The relation between the general intellect of schizophrenic patients and psychopathological deterioration.

The aim of the study was to examine whether the postpsychotic decline in IQ during schizophrenia are due to a dementing process and psychopathological deterioration or this is a state independent premorbid impairment. The IQ score of 32 schizophrenic patients and 25 normal comparison subjects were evaluated three times during an average of 4,5 years, after short (mean 2,3 years) and long (mean 4,6) follow-up periods. The regression analysis was used to evaluate the association of clinical symptoms and IQ scores at the different period of time. The results were examined and related to changes of negative and positive symptoms of the illness. The schizophrenic group had low IQ score at baseline than the normal comparison subjects but showed comparable stability over time. The raw IQ score slightly increased in both groups in follow-up period. The regression analyses revealed that low IQ score especially in the block design (MT) and non-verbal reasoning (LPS3) subtests could be additional predictors for deterioration of negative symptoms. The IQ score of patients with schizophrenia appears to remain stable regardless of psychopathological decline, and even could be improved by learning and rehearsal.

Experience-dependent color constancy in guppies (Poecilia reticulata).

We investigated the ability to recognize the color of surfaces in fish (Poecilia reticulata), bred from birth in conditions of artificial light with constant spectral content. The capacity for color constancy significantly deteriorated when compared that to the control group. Further alteration of lighting conditions and transfer into natural daylight conditions restored the suppressed function to its normal level. We suggest that the color constancy function belongs in the visual system-response functions, the full development of which requires the accumulation of individual visual experience.