A suitable co-agonist is bound. Which glutamate receptor channel admits calcium when glutamate binding overlaps with enough depolarisation to relieve its magnesium block?

• The glutamate-binding NMDA receptor
• The glutamate-binding AMPA receptor
• The voltage-gated calcium channel

A synapse follows the common timing rule taught here. Repeatedly, its input spikes shortly before the target cell spikes. What change does this favour?

• It will tend to become weaker
• It will remain permanently unchanged
• It will tend to become stronger

LTP names a lasting increase in synaptic strength, while LTD names a lasting decrease.

Circle one:   True   False

Calcium enters a receiving cell through NMDA receptors. You have not measured the calcium signal's pattern or the later synaptic response. What can you conclude?

• Calcium entry alone does not identify LTP or LTD
• Calcium entry proves that lasting strengthening has occurred
• Calcium entry proves that lasting weakening has occurred

A synapse follows the common timing rule taught here. A repeated close-pair protocol changes from input-before-target spikes to target-before-input spikes. What does the new order favour?

• LTP, a lasting increase in strength
• LTD, a lasting decrease in strength
• No change, regardless of further activity

A synapse adds working AMPA receptors. The same glutamate test pulse now opens more of these channels. Recording conditions are unchanged. What change in the fast excitatory current is expected?

• A smaller current in the receiving membrane
• No change in current despite more channels opening
• A larger current in the receiving membrane

Glutamate and a co-agonist are bound to NMDA receptors. Summed inputs sufficiently depolarise the local membrane without a target spike. A classmate says calcium entry is impossible. Which reply fits the mechanism?

• Local depolarisation can allow calcium entry
• A target spike is required for any calcium entry
• Glutamate always removes the magnesium block

Repeated input-before-target pairs are followed by LTP. Sam says this proves that the recorded input alone caused every target spike. Which conclusion fits the observations?

• That input was the sole cause of every spike
• Other inputs may also have contributed
• That input played no part in any target spike