title: The effect of methylphenidate on auditory information processing in healthy volunteers: a combined EEG/MEG study.
abstract: BACKGROUND
  The psychomotor stimulant methylphenidate (MPH) has been shown to improve attentional processes, reflected in behavioural measures such as vigilance, reaction time and visual attention tasks. The neural mechanisms of MPH action on sensory information processing, however, remain poorly understood. To the authors' knowledge, this present study is the first to investigate whether a single dose of MPH affects neural substrates of passive attention in healthy adults studied with simultaneous whole-head magnetoencephalography (MEG) and electroencephalography (EEG).
  
  
  METHODS
  Monaural left-ear auditory stimuli were presented in an oddball paradigm with infrequent deviant tones differing in frequency and duration. Neuronal activity was recorded with simultaneous whole-head MEG and EEG in 13 healthy subjects (five females; aged 27 +/- 5 years) after oral administration of 40 mg MPH or placebo in a randomised, double-blind, cross-over design. We analysed both electric and magnetic N100, P200 and mismatch negativity (MMN) components.
  
  
  RESULTS
  MPH increased arousal levels in visual analogue scales. MPH had no effect on the dipole strength of MMN or MMNm in either frequency or duration deviations. MPH did, however, reduce P200 amplitudes in EEG.
  
  
  CONCLUSIONS
  The lack of effect of MPH on either MMN or MMNm suggests no association between catecholaminergic activities and MMN generation. However, our findings imply that MPH may change the neural bases of auditory information processing such as the early stimulus evaluation reflected in the P200 component. Dopamine and noradrenaline neurotransmitter systems could be responsible for the modulation of these processes. The exclusive effect of MPH on the P200 component could have a clinical application.
authors.affiliation: BioMag Laboratory, HUSLAB, Helsinki University Central Hospital, Helsinki, Finland. milena.korostenskaja@gmail.com
authors.forename: Milena
authors.initials: M
authors.lastname: Korostenskaja
authors.forename: Dubravko
authors.initials: D
authors.lastname: Kicić
authors.forename: Seppo
authors.initials: S
authors.lastname: Kähkönen
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001143:Arousal / Q000187:drug effects; D001288:Attention / Q000187:drug effects*; D001931:Brain Mapping; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects; D003265:Contingent Negative Variation / Q000187:drug effects; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography / Q000187:drug effects*; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000187:drug effects*; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D010897:Pitch Discrimination / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D013998:Time Perception / Q000187:drug effects*
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate