Neural correlates of anxiety sensitivity during masked presentation of affective faces

Abstract

Background: Anxiety Sensitivity (AS), the tendency to fear the thoughts, symptoms, and social consequences associated with the experience of anxiety, is associated with increased risk for developing anxiety disorders. Some evidence suggests that higher scores on the Anxiety Sensitivity Index (ASI), a measure of the AS construct, are associated with activation of the anterior insular cortex during overt emotion perception. Although the ASI provides subscale scores measuring Physical, Mental Incapacitation, and Social Concerns of AS, no study has examined the relationship between these factors and regional brain activation during affect processing. We hypothesized that insular responses to fear-related stimuli would be primarily related to the Physical Concerns subscale of the ASI, particularly for a sample of subjects with specific phobias.

Methods: Adult healthy controls (HC; n = 22) and individuals with specific phobia, small animal subtype (SAP; n = 17), completed the ASI and underwent functional magnetic resonance imaging while engaged in a backward-masked affect perception task that presents emotional facial stimuli below the threshold of conscious perception.

Results: Groups did not differ in ASI, state or trait anxiety scores, or insula activation. Total ASI scores were positively correlated with activation in the right middle/anterior insula for the combined sample and for the HC and SAP groups separately. Multiple regression analysis revealed that the relationship between AS and insular activation was primarily accounted for by Physical Concerns only.

Conclusions: Findings support the hypothesized role of the right anterior insula in the visceral/interoceptive aspects of AS, even in response to masked affective stimuli.

© 2011 Wiley-Liss, Inc.

Figures

Figure 1

Correlations between ASI Total scores and cerebral activation during the masked fear > masked neutral contrast are shown in the coronal (top left), sagittal (top right), axial (bottom left) planes for the total combined sample (n = 39). The scatterplot (bottom right) shows that the linear relationship between ASI Total scores and extracted activation (total cluster eigenvariate) within the right insula was similar for the health control (HC; n = 22; r2 = .41), and small animal phobic (SAP; n = 17; r2 = .55) groups. Activation is significant at p < .05 (FDR corrected), k ≥ 5.

Figure 2

The leftmost panel shows a maximum intensity projection of the entire cluster of correlated voxels within the right insula resulting from the correlation between Total ASI scores and activation resulting from the Masked Fear > Masked Neutral contrast (p < .05 [FDR corrected], k ≥ 5). The three scatterplots show the individual associations between the extracted data from this cluster and each of the three factor indices from the ASI, including Physical Concerns (r2 = .36), Mental Concerns (r2 = .14), and Social Concerns (r2 = .03).