Sex differences in longitudinal changes of episodic memory-related brain activity and cognition in cognitively unimpaired older adults with a family history of Alzheimer's disease.

"appendix a supplementary data the following are the supplementary data to this article: supplementary data 1 data availability data will be made available on request."

"Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper."

"Funding sources This work was supported by the CIHR Sex and Gender Research Chair [GS9-171369] awarded to M.N.R; CIHR Grant to A.R.M [PCS 168205], and Ontario Graduate Scholarship to A.D.S."

"Statistical Parametric Mapping software version 12 (SPM12; https://www.fil.ion.ucl.ac.uk/spm/software/spm12/) and the Pairwise Longitudinal Registration toolbox were used for longitudinal preprocessing of the fMRI data. Images from the first 10 s of scanning were discarded to allow equilibration of the magnetic field. Each participant's fMRI scans were motion-corrected within each longitudinal session and then registered across the two longitudinal sessions. The T1 scans from the two sessions were registered using SPM’s Pairwise Longitudinal Registration toolbox, and a longitudinal T1 template was created for each participant. The motion-corrected fMRI scans were then co-registered to the longitudinal T1 scan. A study-specific template was created by averaging all participants’ longitudinal T1 scans using the Diffeomorphic Anatomical Registration Through Exponentiated Lie (DARTEL) toolbox in SPM12 (https://www.fil.ion.ucl.ac.uk/spm/software/spm12/). The participants' motion-corrected, co-registered fMRI scans were then normalized to the study-specific template at 4x4x4mm voxel resolution and smoothed using an 8 mm full-width half maximum (FWHM) isotropic Gaussian kernel. The normalization step included an affine registration to a Tissue Probability Map (TPM) provided by SPM to ensure that the normalized scans were closely aligned to Montreal Neurological Institute (MNI) space (). Participants were excluded from further analyses if their head motion exceeded 4 mm in the x, y, or z axis during the encoding and retrieval fMRI task phases and/or if participants' head motion could not be sufficiently repaired, resulting in distorted brain images, as judged by the examiner."