Lecture 33. Learning and Memory Flashcards
How long does sensory memory last ?
Milliseconds to seconds
How long does short term working memory last ?
Seconds to minutes
How long does long term nondeclarative memory last ?
Minutes to years
How long does long term declarative memory last ?
Minutes to years
What type of capacity does sensory memory have ?
High
What type of capacity does short term working memory have ?
Limited - roughly 7 items
What type of capacity does long term nondeclarative memory have ?
High
What type of capacity does long term declarative memory have ?
High
What type of memory has conscious awareness ?
- Short term working
2. Long term declarative
What type of memory does not have conscious awareness ?
- Sensory
2. Long term nondeclarative
What is sensory memories mechanism of loss ?
Primarily decay
What is short term working memories mechanism of loss ?
Interference and decay
What is long term non-declarative memories mechanism of loss ?
Primarily interference
What is long term declarative memories mechanism of loss ?
Primarily interference
What is the Atkinson and Shiffrin model ?
- Proposes that information is first stored in sensory memory
- From there items selected by attentional processes can move into short term storage
- If the item is rehearsed it can be moved into long term memory
In the Atkinson and Shiffrin model, how can information be lost ?
- Decay
- Interference
- Both decay and interference
What did Baddeley and Hitch model propose ?
A three part memory system consisting of a central mechanism that presides over and coordinates the interaction between two subordinate short term memory stores and long term memory
What are the two subordinate short term memory stores in the Baddeley and Hitch model ?
- Phonological loop
2. Visuospatial sketch pad
What is the general definition of an engram ?
Describes the enduring modification to the nervous system produced by an experience
What is a memory engram ?
The learned information stored in the brain
What is necessary for memory retrieval ?
Synaptic strength
What did Lashley do ?
Discovered the principle of mass action and the principal of equipotentiality
What is the principle of mass action ?
Learned memory is distributed across all parts of the brain instead of being stored in single regions
What is the principle of equipotentiality ?
In the event of damage in one area of the brain, other areas of the brain can sometimes assume the roles of the damaged region
According to Morris’ water maze what can rats with hippocampal lesions do ?
Learn a repeated, practiced task but are unable to relate space information with different contextual information
In Hebblian learning, what happens when a synapse is active when a postsynaptic neuron is active ?
The synapse will be strengthened
What is long term potentiation ?
Long term strengthening of a synapse
What is neuronal plasticity ?
The ability of the nervous system to be modified after birth
What is synaptic plasticity ?
The strengthening or weakening of synaptic junctions
What does long term potentiation in the vertebrate brain involve ?
A lasting increase in the strength of the synaptic transmission
What happens to synapse prior to long term potentiation ?
The NMDA glutamate receptors open in response to glutamate but are blocked by Mg 2+
What happens to establish a long term potentiation ?
- Mg 2+ is released from NMDA receptors upon depolarisation
- The unblocked receptors respond to glutamate by allowing an influx of Ca+2 and Na+2
- The Ca +2 influx triggers insertion of the stored AMPA glutamate receptors into the postsynaptic membrane
What happens when the synapse exhibiting long term potentiation ?
- Glutamate release activates AMPA receptors that trigger depolarisation
- The depolarisation unblocks NMDA receptors
- AMPA and NMDA receptors trigger postsynaptic potentials strong enough to initiate action potentials without input from synapses
What are hippocampal NMDAA receptors crucial for ?
Encoding and recall of spatial memory
What does the formation of new memories require ?
The formation of new proteins to strengthen the connections between brain cells
What did Donald Hebb propose in 1949 ?
Synaptic connections between co-activate cells change in a manner dependent on their activity
What is a common saying for Hebb’s Law ?
Cells that fire together wire together
What is anisomycin ?
A protein synthesis blocker that blocks the formation of long term memory
What is required for cued and contextual fear conditioning ?
Amygdala
What is only requires for contextual fear conditioning ?
Hippocampus
What did Sheena Josselyn work on ?
Selective erasure of a fear memory
What is optogenetics ?
Genes are manipulated so they can express a photosensitive protein that when exposed to light will activate the neuron
What can channelrhodopsin do ?
Activate neurons with milliseconds resolution
What can halarhodopsin do ?
Inactivate neurons with milisecond resolution
