PHYS: Memory & Learning

Question 1

What are 2 types of memory?

Answer 1

• Declarative (explicit)
  
  • Explaining how to work home
• Procedural (implicit or motor/skill)
  
  • Walking home

Question 2

Explain relationship between immediate/short-term, working and long-term memory?

Answer 2

Working memory = holding immediate information from many sources to carry out a task.

Question 3

Which parts of the brain are associated with which aspects of memory?

Answer 3

• Prefrontal cortex - working memory
• Hippocampus - memory storage and formation
• Thalamus - memory recall (although a bit more diffuse)

Question 4

Explain the process of memory consolidation

Answer 4

• Repeated activation ST memory trace => anatomical changes => LT memory
• Memories are codified => similar things stored together (and recalled together)

Question 5

What regulates memory consolidation?

Answer 5

• Hippocampus - memory storage
• Works with limbic system (punishment and reward centres) to create motivation/drive to remember thoughts/experiences.
• Lesion to hippocampus = anterograde amnesia

Question 6

What brain centre is important for memory recall?

Answer 6

Thalamus

Lesion = retrograde amnesia

Probably plays roll in ‘searching’

Also pFC. Damage = RG Amnesia.

Question 7

What are the cellular mechanisms of memory?

Answer 7

• Immediate - reverberating cirtus? Activate, go round, back to that place
• STM - temporary physical or chemical change at the synapse - increased availability of neurotransmitter vesicles
• LTM - structural changes to synapses/networks, plus:
  
  • changes in gene expression
  • changes in synapses
  • physical changes - branching axons, more dendrites being formed

Question 8

Explain positive versus negative learning.

Answer 8

• Negative: habituation
  
  • Learning to ignore stimuli that lack meaning
• Positive: facilitation
  
  • Learning to intensify response to stimuli

Question 9

What are the mechanisms of negative memory?

Answer 9

• Inhibition of synaptic pathways
• Reduction:
  
  • nt production
  • Ca2+ channels at presynpatic bulbs
  • Postsynaptic receptors
  • 2nd messengers -> change gene expression

Question 10

What are mechanisms of positive memory?

Answer 10

• Facilitation of synaptic pathways
• Potentiate:
  
  • nt prodution
  • Ca2+ channels
  • Postsynaptic receptors
  • Synapses
  • 2nd messengers –> changes gene expression

Question 11

Explain the biochemical process of faclitation at the synapse

Answer 11

• Serotonin released by facilittory neurone at the presynaptic neuron
• Coactivation results in potentiation
• Dumps more nts into the synapse
• Greater signal = potentiation lasts

Question 12

Explain long-term potentiation (particularly in hippocampus)

Answer 12

Repetivie/strong excitatory signals exhance responsiveness.

By repeatedly stimulating neurons in the hippocampus - change shape and structure.

Activates dendritic spines that synapse there and with other neurons.

Long term potentiation increases long term communication by increasing number of neurons.

Question 13

What is the role of different receptors in LTP in the hippocampus?

(Very confusing)

Answer 13

AMPA receptor - glutamate binds to AMPA and allows Na+ to flow - creates excitatory post-synaptic potential

NMDA receptor - normally blocked by magnesium. In LTP, Ca2+ displaces magnesium, meaning enhanced synapses

More AMPA receptors.

Retrograe messengers increase nt vesicles in presynpatic knob.

Question 14

Explain the neuronal basis of long-term memory

Answer 14

Dendritic spines are plastic and activity-dependent

Growth/remodelling of dendritic spines reinforces a particular neural pathway –> maintenance of memory over a lifetime.

Question 15

What are the cellular mechanisms of LT memory?

Answer 15

• Structural changes (synaptic plasticity)
• Presynaptic
  
  • increased nt vesible release sites
  • increase number nt vesicles
  • increased number or presynaptic temini
• Postsynaptic
  
  • LTP/LTD
  • Growth/remodelling of dendritic spines