Forschungsdatenbank PMU-SQQUID

PMU-Autor/inn/en

Abstract

We tested the hypothesis whether images of real objects elicit stronger gamma (>25 Hz) synchronization, when compared with scrambled objects. The background of this study is a recent debate about the functional meaning of evoked and induced gamma oscillations. Brain electrical source analysis (BESA) and low resolution electromagnetic tomography analysis (LORETA) was performed on the basis of the event-related potential (ERP) data. A component at around 230 ms (termed C230) showed strongest differences between objects and scrambled objects. Time-frequency analyses were run across electrodes and within the dipole sources. We found increased gamma event-related synchronization (ERS) between 200 and 300 ms for real objects. This effect was strongest in a fronto-medial source. Induced gamma, as also shown in previous studies, reflects the more task-relevant mechanism where object representations become activated.

Useful keywords (using NLM MeSH Indexing)

Adult

Biological Clocks/physiology*

Brain Mapping

Cerebral Cortex/physiology*

Cortical Synchronization*

Discrimination Learning/physiology*

Electroencephalography

Evoked Potentials/physiology*

Female

Humans

Magnetoencephalography

Male

Neurons/physiology

Neuropsychological Tests

Pattern Recognition, Visual/physiology*

Photic Stimulation

Reaction Time/physiology

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