The amygdala and individual differences in human fear... : NeuroReport (original) (raw)

Learning and Memory

Furmark, Tomas1,4; Fischer, Håkan1,3; Wik, Gustav2; Larsson, Mattias1; Fredrikson, Mats1

1Department of Psychology, Uppsala University, Box 1225 S-751 42 Uppsala, Sweden

2Department of Clinical Neuroscience, Karolinska Institute and Hospital, Stockholm, Sweden

3Uppsala University, PET-centre, University Hospital, Uppsala, Sweden

4Corresponding Author: Tomas Furmark

ACKNOWLEDGMENTS: Supported by the Swedish Council for Research in Humanities and Social Sciences and the Swedish Medical Research Council. We thank Britt-Marie Berggren, Walter Pulka, Karin Rehnström and Peter Söderholm for skilful assistance.

Received 29 September 1997; accepted 15 October 1997

Abstract

WHILE animal research on fear conditioning suggests crucial involvement of the amygdala, this has not been corroborated in humans when using subtractive neuro-imaging methodology. Correlation analyses might be more able to reveal relations between individual differences in conditionability and central neural activity. Hence, we performed a directed search for amygdalar participation in human fear conditioning by correlating central and autonomic nervous activity. [15O]Butanol positron emission tomography evaluated regional cerebral blood flow (rCBF) in six subjects before and after aversive conditioning to visual snake stimuli. Nonspecific electrodermal fluctuations (EDA) were recorded simultaneously. A significant positive correlation was obtained between conditioned EDA and conditioned rCBF in the right amygdala (r = 0.75, p < 0.05), supporting involvement of the amygdala in human fear conditioning.