Hemispheric specialization in affective responses, cerebral dominance for language, and handedness: Lateralization of emotion, language, and dexterity.

Hemispheric specialization in affective responses has received little attention in the literature. This is a fundamental variable to understand circuit dynamics of networks subserving emotion. In this study we put to test a modified "valence" hypothesis of emotion processing, considering that sadness and happiness are processed by each hemisphere in relation to dominance for language and handedness. Mood induction and language activation during functional magnetic resonance imaging (fMRI) were used in 20 right-handed and 20 nonright-handed subjects, focusing on interconnected regions known to play critical roles in affective responses: subgenual cingulate cortex, amygdala, and anterior insular cortex. We observed a consistent relationship between lateralization of affective processing, motor dexterity, and language in individuals with clear right-handedness. Sadness induces a greater activation of right-hemisphere cortical structures in right-handed, left-dominant individuals, which is not evident in nonright-handed subjects who show no consistent hemispheric dominance for language. In anterior insula, right-handed individuals displayed reciprocal activation of either hemisphere depending upon mood valence, whereas amygdala activation was predominantly left-sided regardless of mood valence. Nonright-handed individuals exhibited less consistent brain lateralization of affective processing regardless of language and motor dexterity lateralization. In contrast with traditional views on emotion processing lateralization, hemispheric specialization in affective responses is not a unitary process but is specific to the brain structure being activated.

Cluster B personality symptoms in persons at genetic risk for schizophrenia are associated with social competence and activation of the right temporo-parietal junction during emotion processing.

Personality disorders are common in nonpsychotic siblings of patients with schizophrenia, and some personality traits in this group may be associated with an increased risk for full-blown psychosis. We sought to establish if faulty right-hemisphere activation induced by social cognitive tasks, as previously described in patients with schizophrenia, is associated with specific personality symptoms in their unaffected siblings. We observed that cluster B personality symptoms in this group were inversely related to activation in the right temporo parietal junction (rTPJ, a structure critical in social cognitive processing) in response to a basic emotion processing task and also to social competence, whereas in contrast to our initial hypothesis, cluster A traits were not associated with right hemisphere activation during emotion processing or with social competence. These findings suggest the existence of clinical traits in at-risk individuals which share a common neurobiological substrate with schizophrenia, in regards to social performance.

Higher autonomic activation predicts better performance in iowa gambling task.

OBJECTIVE: To evaluate the relationship between the autonomic nervous system basal state and performance in decision-making tasks. BACKGROUND: The link between performance in decision-making tasks and acute changes in autonomic parameters during their execution has been extensively investigated. However, there is lacking evidence regarding the relationship between decision making and basal autonomic state. METHODS: Resting autonomic nervous system activity in 18 healthy individuals was assessed by means of heart rate variability (HRV) analysis before conducting 3 different decision-making tasks: an ambiguous one, the Iowa Gambling Task; a test that assesses risk-taking behavior, the Game of Dice Task; and a test that assesses reversal learning behavior, the Reversal Learning Task. The tasks were administered in a random manner. RESULTS: There was a direct correlation between the Iowa Gambling Task net score and the resting low frequency HRV (r = 0.73; P < 0.001), which is strongly influenced by sympathetic activity. No correlations were found between HRV and the Game of Dice Task net score or the Reversal Learning Task last error trial. CONCLUSIONS: The results are compatible with the idea that a higher basal activation of autonomic nervous system is beneficial for subsequent decision-making process.