Cognitive abnormalities and schizophrenic symptoms1 (original) (raw)
Related papers
Short-term visual memory in schizophrenics
Journal of Abnormal Psychology, 1985
Hypotheses proposed to explain the well-documented backward-masking abnormalities of poor premorbid schizophrenic subjects have not successfully integrated seemingly contradictory results of other cognitive studies of schizophrenic subjects. Integration of several two-process models of early visual information processing helps to reconcile these findings. In normal subjects, a mask that is visually patterned but meaningless (a pattern mask) interferes with processing primarily during an initial stage, whereas a mask that requires the processing of visual information (a cognitive mask) is also disruptive during the later-occurring short-term visual memory (STVM). We hypothesized that the deficit of poor premorbids in backward masking is due to interference in STVM because of their tendency to process a pattern mask as if it were a cognitive mask. We tested this hypothesis in a backward-masking picture-recognition paradigm. Good premorbid schizophrenics (n = 12), nonschizophrenic psychotics (n = 7), and normal subjects (n = 14) all showed differential pattern-and cognitive-mask performance. The performances of poor premorbids (n = 13) were equivalent on both mask types. The results are discussed in light of several theories of the early visual-input dysfunction in schizophrenia.
Disorders of perception and cognition in schizophrenia
Revue Européenne de Psychologie Appliquée/European Review of Applied Psychology, 2004
It is argued in this paper that information processing models may enable us to integrate schizophrenic symptomatology with its neural bases. A review of this research suggests that "it is the weakening of the influence of stored memories of regularities of previous input on current perception which is basic to the schizophrenic condition" (Hemsley, D.R., 1987. An experimental psychological model for schizophrenia. ). Two studies are described which employ paradigms derived from animal learning theory and one from experimental psychology. The results are consistent with the model. The ways in which such a disturbance may result in schizophrenic symptoms are outlined, with particular emphasis on the formation and maintenance of delusional beliefs. © 2004 Published by Elsevier SAS.
A simple (or simplistic?) cognitive model for schizophrenia
Behaviour Research and Therapy, 1993
approach which views schizophrenia as a disturbance of information processing appears promising as a way of linking biological and clininal aspects of the disorder. A review of research in this area led to the suggestion that the basic disturbance in schizophrenia is "a weakening of the influences of stored memories of regularities of previous input on current perception". This formulation leads to the prediction that in certain circumstances, schizophrenics may perform better than normal subjects. Recent studies employing tasks derived from human experimental psychology provide evidence in support of the model. It is argued that the link between information processing disturbances and biological abnormalities may be facilitated by the use of paradigms derived from animal learning theory (latent inhibition and Kamin's blocking effect). On both tasks the pattern of performance of acute schizophrenics is consistent with the cognitive model. The ways in which such an information processing disturbance may lead to schizophrenic symptomatology are outlined, with particular reference to the formation and maintenance of delusional beliefs. The core cognitive abnormality may result from a disturbance in any of the brain structures involved in the prediction of subsequent sensory input. The proposed circuit, which draws heavily on Gray's model, implicates in particular the hippocampus and related areas and is consistent with studies of brain pathology in schizophrenia.
Cognition and Symptomatology in Schizophrenia
Schizophrenia Bulletin, 1985
The experimental work on cognitive processes in schizophrenia is critically reviewed with respect to its relevance in understanding schizophrenic symptomatology. Several logical and empirical issues that complicate any comprehensive attempt to relate schizophrenic symptoms and information processing are discussed. Studies germane to schizophrenic sensory/perceptual, cognitive, affective, and motor anomalies are examined, and it is concluded that the cognitive approach to these areas is promising, but further research and theory elaboration will be required in order to provide a firm basis for cognitively oriented intervention attempts.
Psychiatry Research, 2004
The present study investigated whether schizophrenic patients could develop appropriate visual orientation and motor set under precuing conditions which contrasted attentional (input selective) and intentional (output selective) information. The aim was to evaluate perceptual performance in processing visuospatial information, and executive performance in response preparation. Stimuli andyor elicited responses were controlled for selective hemispheric engagement. Age, sex and handedness matched groups of 33 chronic schizophrenic patients and 33 normal subjects were tested on choice reaction time (RT) tasks in which warning signals were manipulated regarding either where a target stimulus would occur (selective attention) or which hand to use for responding (response preparation). All subjects benefited from precued information regarding subsequent responses. However, schizophrenic patients were not able to use intentional cues as effectively as control subjects did. Interhemispheric asymmetry of spatial attention was found in patients with schizophrenia, with slowing of responses to uncued targets presented in the right visual field. There was also a decreased advantage of within-hemisphere stimulus-response conditions in the schizophrenic group. Our results support the notion that a dysfunction involving parietal and premotor areas has potential importance in the schizophrenic illness. We replicated findings which indicate that deficits of information processing in schizophrenia may affect left hemispheric mechanisms to a larger extent. The results also point toward a possible abnormal connectivity between frontal and parietal circuits in schizophrenia.
Schizophrenic feature recognition deficits are independent of task criterion
Schizophrenia Research, 1992
The present study determined the minimal exposure time (i.e., critical stimulus duration (CSD) necessary for feature registration and recognition by normals and chronic schizophrenics. Our interest was whether the longer exposure times required by schizophrenics than by normals could be attributed to an inability of schizophrenics to maintain attention when the task criteria were stringent as opposed to 'loose'. The present findings support previous findings of impaired feature recognition by chronic schizophrenics. Chronic schizophrenics' and normals' CSDs were not affected by task criterion. The consistent performance by these groups on the 'loose' and 'rigid' task criteria suggest that if attentional lapses occur then they are as likely to occur for chronic schizophrenics as for normals and they are independent of the task's criterion. It is concluded that impaired feature registration for chronic schizophrenics is a consequence of a deficit at the earliest stage of encoding.