The Role of Specific
Brain Areas in
Autism Spectrum
Disorders
PSY- 725
Biological Bases of Behavior
Unit 3 Project
Autism Spectrum Disorders
according to the DSM IV- TR…
(I) A total of six (or more) items from (A), (B), and (C), with at least two from (A), and one each from (B) and (C)
(A) qualitative impairment in social interaction, as manifested by at least two of the following:
1. marked impairments in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body posture, and
gestures to regulate social interaction
2. failure to develop peer relationships appropriate to developmental level
3. a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people, (e.g., by a lack of showing, bringing,
or pointing out objects of interest to other people)
4. lack of social or emotional reciprocity ( note: in the description, it gives the following as examples: not actively participating in simple
social play or games, preferring solitary activities, or involving others in activities only as tools or "mechanical" aids )
(B) qualitative impairments in communication as manifested by at least one of the following:
1. delay in, or total lack of, the development of spoken language (not accompanied by an attempt to compensate through alternative
modes of communication such as gesture or mime)
2. in individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others
3. stereotyped and repetitive use of language or idiosyncratic language
4. lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level
(C) restricted repetitive and stereotyped patterns of behavior, interests and activities, as manifested by at least two of the following:
1. encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity
or focus
2. apparently inflexible adherence to specific, nonfunctional routines or rituals
3. stereotyped and repetitive motor mannerisms (e.g hand or finger flapping or twisting, or complex whole-body movements)
4. persistent preoccupation with parts of objects
(II) Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years:
(A) social interaction
(B) language as used in social communication
(C) symbolic or imaginative play
(III) The disturbance is not better accounted for by Rhett's Disorder or Childhood Disintegrative Disorder
(APA, 2000)
So what is autism?
•
The WHO says it is a spectrum of psychological conditions which is characterized by pervasive
abnormalities in social interactions and communication as well as restricted interests and repetitive
behavior.
•
Today, an estimated 1 in every 110 children is diagnosed with autism. An estimated 1.5 million
people in the U.S. and tens of millions worldwide are affected by autism. Government statistics
suggest the prevalence rate of autism is increasing 10-17% annually. Improved diagnosis and
environmental influences have been given as two reasons for this marked increase. Studies
suggest that boys are more likely than girls to develop autism and will receive the diagnosis three to
four times more frequently. Current estimates are that in the US, one out of 70 boys is diagnosed
with autism.
•
Exact causes of autism spectrum disorders are unknown. There is no conclusive evidence that
vaccinations are responsible. Evidence does suggest that there are multiple genetic and neurologic
components to the disorder.
(Autism Speaks, WHO)
Autism & ___________:
• The Amygdala
• The Anterior Cingulate
• The Basil Ganglia
• The Brain Stem
• The Cerebellum
• The Parietal Lobes
• Wernicke’s Area
The Amygdala
 Located deep within the front
of temporal lobe, just above
hypothalamus gland.
 Involved in emotions, memory,
moderating approach/avoidant
activities.
 Plays key role in regulating fear,
motivation, pleasure
responses.
 Plays key role in social
responses and perceiving
emotions in others.
The Amygdala & Autism
•
Part of the “social brain”: made up of the amygdala, the orbito-frontal cortex (OFC), and the
superior temporal sulcus and gyrus (STG).
•
Processes all types of visceral input and is specifically related to drive related behavior
•
Impairment and neuropathology has shown that there is an impaired fear response in these
monkeys with abnormal amygdala functioning- and individuals with autism that experience
abnormal fear responses and subsequent anxiety due to an inability to regulate normal fears
and anxieties.
•
is essential for normal social interaction, such as facial expression and body postures
•
MRI studies showed that individuals with autism show very little to no activation in the
amygdala while interacting with others (i.e. making eye contact, interpreting others'
behavior), while individuals without autism had activity in the amygdala area during the MRI
scans and while trying to interpret others' behavior
•
Size has been the focus of studies which have determined that amygdala enlargement was
correlated with autism and joint attention
(Amaral, 2003; Baron-Cohen et al., 2000; Brothers, 1990; Bachevalier, 1991; Mosconi, 2009)Muris et al, 1998)
The Anterior Cingulate Cortex
 Involved in the Limbic System
 Regulates blood pressure and
heart rate
 Involved in emotional
awareness of self and others
 Typically involved in effort of
a task, in early learning or
problem solving, working
memory, and information
selection from working
memory
Anterior Cingulate Cortex & Autism
• Alexithymia (and low emotional intelligence) are likely
associated with a deficit in ACC activity during
emotional arousal.
• Anterior (agrandular) insula shares extensive,
reciprocal anatomic connections with the amygdala &
is involved in perceiving & organizing autonomic
responses to aversive or threatening stimuli and to
emotional behavior. Lesions in the ventral region of
the ACC result in autism spectrum symptoms.
(Phillips, et. al 2003; Taylor, 1999)
The Basal Ganglia
•
Shares close ties with cerebral cortex,
prefrontal cortex and thalamus
•
Acts as a conduit for information to and from
the cerebral cortex
•
Related to cognitive and emotional
functioning
•
Associated with functions such as voluntary
motor control, procedural learning related to
routine behaviors or habits, eye movements,
vision processing.
•
Implicated in action selection, and the
decision on timing of the execution of several
pertinent behaviors.
The Basal Ganglia & Autism
• Elevated dopamine levels in the BG appear to be associated with
unnaturally strong learning mechanisms in the BG which allow for
the details to overwhelm the ability of the PFC to sort information
into categories with the result that the details dominate.
• The BG is implicated in the stereotyped behavior, social,
communicative, and motor/gait dysfunction in Autism spectrum
disorders. Boys with autism showed significant compression in the
right anterior-ventral and posterior-dorsal putamen and in the right
anterior caudate and caudate tail; they showed significant
expansion in the mid-dorsal putamen, middle caudate, and
posterior globus pallidus.
(Qui, et. al, 2010; Trafton, 2010)
The Brain Stem
• Consists of a group of structures called the pons,
medulla oblongata and midbrain
• Plays an important role in homeostatis by
controlling autonomic functions such as breathing,
heart rate and blood pressure, etc.
• Can aid in organizing motor movements such as
reflexes and coordinating with the motor cortex and
associated areas to contribute to fine movements of
the limbs and face
• Other areas are responsible for is alertness, sleep,
balance, and the startle response
• Both brainstem and cerebellum have connections
with and affect the function of the limbic system
The Brain Stem & Autism
•
Brainstem and cerebellar components of the brain were found to be significantly smaller in autistic
patients
•
Suggesting that there were early alterations or failures in the development of these areas in the
fetal stages rather than a progressive degenerative process
•
Physiologic studies such as auditory brainstem evoked potentials and short latency somatosensory
evoked potentials have revealed some brain stem dysfuction in those with autism.
•
Neuroraudiologic studies have shown cerebellar hypoplasia (an incomplete or underdeveloped
cerebellum) and/or a small brain stem including the midbrain, pons, and medulla oblongata in
those with autism
•
Neurotransmitters -- serotonin and dopamine-- arise mainly in the brainstem and project into the
limbic system, cortical areas, and basal ganglia, which may lead to the symptoms seen in autism
(Hashimoto, et. al, 1995)
The Cerebellum
• Continuously folded layer of thin neural tissue which
appears to be striated but is actually a single tissue folded
like an accordion.
• Thought to be primarily responsible for gross & fine motor
control and motor learning
•Role in motor learning is to adjust to changes in
sensorimotor relationships and for regulating motor timing
• Consists of numerous types of neurons, most notably
Purkinje cells and granule cells.
• Each Purkinje cell connects with as many as 500 to 1000
parallel fibers & receives two types of input from parallel
fibers creating a massive action potential in the Purkinje cell
which causes burst of action potentials from the cell
•It is thought that this burst of action potentials creates a
long lasting change in parallel fiber inputs and may be an
indicator of new learning and new neural pathways being
created
The Cerebellum & Autism
• Damage to the cerebellum may result in some behaviors seen in children
with Autism and associated disorders such as lack of awareness of body
and feet, lack of awareness of space, hyperactivity and poor coordination
• The link between the hippocampus and the cerebellum is essential in
learning conditioned responses and a deficit in the timing of the
connection in the cerebellum may interfere with learning
• Occupation or activation of the cerebellum through fine motor movement
such as finger tapping may allow for children with autism to focus on
learning new CR
• The cerebellum may play a role in the interpretation of bodily sensations,
evidence from PET scans has shown activation in areas of the cerebellum
when individuals are read stories about bodily sensations.
(DeSchettuer & Steuber, 2009; Kotani, et at., 2003; Saxe & Powell, 2006; Woodruff-Pak, 1999)
The Parietal Lobes
• Positioned above (superior to) the occipital lobe
and behind (posterior to) the frontal lobe
• Play important roles in integrating sensory
information from various parts of the body
• Involved in the understanding of numbers and
their relations (like mathematics) and in the
manipulation of objects
• Portions are involved with visuospatial processing
• Left parietal-temporal damage can effect verbal
memory and the ability to recall strings of digits
• Right parietal-temporal lobe is concerned with
non-verbal memory
The Parietal Lobe & Autism
• Magnetoencephalographic readings obtained while
administering performance of tasks dependent upon
executive function showed that the children on the
ASD continuum lacked the long range, fronto-parietal
coordinated activity that was observed in the control
group of children
• Children with ASD tend to perseverate and show
reduced brain flexibility to move from an old rule to a
new rule, as demonstrated in a card sorting task
(Perez-Velasquez, J.L., et. al., 2009)
Wernicke’s Area
 Located on the superior
surface of the temporal lobe
between the angular gyrus and
the auditory cortex in the left
hemisphere.
 Specializes in storing the
sounds that make up words,
working closely with Broca’s area
(controlling mouth and lips in
motor area).
Wernicke’s Area & Autism
• One theory suggests that areas that support
communication in autistic individuals do not
coordinate well with each other. Difficulties in
sentence comprehension and working
memory contribute to the social challenges
that autistic children experience.
(Kana, et al. 2006)
Summary
It would appear that the aforementioned brain structures and areas are
implicated in the myriad of symptoms that mark Autism Spectrum
disorders. The pervasive nature of these symptoms is clearly illustrated in
the extent to which the brain areas and structures are interconnected and
affected by one another.
Research has found that the amygdala may contribute to autism via an
impaired fear response due to the inability to regulate normal fears and
anxieties. The anterior cingulate cortex plays a role in alexithymia. The
basal ganglia is implicated in the stereotyped behaviors and the fixation on
certain minutiae found in autism. The brain stem has been seen to be
involved, as well as the cerebellum. Dysfunction in the parietal lobes
interferes with the ability to integrate sensory information and to adapt to
changes in the environment or to rules. And even Wernicke’s area has its
part in the communication difficulties often found in autism.
Special Thanks To:
The Amygdala: Adrian Kruer-Zerhusen
The Anterior Cingulate Cortex: Michelle Minnet
The Basal Ganglia: Margo Townley
The Brain Stem: Steve Milburn
The Cerebellum: John Pacheco
The Parietal Lobes: Jill Thompson
Wernicke's Area: June Martinez
Slides and Narration by Margo Townley
Pictures Courtesy of Google Images
*This has been a brain-on-chocolate production.
References
Amaral, D.G., et al., The amygdala and autism: implications from non-human primate studies, Genes, Brain and Behavior (2003) 2: 295–302
American Psychiatric Association (2000). Diagnostic and statistical manual of mental disorders (4th ed., Text Revision). Washington, DC:
Author.
Autism Speaks website: http://www.autismspeaks.org/what-autism
Bachevalier J. An animal model for childhood autism: memory loss and socioemotional disturbances following neonatal damage to the limbic
system in monkeys. In: Tamminga C, Schulz S, editors. Schi- schizophreniaenia research, Advances in Neuropsychiatry and Psychopharmacology, vol. 1. New York: Raven Press, 1991
Baron-Cohen, S., Ring, H.A., Bullmore, E.T., Wheelwright, S., Ashwin, C. & Williams, S.C. (2000) The amygdala theory of autism. Neurosci
Biobehav Rev 24, 355–364.
Brothers, L. (1990) The social brain: a project for integrating primate behavior and neurophysiology in a new domain. Concepts Neuroscience
1, 27–51.
De Schutter, E., & Steuber, V. (2009). Patterns and pauses in purkinje cell simple spike trains: Experiments, modeling and theory.
Neuroscience, 162(3), 816-826. doi:10.1016/j.neuroscience.2009.02.040
Hashimoto, T., Tayama, M., Murakawa, K., Yoshimoto, T., Miyazaki, M., Harada, M., & Kuroda, Y. (1995). Development of the brainstem and
cerebellum in autistic patients found. Journal of Autism and Developmental Disorders, Volume 25, No 1. via Ebscohost on 10/3/2011.
Kana, R. K., Keller, T. A., Cherkassky, V. L., Minshew. N. J., & Just, M. A. (2006). Sentence comprehension in autism: thinking in pictures with
decreased functional connectivity. Brain, 129(9): 2484-2493. doi:10.1093/brain/awl164
Kotani, S., Kawahara, S., & Kirino, Y. (2003). Purkinje cell activity during learning a new timing in classical eyeblink conditioning. Brain
Research, 994(2), 193-202. doi:10.1016/j.brainres.2003.09.036
Mosconi M, et al "Longitudinal study of amygdala volume and joint attention in 2- to 4-year-old children with autism" Arch Gen
Psych 2009; 66: 509-16.
Muris, P., Steerneman, P., Merckelbach, H., Holdrinet, I. & Meesters, C. (1998) Comorbid anxiety symptoms in children with
pervasive developmental disorders.J Anxiety Disord 12, 387–393.
Perez-Velasquez, J.L., et. al. (2009). Decreased brain coordinated activity in autism spectrum disorders during executive tasks:
Reduced long-rage synchronization in the fronto-parietal networks. International Journal of psychopathology. 73. p331-349.
Phillips, M. L., Drevets, W. C., Rauch, S. L., & Lane, R. (2003). Neurobiology of emotion perception I: The neural basis of normal
emotion perception. Biological Psychiatry, 54(5), 504-514.
Qiu, A., Adler, M., Crocetti, D., Miller, M. I., & Mostofsky, S. H. (2010). Basal ganglia shapes predict social, communication, and
motor dysfunctions in boys with autism spectrum disorder. Journal of the American Academy of Child & Adolescent
Psychiatry, 49(6), 539-551. doi:10.1097/00004583-201006000-00003
Saxe, R., & Powell, L. J. (2006). It's the thought that counts. Psychological Science, 17(8), 692-699. doi:10.1111/j.14679280.2006.01768.x
Taylor, G. J., Parker, J. A., & Bagby, R. (1999). Emotional Intelligence and the Emotional Brain: Points of Convergence and
Implications for Psychoanalysis. Journal of the American Academy of Psychoanalysis, 27(3), 339-354. Retrieved from
EBSCOhost
Trafton, A. (2010) Understanding Autism. Taken from: http://www.technologyreview.com/computing/24602/page3/
Woodruff-Pak, D. S. (1999). New directions for a classical paradigm: Human eyeblink conditioning. Psychological Science, 10(1), 13. doi:10.1111/1467-9280.00096
World Health Organization. International Statistical Classification of Diseases and Related Health Problems. 10th ed. (ICD-10).
2006 [cited 2007-06-25]. F84. Pervasive developmental disorders.