The baseline activity of dopaminergic neurons in the VTA are regulated by the ventral hippocampus,
and that the disruptions in dopamine signalling associated with schizophrenia
may be caused by the hippocampal abnormalities reported in the disease.
One area of abnormality behaviour stood out: the CA1 subfield of the hippocampus.The hippocampal CA1 sub-field becomes overactive in schizophrenia
The findings suggest that, in schizophrenia, oxygen use increases in the hippocampal CA1 subfield and the orbitofrontal cortex.
In contrast, it seems to decrease in the dorsolateral prefrontal cortex.
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This dysfunction foretells which high-risk subjects will develop psychosis [ the full schizophrenia ]
The study was on 18 prodromal subjects who met clinical criteria for being at ultra high risk of developing psychosis.
These subjects presented symptoms that did not quite rise to the level seen in psychosis.
For example, prodromal subjects might profess unusual ideas that seem less compelling than delusions.
During the two years of follow-up, seven of the eighteen prodromal subjects became psychotic. Of the three dysfunctional areas seen in subjects with more established disease, only the CA1 subfield in the hippocampus appeared awry in these subjects.
Prediction !Notably, in those judged beforehand as at high risk, high activity in this area predicted the eventual emergence of psychosis, . Importantly, it was as accurate in predicting those that would not develop full schizophrenia
In fact, it did so with a positive predictive value of 71 percent
and a negative predictive value of 82 percent.
Not only do these findings yield insight into the earliest stages of psychosis, they raise hopes for a marker to flag those at greatest risk with the idea of someday preventing the disease from taking its toll.
go to Memory studies in schizophrenia
Anatomical studies of prosepective memory
Experimental study prospective memory