A bizzare study with no data associated with what the chronic caffeine use is especially in the mice with electronic chips attached to their heads.
The study gives the varying amounts of caffeine used.
Here is the table:
https://academic.oup.com/view-large/419181921
For the first 7 days, animals received regular drinking water. Caffeine (Sigma, St. Louis, MO, USA) was then administered in the drinking water at concentrations of 0.3, 0.6, 0.9, and 1.2 mg/ml, each dose for 7 days (the equivalent of ∼5–20 cups of coffee/day in humans when accounting for differences in liver size and metabolism (44)). After caffeine administration, the animals were switched back to regular water, and an additional 7 days (washout period) were recorded. In separate experiments (n = 4), mice received only a single dose of caffeine (0.6 mg/ml) for 7 days followed by washout for 7 days. To verify that water intake remained the same, water bottles were weighed throughout the experiment. We found no differences in average water intake over the entire experiment (Avg 24–33 ml/week; P = 0.59, Mann Whitney U test).”