Limitations
schizophrenia, neurocognitive and social cognitive deficits, psychosis
DISORDERS, MRS
Limitations in our study concern the behavioral task, the ketamine-model for psychosis and whether changes evoked by ketamine reflect changes in glutamate-signalling. In our task, participants relied both on visual and acoustic features of the video clips to perform the social task, while solely visual information mattered in the physical condition, which yields asymmetry between the conditions.A limitation of the ketamine-model for psychosis comes from the smaller impact on PANSS levels of ketamine (mean of 40 in our and similar studiesFinally, since we did not measure glutamate levels after administering ketamine, conclusions about whether the fMRI results were caused by changes in glutamate transmission cannot be drawn. Even though most MRS studies showed that ketamine causes changes in glutamatergic transmission in anterior cingulate, not all studies were able to replicate these effectsTaken together, our findings show that people who received ketamine were exhibiting neurocognitive and social cognitive deficits in a naturalistic mentalizing-task. They mentalized less and demonstrated changes in BOLD-activity and task-related connectivity in right pSTS and precuneus, hinting to how glutamatergic neurotransmission might be tied to emergence of these deficits in disorders like schizophrenia.