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Name dysfunctions of the cerebral cortex:
- UMN paralysis
- Loss of general sensation
- aphasia
- apraxia
- agnosia
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UMN paralysis:
spastic paralysis to the contralateral side of the body
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UMN paralysis is damage to:
the pre-central gyrus or association area
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What does the pre-central gyrus contain?
UMN that feed LMN on opposite side of the body (as well as association motor cortex area)
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What does UMN paralysis cause?
spasticity
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What is spasticity of the cerebral cortex during UMN paralysis?
wiped out UMN and LMN is still intact; mm still innervated due to sensory input; reflexes still occur, but therre is no control b/c UMN is not working to influence LMN
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What causes the spasticity of UMN paralysis?
damage to internal capsule
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What does the internal capsule contain?
axons of UMN (posterior limb of internal capsule)
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What artery feeds the structures affected by UMN paralysis?
middle cerebral artery
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A stroke in which region can cause UMN paralysis?
middle cerebral artery
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What occurs when there is loss of general sensation in the cerebral cortex?
perception and discrimination to contralateral side of the body become unable to discriminate exactly where loss is coming from
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Loss of general sensation is caused by damage to:
post-central gyrus
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What lobe is the post-central gyrus in?
parietal lobe
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Instantaneous spatial coordination of all parts of the body (awareness of what your body is doing in space) is integrated at the:
posterior parietal lobe (special coordination)
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When there is loss of general sensation in the cerebral cortex, what happens to the LMN?
doesn't know what to do and becomes non-functional
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The right parietal lobe is primarily involved in:
spatial organization
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Which parietal lobe is more dominant?
right
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What happens if there is damage on the left parietal lobe?
not as dramatic, so not as likely to have right side body neglect
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Damage in posterior part of right parietal lobe causes deficits in:
perception of person and spatial relationships
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Right side damage results in:
left sided neglect/personal neglect
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Neglect occurs on which side of the body?
contralateral side to lesion (it is as if that side of the body doesn't exist --no spatial coordination)
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Where can neglect occur?
for whole side, regions, or body parts on contralateral side of the body
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Hemi-inattention:
ignoring due to a lack of integration of senses w/ the rest of the body
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What impairments occur with hemi-inattention?
- non-movement of left extremities
- lack of awareness of sensory stimuli
- lack of personal hygiene and grooming
- pt plans movement around the right side of the body
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Bilateral spatial neglect is damage to:
right parietal lobe
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Bilateral spatial neglect:
- lack of understanding of spatial relationships
- pt doesn't include left side in anything (painting only on right side of paper as an example)
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Right sided neglect occurs as a sever damage of:
- left parietal lobe
- must be substantial damage
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Aphasia
- general term for language disorders to include reading, writing, speaking, or comprehension of written or spoken words, generally due to cerebral cortex or conduction dysfunction
- Broca's
- Wernicke's
- Conduction
- Global
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Apraxia:
inability to carry out or regulate a complex or skilled movement when there is no LMN paralysis, no ataxia, loss of sensory input and pt is not confused
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Ataxia:
loss of coordination
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Give an example of apraxia: "Tie your shoe"
pt understands what you've requested, but can't carry out task
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What happens to the cerebral cortex with apraxia?
it is not processing
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Apraxia is due to:
a lesion in the premotor and supplemental motor cortexes
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What happens when the premotor and supplemental motor cortexes are not working?
pre-central gyrus doesn't get correct instructions
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Agraphia:
inability to write (not due to LMN paralysis, ataxia, or sensory input)
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Transmissive apraxia:
inability to carry out a sequence of skilled motor movements
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Where does transmissive apraxia occur?
supramarginal gyrus in parietal lobe
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Agnosia:
inability to perceive sensations through otherwise normally functioning sensory pathways
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With agnosia, dysfunction in the cortex applies to:
general sensation and special senses
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With agnosia, the information is not:
consciously integrated
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What are the types agnosia?
- tactile agnosia
- depth agnosia
- movement agnosia
- prosopagnosia
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What is another name for tactile agnosia?
asterognosis
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Tactile agnosia is the inability to:
recognize familiar object through touch and proprioception due to a lesion
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Tactile agnosia occurs due to a lesion in which lobe?
posterior parietal lobe of dominant hemisphere
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Tactile agnosia is the disturbance of:
body image
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The disturbance of body image is due to:
- parietal lobe lesion
- pt may not recognize their thumb from their pinky finger, they can confuse right and left sides
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Depth agnosia inability to:
appreciate depth and thickness of objects due to a lesion in occipital lobe
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movement agnosia is the inability to:
recognize stationary and moving objects due to a lesion
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Movement agnosia is due to a lesion in which lobe?
occipital
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Prosopagnosia is the inability:
- to recognize faces due to a lesion
- pt can see the face, but not know who it belongs to until they hear the voice of the face
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Prosopagnosia is due to a lesion in which lobe?
temporal
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Is there laterality in the brain?
yes
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Right and left hemispheres functionally and:
anatomically
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Which hemisphere is dominant in most humans?
left side
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Why is the left hemisphere dominant in most humans?
because that is the hemisphere that controls language (Broca's and Wernicke's) in 90% of the population
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The left and right hemispheres are connected by:
corpus callosum
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In seizure pts, the corpus callosum can be:
split to prevent hemispheres from communicating
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If the corpus callosum is split, info presented to the left visual field is not perceived because:
it can't transfer to the left side dominant language area
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If the corpus callosum is split, info presented to the right visual field will:
be perceived b/c it is already on the right and doesn't have to cross
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What are characteristics of the Left Hemisphere?
- contains Broca's and Wernicke's areas
- logical and analytical abilities
- general math ability
- processing large volumes of information
- ability to be rational and pragmatic
- what we think versus what we feel
- doing consciousness -- you are aware (or want to be) about what is going on
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What are the characteristics of the Right Hemisphere?
- geometric spatial orientation
- musical perception and skills (singing, playing an instrument)
- artistic talent
- formation of ideas (non-verbal ideation)
- perception and processing of emotions
- coordination of sensory information
- what we feel versus what we think
- being conscious of our environment and emotion
- prosody: emotions and feelings that go w/ saying something (you're pretty v. boy, you're really beautiful)
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Connectivity is the ability of specific parts of the nervous system to:
communicate w/ each other
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Specific parts of the nervous system communicate w/ each other through:
established pathways and systems of pathways
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How many neurons do these pathways involve?
one or multiple neurons
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Connectivity accounts for how various parts of the NS become involved w/:
functional systems or processes
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Multiple systems get involved w/:
- simple cognitive activity
- --new technology is allowing us to figure out how lesser systems connect to each other
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Connectome:
- highly organized connection matrix of the human brain
- defines how info flows through complex system to do complex task
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What does the connectome use to diagnose communication links?
Diffusion Tensor Imaging (DTI) --fMRI
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When connectome uses DTI, it allows what?
- mapping of molecules in biological tissues
- In nuerons allows mapping of movement water as it moves along axons in brain and spinal cord
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What is the human connectome project?
- will trace and map major neuronal pathways that link approx. 500 major regions in the brain which are the neural substrates for mental processes
- Will become blueprint for human brain
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