Title: 28andMe

Background: In this set of dense-sampling, deep phenotyping studies, we determined whether day-to-day variation in sex hormone concentrations impacts large-scale brain network connectivity. In Study 1 (sessions 1-30, 2018), the female participant was naturally cycling; in Study 2 (sessions 31-60, 2019), the participant was placed on an oral hormonal contraceptive regimen. 

Participant: 
The participant is a right-handed Caucasian female, aged 23 years for duration of the study 1. The participant had no history of neuropsychiatric diagnosis, endocrine disorders, or prior head trauma. She had a history of regular menstrual cycles (no missed periods, cycle occurring every 26-28 days) and had not taken hormone-based medication in the prior 12 months before the first study. The participant gave written informed consent and the study was approved by the University of California, Santa Barbara Human Subjects Committee. 

Study Design: 
The participant underwent daily testing for 30 consecutive days. Each test session began with a daily questionnaire, followed by a time-locked collection of serum and whole blood started each day at 10:00am (±30 min), when the participant gave a blood sample. Endocrine samples were collected, at minimum, after two hours of no food or drink consumption (excluding water). The participant refrained from consuming caffeinated beverages before each test session. The MRI session lasted one hour and consisted of structural and functional MRI sequences.


Behavioral Assessments
To monitor state-dependent mood and lifestyle measures throughout the two studies, the following scales (adapted to reflect the past 24 hours) were administered each morning: Perceived Stress Scale (PSS; Cohen et al., 1983), Pittsburgh Sleep Quality Index (PSQI: Buysse et al., 1989), State-Trait Anxiety Inventory for Adults (STAI: Speillberger, 2010), and Profile of Mood States (POMS: Pollock et al., 1979). Behavioral data can be found under 'participants.tsv'


MRI Acquisition
The participant underwent a daily magnetic resonance imaging scan on a Siemens 3T Prisma scanner equipped with a 64-channel phased-array head coil. First, high-resolution anatomical scans were acquired using a T1-weighted magnetization prepared rapid gradient echo (MPRAGE) sequence (TR = 2500 ms, TE = 2.31 ms, TI = 934 ms, flip angle = 7º, 0.8 mm thickness) followed by a gradient echo fieldmap (TR = 758 ms; TE1 = 4.92 ms; TE2 = 7.38 ms; flip angle = 60º). Next, the participant completed a 10-minute resting-state fMRI scan using a T2*- weighted multi-band echo-planar imaging (EPI) sequence sensitive to the blood oxygenation level-dependent (BOLD) contrast (72 oblique slices, TR = 720 ms, TE = 37 ms, voxel size = 2 mm3, flip angle = 56º, multiband factor = 8). High-resolution anatomical scans were acquired using a T1-weighted magnetization prepared rapid gradient echo (MPRAGE) sequence (TR = 2500 ms, TE = 2.31 ms, TI = 934 ms, flip angle = 7º, 0.8 mm thickness) followed by a gradient echo fieldmap (TR = 758 ms; TE1 = 4.92 ms; TE2 = 7.38 ms; flip angle = 60º). A T2- weighted turbo spin echo (TSE) scan was also acquired with an oblique coronal orientation positioned orthogonally to the main axis of the hippocampus (TR/TE= 8100/50 ms, flip angle = 122°, 0.4 × 0.4 mm2 in plane resolution, 2 mm slice thickness, 31 interleaved slices with no gap, total acquisition time = 4:21 min).

In an effort to minimize motion, the head was secured with a custom, 3D-printed foam head case (https://caseforge.co/) (days 8-30 of Study 1 and days 1-30 of Study 2). Note that physiological recordings were not collected during scanning. 


Reference: https://doi.org/10.1016/j.cobeha.2021.01.012, https://doi.org/10.1016/j.neuroimage.2020.117091, https://doi.org/10.1016/j.neuroimage.2020.117125, https://doi.org/10.1162/netn_a_00169, and https://doi.org/10.1038/s41598-020-77779-4