week 8 part 1 Flashcards
Define Neurodevelopmental disorder
Group of the disorder in which the development of the CNS is disturbed
What can neurodevelopmental disorder include?
- Developmental brain dysfunction
2. manifest as neuropsychiatric problems or impaired motor function, learning, language or non-verbal communication.
What are examples of Neurodevelopmental disorder?
- Down syndrome
- Fragile X
- Rett Syndrome
- Autism spectrum disorders - social awareness and communication
- Other disorders which are classified as neurodevelopmental or as learning disability
What is the history of Autism?
First described by a Swiss psychiatrist, Paul Eugen Bleuler in 1912 to describe symptoms of schizophrenia
What did Hans Asperger describe?
Child psychology in 1938
Reported 4 boys, did not mix with their peer group
did not understand the meaning of terms ‘‘respect’’ and ‘‘polite’’
show unnatural stereotypic movement and habits
now called Asperger’s syndrome
What did Leo Kanner report . in 1943?
8 boys and 3 girls with ‘‘inability to form the usual biologically provided affective contact with people’’
What does autism affect?
1% of the population
Where is Autism detectable?
in children before the age of 3 years old
Where does autism occur in?
All countries, ethnic backgrounds and socioeconomic groups
When is significant changes in development noticed?
between 6 months and 1 years of life
what are some features of autism?
- baby does not turn when called by name
- unusual visual exploration
- lack of preference for people vs objects
- Repetitive use of objects (spinning)
What are the symptoms of 18 months of age?
- Do not automatically direct their attention to the person or object that is the focus of others people’s attention
- Fail to use pointing to direct attention of other people; fail to engage in ordinary make–up play
- signs of delayed and abnormal language development are evident
What is autism?
life-long but not progressive
What leads to marked improvements in behaviour with age?
Special educational programmes and support
What are the three common diagnostic features of ASD?
- Impaired social interaction
- Impaired verbal and non-verbal communication
- Restricted or circumscribed interests with stereotyped behaviours
What does Aspergers show?
Many features of autism
but have a high verbal ability and no delay in language acquisition
What does theory of mind refer to?
Ability to understand the desires, intentions and beliefs of others
skill that develops between 3 and 5 years of age in typically developing children
What is Sally Anne test used in?
Psychological research to investigate ‘‘Theory of Mind’’ in children with autism
who was Sally-Anne study conducted by?
Simon Baron-Cohen
What did Simon Baron-Cohen test?
theory of mind in 3 groups of children:
- Those with autism
- Those with Down’s syndrome
- Control group with no developmental disroder
What did study of Sally-Anne involve?
showing children a story involving two dolls called Sally and Anne
They were shown Sally putting her ball in a basket and leaving the room, while she was out of the room, Anne moved the ball from the basket to her box
When sally came back, the child was asked where Sally would look for her ball and if they had developed theory of mind
They would say in the basket because that there is where Sally left it and she did not know it has been moved
What was the result of the Sally-Anne study?
Most of the control group and most of the children with Down’s Syndrome gave the correct answer but only 20% of those with autism provided the right answer
What is the Genetic component in Autism?
- comes from studies of monozygotic twins
- shows 60-90% concordance of autism
- Dizygotic twins show 10-30% concordance when full autism spectrum is considered
What is ASD usually?
Result of mutations in many genes
What are genetic factors of Autism?
Mutations in genes which are involved in synaptogenesis and axon motility
leading to microstructureal, macrostructural and functional abnormalities in connectivity which is involved in sociomotional processing
What are Environemntal factors of Autism?
- Prenatal
- Perinatal
- Postnatal
All include possibility of viral infections
What do some of the genes associated with ASD involve?
- synaptic proteins
2. Cell adhesion scaffolding proteins that are necessary to organise synapses structurally
Microstructurally
Altered ration of short-to long diameter axons and disorganisation of cortical layers observed
Macrostructurally
MRI studies of brain vole
show cortical and subcortical grey matter overgrowth in early brain development
Functionally
Resting state FMRI
show a narrative of widespread global underconnectivity in socioemotional networks
Task-based FMRI
show decreased activation of networks involved in socioemotional processing
Electrophysiological studies
shows alteration in both resting state and stimulus induced oscillatory activities in patients with ASD
What are some examples of genes associated with Autism?
- SHANK3 - SH3 and multiple ankyrin repeat domain 3
- NRXN1 - Neurexin 1
- CNTN3 - Contactin 3
What gene is associated with Fragile X syndrome?
FMR1
What is neurodevelopmental Disorders and mRNA metabolism?
• Complex and delicate process; depends on tight regulation of gene expression
- Once the genes are transcribed theres a lot of processing that happens in the neurons especially, in the nervous system the amount of post-transcriptional processing of messengers is massive, alternative splicing is the largest within the whole organism so all of this needs to be controlled precisely during development
What does the spatial and temporal regulation of gene expression during development lead to?
Establishment of properly connected neuronal networks
What are early stages of brain development highly susceptoble to?
small changes in MRNA stability and translation
What are the regulatory process important for transcriptome regulation and protein synthesis?
- mRNA nuclear export
- Splicing
- Nonsense-mediated decay
- Translation
Why is localization of mRNA in neurons important?
morphologically specialized cells with long processes
When is mRNA not translated immediately?
As it exists the nucleus but is rather stored and transported to the right location to access terminals and dendrites and then is translated in a signal dependent manner