Objective: Coherent object perception in patients with schizophrenia is known to be impaired. Oscillatory brain dynamics constitute a fundamental mechanism for the coordinated communication of neural circuits. Such dynamics have been proposed to reflect impaired spatio-temporal integration of sensory and cognitive processes during object perception in schizophrenia.
Method: EEG recordings of patients with schizophrenia (n = 23) and control participants (n = 23) were examined. Presented were either an ambiguous (multistable) stimulus, endogenously inducing switching between two perceptual alternatives, or a slightly modified unambiguous control stimulus, during which perceptual reversals were triggered by a minor change in the stimulus configuration. Event-related amplitude modulation induced by perceptual reversals was analyzed for theta (3-8 Hz) and gamma band oscillations (28-48 Hz).
Results: Patients displayed increased reaction times and more errors when indicating unambiguous reversals. The patients´ amplitude enhancement of theta oscillations was diminished in both task conditions. During the control task were gamma amplitudes larger in patients than in healthy participants.
Conclusion: The results indicate that impairments in generating coherent percepts are reflected in alterations of multiple frequency bands and time windows. Changes in gamma band oscillations may reflect the patients' impairments in perceptuo-cognitive integration processes. Diminished theta amplitude modulation in patients further emphasize diminished top-down cognitive control during perceptual reversals.
Significance: This study provides insight into how theta and gamma oscillations underlie changes in object perception, and thereby possibly the generation of core symptoms, in schizophrenia. This paper is dedicated to Prof. Dr. Erol Başar, a pioneer in research on oscillatory braindynamics. He was tireless in his effort to understand brain functions and integratedphilosophy, physics, biology and psychology in his research. His vision on how informationis coded in brain networks inspired many researchers in the last 40 years. With him, we not only lose an exceptional researcher, but also a supportive academic teacher and mentor with a persistent, prolific enthusiasm for international and collaborative projects.
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http://dx.doi.org/10.1016/j.ijpsycho.2020.06.002 | DOI Listing |
Proc Biol Sci
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Department of Neuroscience, Psychology, Pharmacology and Child Health, University of Florence, Florence, Italy.
Perceptual adaptation has been widely used to infer the existence of numerosity detectors, enabling animals to quickly estimate the number of objects in a scene. Here, we investigated, in humans, whether numerosity adaptation is influenced by stimulus feature changes as previous research suggested that adaptation is reduced when the colour of adapting and test stimuli did not match. We tested whether such adaptation reduction is due to unspecific novelty effects or changes of stimuli identity.
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Department of Behavioral Physiology and Sociobiology, University of Würzburg, Würzburg, Germany.
Nature offers a bewildering diversity of flower colours. Understanding the ecology and evolution of this fantastic floral diversity requires knowledge about the visual systems of their natural observers, such as insect pollinators. The key question is how flower colour and pattern can be measured and represented to characterise the signals that are relevant to pollinators.
View Article and Find Full Text PDFJ Exp Psychol Gen
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Department of Experimental Psychology, Helmholtz Institute, Utrecht University.
Predicting the location of moving objects in noisy environments is essential to everyday behavior, like when participating in traffic. Although many objects provide multisensory information, it remains unknown how humans use multisensory information to localize moving objects, and how this depends on expected sensory interference (e.g.
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Department of Experimental Psychology, Justus Liebig University Giessen, Giessen, Germany.
The human visual system possesses a remarkable ability to detect and process faces across diverse contexts, including the phenomenon of face pareidolia--seeing faces in inanimate objects. Despite extensive research, it remains unclear why the visual system employs such broadly tuned face detection capabilities. We hypothesized that face pareidolia results from the visual system's optimization for recognizing both faces and objects.
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