Distinct pattern of structural and functional connectivity changes associated with shyness in healthy adults

Shyness can be described as a personality trait that is reflected as discomfort that takes place especially in social situations that involve new persons or novel situations. Typically the degree of shyness is stronger in childhood, but approximately 10–25% of the adult population can be described as being shy. Importantly, shyness can predict life outcomes involving social relationships and occupational achievement. In neuroimaging studies, shyness and social anxiety have been both associated with enhanced responsiveness in frontal cortical and limbic areas to social stimuli, however, potential overlap between structural and functional connectivity patterns in persons who score high on shyness and social anxiety traits has remained an open question.

In their recent study, Yang et al. (2013) studied a cohort of 61 healthy individuals, assessed for shyness and social anxiety with Cheek and Buss Shyness and Liebowitz Social Anxiety scales, with combination of anatomical and resting-state functional magnetic resonance imaging (MRI/fMRI). Voxel-based gray-matter morphometry was quantified from anatomical MRIs and seed-based resting-state functional connectivity was obtained from the fMRI data. Correlations between these measures and shyness as well as social anxiety were then calculated.

Shyness scores predicted gray matter density in cerebellum, right insula, and bilaterally both superior temporal and parahippocampal gyri. Functional connectivity between several brain regions correlated with shyness, including connectivity between superior temporal gyrus, parahippocampal gyrus and frontal gyri, connectivity between insula, precentral gyrus, and inferior parietal lobule, connectivity between cerebellum and precuneus, as well as connectivity between amygdala and frontal and inferior parietal areas. By contrast, the authors failed to observe any structural or functional connectivity measures correlating with social anxiety.

This study opens up a novel and interesting area of research where research on the neural basis of personality traits is extended to shyness, by suggesting structural and functional connectivity changes in shy persons involving a number of brain areas that have consistently been associated with processing of social and emotional stimuli. Their findings further support the view that shyness should be considered as phenomenon distinct from social anxiety.

Reference: Yang X, Kendrick KM, Wu Q, Chen T, Lama S, Cheng B, Li S, Huang X, Gong Q. Structural and functional connectivity changes in the brain associated with shyness but not with social anxiety. PLoS ONE (2013) 8: e63151. http://dx.doi.org/10.1371/journal.pone.0063151