Physiological models of memory Flashcards
Define learning and memory- purves et al 2004
the acquisition, encoding, storage and retrieval of information in the nervous system
-e.g knowledge, behaviours, skills, values
-many cognitive skills depend on its function
-e.g language, navigation, muscle memory, facial recognitio
Define declarative memory
-consciously accessible
-exam memory, remembering facts and figures
Define non declarative (procedural) memory
-generally unconsciously available
-muscle memory, motor skills, driving, tying shoe laces
Define short term/ immediate memory
fractions of seconds
Define working memory
seconds to minutes
Define long term memory
days to years
Name 3 types of amnesia
-pathophysiological
-anterograde
-retrograde
Why do people forget?
-essential element of memory
-limited capacity in CNS
-training improves retention
-critical for normal functioning
What is anterograde amnesia?
inability to form new memories
usually temporary
may be unable to learn or retain any new information
What is retrograde amnesia?
can’t recall memories from the past
loss of information acquired before the onset of amnesia
-more widespread lesions
Give the proposed site of damage for vascular occlusion of posterior cerebral artery
midline temporal lobe and hippocampus
Give the proposed site of damage for midline tumours
medial thalamus and hippocampus
Give the proposed site of damage for trauma
areas close to the hippocampus
Give the proposed site of damage of surgery
midline temporal lobe and hippocampus
describe the function of the Hippocampus and related areas
-key importance for short term declarative memory
-site of shorter term memory formation but longer term storage elsewhere in brain
Describe the function of the hippocampus
use dependent change in neuronal excitability in the hippocampus have been linked to short term memory formation
-long term potentiation
Describe LTP- cellular process
-presynaptic cell- activated by incoming signal, releases glutamate at synapse
AMPA receptor- activated by glutamate, allows Na+ to enter neuron, post synaptic activation
If receptors produce more glutamate, NMDA looses the block and then can bind glutamate and allow Ca2+ to enter the cell:
NMDA receptor- usually blocked by mg2+, heavy activation removes ca2+ enters the neuron, leads to activation of kinase , changes excitability of neuron
-modulates AMPA receptor activity, recruits more glutamate receptors
Describe long term memory changes involved in gene activation
-CREB- transcription factor
-activation of CREB modulation of gene transcription (can switch on/ off cells)
-changes in production of proteins associated with synaptogenesis, synaptic stabilisation, synaptic strength
-also leads to neurogenesis
describe the simple model for memory consolidation
Neural pathways- associative cortex to hippocampus - encoding for short term memory
Neural pathways- back to associative cortex - longer term storage
use dependent change in short term neuronal excitability, linked to long term changes in connectivity
What is synaptogenesis?
formation of synapses between neurons in the NS
