Hello,
I am translation a book called models of mind by Grace Lindacy and I want to understand what is meant by snapshot in the following:
If it only uses a quick snapshot of its input, however, the noise will dominate.
So how much time does a neuron combine its inputs over?
About 20 milliseconds.
That may not seem like long, but for a neuron it’s plenty.
A spike only takes about 1 millisecond and a cell can be receiving many at a time from all of its different inputs.
Therefore, neurons should be able to take the average over many snapshots of input before deciding to spike.

- Does take the average over = take the average of
- what does it mean by snapshots of input

A snapshot is the values of all the inputs at some point in time.

Yes, "take the average over" is the same as "take the average of", except "over" is more suggestive of a time series, as in "take the average over a period of time".

Thank you.

I have another question please: what is meant by 

uses a quick snapshot of its input in the following sentence?

Just like in the game example, if the neuron takes in this noisy input for a long time before deciding if it has enough to spike, the impact of the noise will be reduced.
If it only uses a quick snapshot of its input, however, the noise will dominate.

Same thing. If data comes in continuously, in an analog system, it means averaging over only a short period of time. Not long enough to eliminate the high-frequency noise.

15 hours ago, noha said:

I am translation a book

Good luck.