Alpha rhythm of the EEG modulates visual detection performance in humans
Autor: | Tolgay Ergenoglu, Tamer Demiralp, Huseyin Beydagi, Zubeyir Bayraktaroglu, Mehmet Ergen, Yağız Üresin |
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Rok vydání: | 2004 |
Předmět: |
Adult
Male medicine.medical_specialty Visual perception genetic structures Cognitive Neuroscience media_common.quotation_subject Experimental and Cognitive Psychology Stimulus (physiology) Audiology Electroencephalography Behavioral Neuroscience Event-related potential Sensory threshold Perception medicine Humans media_common Visual Cortex medicine.diagnostic_test Event-Related Potentials P300 Electrophysiology Alpha Rhythm Amplitude Sensory Thresholds Visual Perception Evoked Potentials Visual Female Psychology Neuroscience |
Zdroj: | Brain research. Cognitive brain research. 20(3) |
ISSN: | 0926-6410 |
Popis: | The effects of the changes in the frequency spectrum of the electroencephalogram (EEG) on the perception of near-threshold visual stimuli and on the event-related potentials (ERPs) produced by these stimuli were investigated on 12 healthy volunteers. The stimulus intensity, at which each subject could detect 50% of the presented stimuli, was defined as the sensory threshold for that subject. Single ERP trials were separated into two groups: trials with detected and undetected stimuli. The ERPs and the average power spectra of the 1 s prestimulus periods were computed for both conditions. P300 amplitudes of the ERPs, and total power and relative band powers of the delta (0.5-4 Hz), theta (4-7.5 Hz), alpha (7.5-13 Hz), beta (13-30 Hz), and gamma (30-70 Hz) frequency bands of the prestimulus power spectra were measured. Between the two conditions, a specific difference was observed in the relative power of the alpha band, which was significantly lower before detected stimuli (p < 0.01) in line with significantly higher amplitudes of the ERPs (p < 0.001). These results show that short-lasting changes in brain's excitability state are reflected the relative alpha power of the EEG, which may explain significant variability in perceptual processes and ERP generation especially at boundary conditions such as sensory threshold. |
Databáze: | OpenAIRE |
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