This variable is only available in MAP.
Synaptosomal-associated protein 25 (SNAP-25) density is determined by immunoassay in the Honer Lab at the University of British Columbia (Vancouver BC, Canada). SP12 antibody is used to quantify SNAP-25 immunodensities from frozen samples of gray matter in 6 cortical regions:
Values are expressed in log10 units, the mean is determined for each participant across the 6 regions, and a z-score is calculated across all participants. Since reported values are inversely proportional to protein levels, scores are multiplied by negative 1 to make results directly related to the amount of target antigen. Higher values indicate greater SNAP-25 protein concentrations.