Lecture 6 - Autism, Asperger's, ADD, ADHD Flashcards
What is the heritability of autism?
?????
5%
What are the proposed causes of Autism?
*******√
•Maternal infections
- Rubella, Herpes, TBC, PKU
- might cause other disorders too, like adhd
• Mirror cells are either absent or non-functional
- enlarged brain size in childhood
What is the prevelance of ADHD?
*******
- 4-5% of children, more common in boys
- 60% keep it as adults: leads to them being antisocial and doing drugs
- Common to see in adult prisoners
Outline the ‘A: Deficitis in social communication and social interaction across multiple context’ Diagnostic criteria for autism
?????
******
A: Deficits in Social Communication and Social Interaction across multiple contexts
- Deficits in social-emotional reciprocity
- back-and-forth, sharing interests, sarcasm, responding to others - Deficits in non-verbal communication
- eye contact/ body language incorrect - Deficits in developing, maintaining and understanding relationships
- problems adjusting behaviour to context
What are the 4 Diagnostic Criteria for Autism
A: Deficits in social communication and social interaction across multiple contexts
B: Restrictive Behaviour
C: Must be present early on in developmental period
D: Symptoms cause significant impairment in areas of functioning
Outline ‘B: Restrictive Behaviour’ Diagnostic criteria for Autism
*******
B: Restrictive Behaviour
- Stereotyped or repetitive moments, use of objects, speech
- Preference for sameness, adherence to routines, ritualised patterns
- Restricted, fixated interests
- Sensory overload
If you meet all 4 criteria what are you diagnosed with?
Autism Spectrum Disorder
If you mainly meet the A criteria what are you diagnosed with?
Social (pragmatic) communication disorder
What are the 4 diagnostic criteria for Social (pragmatic) communication disorder?
?????
******
A: persistant difficulties in the social use of verbal and nonverbal communication
B: This causes limitations in effective communication, social participantion and relationships
C: Onset is in early development
D: Not caused by any other disorder (incl ASD) or low abilities in word structure/ grammar etc
Outline “A: Persistant difficulties in the social use of verbal and nonverbal communication”
?????******
A: Persistant difficulties in the social use of verbal and nonverbal communication
- Deficits in using communication for social purposes
- e.g. greeting/ sharing info - Inability to match communication to context/ needs of listener
- Trouble following conversational rules
- e.g. turn taking, gesticulation, rephrasing if confused - Difficulties understanding what is not explicitly stated
- inferences, nonliteral/ ambiguous language
- take things very literally
Culturally varying depending on rules of conversation in that culture
Outline Mirror Cells
- Mirror Cells in the premotor cortex
- Learning how to do things (hence: motor areas)
- also necessary in doing the thing
- Might be implicated in ASD & Pragmatic Communication Disorders
Outline how we change our facial expression to empathise with other person
?????
- We will change our own facial expression when someone else is crying and share their pain
- Corregator Muscle (between eyebrows) contracts when you’re sad - necessary for empathy as you mirror their facial expression
- Those with Botox cant mirror this facial expression - feel less empathic
- research has found that they experience less depression
Whats the DSM criteria for ADHD?
******
Persistant Pattern of inattention and/ or hyperactivity
- has to be present before 12
- has to be in more than one setting
- generally not focused unless hyper-focus (if really interested)
- persistant pattern over many areas
- Cant be better explained by Sz, or another psychotic disorder: mood, anxiety, dissociative, personality disorders etc - substance abuse
What are gender differences in ADHD roughly?
Girls tend to deal with more attention problems
Boys tend to deal with more hyperactivity problems
What does DSM-5 say ADHD has to interfere with?
- Interefere with or reduce quality of social, academic, or occupational functioning
How many of the symptoms to adults vs children need?
•Adults require 5 or more symptoms
• Children require 6 or more symptoms
- cant be defiance/ reactive - has to be impulsive and hyperactive
What are broad symptoms of inattention (ADD)
Table
- cant sustain or give close attention
- doesnt listen when spoken to
- cant follow instructions
- loses things
- very easily distractable
What are broad symptoms of Hyperactivity & Impulsivity (ADHD)
*******
- Fidgets
- Leaves seat when inappropriate
- Cant play quietly
- Excessive energy, talks, blurts out, cant wait turn
Which Neuropsychological tests do those with ADHD struggle with?
*************
- Spatial working memory - drawing from memory
- Planning & Inhibition - Stroop, mazes,
- Wisconcison card sorting task a bit
- Tower of London test
- Trail making test b (shifting from numbers to letters)
Indicates clear frontal Basal Ganglia issues
What are some potential brain abnormalities in ADHD?
*************
- Enlarged Occipital Lobes
- Smaller Anterior Frontal Regions
- Smaller Caudate Nuclues (In BG)
- Smaller Corpus Callosum
- Higher Density of Dopamine receptors in Caudate and Globus Pallidus (BG) - associated with Dopamine deficit (try and catch it all?)
What do fMRI scans show about brain abnormalities in ADHD?
******
- Hypoactivation in frontostriatal neurons (basal ganglia)
- Ventral PFC and inferior parietal causes issues with motor inhibition and task switching
- can be corrected through DA stimulants
How can Ritalin help ADHD symptoms?
Because people ADHD children are really active, people thought they had too much dopamine, but they actually have a deficit (indicated by the increase of receptors in Caudate and Globus Pallidus
- So ritalin increases amount of dopamine
- this can regulate symptoms
What is SPECT?
*******
single photon emission computed tomography
- looks at metabolism
What has SPECT found in ADHD
*******
- Reduced Cerebral Blood Flow in Frontal lobe and Basal Ganglia
- Increased CBF in occipital
- why they are easily distracted by visual stimuli - Reduced Glucose metabolism during attention tasks in frontal lobes
What is the combination Hypothesis about ADHD?
*******
- the abnormalities in frontal and striatal dopamine is party due to genetics and partly due to environment
Environment + Genes = atypical brain development
What is going wrong at the synpase for those with ADHD?
The problem occurs during reuptake
- Excess dopamine is being reuptaken by DAT - the Dopamine transporter - reuptakes dopamine too much
What was the initial theory about why stimulants work for ADHD patients
- People thought they worked because:
If you are stimulating even more, it means you will swing back like a pendulum and will become calmer - if they are hyperactive, give them a stimulant, it will make them swing back and become calm
Whats the actual reason why stimulants work for ADHD patients?
*******
- Stimulants work by sitting on the DAT receptor and preventing it from reuptaking dopamine
- They block DAT by 60% = more dopamine in synapse
- sitting on D1 receptor, helps inhibition of behaviour - helps them focus and stop being hyperactive
How does cocaine increase dopamine?
Blocks reuptake
- acts on the D1 receptor
- influences reward system (VTA/ PFC)
- Amphetamines do the same thing
Which neurotransmitters does cocaine and amphetamine also effect
*******
Impacts on D1
- Also has effects on Norepinephrine, serotonin, glutamate and acetylcholine
- all associated with reward
What are the effects of inhibiting Dopamine
*******
Euphoria, energy, confidence, libido
- libido can get too high and cause sexual dysfunction
What are short term side effects of blocking dopamine receptors?
*******
- insomnia
- impulsivity
- tachycardia: when heart goes too fast
- anxiety
- Psychosis
- tweaking
- confusion
- panic attacks
- sexual dysfunction
What are long term side effects of blocking dopamine receptors?
- Tolerance increases - paranoia and aggression as effects start wearing off
- Fewer DA neurons in Substantia Nigra - parkinson symptoms
- Overdose = convulsion, strokes
What is the treatment for ADHD?
*******
Methylphenidate (MPH) - also known as Ritalin
- Works like cocaine
- Blocks 60% of DAT receptors
- causes DA to stay in the synapse much longer
Whats the difference between treated and untreated kids?
*******
Treated:
- more DAT in striatum (is this because of treatment?)
Untreated:
- Low DAT density in mesencephalon
- Low DAT in striatal Complex/ caudate
Others:
- no difference in DAT in putamen
How can you argue that DAT is plastic?
DAT is lowered in response to low DA levels
- if low DA, DAT goes down as its not needed
DAT is increased in response to high DA levels
- therefore, if DA is increased via drugs, DAT will go up
What are the 2 genetics tests?
- Candidate Gene approach
- investigate a specific gene on the known chromose location to test their genotype and relate it to a disorder
- know of a specific gene and see if they have it - Genome scan
- do statistics on genetic markers to locate chromosomal regions
- see what they have
What are the 2 possible candidate genes
*******
- Dopamine Transport gene
- DAT Gene - Dopamine receptor type 4/5
- DRD4/5 Gene
Might be a combination of the two causing hypodopaminergic state
- related to lack of frontal inhibition,
- pleasure seeking/ stimuli seeking
- cant inhibit pleasure seeking behaviour
What are the similarities between ADHD and Parksinsons?
*******
Those with ADHD may have higher risk of Lewy Body disease - associated with Parkinsons
- both associated with low levels of DA in SN
Similarities:
•Parksinsons score high on attention deficit and hyperactivity than controls
•But not on impulsivity, oppositional disorder or social adaptation
Link between parkinsons, lewy body and ADHD is probably not genetic
- might implicate similar DA areas/ receptors
Why do Antipsychotics have such a global impact on the brain?
Because they impact the D2 receptors, which are all over the brain
- hence they help motor control as well as disordered thoughts
What are the proposed Heritability causes of ADHD
You inherit a vulnerability to:
•Dopamine receptor genotypes
•Dopamine transporter genotypes
What are the proposed environmental factors causing ADHD?
- Food colouring (debated)
- Sugar (increases hyperactivity - more so in ADHD?)
- Heavy metals (lead = 2-4X higher in ADHD)
- Smoking Mother (2-4X risk during pregnancy)
- Low birthweight/ premature - causes lots of issues
- TBI as children
- Need the genetic vulnerability too
- and these are not exclusive to ADHD as they all often cause other issues
What are tics in tourettes?
Can be:
- Motor: repeitive/ rapid
- Vocal: utterances/ noises
Urge arises, cannot be repressed/ inhibited
What is prevelance of tourettes syndrome?
Rare
- 3-9 in 1000
Boys are 3/4 X more common to get it
Usually gone by adulthood
What is tourettes related to?
*******
Maternal stress, smoking, infections, fetal hypoxia
- note exclusive again
What is Tourettes overlapped with?
Tics can also be seen in ADHD and OCD
- may be related to DA hyperinnervation of striatum
- Used to calm the system down, which is why they increase when they are stressed
- No inhibition from frontal lobes - basal ganglia starts up to calm system down, e.g. via a tic or a checking behaviour
Whats a treatment for Tourettes?
Haldol - an anti-psychotic, a dopamine antagonist
or
Behavioural intervention - teach them to repress the tics etc
How is serotonin involved?
Serotonin inhibts basal ganglia/ PFC
- why prozac helps for OCD
- might help with ADHD or tourettes
