Abstract
Average anatomical brain templates are routinely used in neuroanatomical and functional studies. Several widely used anatomical models were historically constructed with different algorithms and a limited number of subjects. We performed an experiment to determine the number of subjects required to achieve a stable population average and to estimate variability in individual subjects’ registration. We used a random subset of 2000 subjects from the UK Biobank (between 40 and 60 years of age) to generate a “silver standard” population average and then ran a template generation process with a variable number of subjects from 10 to 320, repeating each draw 50 times in a bootstrapping fashion. We compared two methods which are widely used in the literature to generate population averages (ANIMAL and ANTs). Our results showed that 160 subjects are enough to generate a stable population average, and both methods achieve comparable results, with ANTs having advantage over ANIMAL when a smaller number of subjects are available.