Julieta Ramos

GENDER DIFFERENCES IN THE EEG DURING COGNITIVE ACTIVITY

EEG activity of 16 adult volunteers. 8 male and 8 females was monopolarly recorded at P3 and P4 at rest and during solution of three series of tasks: one analytic, one spatial and one mixed demanding both kinds of processing. The following main effects were observed: Men showed significantly higher beta relative power than women, while women showed significantly higher alpha relative power than men during all conditions. Alpha relative power decreased, while theta relative power increased during tasks solution in both sexes. Beta relative power was significantly higher at the left parietal only in men. Interparietal correlation was significantly higher in women than in men during all conditions and bands. For the theta band it increased from baseline values during tasks solution in men, while in women it decreased during the analytic task.

Patterns of interhemispheric correlation during human communication

Correlation patterns between the electroencephalographic activity of both hemispheres in adult subjects were obtained. The morphology of these patterns for one subject was compared with another subjects patterns during control situations without communication, and during sessions in which direct communication was stimulated. Neither verbalization nor visual or physical contact are necessary for direct communication to occur. The interhemispheric correlation patterns for each subject were observed to become similar during the communication sessions as compared to the control situations. These effects are not due to nonspecific factors such as habituation or fatigue. The results support the syntergic theory proposed by one of the authors (Grinberg-Zylberbaum).

Effect of spatial ability and sex inter- and intrahemispheric correlation of EEG activity

Inter- and intrahemispheric correlation of the EEG activity at rest was computed in two groups of men and women, between 17 and 21 years old, with extreme degrees of spatial ability (SA) evaluated by the Spatial Relations Subtest of the Differential Aptitudes Test (DAT). Interhemispheric (INTERr) and intrahemispheric (INTRAr) EEG correlations were computed by means of Pearson product-moment coefficients for 5 EEG bands after digitally filtering with an FFT. Women showed significantly higher INTERr of alpha 1 between left and right centrals, lower INTRAr between right frontal and right central regions and lower INTRAr within the left than in the right hemisphere. High SA subjects showed lower INTERr between left and right frontal derivations and higher INTRAr between frontal and parietal and between central and parietal regions of both hemispheres. Sex interacted with SA in INTRAr of alpha between right frontal and right temporal regions with high SA women showing lower INTRAr than low SA women and than men. The present results indicate a different inter- and intrahemispheric functional organization in men and women and in subjects with high and low spatial ability.

Eeg Activity During Cognitive Performance in Women

EEG activity of 20 female volunteers was monopolarly recorded at P3, P4, C3 and C4 during four resting periods and three series of cognitive tasks: one analytic, one spatial and one demanding analytical and spatial processing or mixed task. Relative power and inter and intrahemispheric correlations were analysed. Beta relative power was significantly higher during the resting periods at the right parietal and the same pattern of asymmetry was maintained during the three series of tasks. Alpha relative power decreased and theta increased during the three series of tasks regardless of their cognitive nature as compared to baseline. Interhemispheric correlation for theta frequencies, and intrahemispheric correlation for the full band were significantly different during task solution. There were no significant differences between left and right intrahemispheric correlations.

Effect of normal sleep and sleep deprivation on interhemispheric correlation during subsequent wakefulness in man

EEG activity was recorded from the right and left central, temporal, parietal and occipital derivations in 10 volunteers under the following conditions: at night before going to sleep, at night before sleep deprivation, in the morning after waking, in the morning after sleep deprivation and in the morning 48 h after recovery. Interhemispheric correlation and relative power were calculated for EEG samples of 20.48 sec. In the morning after normal sleep interhemispheric correlations were higher in all derivations in comparison to presleep values, while in the morning after sleep deprivation, interhemispheric correlations were lower or similar to predeprivation values in all derivations except the temporal cortex. The relative power of beta was significantly lower after normal sleep and higher after sleep loss, while the relative power of low frequencies was higher in the morning after sleep and lower in the morning after deprivation.

Does brain electrical activity react to music

The electrical activity of the left and right central, temporal and parietal cortex was recorded in 14 amateurs of classical music during silence, pleasant (a piece of music) and unpleasant (a recording of an infant crying) stimulation. All the subjects rated the music as a pleasant stimulation and crying as an unpleasant one. Theta relative power was significantly higher while listening to music and lower during crying. Beta relative power did not change across conditions. No interhemispheric differences in the relative power were found. Interhemispheric correlation did not change either.

EEG activity during estral cycle in the rat

EEG activity was recorded from right and left parietal cortex in adult female rats daily during 6 days. Immediately after EEG recording vaginal smears were taken and were microscopically analyzed to determine the estral stage. Absolute and relative powers and interhemispheric correlation of EEG activity were calculated and compared between estral stages. Interhemispheric correlation was significantly lower during diestrous as compared to proestrous and estrous. Absolute and relative powers did not show significant differences between estral stages. Absolute powers of alpha1, alpha2, beta1 and beta2 bands were significantly higher at the right parietal cortex. Comparisons of the same EEG records with estral stages randomly grouped showed no significant differences for any of the EEG parameters. EEG activity is a sensitive tool to study functional changes related to the estral cycle.

Effect of spatial ability and sex on EEG power in high school students

Performance at eight cognitive tests and EEG spectral power at rest was computed in 2 groups of men and women, between 17 and 21 years of age, with extreme degrees of spatial ability (SA) evaluated by the spatial relations subtest of the DAT: a low spatial ability group (10 men, 10 women) with scores below percentile 30 and a high spatial ability group (10 men, 10 women) with scores above percentile 80. Ten EEG artifact free samples, 4.096 sec each, were analyzed and absolute (AP) and relative power (RP) were obtained for 5 frequency bands using an FFT. EEG was submitted to principal component analysis and two way ANOVAs. High SA showed lower AP in the entire spectrum with eyes open and closed, and lower alpha 1 RP with eyes open than low SA group regardless of sex. The difference between low and high SA was better explained by high alpha AP at all derivations and high theta AP at right derivations and at left central and occipital regions. Women showed higher beta 1 and beta 2 AP at all derivations except at temporal regions than men regardless of SA scores.