Immediate-early gene induction in hippocampus and cortex as a result of novel experience is not directly related to the stressfulness of that experience.
Pace TW, Gaylord R, Topczewski F, Girotti M, Rubin B, Spencer RL. Immediate-early gene induction in hippocampus and cortex as a result of novel experience is not directly related to the stressfulness of that experience. Eur J Neurosci. 2005 Oct; 22(7):1679-90.