8. Learning and Memory (Karius) Flashcards
What is Working Memory?
recalling a fact or memory for use, similar to short term memory (long-term memory that we bring back into working knowledge)
-however, neural mechanism for working, short term and long term memory all differ
What is Declarative (explicit) Memory? Describe the 2 subtypes
conscious recognition/recollection of learned facts and memories/experiences
- episodic: memory of events
- semantic: memory of words, language, rules
What is procedural (implicit/non-declaractive/reflexive) memory? What areas help facilitate this?
skills and habits that have been used so often that they are automatic
- Cerebellum: motor skills
- Nucleus accumbens: non-motor
What is post-tetanic potentiation ?
increased activity increases amount of calcium in pre-synaptic terminal, increases NTM release
What is long term potentiation?
changes in both pre and post synaptic responses to NTM release so that the same NTM release creates a larger response (on NMDA receptors). Lasts for hours.
What is CREB?
changes in synapse structure (permanent) and creation of new synapses via protein synthesis
Step 1 of Declarative Memory:Encoding
- attending to new info with focus and attention
- linking it to previous memories
- emotion is important here
Step 2 in creating a Declarative Memory: Storage
- retention of information over time, starts in short term memory
- short term memory is located in the hippocampus, parahippocampal cortex, and prefrontal cortex
- LTP in these areas allows us to store information
Step 3 in creating a Declarative Memory: Consolidation
- makes memory permanent
- involves physical changes in synaptic structure
Step 4 of creating a Declarative Memory: retrieval
*define and name the pathway
- recalling or using the memory , bringing to working memory
- can be modified or lost at this point
1. sent to parahippocampus first
2. hippocampus where it is reconstructed
3. back to the parahippocampus on its way to the cortex (PH important for proloning the life of the memory)
What are the 3 loops and their locations used in working memory when retrieving memories?
- central executive-prefrontal cortex
- phonological loop-broca’s and wernicke’s
- visuospacial loop-occipital cortex associated with vision
anatomical substrates for consolidation in declarative memory formation
- hippocampus
- temporal lobe
- papez circuit
Describe spatial memory
- detailed memory of where info is stored is in the hippocampus using pyramidal cells in CA1 (Place cells)
- serves as a scaffold for reconstruction of the entire memory
What is the location and function of place cells?
- location: hippocampus (CA1)
- activated at specific locations, strongly activated if the memory location is associated with reward
- final mediator of spatial memory
What are Grid cells? What is their location?
- location: entorhinal cortex
- active when exploring an area, b/c creates a grid map of the space you are in
- triangular or hexagonal grid of the area
What are head direction cells?
What are border cells?
which direction is the head pointing to see/explore the area
fire when near a border, wall, etc.
Describe spatial memory and the importance in long term memory
spatial map in hippocampus codes for the physical space of the memory
place neurons in CA1 respond to specific locations within the space
this map anchors the entire memory
what type of memory is used for recalling info for a test?
working
what type of memory are you using while learning and studying?
declarative- facts you learned for the test, event of info stored in memory
what type of memory is used for things like writing or riding a bike?
procedural
what is necessary for production of memories and learning?
neuronal and synpatic plasticity
what is plasticity?
altering synaptic function/physical structure of neurons (include more synapses or new branches to new cells)
how does changes in plasticity change synpatic functioning?
- long-term potentiation
- post-tatanic potentiation
how does changes in plasticity change neuronal structure?
- gain/loss of synapses
- structure changes in dendrites
- change structure of soma of neuron
what conditions are needed for post-tetanic stimulation?
- brief, high freq discharge of pre-syn neuron
- increase in NT release for ~ 60 sec
- increase probability of AP in post-synaptic cell
what is long-term potentiation? give an example of the process
series of changes in pre- and post-synaptic neurons of a synapse which lead to increase response to released NT (usually in response to strong stim)
example: NT binds, increase IC Ca+, activates:
1. calmodulin=increase AC/cAMP=phospho AMPA rec=increase Na+ influx
2. Calcineurin=+NOS=NO prod=increases cGMP and NT release in pre-syn cell
- Associated w/ gene transcription related to increased CREB
what is neuronal plasticity? what proteins are produced (3)?
Gene transcription related to increase CREB in pre and post-syn cells
-proteins produce: NT synthetic enzymes, NT rec, proteins for growth/synapse formation
What are the general overview steps for creating declarative (explicit) memories?
- encoding
- storage info
- consolidation
- retrieval
location of anatomical substrates for short term memory?
- hippocampus
- parahippocampal cortex
- prefrontal cortex
LTP in these areas allows us to store info
how are short-term memories formed?
interconnections to neocortex and amygdala via nucleus basalis of meynert (cholinergic projections, particular target in Alzheimers)
How are short term memories converted to long term memories?
the memory is repeatedly sent thru papez circuit inducing LTP and neuronal plasticity until the Limbic system is no longer required to access the memory, instead it is stored as a long term memory in the cortex related to it’s modality
Continuous loop of
- hypothalamus/mammillary bodies
- anterior thalamus
- cingulate cortex
- hippocampus
where are long term memories stored?
area of cortex related to modality
-ex: visual info stored in visual cortex
anatomical substrates needed for retrieval in creating declarative (explicit) memories?
- neocortex
- parahippocampal regions
- hippocampus
what inputs to space cells receive?
- grid cells: create map of place you are in
- head direction cells
- border neurons
- others
What proteins are being synthesized in greater amounts after learning? Many, but the 3 she mentioned
- receptors for NT
- proteins associated w/ synapse
- NT syn
These increase rec at synapse and form new synapses
long-term memories rely on extensive production of what?
new synapses within cortex for memory storage
physiological substrates for short term memory
LTP
sensitization
consolidating memory from short to long term requires what anatomical substrated?
- hippocampus
- temporal lobes
- limbic, papex circuit
what is the baddeleys 3 component model for recalling a memory, via working model? name associated anatomical substrated for each
- central executive: dorsolateral PFC
- phonological loop-acoustic and linguistic memory: Broca and Wernicke’s, L hemi
- visuospatial: visual processing in occipital cortex
This retrieval also involves parahippocampal cortex, hippocampus, relevant cortical areas
On recall test, patient was only able to recall 3 words after 5 mins. This is consistent with impairement to what type of memory?
short term
Patient is able to correctly state what state, country, and town she is in. What type of memory is intact based on these answers?
long term
which of the 4 processses associating with creating a memory requires synthesis of proteins and creation of a new synapse?
consolidation
A normal person can repeat 3 words back to you after 5 mins due to occurence of what?
LTP
When recalling event, pt describes in great detail how everything looked. Where is the memory of these details stored?
visual cortex
What type of medication can be prescribed in Alzheimers to slow cognitive decline?
AChE
What type of recall is post-tetanic potentiation associated with?
responsible for the shortest recollection of events because it increases NT releast at synapse for about only 30-60 sec. Once Ca+ is moved from presyn terminal, function of that synapse returns to normal and whatever event was assocated with that activity was forgotten
What type of recall is LTP associated with?
words for 5-30 mins
recalling words stated the previous day would be associated with what type of process in memory?
consolidation and long term memory formation
How would an NMDA antagonist help (partially) in Alzheimers disease progression
NMDA allows glutamate to connect to a cell like a boat tying up at a dock. When glutamate is “docked” at an NMDA receptor, it passes calcium into the cell, carrying the electrical or chemical signal that last step. This is important for learning and memory.
If you have Alzheimer’s disease, your cells can make too much glutamate. When that happens, the nerve cells get too much calcium, and that can speed up damage to them. NMDA receptor antagonists make it harder for glutamate to “dock” – but they still let important signals flow between cells.
