Bennett Bennett MR MR Arnold Arnold J J Hatton Hatton SN SN Lagopoulos Lagopoulos J J Regulation of fear extinction by long-term depression: the roles of endocannabinoids and brain derived neurotrophic factor Regulation of fear extinction by long-term depression: the roles of endocannabinoids and brain derived neurotrophic factor Behav Brain Res Behav Brain Res 2017 2017 319 319 148 148 164 164 10.1016/j.bbr.2016.11.029 10.1016/j.bbr.2016.11.029 27867101 27867101. This evidence concerns the gene BDNF and depressive symptom measurement.