Functional neuroimaging of e xtraversion-introversion

Neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography have provided an unprecedented neurobiological perspective for research on personality traits. Evidence from task-related neuroimaging has shown that extraversion is associated with activations in regions of the anterior cingulate cortex, dorsolateral prefrontal cortex, middle temporal gyrus and the amygdala. Currently, resting-state neuroimaging is being widely used in cognitive neuroscience. Initial exploration of extraversion has revealed correlations with the medial prefrontal cortex, anterior cingulate cortex, insular cortex, and the precuneus. Recent research work has indicated that the long-range temporal dependence of the resting-state spontaneous oscillation has high test-retest reliability. Moreover, the long-range temporal dependence of the resting-state networks is highly correlated with personality traits, and this can be used for the prediction of extraversion. As the long-range temporal dependence reflects real-time information updating in individuals, this method may provide a new approach to research on personality traits.

Endocuticle is involved in caste differentiation of the lower termite

Caste differentiation in termites is one of the most conspicuous examples of facultative polyphenism in animals.It is clear that specific cuticular formation occurs in hard exocuticles during caste differentiation.However,the developmental pattern of the soft endocuticle in the differentiation pathways of castes is unknown.To reveal whether the endocuticle is involved in caste differentiation,we compared the exocuticle and endocuticle thickness of individuals in 2 pathways(nymph line and worker line)of caste differentiation in the termite Reticulitermes aculabialis.The endocuticle protein genes were identified by transcriptome analysis and the expression patterns of these genes were confirmed in caste differentiation.We found that the endocuticle structure showed dynamic changes in 2 pathways,and the first difference in endocuticle structure occurred after larvae differentiation bifurcated into workers and nymphs.The thinning of the endocuticle was a significant event from nymphs developing into alates with the thickest exocuticle and thinnest endocuticle.The thickest endocuticle layers were found in the heads of the workers and the ultrastructure of the endocuticle in the heads was more complex than that in the thorax–abdomens.Six endocuticle protein genes were identified and annotated as endocuticle structural glycoproteins SgAbd-2,SgAbd-9,and Abd-5.The expression levels of endocuticle protein genes changed dramatically during caste development and the expression levels in neotenic reproductives(secondary reproductives)were significantly higher than those in alates(primary reproductives).These results reveal the roles of endocuticles in caste differentiation and adaptation to the environment.