1. ¹Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
2. ²Department Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands

Correspondence: Dr JG Ramaekers, Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, PO Box 616, Maastricht, The Netherlands. Tel: +31 43 388 1951; Fax: +31 43 388 4125; E-mail: j.ramaekers@psychology.unimaas.nl

Received 15 September 2008; Revised 19 November 2008; Accepted 19 November 2008; Published online 17 December 2008.

Abstract

Prospective memory refers to the realization of delayed intentions. Several studies have shown that 3,4-methylenedioxy-methamphetamine (MDMA) users perform worse on measures of prospective memory as compared to nondrug users. Interpretation of these data may be limited because of polydrug use, psychosocial stressors, and increased psychopathology that have been reported in MDMA users. This study was designed to directly assess the pharmacological effect of MDMA on prospective memory and brain activity in a double-blind, placebo-controlled, cross-over study. Twelve recreational MDMA users received MDMA 75 mg and placebo and performed an objective prospective memory task during functional imaging. During prospective memory task performance subjects were engaged in a foreground task that consisted of a simple reaction time to visual stimuli (Go trials) and a prospective task of withholding a response during trials that were part of a dynamic memory set (No go trials). Behavioral data showed that a single dose of MDMA increased prospective memory failures in the No go trials, and that number of prospective memory failures was positively correlated to MDMA concentration in plasma. Functional imaging showed that MDMA decreased BOLD activation during Go trials in the thalamus (left), putamen (left), precuneus (left), and the inferior parietal lobules (bilateral), as compared to placebo. During No go trials, MDMA reduced BOLD deactivation in the inferior parietal lobules (bilateral), as compared to placebo. It is concluded that the loss of deactivation in inferior parietal lobules may account for increments in memory failures observed during MDMA intoxication.