Nicotine self-administered directly into the VTA by rats is weakly reinforcing but has strong reinforcement enhancing propertiesFarquhar Morag, Latimer Mary P, Winn PhilipPsychopharmacology Vol 220, pp. 43-54, (2012)http://dx.doi.org/10.1007/s00213-011-2452-8 The pedunculopontine tegmental nucleus and the nucleus basalis magnocellularis: do both have a role in sustained attention?Rostron Claire L, Farquhar Morag J, Latimer Mary P, Winn PhilipBMC Neuroscience Vol 9, pp. 16, (2008)http://dx.doi.org/10.1186/1471-2202-9-16