Guess who's coming to dinner: Brain signatures of racially biased and politically correct behaviors.

The ability to share feelings with those of someone in pain is affected by the racial difference between the target and the onlooker. A differential empathic activation for race (DEAR effect) in favor of in-group members has been documented in the brain pain matrix. However, we are also capable of unbiased responses that manifest politically correct behaviors toward people of a different race. To address the neurofunctional signatures underlying both the DEAR effect and the manifestation of politically correct behaviors, we scanned with fMRI Caucasian participants while watching African or Caucasian actors touched by either a rubber eraser or a needle. Participants were instructed to empathize with the actors during the video presentation (stimulus phase) and to explicitly judge the pain level experienced by the actors (response phase). During the stimulus phase, we found a typical DEAR effect within the pain-matrix. This effect correlated with the level of implicit racial bias as measured by the IAT. On the other hand, during the response phase a significant out-group specific DEAR effect emerged in the prefrontal cortices. This latter effect was coupled with a revealing behavioral pattern: while the magnitude of the painful experience attributed to Caucasians and Africans was the same, our participants were significantly slower when judging the pain experience of the African actors. We propose a model that logically integrates these two contrasting forces at the neurobiological and behavioral level.

With time on our side? Task-dependent compensatory processes in graceful aging.

Graceful aging has been associated with frontal hyperactivations in working- and episodic long-term memory tasks, a compensatory process, according to some, that allows the best normal elders to perform these tasks at a juvenile level, in spite of natural cortical impoverishment. In this study, 24 young and 24 healthy elderly participants were compared. Graceful aging was explored by investigating domains where most healthy elders perform like youngers (e.g. lexical-semantic knowledge) and tasks that are typically more challenging, like episodic long-term recognition memory tasks. With voxel-based morphometry, we also studied to what extent changes of fMRI activation were consistent with the pattern of brain atrophy. We found that hyperactivations and hypoactivations of the elders were not restricted to the frontal lobes, rather they presented with task-dependent patterns. Only hypoactivations and normal levels of activation systematically overlapped with regional atrophy. We conclude that compensatory processes associated with graceful aging may not necessarily be a sign of early saturation of executive resources, if this was to be represented by a systematic frontal hyperactivation, but rather they may represent the ability of recruiting new cognitive strategies. We discuss two possible approaches to further test this hypothesis.

Neural correlates of worry in generalized anxiety disorder and in normal controls: a functional MRI study.

BACKGROUND: Worry is considered a key feature of generalized anxiety disorder (GAD), whose neural correlates are poorly understood. It is not known whether the brain regions involved in pathological worry are similar to those involved in worry-like mental activity in normal subjects or whether brain areas associated with worry are the same for different triggers such as verbal stimuli or faces. This study was designed to clarify these issues. METHOD: Eight subjects with GAD and 12 normal controls underwent functional magnetic resonance imaging (fMRI) mood induction paradigms based on spoken sentences or faces. Sentences were either neutral or designed to induce worry. Faces conveyed a sad or a neutral mood and subjects were instructed to empathize with those moods. RESULTS: We found that the anterior cingulate and dorsal medial prefrontal cortex [Brodmann area (BA) 32/23 and BA 10/11] were associated with worry triggered by sentences in both subjects with GAD and normal controls. However, GAD subjects showed a persistent activation of these areas even during resting state scans that followed the worrying phase, activation that correlated with scores on the Penn State Worry Questionnaire (PSWQ). This region was activated during the empathy experiment for sad faces. CONCLUSIONS: The results show that worry in normal subjects and in subjects with GAD is based on activation of the medial prefrontal and anterior cingulate regions, known to be involved in mentalization and introspective thinking. A dysregulation of the activity of this region and its circuitry may underpin the inability of GAD patients to stop worrying.