PMID-17690132 Disrupted prediction-error signal in psychosis: evidence for an associative account of delusions.
- Hypothesis: the creation and maintenance of psychotic or delusional beliefs is caused by (or causally related to) malfunction in the predictive error circuitry in the brain. (namely, the prefrontal cortex, substantia nigra, and striatum).
- Previous studies have shown that administering Ketamine, a dissociative drug that can cause delusions, effects this same pathway.
- The authors tested the hypothesis by training control and psychotic subjects in an associative task: subjects had to determine if a fictitious patient would be allergic to a meal given example meals and resulting allergic reaction.
- Both sets had about the same behavioral performance; however, activation of the prefrontal cortex, substantia nigra, and left striatum was less in the psychotic (some drug treated) subjects. This comparison of activation was measured between control trials (no prediction error) and violation trials (prediction violated) as well as unovershadowing (a and b causes allergy, but a or b separately do not)
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