2State Academy of Theatre Arts, Saint-Petersburg, Russian Federation
According to recently proposed taxonomy of attention (Chun et al., 2011), is offered to allocate external attention and internal attention. According to literary data, alpha2 power is sensitive to attention orientation (Ray, Cole 1985, Cooper et al., 2003, Tumyalis et al., 2010, etc.). Much less attention is paid to changes in other EEG frequency ranges. In the present work an attempt to compare EEG power changes in different frequency ranges during tasks which involve externally - or internally – oriented attention has been made.
The group of volunteers (N=49) carried out tasks, connected with an internal orientation of attention: 1) a task to reproduce in mind and mentally to walk by a well-known road; 2) a task to imagine and mentally to walk on the fantastic road; 3) a task to visualize a blue background, blue screen before the mind’s eye. Eyes were opened in any of the tasks. Also volunteers carried out tasks, connected with an external orientation of attention: 1) viewing of photos; 2) viewing of the video movie. Default mode state of rest with eyes opened was used as a common referential state. EEG was recorded using 10-20 placement. EEG spectral power was calculated in EEG frequency bands from delta (1,5-4Hz) to low-gamma (30-40Hz).
In the results it was demonstrated that differences between tasks with externally- and internally–oriented attention were reflected in changes of EEG power in low-frequency ranges. So, tasks, connected with external attention orientation, were characterized by alpha2 power reduction in occipital zones and characterized by delta and theta power increases in the majority of cortex regions. Tasks with internal orientation of attention were characterized by increase of alpha2 power in occipital regions and power reduction in the delta and theta EEG ranges on the most regions of a cortex. Obtained changes of alpha power are in accordance with above mentioned literary data. Increase of EEG power in delta and theta ranges during viewing of photos and video can be considered as an indicator of orientation reaction to external stimuli (Basar et al., 1999, 2001, Sasaki et al., 1996). Generalized power reduction in the same ranges during reproduction, imagination or visualization tasks can be considered as a reflection of internally focused attention, as processes of integration of internal and external information (Tei et al., 2009; Cahn et al., 2010), because volunteers carried out internally oriented tasks with open eyes.