Learning, Memory and Alzheimer's

Question 1

Where are memories stored?

Answer 1

Diffusely across the brain

Question 2

Who is HM, what happened to him and what did this teach us?

Answer 2

HM most famous px in neuroscience, has bicycle accident causing LOC and epileptic seizures, neurosurgeon determined seizures were happening in temporal lobes so both were removed = cured epilepsy but caused anterograde amnesia and partial retrograde amnesia = temporal lobes critical for forming long term memories

Question 3

differentiate between the 2 types of long-term memory

Answer 3

declarative: can explain to others, can be episodic: breakfast this morning or semantic: PM name
procedural: things you know that you can show by doing them, can be skill learning: skiing, bike riding, priming: using recently learnt word or conditioning: salivating when seeing steak

Question 4

where are new episodic memories formed?

Answer 4

medial temporal lobes

Question 5

what parts of brain control motor skill and memory?

Answer 5

motor cortex and basal ganglia

Question 6

describe the pathway to storing long-term memories

Answer 6

sensory info -> short term memory -> rehearsal -> consolidation -> long-term memory

Question 7

describe donal hebb’s theory involving cell A and cell B

Answer 7

when an axon of cell A excited cell B repeatedly, growth process/metabolic change occurs in one or both cells so A’s efficiency as one of the cells firing B is increased

Question 8

What effect does increased glu/synaptic activity have in hippocampal synapses and NMDA-Rs?

Answer 8

increased synaptic activity forces magnesium block out, allowing entry of Ca2+ causing greater depolarisation, activating CAMKII which increases AMPA sensitivity to Glu -> LTP

Question 9

differentiate normal transmission at hippocampal synapse (low synaptic activity) to transmission after conditioning train

Answer 9

normal transmission: only AMPA receptors are activated -> brief depolarisation -> excitation
after conditioning train: AMPA, NMDA-R and metabotropic receptors activated -> increased calcium and activation PKC and NOS -> sustained depolarisation -> excitation -> long term changes eg learning

Question 10

What special protein kinase does calcium activate and what effect does this have on AMPA receptors?

Answer 10

calcium activates CAMKII which makes AMPA receptors more responsive by increasing amount of them at synapse

Question 11

What effect does CREB have on long term potentiation?

Answer 11

CREB is activated in LTP and activates gene expression -> more ion channel receptors and new synapses which reinforce synaptic connections between two repeatedly communicating neurons

Question 12

list the different types of dementia

Answer 12

alzheimer’s, vascular, frontotemporal, lewy body

Question 13

describe the impact dementia has on aus population

Answer 13

2ND leading COD

Question 14

Describe Alzheimer’s

Answer 14

memory deteriorating quicker than normal ageing population, progressive, anterograde and retrograde amnesia, impaired short term and implicit memory for verbal and perceptual material, leads to death of neurons in lower brain regions, changes in brain can be happening for 10 years > before symptoms show

Question 15

where are signs of alzheimer’s first noticed in brain?

Answer 15

entorhinal cortex then hippocampus

Question 16

What is the prognosis of Alzheimer’s?

Answer 16

8-12years

Question 17

What can be seen in brain of Alzheimer’s patients?

Answer 17

amyloid plaques between cells and neurofibrillary tangles within individual neurons

Question 18

Describe how amyloid plaques are made and build up

Answer 18

Amyloid precursor protein is broken down by series of secretases, normally cut twice at specific spots and two insoluble pieces travel away, if cut at wrong spot, amyloid is sticky and will stick to other sticky amyloids around

Question 19

describe function of microtubules in cells

Answer 19

act like railroad tracks that transport supplies to and from nucleus of neuron

Question 20

describe function of tau proteins in cells

Answer 20

act like railroad ties that stabalise microtubule structure

Question 21

what happens to tau proteins and microtubules in AD and what effect does this have

Answer 21

tau proteins become tangles, destabalising microtubules in neuron causing loss of axonal transport = cell death

Question 22

what neurons are affected in AD

Answer 22

neurons using Ach

Question 23

Describe mechanism of drugs for AD with NMDA glu receptors as the target and the effects of high and low concentrations

Answer 23

block NMDA receptor ion channel, high concentrations can inhibit learning and memory, low concentrations promote synaptic plasticity and preserve excitotoxic destruction due to death of neurons