Science posts

See science posts on page 14 below.

    • 2010
    • Roshan Cools et al.
    • Serotonin and Dopamine: Unifying Affective, Activational, and Decision Functions
    • Serotonin, like dopamine (DA), has long been implicated in adaptive behavior, including decision making and reinforcement learning. However, although the two neuromodulators are tightly related and have a similar degree of functional importance, compared with DA, we have a much less specific understanding about the mechanisms by which serotonin affects behavior. Here, we draw on recent work on computational models of dopaminergic function to suggest a framework by which many of the seemingly diverse functions associated with both DA and serotonin—comprising both affective and activational ones, as well as a number of other functions not overtly related to either—can be seen as consequences of a single root mechanism.
    • 2015
    • Emiliano Santarnecchi et al.
    • Intelligence-related differences in the asymmetry of spontaneous cerebral activity
    • Recent evidence suggests the spontaneous BOLD signal synchronization of corresponding interhemispheric, homotopic regions as a stable trait of human brain physiology, with emerging differences in such organization being also related to some pathological conditions. To understand whether such brain functional symmetries play a role into higher-order cognitive functioning, here we correlated the functional homotopy profiles of 119 healthy subjects with their intelligence level. Counterintuitively, reduced homotopic connectivity in above average-IQ versus average-IQ subjects was observed, with significant reductions in visual and somatosensory cortices, supplementary motor area, rolandic operculum, and middle temporal gyrus, possibly suggesting that a downgrading of interhemispheric talk at rest could be associated with higher cognitive functioning. These regions also showed an increased spontaneous synchrony with medial structures located in ipsi- and contralateral hemispheres, with su..
    • 2014
    • Nuria Y. AbdulSabur et al.
    • Neural correlates and network connectivity underlying narrative production and comprehension: A combined fMRI and PET study
    • The neural correlates of narrative production and comprehension remain poorly understood. Here, using positron emission tomography (PET), functional magnetic resonance imaging (fMRI), contrast and functional network connectivity analyses we comprehensively characterize the neural mechanisms underlying these complex behaviors. Eighteen healthy subjects told and listened to fictional stories during scanning. In addition to traditional language areas (e.g., left inferior frontal and posterior middle temporal gyri), both narrative production and comprehension engaged regions associated with mentalizing and situation model construction (e.g., dorsomedial prefrontal cortex, precuneus and inferior parietal lobules) as well as neocortical premotor areas, such as the pre-supplementary motor area and left dorsal premotor cortex. Narrative comprehension alone showed marked bilaterality, activating right hemisphere homologs of perisylvian language areas. Narrative production remained predominant..
    • 2015
    • Maren Amft et al.
    • Definition and characterization of an extended social-affective default network
    • Recent evidence suggests considerable overlap between the default mode network (DMN) and regions involved in social, affective and introspective processes. We considered these overlapping regions as the social-affective part of the DMN. In this study, we established a robust mapping of the underlying brain network formed by these regions and those strongly connected to them (the extended social-affective default network). We first seeded meta-analytic connectivity modeling and resting-state analyses in the meta-analytically defined DMN regions that showed statistical overlap with regions associated with social and affective processing. Consensus connectivity of each seed was subsequently delineated by a conjunction across both connectivity analyses. We then functionally characterized the ensuing regions and performed several cluster analyses. Among the identified regions, the amygdala/hippocampus formed a cluster associated with emotional processes and memory functions. The ventral s..
    • 2015
    • Laurens Van der Cruyssen et al.
    • Distinct neural correlates of social categories and personality traits
    • Does the processing of social category-related versus trait-related information generate a different pattern of brain activation? In this fMRI study, we compared the processing of behaviors performed by a member of a social category versus an individual, both possessing similar personality traits. Based on previous behavioral studies we predicted that the processing of social category-related information would recruit more activation in brain areas related to mentalizing than individual trait-related information. Participants read sentences describing behaviors performed by a member of a social category (of which the stereotype involves a given trait) or by an individual possessing the same trait. These behavioral sentences varied on both valence (positive versus negative) and consistency (consistent versus inconsistent) with regard to the social category or trait. The results revealed that social category-related behavioral information showed more activation in mentalizing areas (me..
    • 2014
    • Eyal Abraham et al.
    • Father's brain is sensitive to childcare experiences
    • Although contemporary socio-cultural changes dramatically increased fathers' involvement in childrearing, little is known about the brain basis of human fatherhood, its comparability with the maternal brain, and its sensitivity to caregiving experiences. We measured parental brain response to infant stimuli using functional MRI, oxytocin, and parenting behavior in three groups of parents (n = 89) raising their firstborn infant: heterosexual primary-caregiving mothers (PC-Mothers), heterosexual secondary-caregiving fathers (SC-Fathers), and primary-caregiving homosexual fathers (PC-Fathers) rearing infants without maternal involvement. Results revealed that parenting implemented a global “parental caregiving” neural network, mainly consistent across parents, which integrated functioning of two systems: the emotional processing network including subcortical and paralimbic structures associated with vigilance, salience, reward, and motivation, and mentalizing network involvi..
    • 2014
    • Anna K. Kuhlen et al.
    • Neural coding of assessing another person’s knowledge based on nonverbal cues
    • For successful communication, conversational partners need to estimate each other’s current knowledge state. Nonverbal facial and bodily cues can reveal relevant information about how confident a speaker is about what they are saying. Using functional magnetic resonance imaging, we aimed to identify brain regions that encode how confident a speaker is perceived to be. Participants viewed videos of people answering general knowledge questions and judged each respondent’s confidence in their answer. Our results suggest a distinct role of two neural networks known to support social inferences, the so-called mentalizing and the mirroring network. While activation in both networks underlies the processing of nonverbal cues, only activity in the mentalizing network, most notably the medial prefrontal cortex and the bilateral temporoparietal junction, is modulated by how confident the respondent is judged to be. Our results support an integrative account of the mirroring..
    • 2014
    • Jonathan B. Freeman et al.
    • The medial prefrontal cortex in constructing personality models
    • A recent study by Hassabis et al. suggests that the brain constructs ‘personality models’ of other people. When imagining another individual, multi-voxel patterns of fMRI activation in the medial prefrontal cortex (mPFC) contained information about the individual's unique combination of personality traits. The authors propose that, in concert with other regions, the mPFC assembles a model of another's personality that is ultimately used to predict behavior.
    • 2005
    • Michael X. Cohen et al.
    • Individual differences in extraversion and dopamine genetics predict neural reward responses
    • Psychologists have linked the personality trait extraversion both to differences in reward sensitivity and to dopamine functioning, but little is known about how these differences are reflected in the functioning of the brain's dopaminergic neural reward system. Here, we show that individual differences in extraversion and the presence of the A1 allele on the dopamine D2 receptor gene predict activation magnitudes in the brain's reward system during a gambling task. In two functional MRI experiments, participants probabilistically received rewards either immediately following a behavioral response (Study 1) or after a 7.5 s anticipation period (Study 2). Although group activation maps revealed anticipation- and reward-related activations in the reward system, individual differences in extraversion and the presence of the D2 Taq1A allele predicted a significant amount of inter-subject variability in the magnitudes of reward-related, but not anticipation-related, activations. These res..
    • 2009
    • Luke D. Smillie et al.
    • Variation in DRD2 dopamine gene predicts Extraverted personality
    • Quantitative geneticists estimate the heritability of Extraverted personality to be around 40–60%. Theory and research which links Extraversion with variation in dopaminergic function suggests that dopaminergic genes should be a start-point for molecular genetic investigations of this trait. Recent endeavours in this area have met with some encouragement but also setbacks. In this study, we investigate the relationship between Extraversion and the DRD2 TaqIA/ANKK1 polymorphism in 224 university students. Presence of at least one copy of the A1 allele was associated with significantly higher Extraversion. The robustness of this finding was confirmed through bootstrap analysis. Findings are discussed in relation to the broader literature, in particular, methodological issues which may have obscured this finding in previous research.

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