Hippocampus and nucleus accumbens activity during neutral word recognition related to trait physical anhedonia in patients with schizophrenia: An fMRI study

Emotional memory dysfunction may be associated with anhedonia in schizophrenia. This study aimed to investigate the neurobiological basis of emotional memory and its relationship with anhedonia in schizophrenia specifically in emotional memory related brain regions of interest (ROIs) including the amygdala, hippocampus, nucleus accumbens, and ventromedial prefrontal cortex. Fourteen patients with schizophrenia and 16 healthy subjects performed a word-image associative encoding task, during which a neutral word was presented with a positive, neutral, or control image. Subjects underwent functional magnetic resonance imaging while performing the recognition task. Correlation analyses were performed between the percent signal change (PSC) in the ROIs and the anhedonia scores. We found no group differences in recognition accuracy and reaction time. The PSC of the hippocampus in the positive and neutral conditions, and the PSC in the nucleus accumbens in the control condition, appeared to be negatively correlated with the Physical Anhedonia Scale (PAS) scores in patients with schizophrenia, while significant correlations with the PAS scores were not observed in healthy subjects. This study provides further evidence of the role of the hippocampus and nucleus accumbens in trait physical anhedonia and possible association between emotional memory deficit and trait physical anhedonia in patients with schizophrenia.