Memory Flashcards
learning
acquisition of new information (facts)
Memory
retention of new information
learning and memory enable us to modify our behavior based on
new information and to extrapolate to unfamiliar situations
Procedural memory
implicit memory
non-declarative
reflexive memory
skills and habits that have been used so much they are automatic
procedural memory - anatomic substrates
cerebellum - motor skills
nucleus accumbens - non motor
Declarative memroy
explicit memory
the conscious recognition/ recollection of learned facts and experiences
subdivided into two forms
two forms of declarative memory
episodic - memory of events
semantic - memory of words, language, and rules
Declarative and procedural memory are coded for using
distinct anatomical stubstrates -
the physiology is not very different
Can also classify memory based on duration
short term
long term
working
the neural mechanism for each of these is DIFFERENT
short term memory
sec -hrs
Long term memory
years
WOrking memory
recalling a fact/memory for use - it may be a subset of short term memory
Working memory, ie
recalling a fact for use in a test question
you’ve learned it, now are retrieving it for use
will look very much like short term memory
declarative memory ie
the fact you learned for the test
this is events or facts stored in your memory
procedural memory i.e.
bike riding
motor skills that are used so much that you memorize the motor sequence required to produce the action
short term memory i.e.
the fact that you crammed in 5 minutes before the test began
long term memory i.e.
the memories of your life so far
involve changes in synapses, new synapses, etc
The production of memory and learning requires the induction of
neuronal and synaptic plasticity
Plasticity
alterations in the CNS based on use
may be synaptic function that;s altered
may be changes in the physical structure of the neurons (more synapses, new branches to new cells)
Plasticity - 2 categories
changes in synaptic function
Changes in the structure of neurons
plasticity - changes in synaptic functioning (3)
post - tetanic potentiation
pre-synaptic facilitation
Long term potentiation (LTP)
plasticity - changes in the structure of the neurons (3)
Gain/loss of synapses
structural changes in dendrites
structural changes in the soma of the neuron
Post tetanic stimulation - conditions
breif, high frequency discharge of presynaptic neuron
produces increased NT release
lasts about 60 seconds
Post tetanic stimulation - Mechanism
the high level of stimulation allowed more Ca to enter the terminal than could be death with (faster than the Ca exchange pump can pump the Ca out)
With more Ca, mor vesicles fuse, leading to greater NT release
post tetanic stimulation duration
SHORT lasting, only lasts as long as it take the pump to get the CA out.
but sets the stage for other things.
post tetanic stimulation duration
SHORT lasting, only lasts as long as it take the pump to get the CA out.
but sets the stage for other things.
Pre synaptic facilitation
start with a “normal” chemical synapse–>add another neuron that synapses on the presynaptic terminal of neuron A–>when activated, this terminal releases Serotonin,–> binding of the 5HT leads to activation of adenylyl cyclase and increased cAMP–> K channels in Neuron A become phophoyrlated and opening is delayed = depolarization is delayed
because the AP sticks around longer, we see greater NT release
LTP - definition
a series of changed in the pre and post synaptic neurons of a synapse which leads to increased response to the released NT
must last for HOURS after the stimulation
usually follows strong stimulation
NT can be EAA
LTP - definition
a series of changed in the pre and post synaptic neurons of a synapse which leads to increased response to the released NT
must last for HOURS after the stimulation
usually follows strong stimulation
NT can be EAA
LTP - mechanism (getting Ca into cell)
Eaa binds AMPA receptor, Na enters cell
depolarization–> displacement of Mg in NMDA channel
EAA binds NMDA and Ca can flow into cell
Ca is curcial to the development of LTP
LTP - how we get increased Na influx in response to EAA
Ca binds to calmodulin–> increased AC/cAMP–> phosphorylation of AMPA receptor= leave AMPA open longer to allow more Na into the POSTsynaptic cell (increase likelihood of AP from that cell)
LTP - Ca and presynaptic cell modifications
Ca binds to calcineurin–> activation of NOS–> production of NO–> acts on the PREsynaptic cell to increase cGMP and increase NT release
LTP - CREB
LTP is also associated with gene transcription related to increased CREB.
with crab we can create the proteins that are going to help us with LTP
learning and the formation of new memories can be blocked by blocking ______
this tells us that ____
protein synthesis
protein synthesis is crucial
protein synthesis involves the
pre and post synaptic cells
Gene transcription related to increased CREB in What cells? What do the proteins produced include
pre and post synaptic cells
NT synthetic enzymes
NT receptors
proteins required for growth/synapse formation
post tetanic potentiation
increased activity increases amount of Ca in pre synaptic terminal increasing NT release
presynaptic facilitation
serotonin release/binding to receptors on presynaptic terminal increases NT release by keeping neuron depolarized longer
LTP
changes in both pre and post synaptic responses to NT release so same NT release creates larger response (NMDA receptors)
lasts for hours
CREB
changes in synapse structure (permanent)
Creating declarative (explicit) Memories - 4 parts
- encoding
- storage of the information
- consolidation
- retreival
encoding
attending to new info
linking it to previous memories
higher cognitive funcitoning
storage of the information
retention of information over time
long term capacity not limited
consolidation
process of making a memory permanent
involves physical changes in synaptic structure
Retrieval
recalling or using the memory
bringing it into working memory
can be modified/lost at this point
Retrieval
recalling or using the memory
bringing it into working memory
can be modified/lost at this point
Short term memory - anatomical substrates (3)
hippocampus
parahipocampal cortex
prefrontal cortex
Short term memory - other interconnections
there are also interconnections to the neocortex and amygdala via the nucleus basal is of MEynert (cholinergic projection, a particular target of Alzheimer;s disease)
Short term memory - physiological substrate
LTP
Short term memory - remember!
this is our TEMPORARY storehouse for memory
to move to long term, we need consolidation
Storage of the information - temporary storage
short term memory: hippocampus parahippocampal cortex prefronal cortex LTP in these areas allows us to store information
Consolidation - requires
HIPPOCAMPUS
temporal lobes
Papez circuit
papez circuit
hypothalamus/mammillary bodies –>anterior thalamus–> cingulate cortex–> hippocampus–> REPEAT
consolidating memory from short to long term
the “memory” is repeatedly sent through the Papez circuit, thus setting up the conditions required to induce LTP and neuronal plasticity (the repeated activation), back to the cortex, etc
Eventually the limbic system is not required for access to the memory
Long term memory- stored in the area of the cortex related to
the modality of the individual components (i.e. visual information is stored in visual cortex, etc)
Consolidation
requires continued activation of circuit
ANATOMY - papez circuit, temporal lobes, hippocampus
PHYSIOLOGY - LTP as starting point, continued activation (papez circuit), creates new synapses in required regions of the brain (visual, auditory, etc)
Long term memory “reassembling” - requires
neocortex
parahippocampal regions
hippocampus
Recalling/retreiving memories - information related to each component of the memory is sent to the
parahippocampal regions
from the parahippocampla cortex, the components are sent to
the hippocampus, where the entire memory is “reconstructed”
after the hippocampus “reconstructs” the entire memory, information travels through the ______ to the _____
parahippocampus
cortex
the parahippocampus is important in prolonging he life of the
cortical “trace” of the memory
the parahippocampus is important in prolonging he life of the
cortical “trace” of the memory
retreival
must take the memory components (visual etc) from “storage area”
back to parahippocampal cotex
to hippocampus (reconstructs the memory)
to cortex via parahippocampal region (keeps the trace)
Working memory - using retrieved memories
Three component model
central executive
phonological loop
visuospatial loop
Three component model - functions
central executive - what actually decides the facts you need to start saying “i was sitting here, looking at…”
phonological loop - the words associated with the memory
visuospatial loop - the physical circumstances
Three component model - anatomy
central executive - prefronal cortex
phonological loop - Broca’s and Wernicke’s
visuospatial loop - occipital cortex associated with vision
Spatial memory - a special case
unlike other long-term memories, a detailed memory of space is stored in the HIPPOCAMPUS, using special pyramidal cells in CA1 known as place cells
it appears that this spatial map serves as an anchor for the reconstruction of memory
spatial memory uses special ____ cells in _____ known as _____ cells
pyramidal cells
in CA1
place cells
detailed memory of space is stored in
the hippocampus
______ serves as the anchor for the reconstruction of memory
spatial map created by place cells
Working memory
Central executive (prefrontal cortex) - directs/uses
phonological loop (broca and wernicke) - provide/interpret the auditory information associated with memory
visuospatial loop (occipital cortex, others) - provide/interpret the visual information associated with the memory
Spatial memory
special map in hippocampus codes for the physical space of the memory
place neurons in CA1 respond to specific locations within the space (a window, a door, etc)
this map is believed to anchor the entire memory
