Emotional effect on cognitive control in implicit memory tasks in patients with schizophrenia

The aim of this study was to reveal a potential effect of emotion on cognitive control in the implicit memory task with emotionally neutral and unpleasant words in healthy controls and patients with schizophrenia using a 3.0 T functional MRI (fMRI). A total of 15 patients with schizophrenia and 15 healthy controls underwent the fMRI. fMRI data were obtained while the participants performed the implicit memory tasks with emotionally neutral and unpleasant words. During the implicit memory retrieval with emotionally neutral words, the predominant activation areas observed in patients in contrast to healthy controls included the precuneus, superior parietal gyrus, and dorsolateral prefrontal cortex (dlPFC). In the implicit memory retrieval with unpleasant words, patients with schizophrenia showed dominant activities in the superior and middle temporal gyri, fusiform gyrus, supramarginal gyrus, postcentral gyrus, occipital gyrus, lingual gyrus, parahippocampal gyrus, amygdala, and insula as well as precuneus, superior parietal gyrus, and dlPFC. Blood-oxygen-level-dependent signal changes in the dlPFC were correlated positively with the scores of the negative symptoms under the PANSS during implicit memory retrieval with unpleasant words in patients with schizophrenia. These findings would be useful to understand the neural mechanisms related to general impairment of cognitive and emotional functions commonly observed in schizophrenia.