title: Impaired perception of self-motion (heading) in abstinent ecstasy and marijuana users.
abstract: BACKGROUND
  Illicit drug use can increase driver crash risk due to loss of control over vehicle trajectory. This study asks, does recreational use of +/-3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) and tetrahydrocannabinol (THC; marijuana) impair cognitive processes that help direct our safe movement through the world?
  
  
  OBJECTIVE
  This study assesses the residual effects of combined MDMA/THC use, and of THC use alone, upon perceived trajectory of travel.
  
  
  METHODS
  Perception of self-motion, or heading, from optical flow patterns was assessed using stimuli comprising random dot ground planes presented at three different densities and eight heading angles (1, 2, 4 and 8 degrees to the left or right). On each trial, subjects reported if direction of travel was to the left or the right.
  
  
  RESULTS
  Results showed impairments in both drug groups, with the MDMA/THC group performing the worst.
  
  
  CONCLUSIONS
  The finding that these psychoactive agents adversely affect heading perception, even in recently abstinent users, raises potential concerns about MDMA use and driving ability.
authors.affiliation: Division of Neuroergonomics and Division of Behavioral Neurology and Cognitive Neuroscience, Department of Neurology, The University of Iowa Carver College of Medicine, Iowa City, IA, USA. matthew-rizzo@uiowa.edu
authors.forename: M
authors.initials: M
authors.lastname: Rizzo
authors.forename: C T J
authors.initials: CT
authors.lastname: Lamers
authors.forename: C G
authors.initials: CG
authors.lastname: Sauer
authors.forename: J G
authors.initials: JG
authors.lastname: Ramaekers
authors.forename: A
authors.initials: A
authors.lastname: Bechara
authors.forename: G J
authors.initials: GJ
authors.lastname: Andersen
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology; D009039:Motion Perception / Q000187:drug effects* / Q000502:physiology; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000633:toxicity*; D010468:Perceptual Disorders / Q000139:chemically induced* / Q000523:psychology; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology
chemical_list: D018817:N-Methyl-3,4-methylenedioxyamphetamine
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