Common and distinct neural networks for false-belief reasoning and inhibitory control.

Ample behavioral evidence has shown that the ability to attribute false beliefs as part of a Theory of Mind (ToM) and the ability to inhibit a prepotent response are strongly correlated in both children and adults. Frequently reported areas associated with both processes are the right temporo-parietal junction (TPJ) and the medial prefrontal cortex (MPFC). Nevertheless, the exact nature of the relationship between belief-reasoning and inhibitory control at the neural level remains unclear. A functional magnetic resonance imaging (fMRI) study was conducted to investigate the neural correlates of belief-reasoning and inhibitory control in a within-subjects design using virtually identical visual stimuli. A false-belief task was used to investigate belief-attribution. The neural correlates of response inhibition were measured using a Go/No-Go task. Besides distinct activation for belief-reasoning and inhibitory control, the results also showed a substantial overlap for both processes in the right superior dorsal MPFC, the right TPJ, the dorsal part of the left TPJ, and lateral prefrontal areas. These findings suggest that the previously described behavioral link between belief attribution and inhibitory control may be explained by a common recruitment of brain areas related to domain-general cognitive processes. Also, the results indicate that neither the right TPJ nor MPFC is specific to the attribution of false beliefs.

Neural correlates of emotional working memory in patients with mild cognitive impairment.

Emotional stimuli can have beneficial effects on memory in healthy aged subjects and partly on patients with dementia. So far, no experimental study has explored the effects of memory for emotional stimuli in patients with mild cognitive impairment (MCI), a concept that describes a transitional state between normal aging and dementia. The present fMRI study explored working memory for emotional stimuli in 16 patients with amnestic MCI (aMCI) and 16 healthy aged participants. Subjects performed an n-back task (2-back) with neutral, positive, and negative emotional pictures. The analysis focused on target processing. Results showed that groups did not differ in working memory performance. In healthy aged participants emotional targets had no significant impact on working memory. In patients with aMCI a negativity bias was observed, indicating that negative targets were better remembered compared to neutral and positive targets. Regarding fMRI results, both groups showed an increase in functional activity in prefrontal and lateral parietal brain regions associated with target processing. As a key result, we observed significant group by emotion interaction effects in the precuneus. Healthy aged participants showed a signal decrease in the left precuneus for positive compared to neutral targets. The precuneus deactivation in healthy aged participants may indicate a disengagement of self-referential processes towards task-related processes. Patients with aMCI revealed a signal increase in the right precuneus for negative compared to neutral targets. This increase in precuneus activity, combined with a behavioural facilitation effect, may indicate a mechanism to compensate disease related processes in aMCI.

Dissociation of neural correlates of verbal and non-verbal visual working memory with different delays.

BACKGROUND: Dorsolateral prefrontal cortex (DLPFC), posterior parietal cortex, and regions in the occipital cortex have been identified as neural sites for visual working memory (WM). The exact involvement of the DLPFC in verbal and non-verbal working memory processes, and how these processes depend on the time-span for retention, remains disputed. METHODS: We used functional MRI to explore the neural correlates of the delayed discrimination of Gabor stimuli differing in orientation. Twelve subjects were instructed to code the relative orientation either verbally or non-verbally with memory delays of short (2 s) or long (8 s) duration. RESULTS: Blood-oxygen level dependent (BOLD) 3-Tesla fMRI revealed significantly more activity for the short verbal condition compared to the short non-verbal condition in bilateral superior temporal gyrus, insula and supramarginal gyrus. Activity in the long verbal condition was greater than in the long non-verbal condition in left language-associated areas (STG) and bilateral posterior parietal areas, including precuneus. Interestingly, right DLPFC and bilateral superior frontal gyrus was more active in the non-verbal long delay condition than in the long verbal condition. CONCLUSION: The results point to a dissociation between the cortical sites involved in verbal and non-verbal WM for long and short delays. Right DLPFC seems to be engaged in non-verbal WM tasks especially for long delays. Furthermore, the results indicate that even slightly different memory maintenance intervals engage largely differing networks and that this novel finding may explain differing results in previous verbal/non-verbal WM studies.

Me or you? Neural correlates of moral reasoning in everyday conflict situations in adolescents and adults.

Throughout adolescence, progress in the understanding of the moral domain as well as changes in moral behavior is observable. We tested 16 adolescents (14-16 years of age) and 16 healthy adults (22-31 years of age) on the developmental changes in everyday moral decision making using functional magnetic resonance imaging (fMRI). Using verbal stories describing everyday moral conflict situations, subjects had to decide between a moral standard or a personal desire. In the moral conflict situations, adolescents not only chose significantly more often the hedonistic alternative than adults, but they also reported higher certainty ratings. Contrasted with everyday social conflict situations that required a decision between a social-oriented behavior and a personal need, moral conflict situations induced an activity increase in frontal areas, the middle temporal gyrus, the thalamus, and the parahippocampal gyrus in adolescents compared to adults. Moreover, a closer look at the moral conflict situations revealed that adolescents showed more activity than adults in brain areas that are also centrally involved in theory of mind (ToM) during morally oriented decisions in contrast to personal-oriented decisions. This indicated that the development of moral reasoning may be strongly correlated with the development of ToM reasoning.

Aversive faces activate pain responsive regions in the brain.

Recent evidence points to an overlap in the neural systems processing pain and social distress. In this functional MRI study we focus on the possible interplay between the processing of a psychosocial stressor and somatic pain within pain responsive brain regions, the latter being identified in an independent localizer experiment. A paradigm based on emotional induction (Hariri et al., 2000, Neuroreport 11(1):43-48) was combined with moderate heat pain to yield a factorial design with factor 'pain' as somatic stressor and factor 'faces' as nonpainful psychosocial stressor. Pain responsive regions of interest in the insula, SII cortex, and thalamus were activated by the factor 'faces' to a various extent. The hemodynamic response to both factors tends to aggregate in a compressive manner in these regions.

How should I decide? The neural correlates of everyday moral reasoning.

The present fMRI study is the first that investigates everyday moral conflict situations in which a moral standard clashes with a personal desire. In such situations people have to decide between a morally guided and a hedonistic behaviour. Twelve healthy subjects were presented with verbal stories describing conflicts with either moral or neutral content. The moral stories described conflicts requiring a decision between a personal desire and a conflicting moral standard, whereas the neutral conflicts required a decision between two conflicting personal desires. When compared to neutral conflicts, moral conflicts elicited higher activity in a wide spread neural network including the medial frontal cortex, the temporal cortex and the temporo-parietal junction and the posterior cingulate cortex. Further analyses of the moral conflicts revealed that hedonistic decisions in contrast to morally guided decisions were associated with significantly higher rankings of uncertainty and unpleasant emotions and induced significant more activation in the amygdala/parahippocampal region. The present results generalise findings on the neuroscience of moral understanding by extending it to everyday moral decisions. Furthermore, the results show that the amydala region plays a central role in the processing of negative emotional consequences associated with immoral decisions.