Data from: Diurnal variation of brain activity in the human suprachiasmatic nucleus
Data files
Jan 31, 2024 version files 134.80 KB
Abstract
The suprachiasmatic nucleus (SCN) is the central clock for circadian rhythms. Animal studies have revealed daily rhythms in the neuronal activity in the SCN. However, the circadian activity of the human SCN has remained elusive. In this study, to reveal the diurnal variation of the SCN activity in humans, the SCN was localized, and its activity was investigated using perfusion imaging. We scanned each participant four times a day, every six hours, and higher activity was observed at noon while lower activity was recorded in the early morning. The SCN activity was then measured every thirty minutes for six hours from midnight to dawn and showed a decreasing trend and was comparable with the rodent SCN activity after switching off the lights. These results suggest that the diurnal variation of the human SCN follows the zeitgeber cycles of mammals and is modulated by physical lights rather than the local time.
README: Diurnal variation of brain activity in the human suprachiasmatic nucleus
Oka et al. (2024) Journal of Neuroscience
This study investigated the diurnal variation of brain activity in the suprachiasmatic nucleus (SCN) in humans. In the first experiment, the SCN activity was measured four times a day, every six hours, using perfusion imaging. In the second experiment, the SCN activity was measured every thirty minutes for six hours from midnight to dawn, from 24:00 to 6:00. The results showed that the diurnal variation of the human SCN activity follows the zeitgeber cycles of mammals.
Nifti files showing the regions of interest (ROIs) of the hypothalamus and hypothalamic nucleus and the boundary probability map in the hypothalamus are provided. CSV files showing the data of brain activity in the SCN, MPO, SO, and PVH, which were used to make the line and bar graphs, are provided.
The ROIs of the hypothalamus and hypothalamic nuclei and the boundary probability map
The areal boundary mapping technique was used to generate the probabilistic boundary map, where the probability value represented how likely the voxel is a boundary of a functional area. We identified the human SCN above the optic chiasm and lateral to the third ventricle. The surrounding nuclei (medial preoptic nucleus: MPO, supraoptic nucleus: SO, paraventricular nucleus: PVH) were also localized. These nuclei were ROIs in this study.
The file of ROIs: ROIs.zip
The file of boundary probability map: bpmap.nii
The probability map can be overlaid on the truncated structure image (ravg152T1.nii).
The data of brain activity in the SCN, MPO, SO, and PVH
The brain activity in the hypothalamus nuclei (ROIs) was extracted for further analysis.
In the first experiment, the activity in the SCN was highest at 12:00 in the daytime and lowest at 6:00 in the morning.
The file of the data of brain activity in the SCN in the first experiment: Fig3A.csv and Fig3B.csv
The file of the data of brain activity in the MPO in the first experiment: Fig3-1A.csv
The file of the data of brain activity in the SO in the first experiment: Fig3-1B.csv
The file of the data of brain activity in the PVH in the first experiment: Fig3-1C.csv
In the second experiment, the SCN activity gradually decreased from midnight to dawn.
The file of the data of brain activity in the SCN in the second experiment: Fig4A.csv
The file of the data of brain activity in the MPO in the second experiment: Fig4-1A.csv
The file of the data of brain activity in the SO in the second experiment: Fig4-1B.csv
The file of the data of brain activity in the PVH in the second experiment: Fig4-1C.csv
NaN indicate the lacking data due to technical issues.
Softwares
The Nifti files can be opened using SPM, MRIcron, and FSL.
Methods
In this study, two experiments were conducted, wherein the first investigated the whole cycle of the diurnal activity of the SCN in humans. Participants were scanned four times within 24 hours (18:00, 24:00, 6:00, and 12:00 local time). In the second experiment, we investigated the human SCN activity in more detail during the night. Participants stayed in the scanner throughout the night, except for brief unavoidable interruptions, and were scanned every 30 min from 24:00 to 6:00. Perfusion images of pseudo-continuous arterial spin labeling (pCASL) in each participant were acquired. Twenty-seven and twenty right-handed participants without neurological/psychiatric illness or sleep disorders participated in the first and second experiments.
Whole brain perfusion images were acquired using pCASL imaging with multiband-EPI (number of measurements = 90, repetition time = 4.0 s, echo time = 25.2 ms, partial Fourier = 6/8, flip angle = 90°, labeling duration = 1.5 s, post labeling delay = 1.64 s, slice thickness = 1.82 mm, distance factor = 10%, number of slices = 72, slice acquisition order = ascending, in-plane field of view = 212 × 212 mm2, matrix size = 106 × 106, multiband acceleration factor = 6). Two M0 images, which were included in the pCASL sequence, were also acquired after the label/control images series. The perfusion images were corrected for motion and distortion. The cerebral blood flow (CBF) images in the standard MNI space were calculated using a command line interface of oxford_asl included in FSL software. Spatially minimal smoothing was applied to the CBF images (FWHM = 2.0 mm), and the absolute CBF values [ml/100mg/min] of the regions of interest were extracted and sent for statistical analyses.