diff dx neuro - brain stuff Flashcards
3 principle functions of the brain
- regulating tone or walking= brain stem
- obtaining, processing & storing info
99% of brain fibers are interneurons - programming, regulating & verifying mental activity
hierarchy of brain structures (3)
1. primary areas= projection receive sensory & produce motor 2. secondary areas = association incoming info is processed & motor function is prepared 3. tertiary areas = zones of overlapping most complex form of mental activity
frontal lobe sections (6)
- primary motor area
- premotor area
- supplementary motor area
- frontal eye fields
- prefrontal cortex
- brocas area
motor areas in frontal lobe (3)
controls
- primary motor area
controls complex multijoint movement (hands) - premotor area**
control postural sets before movements (visually guided)
strong interaction with cerebellum - supplementary motor area
controls initiation & planning of movement
types of cells in primary motor area
baetz cells which are monosynaptic with S.C. area they innervate
lesion in premotor area causes (3)
- weakness
- spasticity
- motor apraxia
frontal eye fields in frontal lobe
controls visual tracking, motor aspect of vision
brocas area
location
associated with which type of aphasia
located in frontal lobe
expressive aphasia (non-fluent); problems putting words together to form a sentence (word finding issues) ** understands everything*
frontal lobe syndrome
2 common causes
dorsolateral lesions
general, L & R hemisphere
anterior lesionsPost CVA or TBI (etc….)
dorsolateral lesions => apathy and lack of ability to plan or sequence
if L => poor memory for verbal info
if R => poor memory for spatial info
anterior lesion => impulsive, emotional liability & memory disorders
parietal lobe sections (3) and what they are responsible for
- somatosensory areas
localization of pain, touch, temp, proprioception
*both dorsal colum & spinothalamic synapse here - secondary areas
interpretation (stereognosis & graphesthesia) - association areas
parietal lobe lesions
6 deficits if NON-dominant hemisphere is involved (and definitions)
L side usually dominant (so usually these are the result of R hemisphere lesions)
- left sided neglect
- anosognosia = unaware of deficit, denial of disability
- alexia = inability to read
- agraphia = inability to write
- extinction of bilateral simultaneous stimulation
- ideation apraxia = inability to produce or describe motor tasks
parietal lobe syndrome (lesion in either hemisphere)
ideomotor apraxia = inability to produce purposeful movement on demand
pt may be able to describe task, but can;t execute… has the “idea” of the task
apraxia definition
inability to perform purposeful action
agnosia based on lesion location
parietal lobe
occipital lobe
temporal lobe
- parietal lobe => tactile agnosia (astereognosis)
- occipital lobe => visual agnosia
- temporal lobe => auditory agnosia
auditory cortex
location & purpose
unilateral lesion =>
bilateral lesion =>
located in temporal lobes, allows us to localize sound
unilateral lesion => minimal hearing loss
bilateral lesion => cortical deafness
Wernickes area
location
what it does
type of aphasia
wernickes area is located in the temporal lobe
in charge of preceptive processing of speech sounds
receptive aphasia (non-fluent) - cannot understand language in any form (oral, written, etc)
occipital lobe
two areas and what they do
why is this area not commonly affected
- primary visual cortex
sensation of light, shape, size and brightness - association area
recognition, visual processing
this area has low vascularity so not commonly affected with CVA, but can be affected by TBI
bilateral occipital lobe lesion in primary visual cortex is called…
deficit in primary visual cortex is called…
occipital lobe lesion in primary visual cortex is called cortical blindness
deficit in primary visual cortex is called hemianopsia
lesion in dominant occipital lobe hemisphere causes
- deficit of visual recognition (visual agnosia)
- object agnosia
- verbal agnosia or word blindness = alexia
- facial agnosia = prosopagnosia
what connects the L & R hemispheres of our brian?
corpus callosum
middle cerebral artery infarcts
anatomy & what it supplies
affects…
most common site of stroke*
comes off internal carotid; supplies frontal, parietal, occipital & temporal lobes
affects UE > LE
dominant middle cerebral artery infarcts lead to (3) whats affected most? (2)
contralateral hemiplegia with UE > LE involvement
distal > proximally
because it supplies frontal, parietal, occipital & temporal lobes, infarcts can cause…
- expressive or receptive aphasia
- homonymous hemianopsia (damage to optic radiations)
- contralateral sensory deficits
what vessel is infarcted in a pure motor deficit?
small internal capsule
anterior cerebral artery
supplies
infarcts cause (4)
supplies medial surface of frontal & parietal lobes
infarcts cause:
- contralateral hemiplegia with LE > UE
- mild aphasia (supplementary motor cortex)
- mental changes; loss of inhibition (frontal lobe)
- some sensory deficit in LE
posterior cerebral artery
supplies
infarcts cause (2)
supplies medial & inferior temporal and occipital lobes
has thalamic branches***
infarcts cause:
- impairment of touch & deep sensation (thalamic branches)
- thalamic pain
internal carotid artery infarcts cause (2)
occlusion may be silent or cause massive infarct
infarcts cause:
- hemianopsia
- retinal blindness
