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Neural correlates of visuospatial working memory in the ‘at-risk mental state’

Published online by Cambridge University Press:  10 March 2010

M. R. Broome ,
P. Fusar-Poli ,
P. Matthiasson ,
J. B. Woolley ,
L. Valmaggia ,
L. C. Johns ,
P. Tabraham ,
E. Bramon ,
S. C. R. Williams  and
M. J. Brammer
...Show all authors
M. R. Broome*
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK Health Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry, UK
P. Fusar-Poli
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK Department of Applied and Psychobehavioural Health Sciences, University of Pavia, Italy
P. Matthiasson
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK
J. B. Woolley
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK
L. Valmaggia
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK Department of Psychiatry and Neuropsychology, Maastricht University, The Netherlands
L. C. Johns
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK
P. Tabraham
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK
E. Bramon
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK
S. C. R. Williams
Affiliation:
Neuroimaging Research Group, Department of Neurology, Institute of Psychiatry, King's College London, UK
M. J. Brammer
Affiliation:
Brain Image Analysis Unit, Department of Biostatistics and Computing, Institute of Psychiatry, King's College London, UK
X. Chitnis
Affiliation:
Brain Image Analysis Unit, Department of Biostatistics and Computing, Institute of Psychiatry, King's College London, UK
F. Zelaya
Affiliation:
Neuroimaging Research Group, Department of Neurology, Institute of Psychiatry, King's College London, UK
P. K. McGuire
Affiliation:
Psychosis Clinical Academic Group, Institute of Psychiatry, King's College London, UK
*
*Address for correspondence: Dr M. R. Broome, Warwick Medical School, University of Warwick, Gibbet Hill, Coventry CV4 7AL, UK. (Email: [email protected])
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Abstract

Background

Impaired spatial working memory (SWM) is a robust feature of schizophrenia and has been linked to the risk of developing psychosis in people with an at-risk mental state (ARMS). We used functional magnetic resonance imaging (fMRI) to examine the neural substrate of SWM in the ARMS and in patients who had just developed schizophrenia.

Method

fMRI was used to study 17 patients with an ARMS, 10 patients with a first episode of psychosis and 15 age-matched healthy comparison subjects. The blood oxygen level-dependent (BOLD) response was measured while subjects performed an object–location paired-associate memory task, with experimental manipulation of mnemonic load.

Results

In all groups, increasing mnemonic load was associated with activation in the medial frontal and medial posterior parietal cortex. Significant between-group differences in activation were evident in a cluster spanning the medial frontal cortex and right precuneus, with the ARMS groups showing less activation than controls but greater activation than first-episode psychosis (FEP) patients. These group differences were more evident at the most demanding levels of the task than at the easy level. In all groups, task performance improved with repetition of the conditions. However, there was a significant group difference in the response of the right precuneus across repeated trials, with an attenuation of activation in controls but increased activation in FEP and little change in the ARMS.

Conclusions

Abnormal neural activity in the medial frontal cortex and posterior parietal cortex during an SWM task may be a neural correlate of increased vulnerability to psychosis.

Keywords

ARMSimagingmemoryprodromepsychosisvisuospatial
Type
Original Articles
Information
Psychological Medicine , Volume 40 , Issue 12 , December 2010 , pp. 1987 - 1999
Copyright
Copyright © Cambridge University Press 2010

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