The role of delta, theta and alpha oscillations in learning processes

Aim: · Investigating different responses of the brain to different stimuli under a certain task, and learning processes · The determining of learning strategies Materials and methods: Twenty-six, ?Face Recognition?, 20 visual and 20 auditory oddball experiments were performed in healthy human subjects. These EEG recordings were studied in 13 electrode locations and in primarily delta, theta, and alpha frequency bands. In the assessment of learning, brain responses to simple and complex stimuli, target and non-target differences in visual and auditory modalities and dynamic changes during the experiments have been investigated. Results: Differentiated dynamics of responses to stimuli were found in different locations of the brain and also in different frequency channels. Delta responses (0.5?3.5 Hz) were enhanced to simple light and auditory stimuli in frontal regions and to face stimuli in occipital regions. Theta responses (4-7 Hz) during learning of the unknown face, showed marked increases in right frontal and left occipital regions, at the end of the experiments in comparison to the beginning phase. In the visual oddball paradigm, posterior alpha (8-13 Hz) responses were found to be decreased in amplitude toward the end of the experiments. Conclusion: The brain responds differently to stimulations within the same paradigm. Selective temporal and spatial differentiations in delta, theta and alpha oscillatory frequency bands were shown in different cortical regions in respect to stimulation type, and content of the paradigm. ERP experiments and analyses of oscillations provide a useful tool for assessing the dynamic changes of the whole brain during learning processes which cannot be separated from other cognitive processes.