14/15. memory II-III Flashcards
(14 cards)
What condition does Clive Wearing suffer from?
A ‘7-second memory’ due to herpes viral encephalitis
Despite profound amnesia, he retains intelligence, speech abilities, and musical skills.
What is Donald Hebb’s Postulate?
‘When an axon of cell A is near enough to excite cell B…some growth or metabolic change takes place…such that A’s efficiency in firing B is increased’
Often summarized as ‘neurons that fire together, wire together’.
What does Long-Term Potentiation (LTP) involve?
- Recording stable baseline responses to low-frequency stimulation
- Delivering high-frequency stimulation (tetanus)
- Observing enhanced responses to subsequent stimulation
Enhanced synaptic efficacy persists for hours.
What role do NMDA receptors play in LTP?
Function as ‘coincidence detectors’ that require both glutamate binding and membrane depolarization
Blocked by magnesium at resting potential, allowing calcium influx when both conditions are met.
What triggers downstream events leading to synaptic strengthening during LTP?
Calcium influx
Calcium is crucial for the molecular mechanisms of LTP.
What is an engram?
‘A neural substrate responsible for storing and recalling memories’
Criteria include activation by learning, physical/chemical change by learning, and reactivation during recall.
What does the TRAP method do?
Labels active neurons expressing early genes (c-fos)
This allows visualization and manipulation of specific neuron populations.
What is the purpose of optogenetic memory manipulation?
Allows artificial activation of memory traces
Involves light-sensitive proteins expressed in engram cells.
What was demonstrated by the false memory implantation experiment?
Activated engram cells from neutral context caused freezing in that context when light-activated
This shows the ability to create artificial associations.
What is the significance of memory recovery in Alzheimer’s models?
Suggests that memory traces exist but cannot be naturally accessed
Artificial activation can recover ‘silent engrams’, indicating potential therapeutic approaches.
Which brain regions are involved in memory?
- Hippocampus
- Entorhinal cortex
- Amygdala
- Various cortical regions
Memory involves multiple regions beyond just the hippocampus.
True or False: Memory deficits in Alzheimer’s disease are solely due to the loss of hippocampal synapses.
False
Similar deficits appear in conditions like schizophrenia and bipolar disorder.
Fill in the blank: Memory involves both _______ and network-level changes.
molecular mechanisms (synaptic plasticity)
Different brain regions support different types of memory.
What modern techniques allow for precise manipulation of memory traces?
- Activity-Dependent Labeling
- Optogenetic Memory Manipulation
- Targeted Ablation
These techniques enhance the study of memory engrams.
