Again, a quality check was performed using the total brain density and the ratio of grey/white matter density.
Repeating the analysis controlling for age-related structural changes using the total brain volume as covariate of no interest, the effects remained comparable, in particular, the group by deviant interaction at the right STG ([54,8, 1], k = 16, Z = 4.15).
After 10 days of cold adaption, the brains of the zebrafish were dissected, and total RNAs were extracted from these brains using the total RNA isolation kit (Promega, Madison, USA).
In-house developed software was used to calculate the total brain volume and percent of the intracranial volume.
Lesion areas per slice were used to determine the total brain lesion volume, taking into account the thickness of the 2D slices (total brain lesions covered a mean of 7.33 (1.44 SD) slices in FePro-NPC animals and 7.50 (1.27 SD) slices in control animals).
To control for allometric effects, we subtracted the volume of the brain component under scrutiny from the total brain volume and used this "remaining brain volume" as a covariate in all regression models.
Subsequently, both the hippocampal volumes as marked by the two-dimensional drawings and the total brain volumes were determined using an automatic algorithm programmed in MATLAB and SPM99.
Then, the hypothalamus, hippocampus and the cortex were excised, frozen on dry ice and separately kept at −80°C together with the remainder of the total brain until later use.
Brain activity was corrected for its vascular component using the measured whole blood concentrations, assuming that the cerebral blood volume is 5% of the total brain volume [17].
Core products of Total Brain Health® include the Total Brain Health® Coach program, with over 50 certified coaches throughout the U.S., and the newly launched Total Brain Health® Toolkits line, a series of "programs in a box" designed for use in older adult, wellness and healthcare settings.
Individual-level rescaling was performed in a tissue-specific manner (rather than using total brain volume) for the reason that the relationship between grey and white matter volumes is not linear (Zhang and Sejnowski, 2000), so correction by total brain volume would be less appropriate for our purpose of observing tissue-specific local variations.
