How do temporal and spatial summation improve the processing power of the brain?

Question

A.  Temporal summation allows circadian rhythms to regulate neuronal activity. Spatial summation allows latitude to regulate neuronal activity.
B.  Temporal summation allows a neuron to fire prolonged action potentials, and spatial summation allows a neuron to synapse onto new targets.
C.  Temporal and spatial summation both make the neuron more likely to fire action potentials.
D.  Temporal summation allows a neuron to recognize a persistent signal from a single presynaptic cell, and spatial summation allows a neuron to recognize a broad signal from multiple presynaptic cells.


Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

Gather Content/Choose Answer
· What do you already know about summation? What other information is related to the question?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  Temporal summation allows a neuron to recognize a persistent signal from a single presynaptic cell, and spatial summation allows a neuron to recognize a broad signal from multiple presynaptic cells.


Clarify Question
· What is the key concept addressed by the question?
        o Similarities and differences between spatial and temporal summation.
· What type of thinking is required?
        o Answering this question correctly depended not only on distinguishing between temporal and spatial summation, but on your ability to break down, or analyze, the advantages or benefits of each.

Gather Content/Choose Answer
· What do you already know about summation? What other information is related to the question?
        o To solve this problem, you’ll need to remember that that in spatial summation, graded potentials due to dendrites from different presynaptic neurons that occur at the same time add together to potentially reach an above-threshold voltage and thus initiate an action potential. In temporal summation, a single dendrite can produce sufficient depolarization to produce an action potential if it produces EPSPs that are close enough in time to sum to an above-threshold voltage.

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o If you figured out the correct answer, great! If not, where did you go wrong? Did you think that temporal summation and circadian rhythms were linked because they both have to do with time? It is true that both concepts relate to time, but the question is asking about the processing power of the brain. Temporal summation does not allow for prolonged action potentials (answer B), as they are an all-or-none response, but both temporal and spatial summation can regulate whether an action potential will be elicited by producing above-threshold voltages. Summation does not necessarily make a neuron more likely to fire (answer C), because it depends upon whether the signals that are summed are excitatory or inhibitory.