Localization and bx correlates Flashcards

0
Q

Hippocampal disfunction

A

Ex HM:
- anterograde amnesia
- preserved working memory, retrieval of old
- drilled word recall, shapes - can repeat but gone after 20 min
Alzeimers = similar pattern

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1
Q

Overview of cortical networks

A

Limbic/memory (cingulate, hippo, amyg, mammilary, thalamus)
Language (L temp - parietal)
Visuospatial (R inf parietal)
Face/object recognition (occip - parietal)
Executive function (frontal)

Lesions anywhere in loop cause similar deficits

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2
Q

Transient global amnesia

A

Stress, Valsalva -> venous congestion -> hippocampal disfx

  • retrograde amnesia (months-years) - recovers completely
  • new consolidation - period “in hospital” is lost
  • difficulty with drilled words
  • lasts 2-12 h -> recover most fx
  • DDx: stroke, epilepsy
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3
Q

Alcoholic memory

A

Wernicke’s encephalopathy

  • acute dt thiamine deficiency
  • confusion, ataxia, nystagmus, ophthalmoplelgia

Korsakoff’s syndrome

  • sequelae of Wernicke’s (20%)
  • hemorrhagic necrosis of mammillary, mediodorsal thalamus
  • difficulty consolidating, confabulation

Goal of treating Wernicke’s is to prevent Korsakoff’s

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4
Q

Classic aphasia syndromes

A

Broca’s - narrow, defined region
- can’t generate, frustrated, can’t repeat
- transcortical motor (nearby) - can repeat but can’t produce
Conduction - arcuate fasciculus
- can understand and produce, can’t repeat
Wernicke’s - larger, more complex area
- can’t understand, nonsensical speech
- transcortical sensory (nearby) - can repeat but not follow command

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5
Q

Alexia, agraphia

A

Usually co-occur with aphasia - similar patterns
- Broca’s -> effortful, sparse, aggramatical
- Wernicke’s -> hypergraphic without understanding
Pure agraphia
- Exner’s area - L mid-frontal
- L supramarginal gyrus
Pure alexia
- L fusiform (inf parieto-temp)
L angular gyrus - can be either or combination

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6
Q

Overview of parietal syndromes

A

Superior (either side) - somatic association
- agraphesthesia (can’t place sensation)
- astereognosia (can’t ID object in hand)
L inferior
- angular - Gerstmann syndrome
- supramarginal - idiomotor apraxia - can’t imitate motions
R inferior
- contralateral neglect (without insight)
- localization and spatial disorders (ex dressing)

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7
Q

Gerstmann syndrome

A

L angular gyrus

R-L disorientation
Finger agnosia (can’t place sensations)
Agraphia
Acalculia

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8
Q

Overview of occipital pathways

A
Occip-parietal = WHERE
 - lesion -> Balint's syndrome
Occip-temporal = WHAT
 - agnosia (can't name object)
 - prosopagnosia - can't ID faces (R fusiform)
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9
Q

Balint’s syndrome

A

Disruption of sup occip pathway

  • ocular apraxia - “sticky” vision, can’t follow objects
  • ocular ataxia - hand-eye coordination
  • simultanagnosia - can’t interpret full visual field
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10
Q

Posterior cortical atrophy

A

Similar to Alzheimers (plaques, neurofibrillary tangles)
-> affects different functions -> vision, reading, comprehesion

  • > Balint’s (“where” pathway)
  • Gerstmann - spatial orientation, acalculia
  • agnosia - “thought his wife was a hat”
  • transcort sensory aphasia - difficulty understanding
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11
Q

Overview of frontal lesions

A

Almost always bilateral damage
Almost always combination of syndromes

Orbitofrontal -> disinhibition
Cingulate (ex ant cerebral infarct) -> abulia, apathy
Dorsolateral -> executive fx, working memory

Pick’s disease = degeneration with lesions

  • L -> language aphasia
  • R -> social cues and behavior
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12
Q

Overview of hallucinations

A

Absence of stimuli
Not asleep, no voluntary control

Deafferentiation - Bonnet, musical, phantom limb
- from secondary vs primary cortex
Abnormal stimulation - epilepsy, migraine
Subcortical - peduncular hallucinosis
“Higher order” processing - psychosis

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13
Q

Bonnet syndrome

A

Loss of visual input (ex chronic vision loss) -> hallucinations
More prevalent in dim lighting
Disappears if they close their eyes
Good insight into problem vs reality

Auditory - similar - musical hallucinosis with hearing loss

  • can also be TBI, epilepsy, psychosis
  • may have some control (ie “change song”)
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14
Q

Phantom limb

A

5-10% amputees

Usually painful, often feels malformed
May “move” under volitional control

Central - can’t just fix or block nerves

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15
Q

Peduncular hallucinosis

A

Subcortical lesion
- usually infarct
- brain stem, cerebellar, pontine, thalamus
- will have other symptoms of lesion (ex ophthalmoplegia)
Visual hallucinations
- vivid, entire visual field, usually nature scenes
- more vivid if eyes closed
Good insight into hallucination vs reality

16
Q

Epilepsy and behavior

A

Temporal lobe -> Geschind’s syndrome (type personality)

Forced normalization/alternate psychosis

  • treatment of seizures causes hallucinations
  • normal EEG -> symptoms
  • can last several weeks

Aggression - uncommon during ictal

  • post-ictal - immediate, 5 minutes, generalized
  • common, more common with R hemisphere?
  • interictal - episodic discontrol
  • rage episodes, out of proportion, 20 minutes
  • L hemisphere, low IQ, depression
17
Q

Geschwind syndrome

A

Type personality associated with temporal lobe epilepsy
“Limbic hyperconnection”

Religiousity, profuse writing
Philosophical, hyperemotional (can have rage episodes)
Hyposexual

Vs Kluver-Bucy syndrome = limbic disconnection

  • placid, unemotional
  • hypersexual
18
Q

Pariteal association areas

A
Brodmann area 7
Visual and somatosensory -> spatial
 - orientation, sense of self/agency
 - activation proportional to attention
Damage -> dec attention -> neglect if non-dom (R)
19
Q

Working memory

A

Reverberatory circuits - loss of activity -> loss of information
Localized to type of info
- parietal = objects, spatial
- frontal - explicit

20
Q

Temporal association cortex

A

Broadmann 21 and 22
Visual and auditory -> object recognition and language
Deficit -> agnosias (popagnosia = faces - usually non-dom)
- acalculia - usu dominant, inf and angular

21
Q

Prefrontal association cortex

A

Dorsolateral = 9, 10, 46 - executive, working memory
Orbitomedial = 11, 12 - impulse control, personality
- mood ant cingulate

Key function = inhibition
Damage -> utilization (grabbing objects), perseveration

22
Q

Voluntary movement

A

Begins in supplementary motor - readiness potential
(lesion -> abulia)
-> parietal - illusion/perception of agency

Disrupted connection -> alien hand syndrome (lack of agency)