Sakina Dharsee Psychology - 260. Introduction Autism: Developmental disorder, unique profile of...
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Transcript of Sakina Dharsee Psychology - 260. Introduction Autism: Developmental disorder, unique profile of...
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?