Lecture 3.2 Flashcards
What are the 3 anatomical structures that comprise the basal ganglia?
caudate nucleus
putamen
globus pallidus
What forms the striatum?
caudate nucleus + putamen
What forms the lentiform nucleus?
putamen
globus pallidus
What is the role of the basal ganglia?
nuclei participate in the control of body posture and muscle tone and planning initiating movements
What are the functional units of the basal ganglia?
substantia nigra
subthalamic nucleus
Where do axons from the substantia nigra terminate?
caudate nucleus and putamen
Where do axons from the subthalamic nucleus connect?
globus pallidus
What is the main input unit of the basal ganglia?
striatum (putamen)
What is the main output unit of the basal ganglia?
globus pallidus
What is the sensory relay station?
anterior thalamus -> supplementary motor area
lateral thalamus -> primary motor cortex
What is the internal capsule?
projection fibres between the thalamus and frontal cortex
What is the caudate head?
incoming and outgoing fibres to the prefrontal cortex
What is the role of the thalamus?
relay/gating system rich with connections
have efferent and afferent fibres from the cortex and brainstem/cerebellum coursing through
What is the importance of blood supply to the brain?
blood supply must remain constant
supplies nutrients and oxygen which neurons and tissues need for viability
brain uses 20% of the body’s blood
What are the main arteries involved in the Circle of Willis?
anterior cerebral artery
middle cerebral artery
posterior cerebral artery
What does the vertebral artery feed?
forms basilar artery and later PCA
divides into smaller arteries than supply the cerebellum and pons
What does the middle cerebral artery feed?
lateral aspects of the cortex
also internal capsule, basal ganglia, and thalamus
What do the posterior cerebral arteries feed?
medial occipital lobes, inferior temporal lobes, midbrain, thalamus, some subcortical structures
What does the anterior cerebral artery feed?
medial cortex including medial motor and sensory cortices
some aspects of frontal lobe and corpus striatum
What is a stroke?
brain attack
cerebral vascular accident
interruption of blood supply to the brain
What are the strengths and weaknesses of a CT scan?
strengths:
- excellent spatial and temporal resolution
- geometric accuracy
- widely available
weaknesses
- radiation exposure
- limited versatility
What are the strengths and weaknesses of MRI?
strengths:
- low risk
- versatile
- excellent spatial resolution and soft tissue contrast
weaknesses
- no patients with metallic implants
- possible geometric distortion
What are the strengths and weaknesses of SPECT?
strengths:
- versatile
- widely available
weaknesses:
- radiation exposure
- poor spatial and temporal resolution
- nonquantative measurements
What are the strengths and weaknesses of PET?
strengths:
- versatile
- quantitative measurements possible
weaknesses:
- radiation exposure
- low availability, high cost
What are the primary applications of CT scans?
trauma
cerebrovascular disease
congenital malformation
neoplasm
What are the primary applications of MRI?
cerebrovascular disease
infection
white matter disease
What are the primary applications of SPECT?
dementing illness
epilepsy
cerebrovascular disease
What are the primary applications of PET?
differentiation of recurrent tumour from radiation necrosis
What is ischemia?
inadequate blood supply with neuronal and glial cell death
What are the 2 main types of strokes?
embolic - plaque or debris that developed elsewhere travels into the brain and becomes stuck in anblood vessel
thrombotic - blood clot develops in blood vessel within the brain nd reduces flow
- these 2 make up 80%
hemorrhagic - blood vessel within the brain ruptures and bleeds
What are some risk factors for stroke?
obesity, diabetes, heart disease high blood pressure age smoking male sex recent TIA
What are some mechanisms of injury and degeneration in stroke?
local edema (swelling)
diaschisis
infarction
denervation supersensitivity
What is diaschisis?
distant suppression of metabolic activity in regions connected with the area of the CVA
What is infarction?
loss of oxygen and other nutrients leading to neuronal death
What is denervation supersensitivity?
cells previously dependent on proper neuronal functions become supersensitive to loss of or over-stimulations of neurotransmitters and do not function normally
What is a TBI?
traumatic brain injury
bony interior structures tear delicate neurons, fibres, etc.
even within CSF suspension and meningeal layers
many forces (shearing, tearing, rotational, accelerating, deceleration, torsional)
ischemia, edema, hemorrhages, infections
What are some types of TBI?
coup and contrecoup
- coup = brain damage directly under point of impact
- contrecoup = damage to opposite side of brain from where head is struck
open vs. closed head
What are the types of post-traumatic amnesia?
anterograde amnesia = post-onset
retrograde amnesia = prior to onset
What are some types of progressive neurodegenerative diseases?
motor neuron diseases (ALS)
dementia syndrome (multiple diseases)
substantia nigra degeneration (Parkinson’s)
demyelination (MS)
neurotransmitter and protein changes
What is spontaneous/natural recovery?
usually 1-3 months but maybe as long as 4-6 depending on severity
non-damaged regions made non-functional temporarily resume function within this period of time
no evidence of plateau
What are some components of recovery?
sparing of functions recovery of functions function reorganization
What is sparing of functions in recovery?
functions/processes dependent on complex, diffusely organized processes
redundancy of organization and multiple controls of functions
What is recovery of functions in recovery?
occurs later on
actual restitution of functions or substitution of new strategies to achieve same goal
What is functional reorganization in recovery?
neuroplasticity concept
secondary systems or processes assume larger roles
revisions to previous primary responsibilities
What are some types of therapy used in recovery?
communication
pharmacotherapy
stem cell
What is optimal delivery for therapy during recovery?
intense weekly interventions
8-13 hours per week for 11-12 weeks
service provided best by SLP
What is neural plasticity?
functional capacity of brain changes, reorganizes neuronal functions and connections
sprouting of neuronal outgrowths
activating latent synapses
Does recover differ based on the hemisphere activated?
R hemisphere alone = worse outcomes
need L hemisphere in recovery
What are the described recovery curves for ischemic stroke, hemorrhagic stroke, TBI, and neurodegenerative diseases?
ischemic: negative accelerating curve
hemorrhagic and TBI: stair step
neurodegenerative diseases: negative declining curve
What is tPA?
tissue plasminogen activator
given through IV
only FDA approved treatment for ischemic strokes
dissolves clots, improves blood flow
must be within 3-4 hours of onset on ischemic CVA only
What are the 10 principles of plasticity in recovery? (U2SRITSATI)
use it or lose it use it and improve it specificity repetition matters intensity matters time matters salience matters age matters transference plasticity interference
What is meant by use it or lose it in recovery?
failure to drive specific brain functions can lead to functional degradation
What is meant by use it and improve it in recovery?
training that drives a specific brain function can lead to an enhancement of that function
What is meant by specificity in recovery?
nature of training experience dictates nature of plasticity
What does repetition matters mean in recovery?
induction of plasticity requires sufficient repetition
What does intensity matters mean in recovery?
induction of plasticity requires sufficient training intensity
What does time matters mean in recovery?
different forms of plasticity occur at different times during training
What does salience matters mean in recovery?
training experiences must be sufficiently salient to induce plasticity
What does age matters mean in recovery?
training induced plasticity occurs more readily in younger brains
What does transference plasticity mean in recovery?
plasticity in response to training experiences enhances acquisition of similar behaviours
What does interference mean in recovery?
plasticity in response to one’s training experiences can interfere with acquisition of other behaviours
What are the key factors influencing prognosis?
biological
- age, sex, handedness, education
social
- occupation, social connectedness
neurological
- etiology, size and site of lesion
no single negative factor super potent
What is potentially the most influential factor on prognosis?
severity of aphasia at onset
- global aphasia = most severe, poorest recovery profiles
- anomic aphasia = best recovery profiles
site and size of lesion also matters
How can linguistic abilities affect prognosis?
good: auditory comprehension, writing, verbal skills, visual matching = good recovery profile
also stimulability for correction, self-correction, and strong gestural abilities
unclear results on bilingualism studies
What factors are not good predictors of recovery for aphasia?
handedness
age
sex
Can education affect prognosis?
higher education levels may show faster rate
higher intelligence = better chances of good recovery
What types of health issues can slow recovery?
sensory delays
motor limb and motor speech problems
medical and psychiatric conditions
How can time post-onset affect prognosis?
poorer recovery the longer language and communication treatment is delayed
delay does not capitalize on effects of spontaneous recovery
How can personality and emotional status affect prognosis?
social environment helpful for prognosis
disinhibition and co-occurring depression can negatively impact recovery
