Facial emotion recognition in agenesis of the corpus callosum

Abstract

Background: Impaired social functioning is a common symptom of individuals with developmental disruptions in callosal connectivity. Among these developmental conditions, agenesis of the corpus callosum provides the most extreme and clearly identifiable example of callosal disconnection. To date, deficits in nonliteral language comprehension, humor, theory of mind, and social reasoning have been documented in agenesis of the corpus callosum. Here, we examined a basic social ability as yet not investigated in this population: recognition of facial emotion and its association with social gaze.

Methods: Nine individuals with callosal agenesis and nine matched controls completed four tasks involving emotional faces: emotion recognition from upright and inverted faces, gender recognition, and passive viewing. Eye-tracking data were collected concurrently on all four tasks and analyzed according to designated facial regions of interest.

Results: Individuals with callosal agenesis exhibited impairments in recognizing emotions from upright faces, in particular lower accuracy for fear and anger, and these impairments were directly associated with diminished attention to the eye region. The callosal agenesis group exhibited greater consistency in emotion recognition across conditions (upright vs. inverted), with poorest performance for fear identification in both conditions. The callosal agenesis group also had atypical facial scanning (lower fractional dwell time in the eye region) during gender naming and passive viewing of faces, but they did not differ from controls on gender naming performance. The pattern of results did not differ when taking into account full-scale intelligence quotient or presence of autism spectrum symptoms.

Conclusions: Agenesis of the corpus callosum results in a pattern of atypical facial scanning characterized by diminished attention to the eyes. This pattern suggests that reduced callosal connectivity may contribute to the development and maintenance of emotion processing deficits involving reduced attention to others' eyes.

Keywords: Corpus callosum; Corpus callosum agenesis; Facial emotion.

Figure 1

Sample Ekman image overlaid with region of interest map used in eye-tracking analyses. Modified from Pictures of Facial Affect[53] with permission from Paul Ekman Group.

Figure 2

Emotion recognition accuracy by group and stimulus emotion. Accuracy of emotion recognition for upright faces (A), inverted faces (B), and the difference between correct recognitions for upright minus inverted faces (C). AgCC group in red and control group in blue. Black circles mark the accuracy of individuals with AgCC who met current criteria for autism spectrum.

Figure 3

Average rating matrices by group for emotion recognition tasks. AgCC (A) and control group (B) rating matrices. Ekman stimulus classification is on the x-axis, and the response category is on the y-axis. Each cell represents the relative number of times (percent) that a specific response was given for a specific Ekman stimulus category. Concordant ratings fall along the diagonal. (C) Difference between the matrices in (A) and (B) (AgCC group minus control group). Ang angry, Dis disgust, Fea fear, Hap happy, Neu neutral, Sur surprise.

Figure 4

Eye-tracking results by group for each task and each region of interest. Fractional dwell time (A) by group and region of interest for gender identification, emotion recognition with upright faces, emotion recognition with inverted faces, and passive viewing of faces. Average number of fixations per trial (B) by group and region of interest for emotion recognition with upright faces, emotion recognition with inverted faces, and passive viewing of faces. AgCC group in red and control group in blue. Black circles mark the eye-tracking results of individuals with AgCC who met the current criteria for autism spectrum.