Aberrant brain activation during gaze processing in boys with fragile X syndrome.

CONTEXT

Eye contact is a fundamental component of human social behavior. Individuals with fragile X syndrome (fraX), particularly male subjects, avoid eye contact and display other social deficits. To date (to our knowledge), this behavior in fraX has been studied only in female subjects, who show lesser degrees of gaze aversion.

OBJECTIVE

To determine the neural correlates of the perception of direct eye gaze in adolescent boys with fraX using functional magnetic resonance imaging.

DESIGN

Cross-sectional study.

SETTING

Academic medical center.

PARTICIPANTS

Thirteen adolescent boys with fraX, 10 boys with developmental delay, and 13 typically developing control subjects.

MAIN OUTCOME MEASURES

Behavioral performance and brain activation during functional magnetic resonance imaging were evaluated during the presentation of faces with eye gaze directed to or averted away from subjects and during successive presentations of stimuli with eye gaze directed toward the subject. Whole-brain and region of interest analyses and regression analyses with task performance were performed.

RESULTS

Significantly greater activation was observed in prefrontal cortices in controls compared with boys having fraX, who (in contrast) demonstrated elevated left insula activation to direct eye gaze stimuli. Furthermore, compared with controls, boys with fraX showed greater sensitization in the left amygdala with successive exposure to direct gaze.

CONCLUSIONS

Compared with controls, boys with fraX display distinct patterns of brain activation in response to direct eye gaze. These results suggest that aberrant neural processing of direct eye gaze in subjects with fraX may be related to the associated avoidant response.