Changes in the coherence of cortical biopotentials during performance of a verbal creative task in men and women.

Changes in EEG coherence patterns evoked by performance of a verbal creative task were studied in 14 men and 13 women (university students). EEG coherence was calculated in six frequency ranges from 4 to 30 Hz. The experiment consisted of two series: in the first, the task was performed with the instruction to "create a sentence;" in the second, the instruction was to "create an original sentence." Independently of the instruction given, the reactivity of total coherence of biopotentials (experimental data minus the corresponding baseline measure) in all subjects was negative in the theta-1 and alpha-2 frequency ranges, while reactivity in the beta-2 range was positive. Gender-related differences linked with the type of experimental instruction were seen in changes in intrahemisphere coherence of biopotentials, and these were indifferent in relation to EEG frequencies. Performance of the verbal creative task with the instruction to "create an original sentence" was accompanied in women by substitution of right-hemisphere dominance (greater levels of coherence in the right hemisphere compared with the left) by left-hemisphere dominance as compared to performance with the instruction to "create a sentence," while the reverse changes were seen in men.