. Author manuscript; available in PMC: 2018 Jul 1.
Published in final edited form as: Physiol Behav. 2017 Feb 16;176:101–106. doi: 10.1016/j.physbeh.2017.02.015
This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/