Contradictory findings exist concerning the inhibitory function of low frequency repetitive transcranial magnetic stimulation (rTMS). Therefore, the study examines the impact of different duration of low frequency rTMS on ERPs. In 17 subjects, auditory ERPs were measured before and after 1 Hz rTMS delivered over the left prefrontal cortex during l0min (600 pulses) and 15min (900 pulses). Results showed that 15 min of 1 Hz rTMS induced a significant increase of P300 latency. There was no effect for early ERP components (N100, P200 and N200). This study confirms and extends that 1 Hz rTMS produces a real inhibitory effect only when the duration of the stimulation is about 15 min. The data suggest that rTMS modifies the speed of cognitive processing rather than the energetical aspect of information processing, and that cortical inhibition induced by the magnetic stimulation affects principally the controlled cognitive processes and not the automatic ones.

a b s t r a c tThis study aimed at investigating the brain correlates of trait emotional intelligence. Trait emotional intelligence (trait EI) is a constellation of emotion-related traits, capturing the extent to which people experience, attend to, identify, understand, regulate, and utilize their emotions and those of others. As previous studies have provided converging evidence that frontal asymmetries were one of the determinants of emotion dispositions and behaviors, and as observations on individuals with a high level of emotional intelligence parallel those on people with a left-sided frontal cortical asymmetry in nearly every respect, we hypothesized that the level of emotional intelligence might be associated with differential frontal activation. Results supported the hypothesis: the pattern of resting electroencephalographic (EEG) activation recorded in the frontal areas was significantly associated with emotional intelligence. Individuals with higher trait EI evidence greater resting left frontal activation.

Several studies found strong relationships between main personality dimensions and emotions, and more particularly between neuroticism and negative emotions, as well as between extraversion and positive ones. In these studies, personality was mainly assessed with respect to the big five model, and emotions were evaluated with subjective rating scales. To extend the exploration of the associations between personality and emotion, the aim of the present study was to investigate the relationships between Cloninger's dimensions of personality and emotional reactivity assessed by skin conductance response (SCR). In 55 normal subjects, SCR was recorded while they were presented pictures selected as positive, negative and neutral from the International Affective Picture System. The results showed no influence of personality on response magnitude, but subjects with higher harm avoidance scores showed longer half-recovery times for negative relative to neutral pictures. This result is consistent with the dispositional bias of harm avoidance to respond intensely to signals of aversive stimuli.

Repetitive transcranial magnetic stimulation (rTMS) is considered a powerful method for the study of the relationships between cortical activity and cognitive processes. Previous ERPs studies that focused on P300 response have shown that inhibitory/excitatory effects on prefrontal cortex (PFC), induced by low- and high-frequency rTMS, were able to modulate controlled but not automatic information processing. The present study assessed the impact of inhibition over left and right PFC induced by rTMS on mismatch negativity (MMN), which is known to represent automatic cerebral processes for detecting change. Auditory MMN was recorded in 20 subjects before and after application of left and right PFC 1-Hz rTMS for 15 min. MMN was also recorded before and after a sham-occipital 1-Hz rTMS as control condition. Results showed that 1-Hz rTMS induced no modification to either MMN latency or amplitude. In addition, N100 and P200 components to the frequent tones were not affected by rTMS. These results are consistent with previous findings showing that rTMS over both PFC is unable to disrupt automatic information processing. However, since two sites were stimulated in the present study, no definite conclusions about the inability of rTMS to disrupt automatic processing can be made.