Memory and sleep Flashcards
What is the engram
The physical embodiment of a memory
What are the 2 memory systems
Procedural memory (implicit) - skills and associations, unavailable to the conscious mind
Declarative (explicit) - available to the conscious mind, symbols and language
What are the different lengths of memory
Immediate - few seconds
Short term - seconds/mins
Long - days,months,years
What parts of the brain does playing the piano require
Auditory cortex and motor cortex
What parts of the brain does taking an exam require
Amygdala and frontal cortex
What does the temporal lobe do
Responsible for creating and preserving conscious and long-term memory
Patient HM had 8cm of medial temporal lobe removed –> intelligence and personality was intact but had extreme anterograde amnesia
What does the pre-frontal cortex do
Allows access to the working memory
What does the hippocampus do
Converts short - long term memory
Declarative memory
What does the amygdala do in memory
Multiple processed sensory inputs which allow for learnt fear
What does the cerebellum do in memory
Procedural memory
Sensorimotor memory - difference between you and environment
How many layers in the hippocampus
3 layered cortex
Where does the hippocampus get its inputs
Mainly the entorhinal cortex
When would the hippocampus be enlarged
In people whose work requires good spatial memory
What are reverberating ciruits
A neural circuit which nerve impulses that were initially activated in response to stimulus are more or less continuously reactivated so that he retrieval of information on demand is possible
What is the Hebbian synapse
A junction between neurons which is strengthened every time it successfully fires
What is long term potentiation
a process involving persistent strengthening of synapses that leads to a long-lasting increase in signal transmission between neurons
What is in the temporal lobe
the olfactory cortex, the hippocampus and the amygdala
What is long term depression
The process at which synaptic connections become weaker
Allows for new memories
How does LTD occur
NMDA blocked by Mg2+
AMPA activation causes depolarisation so Mg2+ removed
Ca2+ can re-enter the neuron causing further depolarisation
Low level of calcium is insufficient to activate LTP
Activates cellular cascade to remove AMPA receptors which weakens the synapse
When does LTD happen
Prolonged low intensity stimulation
How does LTP occur
Mg2+ block on NMDA receptors removed by glutamate so Ca2+ can enter the cell
Influx of calcium creates more AMPA receptors so more postively charged ions can enter the cell
Postsynaptic receptor becomes more receptive to glutamate so more Ca2+ can enter
What is habituation
A decrease in response to a stimulus after repeated presentations
How is habituation achieveved
Repeated stimuation calcium channels becomes less responsive so less calcium crosses the presynaptic membrane
Less neurotransmitter released
Less depolarisation of the post-synaptic membrane so no action potential is triggered in the motor neuron
What changes in habituation
Less neurotransmitters so fewer APs
