Caucasian American Individuals Research Articles

Racial identification modulates default network activity for same and other races

Racial identification shapes self-concept and how people share in and respond to the emotional states of others around them. Prior neuroimaging studies have demonstrated the role of the neural default network in self-referential and empathic processing. However, how racial identification affects neural processing of social information remains unknown. Here, we examined the effect of racial identification on neural response related to social perception among African American and Caucasian American individuals using functional magnetic resonance imaging. Our results demonstrate that degree of racial identification predicts activity within cortical midline structures of the default network in response to viewing racial ingroup, relative to outgroup members, and activity within the medial temporal lobe subsystem of the default network in response to viewing racial outgroup, relative to ingroup members. Broadly, our findings suggest that the strength of racial identification is associated with differential recruitment of neural and cognitive processes to understand and respond to other people within and outside of one's racial group.

Neural basis of extraordinary empathy and altruistic motivation

A central evolutionary challenge for social groups is uniting a heterogeneous set of individuals towards common goals. One means by which social groups form and endure is by endowing group members with extraordinary prosocial proclivities, such as ingroup love, towards other group members. Here we examined the neural basis of extraordinary empathy and altruistic motivation in African-American and Caucasian-American individuals using functional magnetic resonance imaging. Our results indicate that empathy for ingroup members is neurally distinct from empathy for humankind, more generally. People showed greater response within anterior cingulate cortex and bilateral insula when observing the suffering of others, but African-American individuals additionally recruit medial prefrontal cortex when observing the suffering of members of their own social group. Moreover, neural activity within medial prefrontal cortex in response to pain expressed by ingroup relative to outgroup members predicted greater empathy and altruistic motivation for one's ingroup, suggesting that neurocognitive processes associated with self identity underlie extraordinary empathy and altruistic motivation for members of one's own social group. Taken together, our findings reveal distinct neural mechanisms of empathy and altruistic motivation in an intergroup context and may serve as a foundation for future research investigating the neural bases of intergroup prosociality, more broadly construed.

Cytokine genetic polymorphisms and prostate cancer aggressiveness

Prostate cancer (PCa) is one of the most common cancers in the world. Inflammation has been described as a risk factor for PCa and depends on the production of cytokines in response to tissue damage or the presence of stimuli that induces cellular stress. Interindividual variation in cytokine production is partially controlled by single-nucleotide polymorphisms (SNPs) that have been associated with differential production of cytokines. We have recently showed that SNP-SNP interactions of cytokine genes are associated with PCa risk. However, little is known about the association of cytokine SNPs and PCa aggressiveness. In this study, we evaluated the association of 15 SNPs in five cytokine genes and aggressiveness of PCa in African- and Caucasian-American individuals. Caucasian Americans with the genotypes IL10-1082GG or IL1B+3954TT had 2.31-fold [95% confidence interval (CI) = 1.13-4.72] and 3.11 (95% CI = 1.20-8.06)-fold risk, respectively, of developing aggressive PCa, as compared with individuals without those genotypes. We did not find any associations in the African-American group. Using Multivariate Adaptive Regression Splines modeling for exploratory SNP-SNP interactions, our results showed that more aggressive PCa in Caucasians Americans is associated with the CT genotype at IL8-47 [odds ratios (OR) = 3.50; 95% CI = 1.13-10.88] or combined genotypes of IL1B-511CC and IL10-1082GG (OR = 3.38; 95% CI = 1.70-6.71). Unfortunately, the same analysis could not be performed in the African-Americans due to limited number of individuals. With limited sample size, the results from this study suggest that SNPs in cytokine genes may be associated with PCa aggressiveness. More extensive studies are warranted to validate our findings.

An fMRI investigation of race-related amygdala activity in African-American and Caucasian-American individuals.

Functional magnetic resonance imaging (fMRI) was used to examine the nature of amygdala sensitivity to race. Both African-American and Caucasian-American individuals showed greater amygdala activity to African-American targets than to Caucasian-American targets, suggesting that race-related amygdala activity may result from cultural learning rather than from the novelty of other races. Additionally, verbal encoding of African-American targets produced significantly less amygdala activity than perceptual encoding of African-American targets.

High degree of genetic polymorphism in apolipoprotein(a) associated with plasma lipoprotein(a) levels in Japanese and Chinese populations.

We have developed a sensitive, high-resolutin method for the analysis of the apolipoprotein(a) [apo(a)] isoforms using sodium dodecyl sulfate (SDS)-agarose/gradient polyacrylamide gel electrophoresis. In an analysis of the genetic polymorphism of apo(a) isoforms and their relationship with plasma lipoprotein(a) [Lp(a)] levels in Japanese and Chinese, this method identified 25 different apo(a) isoforms and detected one or two apo(a) isoforms in more than 99.5% of the individuals tested. The apparent molecular weights of the apo(a) isoforms ranged from 370 kDa to 950 kDa, and 22 of the 25 different apo(a) isoforms had a higher molecular weight than of apo B-100. Studies on Japanese families confirmed the autosomal codominant segregation of apo(a) isoforms and the existence of a null allele at the apo(a) locus. The observed frequency distribution of apo(a) isoform phenotypes fit the expectations of the Hardy-Weinberg equilibrium in both the Japanese and Chinese populations. Our data indicate the existence of at least 26 alleles, including a null allele, at the apo(a) locus. The frequency distribution patterns of the apo(a) isoform alleles in Japanese and Chinese were similar to each other and also similar to that of apo(a) gene sizes reported in Caucasian American individuals. The average heterozygosity at the apo(a) locus was 92% in Japanese and 93% in Chinese. A highly significant inverse correlation was observed between plasma Lp(a) levels and the size of apo(a) isoforms in both the Japanese (r = 0.677, P = 0.0001) and the Chinese (r = -0.703, P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)