tokens: To address the potential confounding effects of the cannabis use of the ecstasy using group , a second analysis included 14 previously tested cannabis users ( Nestor , L . , Roberts , G . , Garavan , H . , Hester , R . , 2008 . Deficits in learning and memory : parahippocampal hyperactivity and frontocortical hypoactivity in cannabis users . Neuroimage 40 , 1328 - 1339 ) .