Biomedical subjects

Peter J Uhlhaas

Publications and source records attributed to Peter J Uhlhaas.

9 recordsLinked to original sources

PubMed2006

Perceptual anomalies in schizophrenia: integrating phenomenology and cognitive neuroscience.

From phenomenological and experimental perspectives, research in schizophrenia has emphasized deficits in "higher" cognitive functions, including attention, executive function, as well as memory. In contrast, general consensus has viewed dysfunctions in basic perceptual processes to be relatively unimportant in the explanation of more complex aspects of the disorder, including changes in self-experience and the development of symptoms such as delusions. We present evidence from phenomenology and cognitive neuroscience that changes in the perceptual field in schizophrenia may represent a core impairment. After introducing the phenomenological approach to perception (Husserl, the Gestalt School), we discuss the views of Paul Matussek, Klaus Conrad, Ludwig Binswanger, and Wolfgang Blankenburg on perception in schizophrenia. These 4 psychiatrists describe changes in perception and automatic processes that are related to the altered experience of self. The altered self-experience, in turn, may be responsible for the emergence of delusions. The phenomenological data are compatible with current research that conceptualizes dysfunctions in perceptual processing as a deficit in the ability to combine stimulus elements into coherent object representations. Relationships of deficits in perceptual organization to cognitive and social dysfunction as well as the possible neurobiological mechanisms are discussed.

Attention↗

PubMed2006

Perceptual grouping in disorganized schizophrenia.

This study evaluated visual perceptual grouping in schizophrenia to test the hypothesis that the disorganization syndrome in schizophrenia is related to a deficit in cognitive coordination. Perceptual grouping was examined with three psychophysically well-controlled tasks in patients with disorganized schizophrenia (n=11), non-disorganized schizophrenia (n=24), psychotic disorders other than schizophrenia (n=31) and non-psychotic psychiatric disorders (n=35). These measures assessed processing of both concurrent and preceding stimulus context. Deficits in perceptual grouping were observed on all three tasks in disorganized schizophrenia patients. Dysfunctional perceptual grouping mechanisms produced both enhanced and impaired task performance suggesting that the pattern of performance observed was the result of a specific deficit in the grouping of stimulus elements. We interpret these data as further support for the hypothesis that the disorganization syndrome in schizophrenia reflects a widespread deficit in the cognitive coordination of contextually related stimuli, leading to dysfunctional grouping of stimulus features in vision, thought and language.

Adult↗

PubMed2006

Neural synchrony in brain disorders: relevance for cognitive dysfunctions and pathophysiology.

Following the discovery of context-dependent synchronization of oscillatory neuronal responses in the visual system, novel methods of time series analysis have been developed for the examination of task- and performance-related oscillatory activity and its synchronization. Studies employing these advanced techniques revealed that synchronization of oscillatory responses in the beta- and gamma-band is involved in a variety of cognitive functions, such as perceptual grouping, attention-dependent stimulus selection, routing of signals across distributed cortical networks, sensory-motor integration, working memory, and perceptual awareness. Here, we review evidence that certain brain disorders, such as schizophrenia, epilepsy, autism, Alzheimer's disease, and Parkinson's are associated with abnormal neural synchronization. The data suggest close correlations between abnormalities in neuronal synchronization and cognitive dysfunctions, emphasizing the importance of temporal coordination. Thus, focused search for abnormalities in temporal patterning may be of considerable clinical relevance.

Alzheimer Disease↗

PubMed2006

Dysfunctional long-range coordination of neural activity during Gestalt perception in schizophrenia.

Recent theoretical and empirical research on schizophrenia converges on the notion that core aspects of the pathophysiology of the disorder may arise from a dysfunction in the coordination of distributed neural activity. Synchronization of neural responses in the beta-band (15-30 Hz) and gamma-band range (30-80 Hz) has been implicated as a possible neural substrate for dysfunctional coordination in schizophrenia. To test this hypothesis, we examined the electroencephalography (EEG) activity in 19 patients with a Diagnostic and Statistical Manual of Mental Disorder, edition IV criteria, diagnosis of schizophrenia and 19 healthy control subjects during a Gestalt perception task. EEG data were analyzed for phase synchrony and induced spectral power as an index of neural synchronization. Schizophrenia patients were impaired significantly in the detection of images that required the grouping of stimulus elements into coherent object representations. This deficit was accompanied by longer reaction times in schizophrenia patients. Deficits in Gestalt perception in schizophrenia patients were associated with reduced phase synchrony in the beta-band (20-30 Hz), whereas induced spectral power in the gamma-band (40-70 Hz) was mainly intact. Our findings suggest that schizophrenia patients are impaired in the long-range synchronization of neural responses, which may reflect a core deficit in the coordination of neural activity and underlie the specific cognitive dysfunctions associated with the disorder.

Action Potentials↗

PubMed2006

Perceptual organization in first episode schizophrenia and ultra-high-risk states.

Deficits in perceptual organization have been consistently reported in schizophrenia, as has an association between these deficits, disorganized symptoms, and poorer premorbid functioning and prognosis, suggesting that they may be an index of illness severity or progression. It is unclear, however, whether the impairment is present at, or before the first psychotic episode. This study examined perceptual organization in young people considered to be at high-risk for schizophrenia, defined by the "close-in" strategy [Yung, A.R., McGorry, P.D., McFarlane, C.A., Jackson, H.J., Patton, G.C., Rakkar, 1996. Monitoring and care of young people at incipient risk of psychosis. Schizophrenia Bulletin, 22, 283-303]. The high-risk group (n=70) was compared to first-episode patients (n=54), and nonpatients (n=24) using a task with known sensitivity to perceptual organization deficits in schizophrenia, and whose scores have predicted long-term outcome and disorganized symptomatology in past studies [Knight, R.A., Silverstein, S.M., 1998. The role of cognitive psychology in guiding research on cognitive deficits in schizophrenia. In Lenzenweger, M., Dworkin, R.H., (Eds.), Origins and Development of Schizophrenia: Advances in Experimental Psychopathology. APA Press, Washington DC, pp. 247-295.; Silverstein, S.M., Knight, R.A., Schwarzkopf, S.B., West, L.L., Osborn, L.M. Kamin, D., 1996b. Stimulus configuration and context effects in perceptual organization in schizophrenia. Journal of Abnormal Psychology 105, 410-420.; Silverstein, S.M., Schenkel, L.S., Valone, C., Nuernberger, S., 1998a. Cognitive deficits and psychiatric rehabilitation outcomes in schizophrenia. Psychiatric Quarterly 69, 169-191.; Silverstein, S.M., Bakshi, S., Chapman, R.M., Nowlis, G., 1998b. Perceptual organization of configural and nonconfigural visual patterns in schizophrenia: effects of repeated exposure. Cognitive Neuropsychiatry 3, 209-223]. There were no differences between groups, and the first-episode group demonstrated non-significantly more sensitivity to stimulus organization than the other groups. When the high-risk group was broken down into its 3 subgroups (A--family history of psychotic illness and recent drop of 30+ points in the GAF scale; B--history of attenuated psychotic symptoms; C--brief limited intermittent psychotic symptoms), only group A demonstrated evidence of impairment, but this group differed significantly only from first- and young, later-episode schizophrenia patients, not from nonpatients. These findings are consistent with recent data on pre-attentive processes in schizophrenia which indicate that performance is not impaired and may even be enhanced, early in the illness, with dysfunctions beginning with increased chronicity.

Adolescent↗

PubMed2005

Perceptual organization in schizophrenia spectrum disorders: empirical research and theoretical implications.

The research into perceptual organization in schizophrenia spectrum disorders has found evidence for and against a perceptual organization deficit and has interpreted the data from within several different theoretical frameworks. A synthesis of this evidence, however, reveals that this body of work has produced reliable evidence for deficits in schizophrenia, as well as for the clinical, stimulus, and task parameters associated with normal and abnormal performance. Recent models of cognition have also advanced understanding of the underlying pathophysiological processes of perceptual organization dysfunction in schizophrenia spectrum disorders. These suggest that deficits in perceptual organization may be one manifestation of a wider disturbance in the integration of contextually related information across space and time.

Empirical Research↗

PubMed2004

The course and clinical correlates of dysfunctions in visual perceptual organization in schizophrenia during the remission of psychotic symptoms.

This study evaluated deficits in visual perceptual organization in schizophrenia over the course of inpatient treatment, in relation to the remission of particular psychotic symptoms. Disorganized (n=14) and non-disorganized (n=33) schizophrenia patients were tested upon admission to an inpatient psychiatric unit, and again after 3 weeks of treatment, on two measures of visual perceptual organization. Performance of schizophrenia patients was compared to groups of patients with psychotic disorders other than schizophrenia (n=19) and non-psychotic psychiatric disorders (n=25). Symptom ratings were collected at both assessment points. Deficits in visual perceptual organization were observed for both tasks in disorganized schizophrenia patients at index and these deficits improved during the course of treatment. Moreover, improvement in visual perceptual organization correlated significantly with reductions in disorganized symptoms in the schizophrenia group. We interpret these data as further support for the hypothesis that the disorganization syndrome in schizophrenia reflects a widespread deficit in the cognitive coordination of contextually related stimuli, leading to dysfunctional organization of stimulus features in vision, thought and language.

Adult↗

PubMed2004

Evidence for impaired visual context processing in schizotypy with thought disorder.

Visual context processing was examined in relation to schizotypy in a large nonclinical university population. Schizotypal status was assessed with the Schizotypal Personality Questionnaire (SPQ) [Schizophr. Bull. 17 (1991) 555]. Schizotypal (n=32) and non-schizotypal (n=37) subjects were tested on a contour integration task (where context processing is necessary for good performance) and a visual size perception task (where context processing impairs accurate performance). In addition, a short form of the Thought Disorder Index (TDI) [Psychol. Assess. 5 (1993) 75] was administered to 28 schizotypal subjects. Thought disordered schizotypal subjects showed significantly impaired performance on the contour integration task but more accurate performance on the visual size perception task. These results support the hypothesis that deficits in visual context processing are the manifestation of a larger disturbance of cognitive coordination in schizotypy and schizophrenia.

Adult↗

PubMed2004

Gestalt psychology: the forgotten paradigm in abnormal psychology.

Gestalt views of psychopathology are almost completely ignored in mainstream psychology and psychiatry. However, a review of available evidence indicates a remarkable consistency between these views and current data from experimental psychopathology and cognitive neuroscience. This consistency is especially pronounced in the area of schizophrenia. In addition, there is a convergence of cognitive and neurobiological evidence regarding the validity of early Gestalt views of both normal brain-behavior relationships and disordered ones, as in schizophrenia. This article reviews some contributions of Gestalt psychology regarding schizophrenia and examines these views in light of more recent findings from cognitive psychology, cognitive neuroscience, and experimental psychopathology. We conclude that Gestalt theory is a viable theoretical framework from which to understand schizophrenia. Specifically, it appears that a breakdown of Gestalt organizational processes may characterize both the cognitive and the brain processes in schizophrenia.

Gestalt Therapy↗