Cingulate activity and fronto-temporal connectivity in people with prodromal signs of psychosis

• Published in: NeuroImage (Orlando, Fla.) Vol. 49; no. 1; pp. 947 - 955
• Main Authors: Allen, Paul, Stephan, Klaas E., Mechelli, Andrea, Day, Fern, Ward, Nicholas, Dalton, Jeffery, Williams, Steven C., McGuire, Philip
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2010; Elsevier Limited; Academic Press
• Subjects: Achievement tests; Adult; Anterior cingulate cortex; Bayes Theorem; Bayesian model selection; Brain Mapping; DCM; Dynamic causal modelling; Ethnicity; Female; Frontal Lobe - pathology; Frontotemporal connectivity; Humans; Hypotheses; Illnesses; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Mental Processes - physiology; Models, Psychological; Nerve Net - pathology; Neuropsychological Tests; NMR; Nuclear magnetic resonance; Prodromal psychosis; Psychiatric Status Rating Scales; Psychosis; Psychotic Disorders - pathology; Psychotic Disorders - psychology; Studies; Temporal Lobe - pathology; Young Adult; Frontotemporal connectivity; Bayesian model selection; Magnetic Resonance Imaging; Anterior cingulate cortex; Prodromal psychosis; Dynamic causal modelling; DCM
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2009.08.038

Schizophrenia is associated with fronto-temporal dysconnectivity, but it is not clear whether this is a risk factor for the disorder or is a consequence of the established illness. The aim of the present study was to use fMRI to investigate fronto-temporal connectivity in subjects with prodromal signs of schizophrenia using the Hayling Sentence Completion Task (HSCT). Thirty participants, 15 with an at risk mental state (ARMS) and 15 healthy controls were scanned whilst completing 80 sentence stems. The congruency and constraint of sentences varied across trials. Dynamic causal modelling (DCM) and Bayesian model selection (BMS) were used to compare alternative models of connectivity in a task related network. During the HSCT ARMS subjects did not differ from Healthy Controls in terms of fronto-temporal activation, i.e. there was neither a main effect of group nor a group-by-task interaction. However, there was both a significant main effect of group and a significant interaction in the anterior cingulate cortex (ACC), with greater ACC activity in the ARMS subjects. A systematic BMS procedure among 14 alternative DCMs including the ACC, middle frontal, and middle temporal gyri revealed intact task-dependent modulation of fronto-temporal effective connectivity in the ARMS group. However, ARMS subjects showed increased endogenous connection strength between the ACC and the middle temporal gyrus relative to healthy controls. Although task related fronto-temporal integration in the ARMS was intact, this may depend on increased engagement of the ACC which was not observed in healthy control subjects.