Karius: learning and memory Flashcards
what are the different types of memory?
- working
- declarative
- Procedural
- short term
- long term
Describe Procedural memory
- aka implicit, non-declarative, reflexive
- skills and habits that have been used so much they are automatic
- like riding a bike
What are the anatomic substrates for procedural memory
- Cerebellum - motor skills
- Nucleus accumbens - non motor
Describe Declarative memory
- aka explicit memory
- the conscious recognition/recollection of learned fact and experiences
what are the 2 forms of declarative memory
- Episodic: memory of events
- Semantic: memory of words, language, and rules
Describe working memory
- you’ve learned it, now you are retrieving it for use
- will look very much like short term memory
The production of memory and learning requires the induction of what?
neuronal and synaptic plasticity
what are the changes in synaptic function that occur with plasticity
- Post-tetanic potentiation
- Pre-Synaptic facilitation
- Long-term potentiation (LTP)
What are the changes in the structure of the neurons that occurs with plasticity?
- Gain/loss of synapses
- Structural changes in dendrites
- Structural changes in the soma of the neuron
Describe Post-Tetanic Stimulation
- brief, high frequency discharge of presynaptic neuron
- Produces increased neurotransmitter release
- lasts about 60 seconds
- The high level of stimulations allowed more Ca to enter to the terminal than could be “dealt” with
Describe Pre-synaptic facilitation
- Start with a normal chemical synapse
- now add another neuron that synapses on the presynaptic terminal of the first neuron
- when activated this terminal releases serotonin (5HT)
- leads to activation of adenylyl cyclase and increased cAMP
- K+ channels in the neuron become phosphorylated and opening is delayed thus repolarization is delayed
- this leads to greater neurotransmitter release
Describe Long-term potentiation
- A series of changes in the pre and post synaptic neurons of a synapse which leads to increased response to the released neurotransmitter
- by definition, this increase in response must last for hours after the stimulation
- usually follows strong stimulation
mechanism of increased response in long term potentiation in POST synaptic neuron
- increased intracellular Ca: via influx through NMDA receptors and release from intracellular stores
- increased binding of Ca to neuronal calmodulin: increased adenylyl cyclase activity and increased CAM-kinaseII
- increase cAMP
- protein kinase A activation
- increased phosphorylation of AMPA receptors
- CAM-kinase II autophosphorylates: leads to prolonged activation. it also phosphorylates AMPA and NMDA
- increases the amount of current ions flowing into the cell
- leads to an increased epsp amplitude in response to same amount of neurotransmitter release from pre synaptic neuron
how does long term potentiation affect PRE synaptic neuron
- increased Ca in post synaptic leads to activation of NOS
- produces NO which diffuses out and into pre synaptic
- increase in cGMP
- increased neurotransmitter release with future action potentials
Long term potentiation is associated with gene transcription related to increase in what?
CREB: cAMP response element binding protein
Learning and the formation of new memories can be blocked by blocking what?
protein synthesis
what proteins are produced by CREB
- NT synthetic enzymes
- NT receptors
- Proteins required for growth/synapse formation
in the physiological and anatomic changes associated with synaptic plasticity, list the changes from shortest time to longest time
- Post-tetanic potentiation
- Pre-synaptic facilitation
- Long term potentiation
- CREB
What are the processes involved in Creating declarative (Explicit) memories
- Encoding
- Storage of the information
- Consolidation
- Retrieval
Describe Encoding
- Attending to new info
- Linking it to previous memories
Describe Storage of the info
- Retention of information over time
- Long term capacity not limited . ie your brain has infinite storage capacity
Describe consolidation
- Process of making a memory permanent
- Involves physical changes in synaptic structure
Describe Retrieval
- Recalling or using the memory
- Bringing it into working memory
- Can be modified/lost at this point
what are the anatomic substrates for short term memory
- Hippocampus
- Parahippocampal cortex
- Prefrontal cortex
Describe the other interconnections used for short term memory
-interconnections to the neocortex and amygdala via the nucleus basalis of Meynert (cholinergic projection, a particular target of Alzheimer’s disease)
What is the PHYSIOLOGICAL substrate for short term memory
long term potentiation
what is the termporary storehouse for memory
long term potentiation in the hippocampus, parahippocampal cortex, and prefrontal cortex
Consolidating memory from short to long term requires what anatomical structures
- hippocampus
- temporal lobes
- Papez circuit
Describe the loop of consolidating a memory from short to long term
-hippocampus –> hypothalamus –> Anterior Thalamus –> Cingulate cortex –> Hippocampus
- just a repeating circular loop
- the memory is repeatedly sent through the papez circuit thus setting up LTPs and back to cortex . . eventually the limbic system is not required for access of the memory
where are long term memories stored
-areas of cortex related to the modality of the individual components . . so visual information stored in visual cortex etc
Long term memory . “reassembling” requires what areas
- Neocortex
- parahippocampal regions
- hippocampus
describe the process of recalling/retrieving memories
- information related to each component of the memory is sent to the parahippocampal regions
- then sent to hippocampus where the entire memory is “reconstructed”
- then travels back though the parahippocampus to the cortex
What is important in prolonging the life of the cortical “trace” of the memory
parahippocampus
What are the 3 components of working memory (using retrieved memories)
- Central Executive
- Phonological loop
- Visuospatial loop
Describe here each of the 3 components of working memory are located
- Central executive (prefrontal cortex)
- Phonological loop (Broca’s and Wernicke’s)
- Visuospatial loop (occipital cortex associated with vision)
Describe spatial memory
- Stored in HIPPOCAMPUS
- uses special pyramidal cells in CA1 known as PLACE cells
- spatial map serves as an anchor for the reconstruction of memory
