Neurology and mental health Flashcards
What is learning?
acquisition of new information or knowledge
What is memory?
storage or retention of acquired knowledge
What is an engram?
physical representation or location of memory, a collection of neurones
What are the three classificaitons of memory?
Declarative, emotional, procedural
Examples of declarative memory?
Daily episodes (remembering address), words and meanings, history
Example of emotional memory?
Preferences/aversions–> things we do/dont like depending on past expiriences
Examples of procedural memory?
Motor skills, solving puzzles, priming cues, association and linking
Which areas of the brain are involved in memory?
All
Which brain regions involve emotional memories?
Amygdala, hypothalamus
Which part of the brain is responsible for motor memory?
Cerebellum (used for playing instrument riding bike etc)
Which areas of the brain are involved in declarative memories?
Hippocampus, entorhinal and parahippocampal cortex
Which areas of the brain are involved in procedural memories?
Cerebellum, striatum, brainstem and spinal motor output
Which brain area is seen as a hub of learning and memory?
Hippocampus
What is anterograde amnesia?
inability to form new memories/learn new things
What is retrograde amnesia?
Can’t recall things
What is working memory?
Short term memory
Order of solidifying a memory?
Input–> short term (working) memory–> long term memory
What is Hebbs law?
If there are two connected neurons in the brain, and one repetitively fires APs onto the other (and vice versa), the synapse that connects them becomes permanently stronger
What kinds of memories does the engram theory work with?
All of them
In terms of an engram, what is short term memory?
Reverberating activity between synapses
What does reverberating activity between synapses do to them?
Strengthens them
What happens once synapses between neurons reverberate enough?
The synapses become permanently strengthened, thus creating a long term memory
Why does only part of a stimulus need to be viewed for an engram to be activated?
Part of the stimulus only triggers a few neurons, but bc they have strengthened synapses they will all end up firing APs
What are all memories down to?
Strengthening synapses
Which brain area has been the focus of most of research in synaptic strengthening?
Hippocampus/entorhinal cortex
Which type of NT neurons are involved in memories?
Glutamatergic
How is synapse strengthening studied?
Stimulate axons in the entorhinal cortex that innervate the hippocampus, causing them to fire APs. Can record membrane potential of postsynaptic neuron
How does a synapse get stronger?
If a burst of activity happens in the presynaptic neuron (100APs in 100miliseconds) the strength of the synapse is increased–> there is a potentiated AMPAr EPSP which lasts forever–> a larger EPSP as a result of more APs being fired down
What is long term potentiation?
Increase in the strength of a synapse after repeated stimulation–> lasts long term
What is a tetanus?
A high frequency burst of APs
What is the memory response caused by?
Opening of AMPA receptors
What happens if NMDA receptors are blocked during memory formation/synapse strengthening?
The potentiated EPSP doesnt occur (LTP doesnt form)
What happens if Ca2+ entry via NMDA receptors is limited during synapse strengthening?
The LTP doesnt occur
Where is the change that allows a LTP to form?
AMPA receptor
What is the change to AMPA receptors caused by?
NMDA receptors
State of NMDA receptor pore at normal membrane potential?
Blocked by Mg2+
What are NMDA receptors permeable to?
Ca2+ and Na+ both going in
How is an LTP manifested postsynaptically?
Intracellular AMPA receptors get trafficked to CSM, the AMPA receptors are more sensitive and there is more synapses
How is an LTP manifested presynaptically?
Increased release of NT, more release sites and more vesicles
Other than EPSP what can calcium be used for in the postsynaptic neuron?
Signalling
What can calcium do as a signalling molecule in the postsynaptic neuron?
Activate kinases, e.g. Protein Kinase C, calcium calmodulin kinase II
What can protein kinase C phosphorylate?
AMPA receptor
What does phosphorylating AMPA receptors do?
Make it more sensitive–> it opens wider per glutamate molecule that binds to it
What does calcium comodulase kinase II do?
Acts as the trigger for causing intracellular AMPA receptors to traffic to the cell membrane.
How does calcium cause production of nitric oxide?
Via activity of guanylyl cyclase
What is NO used as in LTP?
An NT
Good things ab using NO as an NT?
It is a gas so it can freely diffuse from postsynaptic to presynaptic
Role of NO presynaptically?
Increased amounts of vesicles, increase probability that a vesicle is released per AP
What is a retrograde transmitter?
Goes from postsynaptic to presynaptic
Morris water maze?
Opaque body of water with a platform that lets them stand
Morris water maze use?
Studying memory
How was a morris water maze used to study memory?
Trained them to find the platform (same place) then did that with a NMDA agonist–> when agonist was present they didnt learn where the platform was
What is a priming cue?
A stimulus that can trigger memories
What kinds of memories can a priming cue trigger?
Conscious–> remember event, subconscious–> feeling ill, anxious
What is pavlovian/classical conditioning?
To do with memory linkage: Dog will salivate in response to food, if you combine food and bell then the dog will salivate, if you do it enough the dog will end up salivating if you only ring the bell and don’t present food
Why is pavlovian conditioning linked to drug abuse?
People associate the place they are, people they are around, music that is playing with taking drugs–> people would crave a drug if they go into the room where they used to take them
Outcome of a cocaine user watching a video of nature, then someone doing coke?
Brain activity when nature video was normal but different when they watched someone take coke
