Social cognitive and affective neuroscience
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Soc Cogn Affect Neurosci · Dec 2009
Variation in orbitofrontal cortex volume: relation to sex, emotion regulation and affect.
Sex differences in brain structure have been examined extensively but are not completely understood, especially in relation to possible functional correlates. Our two aims in this study were to investigate sex differences in brain structure, and to investigate a possible relation between orbitofrontal cortex subregions and affective individual differences. We used tensor-based morphometry to estimate local brain volume from MPRAGE images in 117 healthy right-handed adults (58 female), age 18-40 years. ⋯ Men had larger left planum temporale. Women had larger ventromedial prefrontal cortex (vmPFC), right lateral orbitofrontal (rlOFC), cerebellum, and bilateral basal ganglia and nearby white matter. vmPFC but not rlOFC volume covaried with self-reported emotion regulation strategies (reappraisal, suppression), expressivity of positive emotions (but not of negative), strength of emotional impulses, and cognitive but not somatic anxiety. vmPFC volume statistically mediated sex differences in emotion suppression. The results confirm prior reports of sex differences in orbitofrontal cortex structure, and are the first to show that normal variation in vmPFC volume is systematically related to emotion regulation and affective individual differences.
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Soc Cogn Affect Neurosci · Dec 2009
Type I and Type II error concerns in fMRI research: re-balancing the scale.
Statistical thresholding (i.e. P-values) in fMRI research has become increasingly conservative over the past decade in an attempt to diminish Type I errors (i.e. false alarms) to a level traditionally allowed in behavioral science research. In this article, we examine the unintended negative consequences of this single-minded devotion to Type I errors: increased Type II errors (i.e. missing true effects), a bias toward studying large rather than small effects, a bias toward observing sensory and motor processes rather than complex cognitive and affective processes and deficient meta-analyses. ⋯ This joint threshold produces high but acceptable Type II error rates and produces a FDR that is comparable to the effective FDR in typical behavioral science articles (while a 20 voxel extent threshold produces an actual FDR of 0.05 with relatively common imaging parameters). We recommend a greater focus on replication and meta-analysis rather than emphasizing single studies as the unit of analysis for establishing scientific truth. From this perspective, Type I errors are self-erasing because they will not replicate, thus allowing for more lenient thresholding to avoid Type II errors.
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Soc Cogn Affect Neurosci · Mar 2009
Amygdala activation during reading of emotional adjectives--an advantage for pleasant content.
This event-related functional magnetic resonance imaging (fMRI) study investigated brain activity elicited by emotional adjectives during silent reading without specific processing instructions. Fifteen healthy volunteers were asked to read a set of randomly presented high-arousing emotional (pleasant and unpleasant) and low-arousing neutral adjectives. Silent reading of emotional in contrast to neutral adjectives evoked enhanced activations in visual, limbic and prefrontal brain regions. ⋯ Furthermore, pleasant adjectives were better remembered than unpleasant and neutral adjectives in a surprise free recall test conducted after scanning. Thus, visual processing was biased towards pleasant words and involved the amygdala, underscoring recent theoretical views of a general role of the human amygdala in relevance detection for both pleasant and unpleasant stimuli. Results indicate preferential processing of pleasant information in healthy young adults and can be accounted for within the framework of appraisal theory.
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Soc Cogn Affect Neurosci · Mar 2009
Knowing when to trust others: an ERP study of decision making after receiving information from unknown people.
To address the neurocognitive mechanisms that underlie choices made after receiving information from an anonymous individual, reaction times (Experiment 1) and event-related brain potentials (Experiment 2) were recorded as participants played three variants of the coin toss game. In this game, participants guess the outcomes of unseen coin tosses after a person in another room (dubbed 'the reporter') observes the coin toss outcomes and then sends reports (which may or may not be truthful) to participants about whether the coins landed on heads or tails. Participants knew that the reporter's interests were aligned with their own (common interests), opposed to their own (conflicting interests) or opposed to their own, but that the reporter was penalized every time he or she sent a false report about the coin toss outcome (penalty for lying). ⋯ Reaction time results indicated that participants took similar amounts of time to respond in the common interests and penalty for lying conditions and that they were reliably faster than in the conflicting interests condition. Event-related potentials timelocked to the reporter's reports revealed a larger P2, P3 and late positive complex response in the common interests condition than in the other two, suggesting that participants' brains processed the reporter's reports differently in the common interests condition relative to the other two conditions. Results suggest that even when people behave as if they trust information, they consider communicative efforts of individuals whose interests are aligned with their own to be slightly more informative than those of individuals who are made trustworthy by an institution, such as a penalty for lying.