Memory and Alzheimers

What surgery did Henry Molaison undergo?

medial temporal lobectomy

What parts of Henry’s memory were intact?

Old memories from childhood, short term memory and personality

What did Henry suffer from after the surgery?

Partial retrograde amnesia and profound anterograde amnesia

What is retrograde amnesia?

Difficulty in retrieving some memories

What is anterograde amnesia?

Difficulty in forming new memories

What is short-term memory?

Cognitive system used to hold little info for a short time

How much can our short-term memory hold?

About seven numbers, plus or minus two

What is working memory?

A portion of short-term memory where you are actively manipulating it to control behavior.

How long does working memory last?

Lasts for seconds, or for as long as you are rehearsing that information in your mind

What is long-term memory?

Vast storage of knowledge, and a record of prior events

How long does long-term memory last?

Unlimited capacity and lasts indefinitely

What is declarative memory?

Facts you learn, things about yourself

What is non-declarative memory?

Things that you do, skills that you learn

What is semantic memory?

Facts and general knowledge

What is episodic memory?

Personally experienced events

Both types of explicit memories require what?

The medial temporal lobe (including the hippocampus)

What types of nondeclarative memory are there?

Procedural memory, priming and conditioning

What is procedural memory?

Motor and cognitive skills

What parts of the brain are used in procedural memory?

Motor cortex, basal ganglia, and cerebellum

What is priming?

Enhanced identification of objects or words

What parts of the brain are used in priming?

Neocortex

What is classical conditioning?

When we take two stimuli and pair them together, they become associated

What parts of the brain are used in classical conditioning?

Cerebellum, amygdala

What is consolidation?

the process by which short term memories are transferred into long-term memories

What is retrieval?

movement of information from long-term memory into working and short-term memory

How do we transfer information from short-term memory to long-term memory?

Consolidation

What is the testing effect?

Long-term memory is increased when a learning period is devoted to retrieving the remembered information

What is a memory?

A memory represents a change in the brain

What is the saying that describes neuroplasticity?

“Cells that fire together wire together”

What is neuroplasticity?

When an axon successfully stimulates another neuron, it will be even more successful in the future

What is a Hebbian synapse?

A synapse that increases in effectiveness because of simultaneous activity in pre and post synaptic neurons

If a memory involves strengthened synapses, how do they become strengthened and what changes are occurring?

More neurotransmitters may be released from the axon terminal after learning occurs

When more neurotransmitter is released, is this a pre or post-synaptic change?

This is a presynaptic change

When the receptive area on the postsynaptic membrane becomes larger and/or more sensitive to neurotransmitters, is this a pre or post-synaptic change?

This is a postsynaptic membrane change.

When the synapse enlarges on both sides of the synaptic cleft and there’s growth on the dendritic spine, is this a pre or post-synaptic change?

This is both a pre and post-synaptic change.

When an interneuron causes more release of neurotransmitter per nerve impulse, is this a pre or post-synaptic change?

This is a pre-synaptic change.

When the number of synaptic contacts increased and new synapses are formed, is this a pre or post-synaptic change?

This is both a pre and post-synaptic cell change.

What is long-term potentiation?

Stable and enduring increase in effectiveness of synapses following repeated strong stimulation.

What is the opposite of long-term potentiation?

Long-term depression

Where does long-term potentiation occur?

Hippocampus

How much repeated, strong excitation is needed for LTP?

100 excitations per second for 1-4 seconds

What are the ionotropic receptors involved in LTP?

AMPA and NMDA

What type of receptors are these?

These are glutamate receptors

What are the similarities between AMPA and NMDA receptors?

Both are ligand-gated and ionotropic

What does an AMPA receptor do?

When glutamate binds to an AMPA receptor, sodium can enter the channel

What does sodium entering an AMPA receptor do?

It causes an EPSP and the cell depolarizes.

What does an NMDA receptor do?

It allows sodium and calcium into the cell

What is the NMDA receptor blocked by?

A magnesium ion

When sodium enters the AMPA receptor, how does it effect the NMDA receptor?

Causes the magnesium to pop off, opening the channel

What does calcium do to these receptors?

It’s a signaling molecule that causes the synapse to grow larger

What are two synaptic molecules involved in LTP?

Nitric oxide and CaMKII

What does CaMKII do?

It lets AMPA receptors become more responsive to glutamate

What does nitric oxide do?

Increases the release of neurotransmitter

What causes changes on the postsynaptic cell?

CaMKII

What causes changes on the presynaptic cell?

Nitric Oxide

What is Alzhiemer’s disease?

The most common form of dementia

What is dementia?

A group of thinking and social impairments severe enough to interfere with daily functioning

What is amnesia?

Memory loss

What is agnosia?

Loss of ability to recognize objects, faces, places, etc.

What is apraxia?

Inability to do everyday movements or gestures

What is aphasia?

Loss of ability to understand and express speech

What happens in the brain during Alzheimer’s?

Deterioration of cellular volume, especially white matter and enlarged ventricles

What are plaques?

Beta-amyloid protein accumulating within neurons

What are tangles?

Irregular unwound microtubules between neurons

What is brain atrophy?

the loss of volume, especially of white matter within the brain​

What are microbleeds?

small brain hemorrhages that happen around the brain​

What is the protein that forms tangles?

Tau

What is the protein that forms plaques?

beta-amyloid

What is the name of the larger transmembrane beta-amyloid is cut from?

Amyloid precursor protein

What is the normal function of tau?

to stabilize microtubules and help transport molecules and nutrients between the soma and the axon.

What are three risk factors for Alzheimer’s disease?

Age, history of traumatic brain injury, and obesity

What are some protective factors?

Diet and advanced education

What is a protein that increases risk factor for Alzheimer’s?

Apolipoprotein (ApoE4 allele)