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

Right Brain vs. Left BrainRight Brain vs. Left Brain

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

Temporal LobeTemporal Lobe•Speech•Memory•Hearing

Wernicke and Broca’s AreaWernicke and Broca’s Area

Part of Brodmann’s AreaPart of Brodmann’s Area

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

Geschwind’s TerritoryGeschwind’s Territory

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

Dr. Joe Piven, UNC Chapel HillDr. Joe Piven, UNC Chapel HillM.I.N.D. Institute Lecture Series, UC Davis, M.I.N.D. Institute Lecture Series, UC Davis,

February 7, 2007February 7, 2007