[1] Univ Toronto, Dept Physiol, Toronto, ON M5T 1R8, Canada
[2] Univ Toronto, Ctr Addict & Mental Hlth, Dept Neurosci, Clarke Div, Toronto, ON M5T 1R8, Canada
[3] Univ Toronto, Dept Psychiat, Toronto, ON M5T 1R8, Canada
[4] Univ Toronto, Inst Med Sci, Toronto, ON M5T 1R8, Canada