1. ¹Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
2. ²Department of Psychiatry, University of Chicago, IL, USA
3. ³Neuroscience Program, University of Michigan, Ann Arbor, MI, USA
4. ⁴Department of Psychiatry, Veterans Administration Medical Center, Ann Arbor, MI, USA

Correspondence: Dr SF Taylor, Department of Psychiatry, University of Michigan Medical Center, UH 9D Box 0118, 1500 E Medical Center Drive, Ann Arbor, MI 48109-0118, USA. Tel: +1 734 936 9760; Fax: +1 734 936 7868; E-mail: sftaylor@umich.edu

Received 12 August 2004; Revised 12 November 2004; Accepted 6 December 2004; Published online 2 February 2005.

Abstract

Neuroimaging probes of brain regions implicated in emotion represent an important research strategy for understanding emotional dysfunction in schizophrenia. Anterior limbic structures, such as the ventral striatum and the amygdala, have been implicated in the pathophysiology of schizophrenia and the generation of emotional responses, although few studies to date have used emotion probes to target these areas in schizophrenia. With this goal in mind, emotionally salient visual images were used in a simple, nondemanding task. In all, 13 medicated, schizophrenic patients, five unmedicated patients, and 10 healthy volunteers viewed complex visual pictures and a nonsalient, blank screen while regional cerebral blood flow was measured with the [O–15] water technique. Pictures consisted of real world scenes with aversive, positive, and nonaversive content. Eye movements were recorded simultaneous with scan acquisition. Positron emission tomography images were analyzed for baseline, tonic activity, in addition to phasic changes ('activation') to salient stimuli. Lateral eye movement measures and on-line ratings showed good behavioral compliance with the task. Patients with schizophrenia showed impaired neural responses to salient stimuli in the right ventral striatum (VS), and they exhibited elevated tonic activity levels in the right VS and bilateral amygdala, inversely correlated with overall symptom severity. The patients also showed reduced modulation of visual cortex by salient stimuli. The results show that patients with schizophrenia exhibit impaired neural responses to emotionally salient stimuli in the VS, supporting a role for this structure in the pathophysiology of the illness. Reduced modulation of visual cortex by emotionally salient stimuli also suggests a failure to organize cerebral activity at a global level.