Sex differences in the association of photoperiod with hippocampal subfield volumes in older adults: A cross‐sectional study in the UK Biobank cohort

Abstract

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Novel characterization of the relationship between verbal list‐learning outcomes and hippocampal subfields in healthy adults

“…For Sample 1, hippocampal subfield volumes were obtained by processing the T1w images. T1w scans of 1 mm 3 are commonly used in large cohort studies, such as the UK‐Biobank (Alfaro‐Almagro et al, 2018; for examples of hippocampal subfield volumetry studies: Foo et al, 2021; Majrashi, Ahearn, Williams, & Waiter, 2020) or the Dallas LifeSpan Brain Study (https://dlbsdata.utdallas.edu/StructuralMriProtocol; Zheng et al, 2018), where they represent optimized imaging sequence both in terms of spatial resolution and acquisition time, given the large size of the samples studied. A recent commentary has cautioned against using HsVol obtained from 1 mm isotropic T1w scans (Wisse et al, 2021).…”

A systematic review of previous MRI studies demonstrating the relationship between season and brain volume

“…This study found that there was a positive relation between photoperiod and brainstem volumes. Another crosssectional studies by (Majrashi et al, 2020;Miller et al, 2015) have also found a positive correlation between changes in photoperiod and hippocampal volume in both females and males. Although seasonal changes in brain volumes have been widely studied in animals, is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) seasonal differences nor changes in human brain volumes have not yet been established well.…”

“…The systematic review has reviewed and summarized all previous studies investigating the relationship between changes in season or photoperiod and brain volumes. In brief, previous studies (Majrashi et al, 2020; Miller et al, 2015) found a significant correlation between photoperiod and total and hippocampal subfield volumes corrected for age and total brain volume within a large population cohort. Hippocampal and subfield volumes were found to be larger during summer season (longer photoperiod days) and smaller during winter season (shorter photoperiod days).…”

“…All studies employed a cross-sectional MRI design and primary analyses were significant for all studies. Three studies (Miller et al, 2015;Majrashi, Ahearn & Waiter, 2020…”

“…Other variables studied in this study included the change in the hippocampal volume in relation to seasonal changes. A previous study (Majrashi, Ahearn & Waiter, 2020) has also studied the brainstem volume against mood and depression in seasonal variations in large dataset. This study found that there was a positive relation between photoperiod and brainstem volumes.…”