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The main objectives of the study were: to investigate whether training on working memory (WM) could improve fluid intelligence, and to investigate the effects WM training had on neuroelectric (electroencephalography - EEG) and hemodynamic (near-infrared spectroscopy - NIRS) patterns of brain activity. In a parallel group experimental design, respondents of the working memory group after 30 h of training significantly increased performance on all tests of fluid intelligence. By contrast, respondents of the active control group (participating in a 30-h communication training course) showed no improvements in performance. The influence of WM training on patterns of neuroelectric brain activity was most pronounced in the theta and alpha bands. Theta and lower-1 alpha band synchronization was accompanied by increased lower-2 and upper alpha desynchronization. The hemodynamic patterns of brain activity after the training changed from higher right hemispheric activation to a balanced activity of both frontal areas. The neuroelectric as well as hemodynamic patterns of brain activity suggest that the training influenced WM maintenance functions as well as processes directed by the central executive. The changes in upper alpha band desynchronization could further indicate that processes related to long term memory were also influenced., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The study investigated gender differences in resting EEG (in three individually determined narrow alpha frequency bands) related to the level of general and emotional intelligence. Brain activity of males decreased with the level of general intelligence, whereas an opposite pattern of brain activity was observed in females. This difference was most pronounced in the upper-alpha band which is related to semantic memory processes. It was further found that highly intelligent males displayed greater decoupling of frontal brain areas, whereas highly intelligent females showed more coupling between frontal and parietal/occipital brain areas. Similar, but less significant differences were observed for the two area scores of strategic and experiential emotional intelligence. It appears that males and females have different resting EEG correlates of IQ.

Participating in the study were 30 respondents, who could be clustered as high-average verbal/performance intelligent (HIQ/AIQ), or emotionally intelligent (HEIQ/AEIQ). The EEG was recorded while students were performing two tasks: the Raven's advanced progressive matrices (RAPM), and identifying emotions in pictures (IDEM). Significant differences in event-related desynchronization/synchronization (ERD/ERS) related to verbal/performance intelligence were only observed while respondents solved the RAPM. The HIQ and AIQ groups displayed temporal and spatial differently induced gamma band activity. Significant differences in ERD/ERS related to emotional intelligence were only observed for the IDEM task. HEIQ individuals displayed more gamma band ERS and less upper alpha band ERD than did AEIQ individuals. It can be concluded that HIQ and HEIQ individuals employed more adequate strategies for solving the problems at hand. The results further suggest that emotional intelligence and verbal/performance intelligence represent distinct components of the cognitive architecture.

Thirteen high intelligent (H-IQ) and 13 low intelligent (L-IQ) individuals solved two figural working-memory (WM) tasks and two figural learning tasks while their EEG was recorded. For the WM tasks, only in the theta band group related differences in induced event-related desynchronization/synchronization (ERD/ERS) were observed. L-IQ individuals displayed greater theta synchronization in the later phases of task completion (1000-2000 ms) as compared to H-IQ individuals. For the learning tasks group related differences in the three alpha bands were observed. In the upper alpha band L-IQ individuals showed greater ERD in the frontal brain areas, whereas H-IQ individuals displayed greater ERD in the parieto-occipital brain areas.

Differences in current density between high intelligent (IQ=124), and average intelligent individuals (IQ=110), while solving two complex cognitive tasks (analytical-figural, and identification of emotions) were analyzed with low resolution brain electromagnetic tomography (LORETA). High intelligent individuals, as compared with average ones in both tasks displayed a lesser full width at half maximum (FWHM) volume-indicating the amount of spatial dispersion of the source. High and average intelligent individuals also differed in their source location. The source location of high intelligent individuals was in the inferior right hemispheric brain areas, whereas the source location of average intelligent individuals was in the superior left hemispheric brain areas. The findings were explained in the light of the neural efficiency model.

High (emotional intelligence scores (EIQ)=120) and average emotional intelligent individuals (EIQ=89) were solving tasks from an emotional intelligence test while their electroencephalogram was recorded. Significant differences relating to emotional intelligence were observed in induced and event related band power in the theta (4.4-6.4 Hz), lower-2 alpha (8.4-10.4 Hz), and upper alpha band (10.4-12.4 Hz). High emotional intelligent individuals displayed less desynchronization in the upper alpha band, as well as more left hemispheric theta desynchronization. Further a significant positive correlation between the mean frequency and emotional intelligence was observed. The results are similar to those reported for verbal and performance components of general intelligence.

Differences in current density between high intelligent (IQ=127), and low intelligent individuals (IQ=87), while solving two oddball tasks (auditive and visual) were analyzed with low resolution brain electromagnetic tomography (LORETA). In highly intelligent individuals a decrease in the volume of activated cortical gray matter between the P300 onset and the P300 peak amplitude was observed. The EEG of low intelligent individuals showed a reverse pattern of cortical activity. In the auditive oddball task the decrease in the activated cortical volume in high intelligent individuals was accompanied by an increase in current density, and a more left hemispheric source location at maximum current density. The results suggest that high intelligent individuals more efficiently distributed their cognitive resources needed to cope with the oddball tasks.

The present study investigated differences in ERP parameters related to intelligence. For that purpose 74 individuals (Intelligence: M=107; S.D.=12; range 73-135), of average creativity passively listened to two tones and performed two auditory, and two visual oddball tasks while their EEG was recorded. The approximate entropy parameters, peak latencies and amplitudes were determined. The correlation coefficients indicated that in the attended conditions, the more intelligent individuals showed more regular ERP waveforms than less intelligent individuals. It was further found that less intelligent individuals showed increased P300 latencies and reduced amplitudes. The differences were explained with a more specific engagement of neural networks in more intelligent individuals.

High (intelligence quotient (IQ)=126) and low intelligent individuals (IQ=88) were listening to tone pips and performed an auditory oddball task while their electroencephalogram was recorded. Significant differences relating to intelligence were observed in induced and event related band power in the theta (4-7 Hz) and upper alpha band (10-13 Hz). In the oddball task high intelligent individuals displayed less theta synchronization and more synchronization in the upper alpha band. The results were explained by the more efficient engagement of neural networks in more intelligent individuals.