Higher hypothalamic and hippocampal neural activity in type A than type B women Mats Fredrikson a, *, Gustav Wik b, c , HaÊkan Fischer a, d a Department of Psychology, Uppsala University, Uppsala, Sweden b Department of Clinical Neuroscience, Karolinska Institute and Karolinska Hospital, Stockholm, Sweden c Klinik und Poliklinik fu Èr Psychiatrie, Martin-Luther-Universita Èt, Halle, Wittenberg, Germany d Uppsala University PET-centre, Academic Hospital, Uppsala, Sweden Received 30 June 1997 Abstract The type A behavior characterized by hostility, competitiveness and time urgency, as compared to its type B counterpart, is associated with increased responsiveness in peripheral measures of the pituitary adrenal and cortical responses as well as in the autonomic nervous system. The aim of the present report was to study central neural activity in type A and B women. Positron emission tomography and [ 15 O]-butanol was used to measure regional cerebral blood (rCBF) during a neutral videotaped park scene. Absolute rCBF was higher among type A than type B women bilaterally in the hypothalamus, and the hippocampus. Absolute rCBF was similar in the putamen, the caudate nucleus, the anterior cingulate gyrus, the secondary visual cortex, the prefrontal, the orbitofrontal and the temporopolar cortex. This supports the view that dierences in subcortical neural activity between type A and B individuals may underlie dierences in autonomic nervous system regulation and contribute to the increased risk for cardiovascular disease associated with type A behavior. # 1998 Elsevier Science Ltd. All rights reserved. Keywords: Type A behavior; Regional cerebral blood ¯ow; Central nervous system 1. Introduction Type A behavior has been associated with increased autonomic nervous system activity (Williams et al., 1982). Studies have demonstrated an enhanced catecholamine excretion in type Personality and Individual Differences 26 (1999) 265±270 0191-8869/98/$ - see front matter # 1998 Elsevier Science Ltd. All rights reserved. PII: S0191-8869(98)00127-5 PERGAMON * To whom all correspondence should be addressed. Tel.: +46-18-471-21-12; Fax: +46-18-471-21-23; E-mail: mats.fredrikson@psyk.uu.se