ABSTRACT
Primates display significant differences in color vision. The purpose of this study was to assess the ability of capuchin monkeys in discriminating chromatic and achromatic Munsell color chips through behavioral tests. The subjects were trained in a simple and reverse discrimination learning procedure. All subjects were capable of discriminations along five color categories investigated. The results are discussed in terms of the hypothesis of male dichromatism in New World monkeys, the role of color vision in adaptation to feeding ecology, as well as to aspects regarding primate evolution.
Subject(s)
Color Perception/physiology , Color , Discrimination, Psychological/physiology , Animals , Cebus , Discrimination Learning/physiology , Female , Male , Photic StimulationABSTRACT
gamma-Aminobutyric acid (GABA) concentration was determined in cerebrospinal fluid (CSF) of acute and chronic schizophrenic patients, in persons with psycho-organic or personality disorders, and in nonpsychiatric controls. The mean CSF GABA level in the chronic schizophrenic patients was found to be significantly higher than in any of the other groups. No other statistically significant differences were found. Statistical analysis revealed that the elevated CSF GABA concentration in the chronic schizophrenic patients was unlikely to be caused by medication. These results are interpreted as evidence for possible primary or secondary GABAergic overactivity in the brain in chronic schizophrenia.
