AFNI program: @ShowDynamicRange
Output of -help
Usage @ShowDynamicRange <afni dset>
The script checks the dynamic range of the time series data
at locations inside the brain.
The input dataset is an epi timeseries that has just been assembled
from your reconstructed images
The output consists of the following:
- A dataset whose prefix ends with minpercchange
which shows the percent signal change that an increment of 1 digitized
value in the time series corresponds to.
- A dataset whose prefix ends with .range
which shows the number of discrete levels used to
represent the time series.
The scripts output the average range and the average %change corresponding
to a unit digitized signal
To be safe, one should have a dynamic range that does not introduce noise
at the level of expected response differences between tasks.
For example, if a unit step corresponds to 0.3% signal change then you may
not be able to detect differences of comparable magnitude in the FMRI
response to two tasks.
These differences may be obscured by digitization noise.
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Tue Dec 17 06:56:20 PM EST 2024