title: Interplay of neuronal processes during response inhibition: results from a combined event-related potentials (ERPs)/transcranial magnetic stimulation (TMS) study on methylphenidate.
abstract: The neuronal processes underlying response inhibition are often studied using either event-related potentials (ERPs) or by applying transcranial magnetic stimulation (TMS) to investigate excitatory and inhibitory processes in the motor system. We performed a more refined analysis of response inhibition by combining both approaches with the aim of identifying an interplay between ERPs and TMS parameters. During a go/nogo task, motor system excitability was measured using TMS single and double pulses and brain electrical activity was recorded in healthy adults (n=14). Each participant completed two testing sessions, once on placebo and once on methylphenidate (double-blind, crossover design). Studying the effects of methylphenidate served as an example application for this combined approach. Developing regression models, inhibition-related TMS measures (e.g., short intracortical inhibition) and the contingent negative variation explained about 85% of the variance of the nogo-P3 under both MPH and placebo medication. The smaller the inhibitory effect in the motor system, the more terminal response control was required and the more resources were allocated for the evaluation of the inhibitory process, respectively, as indicated by a larger P3. Thus, an interplay between processes in the motor system (cortex) and control processes with sources in the prefrontal cortex and the anterior cingulate cortex (ACC) may take place, acting complementarily to facilitate a correct nogo-response. While ERPs rather represent initiation and monitoring of inhibitory processes and response control, motor inhibition may be best analyzed using TMS. A combined ERP/TMS analysis may allow for the development of distinct models concerning the interplay of processes involved in response inhibition.
authors.affiliation: Dept. of Child and Adolescent Mental Health, University of Erlangen-Nürnberg, Schwabachanlage 6+10, 91054 Erlangen, Germany. thomas.hoegl@uk-erlangen.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Hoegl
authors.forename: Hartmut
authors.initials: H
authors.lastname: Heinrich
authors.forename: Björn
authors.initials: B
authors.lastname: Albrecht
authors.forename: Martin
authors.initials: M
authors.lastname: Diruf
authors.forename: Gunther H
authors.initials: GH
authors.lastname: Moll
authors.forename: Oliver
authors.initials: O
authors.lastname: Kratz
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003265:Contingent Negative Variation / Q000187:drug effects* / Q000502:physiology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D009044:Motor Cortex / Q000187:drug effects*; D009433:Neural Inhibition / Q000187:drug effects* / Q000502:physiology; D009483:Neuropsychological Tests; D009716:Numerical Analysis, Computer-Assisted; D011930:Reaction Time / Q000187:drug effects; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate