Memory Mechanisms and Learning

Question 1

What is Long-term potentiation (LTP)?

Answer 1

A persistent increase in synaptic strength following high-frequency stimulation of a chemical synapse

Question 2

What are the two key properties of LTP proposed by Hebb?

Answer 2

• Endurance for months
• Coincident firing

Question 3

What does it mean for LTP to endure?

Answer 3

LTP can last for months

Question 4

What is meant by coincident firing in LTP?

Answer 4

LTP develops only if the presynaptic neuron fires followed by the postsynaptic neuron firing

Question 5

What happens when the presynaptic neuron fires but the postsynaptic neuron does not?

Answer 5

LTP does not develop

Question 6

What is Hebb’s postulate for learning?

Answer 6

The co-occurrence of firing in presynaptic and postsynaptic cells is necessary for learning and memory

Question 7

Is the evidence for LTP in learning and memory direct or indirect?

Answer 7

Much evidence is indirect and laboratory-induced

Question 8

How is the evidence for LTP often obtained?

Answer 8

Through electrical stimulation in laboratory settings

Question 9

True or False: LTP can develop when the postsynaptic neuron fires without the presynaptic neuron firing.

Answer 9

False

Question 10

Fill in the blank: LTP is recognized as a critical physiological necessity for _______.

Answer 10

learning and memory

Question 11

What role does the NMDA receptor play in memory formation?

Answer 11

Acts like a gate at synapses where memories are built

Question 12

Which neurotransmitter does the NMDA receptor respond to?

Answer 12

Glutamate

Question 13

What two conditions must be met for the NMDA receptor to function effectively?

Answer 13

• Glutamate must bind to the receptor
• The receiving brain cell must be partially active (partially depolarised)

Question 14

What type of ions do AMPA receptors allow to enter the neuron?

Answer 14

Sodium ions

Question 15

What is the primary function of AMPA receptors?

Answer 15

Responsible for fast excitatory signaling in the brain

Question 16

What blocks NMDA receptors under normal conditions?

Answer 16

Magnesium ions

Question 17

How does AMPA receptor activity affect NMDA receptors?

Answer 17

Depolarises the neuron enough to remove the magnesium block

Question 18

What is long-term potentiation (LTP)?

Answer 18

Strengthens connections between brain cells, making memories last longer

Question 19

What combination is needed to trigger long-term potentiation (LTP)?

Answer 19

• Glutamate binding to NMDA receptors
• Neuron being sufficiently depolarised by AMPA receptor activity

Question 20

What cascade of events does calcium entering through NMDA receptors trigger?

Answer 20

Enhances memory connections

Question 21

Fill in the blank: NMDA acts as a _______ for memories, ensuring they’re worth keeping.

Answer 21

security guard

Question 22

What do AMPA receptors help facilitate in relation to NMDA receptors?

Answer 22

Get the door open for calcium to enter

Question 23

True or False: AMPA receptors and NMDA receptors work independently of each other.

Answer 23

False

Question 24

What phenomenon is primarily researched in relation to memory in the hippocampus?

Answer 24

NMDA receptor-mediated LTP

LTP stands for long-term potentiation, a process that strengthens synapses based on recent patterns of activity.

Question 25

What has been revealed about LTP beyond the hippocampus?

Answer 25

LTP has been documented in various parts of the central nervous system and mediated by different mechanisms ## Footnote This indicates that LTP is more widespread than initially thought.

Question 26

What is the opposite phenomenon of long-term potentiation (LTP)?

Answer 26

Long-term depression (LTD) ## Footnote LTD occurs in response to extended low-frequency stimulation of presynaptic neurons.

Question 27

What is essential for truly comprehending LTP and its role in memory?

Answer 27

Knowledge of long-term depression (LTD) ## Footnote Understanding LTD helps contextualize the role of LTP in memory formation.

Question 28

What was the traditional view of astrocytes in relation to synaptic activity?

Answer 28

Astrocytes were traditionally viewed as passive support cells ## Footnote This view has evolved with new research indicating their active role in synaptic modulation.

Question 29

What do astrocytes release that may influence LTP?

Answer 29

Glitransmitters ## Footnote Glitransmitters are a type of signaling molecule involved in communication between astrocytes and neurons.

Question 30

List the functions of astrocytes in relation to synaptic plasticity.

Answer 30

* Regulate extracellular ion concentrations * Clear excess neurotransmitters * Contribute to synaptic plasticity ## Footnote These functions highlight the multifaceted role of astrocytes in neural processes.

Question 31

What is still being investigated regarding astrocytes and LTP?

Answer 31

The precise mechanisms by which astrocytes affect LTP ## Footnote This includes whether astrocytes enhance or modulate synaptic strength.

Question 32

What has the study of LTP contributed to the broader understanding of the brain?

Answer 32

Advanced knowledge of neural system functions and adaptability ## Footnote This contributes significantly to unraveling the neural basis of learning and memory.