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During a social evaluation, the right temporo-parietal junction (rTPJ) plays an important role according to its contribution in making inferences about the mental states of others. However, what is the neural response if rTPJ function is inhibited during a mentalizing task? In this study, participants played the Dictator Game with two confederates: one playing cooperation (C) and other playing non-cooperation (NC) role and then they were scanned during a mentalizing test. However, we inhibited rTPJ using transcranial magnetic stimulation (TMS) after they played the game and before they were scanned. In this test, participants read negative (Neg) or positive (Pos) personal situations and then they watched confederate's pictures. Images from the TMS group were compared against controls with no TMS stimulation. After statistical comparison, we found a significantly higher activity in right and left visual association areas (BA 18) during the NCPos > NCNeg condition in the TMS group compared with the No-TMS group. Same visual association areas have been described before when participants are processing visual emotional information or when making a fast social categorization. This could reflect a neural mechanism of socio - emotional categorization that emerges after rTPJ inhibition.

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This paper shows the brain correlates of Cloninger's personality model during the presentation of social scenarios under positive or negative valence situations. Social scenarios were constructed when participants played the Dictator game with two confederates that had two opposites roles as the cooperator (Coop) and non-cooperator (NoCoop). Later the same day during a fMRI scanning session, participants read negative (Neg) and positive (Pos) situations that happened to confederates in the past. Participants were asked to think "how do you think those people felt during that situation?" A dissimilarity matrix between stimuli were obtained from fMRI results. Results shown that Harm Avoidance trait people make use of right middle frontal gyrus and left superior frontal gyrus to discriminate between Coop and NoCoop. Cooperation as a trait makes use of the right superior temporal gyrus and the right precuneus to discriminate between Coop and NoCoop in positive social scenarios. Finally, Self-directedness trait people make use of the right inferior parietal lobe to discriminate between Coop and NoCoop in negative social scenarios and the right precuneus to discriminate between Coop and Strangers. An intuitive link between discrimination findings and behavioral patterns of those personality traits is proposed.

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Short-term memory and working memory are two closely-related concepts that involve the prefrontal and parietal areas. These two types of memory have been evaluated by means of the spatial span task in its forward and backward conditions, respectively. To determine possible neurofunctional differences between them, this study recorded electroencephalographic activity (EEG) in the frontopolar (Fp1, Fp2), dorsolateral (F3, F4), and parietal (P3 and P4) areas during performance of the forward and backward conditions of this task in young men. The backward condition (an indicator of working memory) was characterized by fewer correct answers, higher absolute power (AP) of the delta band in dorsolateral areas, and a lower correlation between frontopolar and dorsolateral regions in the fast bands (alpha, beta and gamma), mainly in the right hemisphere. The prefrontal EEG changes during backward performance may be associated with the higher attentional demands and inhibition processes required to invert the order of reproduction of a sequence. These data provide evidence that the forward and backward conditions of the spatial span task can be distinguished on the basis of neurofunctional activity and performance, and that each one is associated with a distinct pattern of electrical activity and synchronization between prefrontal areas. The higher AP of the delta band and lower correlation of the fast bands, particularly between right prefrontal areas during the backward condition of this visuospatial task, suggest greater participation by the right prefrontal areas in working memory.

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RESUMEN

Pregnancy is a dynamic process during which significant cognitive changes take place. It has been suggested that working memory (WM) is affected during gestation as a result of functional changes among cortical areas, such as the prefrontal and parietal cortices. This study examined cortical electroencephalographic correlations (rEEG) during performance of WM tasks in each trimester of pregnancy. Forty women were divided into 4 groups: first (T1), second (T2), and third (T3) trimester of pregnancy, and a control group of non-pregnant women. Electroencephalographic activity (EEG) was recorded from the frontopolar, dorsolateral and parietal cortices during performance of one verbal and one visuospatial working memory task. Only groups T2 and T3 showed increased onset latency in the visuospatial WM. During the verbal WM task, the T1 group showed a higher correlation between dorsolateral areas in the theta and alpha bands, as well as a lower left prefrontal-parietal correlation in the gamma band. During the visuospatial WM task, the T1 and T3 groups showed a higher left EEG correlation in the delta and alpha1 bands, whereas T2 presented a higher right prefrontal-parietal correlation in the gamma band. Although pregnancy had only a subtle effect on the visuospatial WM task, these different patterns of cortical synchronization in each trimester of pregnancy could represent adaptive mechanisms that enabled the pregnant women to focus their attention and use more cognitive resources and so adequately solve the WM tasks.

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