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Brain Based Pathology of Brain Based Pathology of Autism Spectrum DisordersAutism Spectrum Disorders
Asynchronous Webinar Asynchronous Webinar
877.551 Survey of Autism 877.551 Survey of Autism
Graduate Certificate in the Graduate Certificate in the Education of Students with Autism: Education of Students with Autism:
Hybrid ModelHybrid Model
Chris SwansonChris Swanson
Johns Hopkins UniversityJohns Hopkins University
Everyday AutismEveryday Autism
You Tube: http://www.youtube.com/v/AGmXuSY4gx0You Tube: http://www.youtube.com/v/AGmXuSY4gx0
The Parts of the BrainThe Parts of the Brain
Kailasanath & Fu, HOPES Brain Tutorial – Stanford University, Kailasanath & Fu, HOPES Brain Tutorial – Stanford University, http://www.stanford.edu/group/hopes/basics/braintut/brain.swfhttp://www.stanford.edu/group/hopes/basics/braintut/brain.swf
Brain Structures Implicated in Brain Structures Implicated in AutismAutism
http://kamisjourney.com/autism/brain.php
Brain DevelopmentBrain Development
Abnormally large growth Abnormally large growth spurt at 6 months.spurt at 6 months.
Average weight by Average weight by adolescenceadolescence
Larger head circumferenceLarger head circumference Under Under
connectivity/formation of connectivity/formation of neocortical neural systemsneocortical neural systems
Lack of typical symmetry Lack of typical symmetry
Brain DevelopmentBrain Development
Over development of white matterOver development of white matter Truncation of dendritic treeTruncation of dendritic tree Decreased neuronal connections in Decreased neuronal connections in
cerebellumcerebellum Increased cell density in hippocampus & Increased cell density in hippocampus &
amygdala among other regionsamygdala among other regions Impacts the limbic system – learning, Impacts the limbic system – learning,
memory, behavior & emotionmemory, behavior & emotion
ResearchResearch
Gains since the 1980sGains since the 1980s Focused on High-Functioning ASDFocused on High-Functioning ASD Greatly improved by fMRI and PETGreatly improved by fMRI and PET Evoked Potentials (EPs) – scalp electrodes Evoked Potentials (EPs) – scalp electrodes
measuring response to stimulimeasuring response to stimuli Exogenous Potentials – Reflex reaction to a Exogenous Potentials – Reflex reaction to a
visual stimulivisual stimuli Endogenous Potentials – Mental tasksEndogenous Potentials – Mental tasks EP research not focused on social, language, EP research not focused on social, language,
and reasoning deficitsand reasoning deficits MRI and CT measure topographyMRI and CT measure topography
LanguageLanguage
Cerebrum (forebrain):Cerebrum (forebrain):• Frontal LobeFrontal Lobe• Occipital LobeOccipital Lobe• Parietal LobeParietal Lobe• Temporal LobeTemporal Lobe• Right HemisphereRight Hemisphere• Left HemisphereLeft Hemisphere• Cerebral CortexCerebral Cortex
Corpus CallosumCorpus Callosum
Significant Findings Significant Findings
Less lateralization (MLess lateralization (Müüller et al., ller et al., 1999; Boddaert at al, 2003; Just et 1999; Boddaert at al, 2003; Just et al., 2004)al., 2004)
Reversed asymmetry (Herbert et al., Reversed asymmetry (Herbert et al., 2002; Just et al, 2004)2002; Just et al, 2004)
Suggest left temporal impairmentsSuggest left temporal impairments Significantly longer communication Significantly longer communication
between spheresbetween spheres
Broca’s AreaBroca’s Area
Production of speechProduction of speech Sends information for oral-motor Sends information for oral-motor
activitiesactivities Typical impairments seen in Typical impairments seen in
stutterersstutterers
Wernicke’s AreaWernicke’s Area
Receptive Language CenterReceptive Language Center Language is recognized and Language is recognized and
understoodunderstood
HippocampusHippocampus
Associative Associative memory and memory and chainingchaining
Spatial navigationSpatial navigation Behavior InhibitionBehavior Inhibition Inconsistent Inconsistent
findings, but findings, but altered sizealtered size
Frontal LobeFrontal Lobe
Executive Functioning Executive Functioning • Behavior InhibitionBehavior Inhibition• Linked causal relationshipsLinked causal relationships• Similarities and differencesSimilarities and differences• Long-term memory Long-term memory • Organization and planningOrganization and planning• Information retrievalInformation retrieval• Emotional regulation/motivationEmotional regulation/motivation• Higher-level abstract reasoningHigher-level abstract reasoning
Parietal LobeParietal Lobe
Integrates sensory informationIntegrates sensory information Knowledge of numbers and relationsKnowledge of numbers and relations Manipulation of objectsManipulation of objects Contributes to visuospatial Contributes to visuospatial
processingprocessing
Occipital LobeOccipital Lobe
Processes visual information and Processes visual information and sends to the visual cortexsends to the visual cortex
Dysgraphia seen in occipital Dysgraphia seen in occipital impairments impairments
Cingulate CortexCingulate Cortex
Ridge in the medial part of the brainRidge in the medial part of the brain Connects to the thalamus, neocortex, Connects to the thalamus, neocortex,
and the cerebral cortexand the cerebral cortex Works with the limbic system to Works with the limbic system to
control emotion, learning, and control emotion, learning, and memorymemory
Unconscious priming (executive Unconscious priming (executive function)function)
Social FunctioningSocial Functioning
•Deficits in social perception:
•Reading facial expressions•Social cognition/Theory of Mind•Social Motivatoin
Fusiform GyrusFusiform Gyrus
Small ridge on the underside of the Small ridge on the underside of the temporal lobetemporal lobe
Designed to discriminate faces from Designed to discriminate faces from other objectsother objects
Fusiform Face Area (FFA) – recognition of Fusiform Face Area (FFA) – recognition of facesfaces
Superior Temporal Sulcus (STS) – Superior Temporal Sulcus (STS) – recognition of human speech and other recognition of human speech and other non-verbal social cues from other soundsnon-verbal social cues from other sounds
Fusiform Gyrus Fusiform Gyrus
Waiter et al (2004) found enlargement in ASDWaiter et al (2004) found enlargement in ASD Specific enlargements seen in the FFA regionSpecific enlargements seen in the FFA region
AmygdalaAmygdala Pre-frontal cortexPre-frontal cortex Temporal lobeTemporal lobe Frontal lobeFrontal lobe
BehaviorBehavior
Outward AggressionOutward Aggression Self-InjurySelf-Injury Repetitive Repetitive StereotypicStereotypic Self-StimulatorySelf-Stimulatory
CerebellumCerebellum
Sensory perception and motor controlSensory perception and motor control Increased size/ white matterIncreased size/ white matter Lack of vermis originally theorizedLack of vermis originally theorized
AmygdalaAmygdala
Social behavior, Social behavior, emotion, cognitionemotion, cognition
Inconsistent Inconsistent findingsfindings
Range in sizesRange in sizes Asperger’s shows Asperger’s shows
larger left side larger left side amygdala than amygdala than infantile autisminfantile autism
Amygdala & EmotionsAmygdala & Emotions
YouTube: http://www.youtube.com/watch?v=K9BErDQF3CUYouTube: http://www.youtube.com/watch?v=K9BErDQF3CU
Basal GangliaBasal Ganglia
Associated with Associated with motor and learning motor and learning (group of (group of structures)structures)
Speculated cause Speculated cause of repetitive of repetitive behaviorsbehaviors
Larger the caudate, Larger the caudate, the more repetitionthe more repetition
ThalamusThalamus
Kind of connector – Kind of connector – arousal, alertness, arousal, alertness, sleep, sleep, consciousness, consciousness, information information processingprocessing
Underdeveloped Underdeveloped connectionsconnections
Corpus CallosumCorpus Callosum
White matter that connects the White matter that connects the hemisphereshemispheres
Some studies report reduction in sizeSome studies report reduction in size Don’t know muchDon’t know much
BrainstemBrainstem
Controls body Controls body functionsfunctions
Contrasting Contrasting findingsfindings
How this Impacts LearningHow this Impacts Learning
Needs:Needs:• AbstractionAbstraction• Conceptual reasoningConceptual reasoning• Memory and languageMemory and language• Spatial reasoningSpatial reasoning• Sensoriperceptual reasoningSensoriperceptual reasoning• Motor abilities (Rumsey & Hamburger, Motor abilities (Rumsey & Hamburger,
1988/1990)1988/1990)
HFA/Asperger’sHFA/Asperger’s
Enhanced Abilities:Enhanced Abilities:• AttentionAttention• Sensory perceptionSensory perception• Elementary motor planningElementary motor planning• Simply memorySimply memory• Formal languageFormal language• Rule learningRule learning• Visuospatial processingVisuospatial processing