Altered alpha brain oscillations during multistable perception in schizophrenia.
Schizophrenia is a complex mental disorder with impairments in integrating sensory and cognitive functions, leading to severe problems in coherent perception. This impairment might be accelerated during multistable perception. Multistable perception is a phenomenon, where a visual pattern gives rise to at least two different perceptual representations. We addressed this issue by assessing event-related alpha oscillations during continuous viewing of an ambiguous and unambiguous control stimulus. Perceptual reversals were indicated by a manual response, allowing differentiation between phases of reversion and non-reversion (that is perceptual stability) in both tasks. During the ambiguous task, patients and controls showed a comparable number of perceptual reversals. Alpha amplitudes in patients were larger in non-reversion phases, accompanied by a stronger decrease of alpha activity preceding the perceptual reversal. This group difference was pronounced for lower alpha activity and not apparent during the unambiguous task. This indicates that ambiguous perception taps into the specific deficits that patients experience in maintaining coherent perception. Given that top-down influences in generating a meaningful percept seems to be low in patients, they appear more dependent on sensory information. Similar, bottom-up mechanisms might be more important in triggering perceptual reversals in patients than in controls.
University of Bremen, Institute of Psychology and Cognition Research, Grazer Str.4, D-28359 Bremen, Germany; Centre for Cognitive Science, Bremen, Germany. Electronic address: cbasar@uni-bremen.de.
Canan
C
Basar-Eroglu
University of Bremen, Institute of Psychology and Cognition Research, Grazer Str.4, D-28359 Bremen, Germany; Centre for Cognitive Science, Bremen, Germany.
Birgit
B
Mathes
University of Bremen, Institute of Psychology and Cognition Research, Grazer Str.4, D-28359 Bremen, Germany; Centre for Cognitive Science, Bremen, Germany.
Ksenia
K
Khalaidovski
University of Bremen, Institute of Psychology and Cognition Research, Grazer Str.4, D-28359 Bremen, Germany; Centre for Cognitive Science, Bremen, Germany.
Andreas
A
Brand
University of Bremen, Institute of Psychology and Cognition Research, Grazer Str.4, D-28359 Bremen, Germany; Centre for Cognitive Science, Bremen, Germany.
Christina
C
Schmiedt-Fehr
D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D000704:Analysis of Variance; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000150:complications* / Q000473:pathology*; D013057:Spectrum Analysis; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
Bottom-up; Brain oscillations; Multistable perception; Object perception; Spatio-temporal integration; Top-down