M.D., compared a group of gene carriers to a group of people who were not at risk of developing Huntington's. On a series of tests of mental ability and of emotion recognition, the groups performed equally well--except that the carriers' capacity to identify disgust was impaired.

Gray's research does more than open a new window on a puzzling disorder; it supports the theory that different emotions may spring from separate neurological systems.

It may also explain the abnormal social behavior common among Huntington's patients. Identifying and empathizing with others' emotions is a cornerstone of social interaction, and lacking that ability, people may act in strange or inappropriate ways.

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