Biological Psychology

Question

1. What is the primary difference between temporal summation and spatial summation?

a.Only spatial summation can produce an action potential.

b.Temporal summation produces a hyperpolarization instead of a depolarization.

c.Spatial summation alters the response of more than one postsynaptic cell.

2. Autoreceptors monitor the amount of reuptake.

a.False

b.True

d.Spatial summation depends on contributions from more than one sensory neuron.

3. Depolarization is to decreasing the threshold, and hyperpolarization is to increasing the threshold.

a.False

b.True

Answer 1

Greetings Leby!

When thinking of temporal vs. spatial summation think of time and space. For temporal summation think time since this type of summation involves the frequency (or number of times stimulation occurs) of a single signal and when added up, may cause an action potential. For spatial summation think of space. For an action potential to occur, if it reaches the threshold of course, the post-synaptic neuron receives multiple signals from multiple dendrites and when added up may cause an action potential. Both may cause an action potential or not cause one by not reaching the threshold or creating a greater voltage difference.

In terms of autoreceptors, the prefix “auto-“ refers to self. Think autoimmune as the immune system attacking itself. You can also think of “autopilot” as an airplane flying itself. Autoreceptors are no different in that they are the receptors for the ligand that its own cell produces. Therefore, it does manage the amount of reuptake.

Regarding hyperpolarization, I would associate this to needing to “be more hyper” in order to reach threshold. When a neuron undergoes hyperpolarization, the membrane potential decreases (becomes more negative in most cases), making it much harder to reach threshold and therefore initiate an action potential. This is commonly seen in inhibitory signals.

Depolarization is the membrane potential getting closer to the necessary threshold. So when a neuron is depolarizing, the difference between the current potential and the membrane potential decreases as they get closer.

Let me know if you have any further questions or need any clarification, Leby!