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108 Cards in this Set
- Front
- Back
What does the acronym M2OVE refer to?
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The limbic system:
Motivation Memory Olfaction Visceral functions Emotion |
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What is the broad function of the limbic system?
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Interface our internal drives and emotional states with out decision-making and cognitive functions. Acts to match the appropriate visceral response with a given behavioral and/or conscious emotional response.
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What structure may be damaged when there is an inability to match a stimulus with an appropriate response at either the cognitive or autonomic level?
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Limbic system
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What are the major pathways of the limbic system?
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Fornix
Mammilothalamic tract Stria terminalis Stria medullaris Medial forebrain bundle Cingulum |
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Describe the fornix.
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C-shaped structure that starts in the hippocampus and terminates in the mammillary bodies (primary target). Links hippocampus to the septal nucleus and hippocampus to anterior thalamic nucleus. Contains hippocampal commissure.
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What is the mammilothalamic tract?
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Connects the mammillary bodies to the anterior thalamic nuclei.
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What is the stria terminalis?
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Starts in the amygdala and terminates in the septal nucleus and hypothalamus.
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What is the stria medullaris?
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Starts in the septal area and terminates in the habenula
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Where is the habenula?
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Adjacent to the thalamus
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What is the medial forebrain bundle?
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Connects the septal area, hypothalamus, and the amygdala to the autonomic nuclei in the brainstem and spinal cord
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Where is the Septal Nuclei?
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Where is the Cingulate Gyrus?
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Where is the medial forebrain bundle?
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Where is the anterior nucleus of the thalamus?
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Where is the Habenular nucleus?
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Where is the Fornix?
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Where is the stria terminalis?
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Where is the Hippocampus?
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Where are the mammillary bodies?
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What is the Papez Circuit?
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There is an interaction between the autonomic and somatic portions of the emotional brain. The hypothalamus and the cingulate gyrus form the ends of the circuit.
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What are the pathways of the Papez circuit?
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Cingulate gyrus → hippocampus → mammillary body of the hypothalamus → anterior thalamic nuclei → cingulate cortex
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What structures are part of the hippocampal formation?
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Hippocampus
Dentate gyrus Subiculum Entorhinal cortex Fimbria |
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Don't know the two hippocampal pathways!
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Let me know if you can decipher the notes.
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What is the function of the Hippocampal formation?
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Buffer memories;
Navigation and spatial memory through use of place cells; Depression and Schizophrenia |
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What are the outputs of the Amygdala?
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Stria terminalis (connects it to the hypothalamus
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What is the amygdala involved in?
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Emotional responses and fear conditioning (emotion memory)
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What is Klüver-Bucy syndrome?
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Increased appetite and hypersexuality as a result of the removal of temporal lobes (including amygdala and hippocampus); hypersexuality only seen in monkeys
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Where is the amygdala located?
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Tip of the temporal horn of the lateral ventricle, anterior and rostral to the hippocampus
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What limbic structure is associated with korsakoff's?
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mammillary bodies
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What is the function of the habenula?
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Behavioral functions (pain, stress, learning, and internal drives)
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Where is the fornix?
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Where are the Mammilary bodies?
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Where is the Stria medullaris?
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Where is the mammilary bodies?
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Where is the fornix?
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Where is the Anterior thalamic group?
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What did Phineas Gage lose?
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Anterior Cingular Gyrus and Prefrontal Cortex; defects in rational decision making and emotional control
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Why was Phineas Gage significant?
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Showed that human behavior was controlled by specific and different parts of the brain.
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What is the significance of patient S.M.?
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Damage to amygdala resulted in problems recognizing emotions (especially fear)
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What is Non-Associative Learning?
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Neural mechanisms that mediate non-associative contribute to more complex types of learning.
Forms: Habituation Dishabituation Sensitization |
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What is Habituation?
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Non-associative:
Decrease in response to repetitive stimuli that is not the result of fatigue or sensory adaptation. |
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What is Dishabituation?
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Non-associative:
Increase in a habituated response due to the presentation of a very |
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What is sensitization?
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Non-associative:
Increase in response due to the presentation of a strong or salient stimulus. |
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What is associative learning?
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Forming an internal, cognitive connection (association) between two environmental stimuli.
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What are the two basic forms of associative learning?
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Classical Conditioning
Operant Conditioning |
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What is Classical Conditioning?
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Learning that one stimulus acts as a cue (Conditioned Stimulus) that predicts the arrival of second stimulus (outcome; Unconditioned stimulus).
Pavlovian Dog |
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What is stimulus generalization?
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The use of a stimulus other than the CS to generate a CR if the second stimulus is sufficiently similar.
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What is extinction?
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Elimination of the CR to the CS by presenting the CS without the US.
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What is operant conditioning?
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Instrumental conditioning; behavior is paired with a reinforcing stimulus; example is skinner box experiments
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What is are the skinner box experiments?
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Device that allows one to easily train rodents using operant conditioning; teach rat to push a button to get food
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What is LTP?
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Cellular mechanism that increases synaptic transmission.
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How is LTP activated during learning?
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Co-activation of pre- (CS) and postsynaptic (US) neurons; convergence of glutamate by the presynaptic neuron and the depolarization of the postsynaptic neuron activates NMDA to initiate LTP
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Early LTP is the result of what?
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Increase in AMPA-R
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Long term LTP is the result of what?
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Growth of new synaptic connections
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What is one way learning may be impacted in Down's syndrome?
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Higher threshold for LTP
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How were experimenters able to increase LTP in "Down's" mice?
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GABA antagonist
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What are the stages of memory formation?
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Acquisition
Consolidation (Storage) Retrieval |
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What is Declarative memory?
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Memory for facts (semantic) and events (episodic)
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Where is declarative memory primarily mediated?
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Hippocampus and the association cortices (final storage area)
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How does the hippocampus act in terms of memory formation?
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Memory buffer (like computer RAM) until information can be encoded in the neocortex (consolidation)
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What can a lesion to the hippocampus do in terms of memory formation?
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Prevent the encoding of new long term memory
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What is consolidation?
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Process of storing information by encoding the neocortex
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Why is H.M. a significant case?
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Removal of patient's Hippocampus resulted in severe anterograde amnesia
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What is Procedural memory?
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Memory of how to perform motor skills; largely unconscious
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What type of memory did patient H.M. mostly loose?
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Declarative
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What anatomical systems are involved in procedural memory?
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Striatum (Mediates procedural memory that enhances the performance)
Cerebellum (mediates procedural memory that alters reflexes in response to new learned stimuli) |
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What is an example of procedural memory?
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Eye-blink conditioning
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What is emotional memory?
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Stores information on preferences and aversion to events; unconscious
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What is the primary location for emotional memory?
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amygdala (esp. for fear conditioning)
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Can declarative memory be modulated?
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Yes, especially by emotional memory. Strong emotional events are better remembered.
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What type of memory was largely found intact in H.M.?
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Procedural
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What are the temporal categories of memory?
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Immediate
Short term/Working Long term |
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What is immediate memory?
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<1 second; involves brainstem, frontal cortex, and association cortices; necessary for normal attention; AKA immediate recall
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What is Short term memory?
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Seconds to minutes; frontal cortex and other associational cortices; storage for a short period; working memory
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What is Working memory?
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Short term memory; capacity to hold information long enough to carry out a sequence of actions; requires intact frontal lobe; digit span test
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What is long term memory?
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Hours to days to years; requires hippocampus (to get past consolidation phase) and associational cortices (to store); requires gene modification and protein synthesis
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What area of damage is associated with retrograde amnesia?
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cortical damage; association cortex is where long term memory is stored
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What area of damage is associated with anterograde amnesia?
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Hippocampal or cortical
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Does repetition of learning improve the retention of memory?
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Yes
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What is "spacing out"?
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Repeating learning over longer periods of time; improves cellular processes that mediate consolidation and storage
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What are the main types of dementia?
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Alzheimer's Disease
Vascular Dementia (Multi-infarct) Frontotemporal Dementia Huntington's Lewy Body Dementia Korsakoff's Syndrome Creutzfeldt-Jacob |
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What is dementia?
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Decline in memory and other cognitive functions
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Alzheimer's Disease?
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Most common dementia
Gradual progression and later onset |
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Vascular Dementia?
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Second most common form of dementia;
Accumulation of mini-strokes; Step-like progression and earlier onset |
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Frontotemporal Disease?
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Earlier onset <60yrs;
severe apathy and disinhibition (poor impulse control); Neurofibrillary tangles but no Abeta plaques |
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Huntington's?
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Procedural memory (striatal disease)
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What is tau?
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microtubule protein
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What is Lewy Body dementia?
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Can accompany parkinson's (early-onset); level of dementia fluctuates; visual hallucinations
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Korsakoff's?
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Result of thiamine deficiency (alcoholics); both retrograde and anterograde amnesia; confabulation is characteristic
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Creutzfeldt-Jacob?
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Rapid Progression and early onset (40-50 yrs); cortical and cerebellar atrophy; prion
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Besides neurodegenerative diseases how else can memory and cognition be impacted?
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Seizure, blow to head, traumatic brain injury, and various types of tumors
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What characterizes the early stages of alzheimer's?
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Impairment in the ability to generate memories of recent events but recall is intact.
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What does the initial impairment of alzheimer's indicate?
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Hippocampal dysfunction
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What are the four neuropathic features of alzheimer's?
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Extracellular deposits of amyloid-Beta plaques.
Intracellular accumulation of tau neurofibrillary tangles (NFT). Loss of neurons starting in hippocampus and progressing (40% reduction in volume). Loss of synapses. |
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What three genes have been implicated in familial early onset alzheimer's?
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Presenilin 1
Presenilin 2 Amyloid Precursor Protein |
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What do presenilin 1 and 2 do?
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Cleave APP to form the ABeta
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What may ApoE do in Alzheimer's?
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stabilize AB plaques; 10-12x for homozygous
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Amyloid Beta is how long?
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40-42 amino acids
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What causes aggregation of ABeta?
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high concentrations
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What is presenilin?
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Gamma-secretase
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What is the Abeta hypothesis?
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High extracellular levels of Abeta aggregate into plaques and are toxic to neurons and glia
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What are the main issues with the Abeta hypothesis?
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Plaques and the amount of neurodegeneration were not always consistent; plaques were found first in cortex then hippocampus (opposite expected if considering symptoms)
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What is the current widely accepted alzheimer's theory?
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Modified AB hypothesis; soluble AB is actually the toxic form and extracellular plaques are result of protective action
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How to soluble AB oligomers support the current Alzheimer's hypothesis?
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Correlate with level of dementia; seen early in hippocampus; disrupt synaptic transmission (LTP and LTD); cause neuroinflammation and neurodegeneration
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How is tau implicated in alzheimer's?
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Tau with Abeta seems to match alzheimer's more closely; disribution of tau matches progression better than Abeta
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How does donepezil (aricept) work?
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Chlinesterase inhibitor; increases hippocampal cholinergic input from the septal nuclei; moderately effective
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How does memantine (Namenda) work?
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NMDA-receptor antagonist; prevents neuron loss by limiting toxic Ca2+ levels via NMDA excitation; Open channel blocker (works when channel is open) so prevents the channel from opening too long; fast dissociation kinetics
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Ab peptides/antibodies?
Bapineuzumab |
Help body to mount immune response to Abeta plaques; new antibody treatment most effective in apo e
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