EEG frequency ranges during perception and mental rotation of two- and three-dimensional objects

Area of Science:

• Neuroscience
• Cognitive Psychology
• Electrophysiology

Background:

• The brain's electrical activity, measured by electroencephalogram (EEG), changes during cognitive tasks.
• Specific frequency bands, like alpha and gamma, are associated with different cognitive processes.

Purpose of the Study:

• To investigate changes in spectral EEG power during mental rotation of 2D and 3D objects.
• To explore the relationship between EEG frequency power, task complexity, and brain regions.

Main Methods:

• EEG spectral power analysis in alpha (8-13 Hz) and higher frequencies (15-45 Hz) was performed on 20 subjects.
• Subjects performed mental rotation tasks with varying object dimensions and rotation angles.
• Analysis focused on EEG segments with identical solution times.

Main Results:

• Alpha power decreased during task performance compared to controls.
• Higher frequencies (15-45 Hz) showed increased power during tasks, indicating greater cortical activation.
• 2D object rotation tasks elicited higher power than 3D tasks, linked to rotation angle.
• Occipital regions showed significantly higher power in the 15-45 Hz range.
• Gamma band (35-45 Hz) power was higher in the initial task phase, suggesting a role in perception.

Conclusions:

• Mental rotation tasks involve alpha desynchronization and higher-frequency synchronization, particularly in visual areas.
• Task complexity, specifically the angle of rotation, influences cortical activation levels.
• Gamma band activity may be crucial for the initial perception and recognition stages of mental rotation.