This variable is only available in MAP.
Vesicle-associated membrane protein (VAMP) density is determined by immunassay in the Honer Lab at the University of British Columbia (Vancouver BC, Canada). SP10 antibody is used to quantify VAMP 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 brain 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 VAMP protein density.