For the analyses of the relative amounts of Bid and tBid in P4 vs. P7 cerebellum following exposure to experimental conditions, tissue was fractionated, to separate cytosolic and mitochondrial contents. Full-length Bid is a cytosolic protein, and was assessed in cytosolic fractions, while tBid moves to the mitochondrial membrane and was accessed in mitochondrial fractions. For this procedure, cerebellae were harvested immediately after termination of experimental treatment. Tissues were homogenized and separated into fractions using the Mitochondrial/Cytosol Fractionation Kit and protocol provided by BioVision Inc. (Mountain View, CA; catalog #K256), as described in detail previously (e.g., Heaton et al., 2011 (link); 2013 (link)).