Learning and memory and Alzheimer's disease Flashcards
What is the definition of learning?
Acquisition of new information or knowledge
What is the definition of memory?
Storage or retention of acquired knowledge
What is the definition of engram?
Physical representation or location of memory
What are the 3 classes of memory?
Declarative, Emotional and Procedural
Declarative memory includes:
Daily episodes
Words and meanings
History
Emotional memory includes:
Preferences and aversions
Procedural memory includes:
Motor skills
Associations
Priming cues
Puzzle solving
Which areas of the brain are associated with Procedural memory?
Cerebellum and striatum
Brainstem and spinal motor output
Which areas of the brain are associated with Emotional memory?
the Amygdala
Hypothalamus, autonomic and hormonal output
Which areas of the brain are associated with Declarative memory?
the Entorhinal/parahippocampal cortex and the Hippocampus
What lobe is important to memory?
the temporal lobe
Describe Hebb’s law
When two neurones are active, if one is firing neurotransmitters and the other is firing action potentials, the synapse with become stronger.
(Memory depends on populations of interacting neurones)
How are memories stored?
As patterns of strengthened synapes
TRUE/FALSE? A partial stimulus can activate a full memory
True
What is Long Term Potentiation (LTP)?
Increase in strength of an EPSP after repeated stimulation
Has a threshold for establishment
How can LTP be prevented?
Pharmacological blockage of NMDA receptors (with 2-AP5)
Reducing extracellular Ca from 2 to 0.2mM (i.e Low conc of Ca)
How is LTP manifested postsynaptically?
More AMPAr
More sensitive AMPAr
More synapses
How is LTP manifested presynaptically?
Increased release
More release sites
More vesicles
What are the 3 LTP induction mechanisms?
- Phosphorylation of AMPAr by PKC
- Insertion of new receptors/synthesis of new receptors
- Retrograde messengers (e.g NO)
TRUE/FALSE? Reactivating a memory strengthens it
True
What are some examples of cognition enhancers?
AMPAkines Cholinergic modulation (increase Ach) Stimulants Dopaminergics 5HT drugs GABAr blockers
What can cause Amnesia?
Drug induced (alcohol) Head trauma (temporary or permanent) Retrograde or anterograde
What is Dementia?
A syndrome characterized by a decline in cognitive function sufficient to cause impairment in social and occupational performance
Inability to form new memories (learning)
General cognitive decline
What is the prevalence and characteristics of Alzheimer’s disease?
Most common form of dementia at >65 years
More common in females (2:1 ratio)
Memory, initiation, visuo-spatial, and language deficits
Impaired judgement/risk assessment
Describe the pathology of Alzheimer’s (in relation to the brain)
Early shrinkage of temporal poles, frontal cortex
Earliest damage in entorhinal cortex (memory and speech deficits)
Progressive spread to whole cortex and subcortical structures
What are neuritic plaques (NP)?
Extracellular
Amyloid-B-protein
(Diagnostic hallmark)
What are neurofibrillary tangles (NFT)?
Intracellular
Abnormal ‘Tau’ protein
(Diagnostic hallmark)
What do NPs and NFTs primarily affect?
Glutamate and Ach neurones and terminals
Plaque formation leads to…
Destruction of terminals and dendrites
Plaque -> tangle
Tangle formation leads to…
Neuronal death
What is memory loss?
Loss of neurones and their connections
How is alzheimer’s treated?
Cholinesterase inhibitors (e.g donepezil, rivastigmine)
Menantine (non-competitive NMDAr blocker)
Nootropics (e.g piracetam and aniracetam i.e cognition enchancers) - enchance AMPAr activity
