# AM¶

AM is calculated as the average amplitude and the standard deviation of the mean-subtracted time series. The AM represents the strength of time series’ temporal fluctuation, which is similar to ALFF/fALFF.

**mask**: could be whole brain mask or gray matter mask.**id index**: identifier to find unique string for each subject**filetype**: files in the filetype will be searched in input directories.**4D nifti files**: if the input data is 4D, check this item. Otherwise uncheck.**input dirs**: directories can be input either using a`*.txt`

file or spm select window.**time series**: choose the time series to calculate, seperated by ‘,’.**mean temporal ampilitude**: calculate absolute value of detrended and demeaned time series.**standard deviation**: calculate standard deviation of time series**variation**: calculate variation of time series**normalize transform**: in output file, a suffix of*_m*means the output is divided by mean intensity in the mask; a suffix of*_z*means the output is subtracted by mean intensity and divided by standard deviation.**out dir**: output directory for saving results.

**Buttons**:**S**: Save parameters of the current panel to a`*.mat`

file. The`*.mat`

can be further loaded for the panel or be used in a script processing.**L**: Load parameters from`*.mat`

for the current panel.**?**: Help information.

**Reference**:

- Liu Y, Yu C, Zhang X, Liu J, Duan Y, Alexander-Bloch AF, et al. Impaired long distance functional connectivity and weighted network architecture in Alzheimer’s disease.
*Cereb Cortex 2014*; 24(6): 1422-35.