GAZE FIXATION AND THE NEURAL CIRCUITRY OF FACE PROCESSING

IN AUTISM

Sakina Dharsee

Psychology - 260

Introduction• Autism: Developmental disorder, unique profile of social and emotional behavior.

• Symptomatology: Diminished gaze fixation, lack of social or emotional reciprocity.

Previous research: Fusiform gyrus less activated in autistic patients.

Deficit: Which circuits are highly activated compared to normal?

Hypothesis

• Fusiform gyrus hypoactivation - Less time fixating on eye regions: Cause or consequence?

• Hyperactivation in amygdala (region responsible for processing threatening, social and emotional cues)

Experimental TaskStimulation: Mock-up of MRI scanner.MRI ScanEye movement: Eye-tracking device.

Study 1:• 14 autistic males (M:15.9, SD: 4.71)• 12 normal males (M: 17.1, SD: 2.78)• Task: Is the picture emotional or neutral?• Half straight, half turned.

Study 2:• 16 autistic males (M:14.5, SD: 4.60)• 16 normal males (M: 14.5, SD: 4.56)• Task: Is the picture familiar to you?• Ten photographs of family or friends.

ResultStudy 1:

Autistic group: • Longer judgement time for emotional and straight ahead faces.• Significantly less time fixating on eyes.• More activation in left amygdala.

Control group:• More activation in bilateral fusiform gyrus.

a – Right fusiform gyrusb – Left fusiform gyrus

Study 2:

Control group:• More activation in bilateral fusiform gyrus.

Autistic group:• Significantly less time fixating on eyes.• More activation in right amygdala.• No differences in judgement time.

Average duration of fixation on mouth, eye region and face in

general.

Study 2: e – Right amygdalaStudy 1: g – Left amygdala

Discussion• Individuals with autism scan and process faces differently.

• Deficits in processing emotional cues and in processing socially engaging faces.

• Greater amygdala activation in autistic group for both studies.

• Eye fixation creates a negative over-arousal mediated by the amygdala – diminished gaze fixation reduces this.

Negative over-arousal

Increased sensitivity to social stimuli

Diminished gaze fixation

Hypoactivation of fusiform gyrus

Strengths and LimitationsStrengths:

• Experimental control.• Attempt to reduce performance anxiety. • Stimulation session.

Limitations:

Future directions: - Lateralization of amygdala – left for emotion, right for familiarity? (Baas et al., 2004)- Treatment research: Can autistic patients be trained to scan and process faces normally, resulting in normal levels of fusiform gyrus activation?

• Based solely on data obtained from males.• Inconsistency.

Personal Opinion• Congruent with previous findings, and makes a new discovery.

• Research can contribute towards the treatment and counselling of autistic children.• Leads into further research on the disorder – what are the circuits associated with other symptoms?

Thank You!Any questions?