FINAL Flashcards
What are the two domains of compromised development that provides the basis of the DSM diagnosis for autsim spectrum disorder
- Social and communication deficits
- Repetitive sensory-motor behaviours and fixated interests
Symptoms emerge in early childhood
What is the prevalence of autism spectrum disorder?
1 in 88
3-4 times as many boys as girls (could be from missed diagnoses based on outward symptoms)
Define social cognition
Learning that occurs through a social context
How do social stimuli affect children?
- Social stimuli are generally more salient for children (caregivers are salient for children)
- Saliency drives attention, attention drives learning at an early age.
Define theory of mind
The ability to attribute mental states to others
- This is a key milestone in development that develops at around 5 years old
Define joint attention
The capacity to coordinate one’s visual attention with the attention of another person
What are fixated interests in ASD?
- Preoccupation with one or more stereotyped and restricted pattern of interest that is abnormal in intesity or focus
- Can lead to Savant Talents
- Prefer routines, become distressed with change
How are genetics related to ASD? (5)
- ASD has a strong genetic contribution
- High heredity and family clustering
- Hundreds of genes identified
- Mix of risk variants and de novo mutations, with mutations more frequent with older parents
- ASD is highly comorbid with other disorders
What is the SCN2A gene?
A gene that encodes the voltage-gated sodium channel Na(v)1.2, which plays an important role in the initiation and conduction of action potentials
What is the growth dysregulation hypothesis of ASD?
Normally well-controlled processes of brain growth and organization go awry, leading to the symptoms of ASD
- growth w/o guidance
- frontal/temporal regions (amygdala)
- 2-4 year old with ASD larger MRI based brain volume
What is the over-pruning hypothesis of ASD?
Too many neurons are pruned in the motor and/or sensory regions
- 8-16 year old with ASD smaller MRI based volume
How are mirror neurons affected in ASD?
- Activity in the anterior component of the MNS was found to be reliably greater in typically developing children
- There is a negative correlation between scores on social subscales and MNS activity
What is the empathizing-systemizing theory in ASD?
- Systemizing is the drive to analyze or construct systems (orderly/patterns)
- There seems to be an inverse correlation between having: below-average empathizing, above-average systemizing
- Males tend to be more systemizers than females
What are some current pharmacological interventions of ASD?
Oxytocin has been used to reduce social impairment in ASD. Oxytocin reduced the tendency for participants with ASD to fixate on the most systemized stimuli.
- Oxytocin is elevated following childbirth and facilitates bonding and empathy
- Mixed results: Some studies show benefits while others do not (which could be related to dosing, timing, heterogeneity of ASD)
Who is the first person to claim that the left hemisphere was asymmetrically dominant for speech?
Marc Dax
How did Broca discover the left hemisphere’s dominance in language?
Paul Broca reported the results of postmortem exams of two aphasic patients that they had diffuse left hemisphere damage, centering in an area of the inferior left prefrontal lobe, just in front of the primary motor face area.
- “LeBrougne” was one of his patients that was only able to say “tan”.
What are the three core symptoms that defines Broca’s aphasia?
- Agrammatism: severe issues using grammar
- Anomia: inability to produce the right words
- Articulation problems
What did Carl Werincke report on?
A new type of language disorder: Wernicke’s aphasia (inability to comprehend language, but can speak fluently)
What was Liepmann’s work with the left hemisphere?
Liepmann showed that apraxia was almost always associated with left hemisphere damage.
What is apraxia?
Difficulty performing movements with either side of the body when asked to do so, but not when performing them spontaneously
What is the Wada Test (aka Sodium Amytal test)?
- Sodium amytal is injected into one carotid artery; this anesthetiezes the ipisilateral hemisphere and allows the abilitites of the contralateral hemisphere to be assessed.
- Administered to patients prior to neurosurgery to determine side of speech lateralization.
What is the dichotic listening task?
- Two different syllables played to different ears.
- The ear that hears one sound the most means that the contralateral hemisphere is dominant for language
What has fMRI data shown for lateralization?
- During word generation task, (where participants are shown a probe letter and have to think of as many words starting with that letter as possible within 30s) increased fMRI activation found in the dominant hemisphere
- During passive listening there is increased activation in the dominant hemisphere
- There is still some activation in the non-dominant hemisphere though!
What did the study by Hausmann find in regards to lateralization?
When participants spoke, a majority opened the right half their mouth slighty more than the left
What are the statistics for laterality and handedness?
- Left hemisphere dominance: 88% of right-handers, 78% of left-handers
- Ambilateralization: 12% of right-handers, 15% of left-handers
- Right hemisphere dominance: 0% of right-handers, 7% of left-handers
What are the sex differences in laterality?
- Early research seemed to suggest that the brains of males are more lateralized than those of females
- However, more recent evidence has failed to confirm this
What ability displays the greatest degree of laterality?
Language
What is the Wernicke-Geschwind model of language for responding to a heard question?
- Auditory language information is heard by the primary auditory cortex, which then travels to Wernicke’s area where comprehension occurs, and the thought of the response is generated.
- Then to Broca’s area, where the program of articulation is gneerated and passed to the primary motor cortex
What is the Wernicke-Geschwind Model of reading aloud?
- Words read aloud “read” by primary visual cortex
- Information travels to the angular gyrus, where it is translated into an auditory form
- Information then travels to Wernicke’s area for comprehension and response-thought generation
- Then to Broca’s area and the primary motor cortex, for output
What is the current status of the Wernicke-Geschwind Model of language? (4)
- Broca’s and Wernicke’s area are important in language
- Expressive aphasia generally results from anterior damage
- Receptive (fluent) aphasia generally results from posterior damage
- Little support for other aspects of the model
What are 5 problems with the Wernicke-Geschwind model of language (not including stimulations)?
- No aphasic patients have damage restricted only to Broca’s area or Wernicke’s area
- Aphasic patients almost always have significant damage to subcortical white matter
- Damage associated with aphasia is usually not related to damage to Wernicke-Geschwind areas
- Large anterior lesions are more likely to produce epxressive symtoms, while large posterior lesions are more likely to produce receptive symptoms
- Fails to consider roles of subcortical structures, like the cerebellum
What are other problems with the Wernicke-Geschwind model of language (in terms of stimulation experiments)?
Stimulations of brain regions are more diffuse than the regions outlined by the model
What are the 3 premises of the cognitive neuroscience approach to language?
- Constituent cognitive processes
- Language areas are not exclusive
- Areas are small and widely distributed
What is the dual stream model of language?
- Dorsal stream for sensorimotor integration (mostly dominant)
- Ventral stream for speech comprehension (bilateral)
What is aphasia?
- Aphasia is a disorder that results from dysfunction of the brain’s language systems
- The disorder can impair the expression and/or understanding of language, as well as reading + writing
Describe the progession of aphasia
Usually occurs suddenly, often following a stroke or head injury, but it may also develop slowly, as the result of a brain tumor or neurodegenerative disease
What is another condition that can co-occur with aphasia?
May co-occur with other speech disorders, such as apraxia of speech
What is global aphasia?
- Speech is not fluent
- Lack of language comprehension
- Cannot repeat words or phrases
- Damage to extensive portions of the language networks
What is Broca’s aphasia?
- Speech is not fluent
- Has language comprehension
- Unable to repeat words/phrases
What is Wernicke’s aphasia?
- Fluent speech
- Lack of language comprehension
- Cannot repeat words/phrases
What is anomic aphasia?
- Speech is fluent
- Has language comprehension
- Can repeat words/phrases
- Word retrieval failures and cannot express the words they want to say (particularly nouns + verbs)
- Lesions associated are the least well-defined, spanning a wide range of areas in the left hemisphere
What is primary progressive aphasia?
- A syndrome wherein language capabilities become slowly and progressively impaired
- Unlike other forms of aphasia, it is usually cuased by neurodegenerative diseases (e.g. Alzheimer’s Disease), where there is progressive damage to language related areas
What are 4 factors that influence recovery from aphasia?
- Cause of injury
- Area and extent of damage
- Age
- General health