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Anhedonia, the reduced capacity to gain pleasure from pleasurable experiences, is a key symptom of major depression and schizophrenia. Reduced hedonic capacity can also be measured as an enduring trait in non-clinical subjects. Such altered hedonic capacity is likely the result of a basic neuropsychophysiological dysfunction and a vulnerability marker that potentially precedes and contributes to the liability of developing psychiatric disorders. The characterization of the structural and functional neural correlates of trait anhedonia in nonclinical individuals may provide new insights for the early detection of such psychiatric diseases. Twenty-nine non-clinical subjects were scanned at the Montreal Neurological Institute. Trait anhedonia was measured using the Chapman Revised Physical Anhedonia Scale. Semi-automated and automated structural MRI segmentation techniques were used to explore structural correlates of trait anhedonia. Seventeen of the 29 subjects also underwent a functional imaging task where responses to the viewing of affective stimuli were examined to identify the functional correlates of trait anhedonia. Trait anhedonia was inversely related to anterior caudate volume, but positively related to ventromedial prefrontal cortex activity during the processing of positive information. These findings may reflect a specific kind of vulnerability for the development of psychiatric affective disorders and suggest that trait anhedonia may be linked to a volumetric reduction in the basal ganglia and to a prefrontal functional abnormality during hedonic processing.

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Our previous work has linked verbal learning and memory with cognitive insight, but not clinical insight, in individuals with a first-episode psychosis (FEP). The current study reassessed the neurocognitive basis of cognitive and clinical insight and explored their neural basis in 61 FEP patients. Cognitive insight was measured with the Beck Cognitive Insight Scale (BCIS) and clinical insight with the Scale to assess Unawareness of Mental Disorder (SUMD). Global measures for 7 domains of cognition were examined. Hippocampi were manually segmented in to 3 parts: the body, head, and tail. Verbal learning and memory significantly correlated with the BCIS composite index. Composite index scores were significantly associated with total left hippocampal (HC) volume; partial correlations, however, revealed that this relationship was attributable largely to verbal memory performance. The BCIS self-certainty subscale significantly and inversely correlated with bilateral HC volumes, and these associations were independent of verbal learning and memory performance. The BCIS self-reflectiveness subscale significantly correlated with verbal learning and memory but not with HC volume. No significant correlations emerged between the SUMD and verbal memory or HC volume. These results strengthen our previous assertion that in individuals with an FEP cognitive insight may rely on memory whereby current experiences are appraised based on previous ones. The HC may be a viable location among others for the brain system that underlies aspects of cognitive insight in individuals with an FEP.

Context: Memory is one of the cognitive functions most affected in schizophrenia, with deficits observed from the first episode of psychosis (FEP). Previous studies have indicated that some memory processes may be more affected than others.Objective: To examine the neural correlates of 3 specific memory processes in FEP by means of functional magnetic resonance imaging (fMRI).Design: Case-control study. Main Outcome Measures:Behavioral performance and regional brain activity measured during memory encoding by fMRI. Our fMRI design included 3 within-subject contrasts (associative vs item-oriented encoding, encoding of arbitrary vs semantically related image pairs, and successful vs unsuccessful memory encoding) that were then used for group conjunctions and between-group analyses.Results: Patients with FEP showed normal activation of several brain regions, including the prefrontal cortex, hippocampus, and parahippocampal cortex, during successful memory encoding and associative encoding. In contrast, the hippocampus and surrounding medial temporal areas showed reduced activity during the encoding of arbitrary pairs. This selective dysfunction reflected by abnormal brain activation during encoding was accompanied by a greater deficit for subsequent recognition of arbitrary pairs relative to the semantically related pairs.Conclusions: This study demonstrated that, in the same group of patients with FEP, the hippocampus could show either normal or abnormal modulation of activation depending on the specific cognitive process that was examined. The normal modulation of hippocampal activation observed during successful memory encoding in FEP argues against a general inability to recruit this region. Instead, the dysfunction was specifically linked to semantic relatedness. This selective deficit seems to affect memory performance in FEP and denotes an important representational problem that may confer greater vulnerability to psychotic disorders and would thus be interesting to examine in high-risk populations. Psychiatry. 2007;64(9):999-1014 Arch Gen

These results suggest that many of the brain regions involved in emotional face perception, including the amygdala, are equally recruited in both schizophrenia and controls, but flat affect can also moderate activity in some other brain regions, notably in the left amygdala and parahippocampal gyrus bilaterally. There were no significant group differences in the volume of the amygdala.

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