Fig. 4. Rate of rewarming (RW) does not affect cell death in CA1, CA3, or dentate regions after profound hypothermia (PH, 4°C for 6 h). Controls are cultures remaining at 37°C; slow RW is RW to 25°C over 1 h, then to 37°C over the following 1.5 h; and 1-h RW is our “standard RW” protocol involving RW from 4°C to 37°C over 1 h. DG = dentate gyrus. The number of cultures in each treatment group is indicated with numbers above the bars . The lines  and asterisks  above the error bars  describe statistical differences between different treatment groups as follows: *P  less than 0.05, **P  less than 0.01, and ***P  less than 0.001, measured with analysis of variance and a Tukey multiple comparison posttest.