Handlungskontrolle bei Patienten mit Schizophrenie oder Zwangsstörungen
Zusammenfassung der Projektergebnisse
Schizophrenia (SZ) and obsessive-compulsive disorder (OCD) are mental disorders that appear to involve some disturbance in action control. To improve our understanding of the affected cognitive and neural mechanisms, experimental eye movement tasks are particularly suitable because they address relatively few neuropsychological functions. For both diagnostic groups, previous research suggested impairments in the volitional generation of action as indicated by abnormally high latencies of volitional saccades, i.e. intentional eye movements toward a symbolically instructed location, compared to normal latencies in visually-guided saccades, which are triggered by the appearance of a peripheral visual target. In a series of experimental studies, the hypothesis of abnormally high volitional saccade latencies in both diagnostic groups was confirmed in some but not all studies. Systematic variation of experimental conditions suggested that the detection of deficits depends on specific task characteristics. In schizophrenia studies, a deficit most likely occurs if a volitional saccade is fully specified in advance of the imperative stimulus and if the release of the preceding fixation is not exogenously triggered by the disappearance of the fixation stimulus. In OCD patients, a deficit most likely occurs if the saccade direction is not specified in advance of the peripheral stimulus. These patterns suggest that performance deficits may reflect slowed response initiation in SZ patients and dysfunctional response selection in OCD patients. However, the results also showed that group differences may critically depend on subtle changes of stimuli, so that further research is needed to confirm these preliminary conclusions and to specify the affected functions. This will also set the prerequisite for further research on the neural implementation of the affected functions and their etiological role. So far, the present project showed that first-degree relatives of OCD patients have similar deficits as OCD patients, suggesting that the putative dysfunction is associated with the vulnerability for the disease. Brain activation was only investigated in schizophrenia patients and healthy control subjects. SZ patients showed task specific hyperactivation in the frontal and supplementary eye fields, which might reflect compensatory mechanisms in brain structures that are usually used for volitional control of saccades.
Projektbezogene Publikationen (Auswahl)
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(2009). Does the Lateralized Readiness Potential Reflect Impaired Response Selection in Schizophrenia? Psychophysiology, 46, S185-S185
Möllers, D., Reuter, B., Kloft, L., Gallinat, J., & Kathmann, N.
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(2010, November). Dysfunctional volitional action generation as a risk marker for obsessive-compulsive disorder? 9th Conference on Cognitive Neuropsychiatry, Strasbourg, France
Kloft, L., Reuter, B., Riesel, A., & Kathmann, N.
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(2010, November). Response selection deficits in schizophrenia: evidence from lateralized movement-related and attention-related brain potentials. 9th Conference on Cognitive Neuropsychiatry, Strasbourg, France
Reuter, B.
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(2011). Evidence for a deficit in volitional action generation in patients with obsessive-compulsive disorder. Psychophysiology, 48(6), 755-761
Kloft, L., Kischkel, E., Kathmann, N., & Reuter, B.
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(2011). Volitional saccades and attentional mechanisms in schizophrenia patients and healthy control subjects. Psychophysiology, 48(10), 1333-1339
Reuter, B., Möllers, D., Bender, J., Schwehn, A., Ziemek, J., Gallinat, J., & Kathmann, N.
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(2011, April). Impaired volitional action initiation as a candidate endophenotype for obsessive-compulsive disorder? 18th Annual Meeting of the Society of Cognitive Neuroscience, San Francisco, USA
Kloft, L., Reuter, B., Riesel, A., & Kathmann, N.
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(2011, May). Warum so langsam? Ein Defizit der selektiven Aufmerksamkeit oder der willentlichen Handlungskontrolle bei Patienten mit Schizophrenie? [Why slow? A deficit in selective attention or arbitrary action control in patients with schizophrenia]. `7. Workshopkongress der DGPs Fachgruppe für Klinische Psychologie und Psychotherapie´ (7th workshop meeting of the Clinical Psychology and Psychotherapy section of the German Society for Psychology), Berlin, Deutschland
Möllers, D., Lüdeking, S., Lautenschlager, M., Gallinat, J., Kathmann, N., & Reuter, B.
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(2012). Indexing the volitional control of different saccade tasks with the Hick effect. Experimental Brain Research, 222(4), 345-353
Kloft, L., Viswanath, J., Reuter, B., Kathmann, N., & Barton, J.
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(2013). Impaired volitional saccade control: first evidence for a new candidate endophenotype in obsessive-compulsive disorder. European Archives of Psychiatry and Clinical Neuroscience, 263(3), 215-222
Kloft, L., Reuter, B., Riesel, A., & Kathmann, N.
