1 Csilla Marosi
2 Gábor Csukly
1 Department of Psychiatry and Psychoterapy, Semmelweis University, Budapest
2 Department of Psychiatry and Psychoterapy, Semmelweis University, Budapest
Introduction: Schizophrenia is a major mental disorder that affects approximately 1% of the population worldwide. Cognitive deficits are a key feature of schizophrenia and a primary cause of long-term disability. However the exact neurobiological background of the disorder is still unclear. According to the bottom-up theory early sensory deficits lead to higher level process such as facial expression encoding impairments, which further contribute to the psychosocial functioning deficits in schizophrenia.
Aims: This study aimed to explore the characteristics of event-related potentials evoked by basic sensory stimuli in patients with schizophrenia.
Method: In this case-control study we analyzed the high density (128-channel) EEG data of 35 patient with schizophrenia and 32 healthy controls. The two groups were matched by gender, age, and education. During the early stage sensory perceptual processing task 224 low spatial frequency- 0.8 cycle/degree- (LSF, magnocellularly biased) and 224 high spatial frequency-5.0 cycle/degree- (HSF, parvocellularly biased) Gabor-patches and 25 faces of the ’Karolinska Directed Emotional Faces (KDEF)’ were presented to the participants. Subjects were asked to identify the faces by button press. The investigated event-related potential was P100 focusing on the parieto-occipital brain regions. Average evoked potential waveforms were computed from epochs for each stimulus type and for both groups.
Results: Schizophrenic patients showed significantly (p <0.05) decreased P100 amplitude in low spatial frequency Gabor-patch condiction, in the parieto-occipital regions, in the 100-140 ms interval. There was no significant difference between groups in the high spatial frequency condition.
Conclusion: According to our findings schizophrenic patients have a magnocellular deficit indexed by decreased P100. This deficit in early sensory perception may lead to higher level disfunctions, such as emotion recognition, witch further contribute to the psychosocial functioning deficit.
Doctoral School: Mental Health Sciences
Supervisor: Gábor Csukly
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