Modulation of motorcortical excitability by methylphenidate in adult voluntary test persons performing a go/nogo task.
This study investigated the interaction between motorcortical excitability (short interval cortical inhibition, intracortical facilitation and long interval cortical inhibition), different requirement conditions [choice reaction test (CRT), attention/go/nogo], and their pharmacological modulation by methylphenidate (MPH) in normal healthy adults (n = 31) using a transcranial magnetic stimulation paradigm. MPH was administered in a dosage of 1 mg/kg body weight, maximum 60 mg. Additionally, serum level and clearance of MPH were controlled. The statistical analysis of variance revealed a significant three-way interaction of 2 (MPH) x 3 (CRT) x 6 (ISI) predicting motor evoked potential amplitudes (P = 0.032, MPH none and full dose, n = 31). In order to compare effects of dosage an additional between-subjects factor (half vs. full MPH dose) was introduced. None of the interactions involving this between-subject factor reached statistical significance. Exploring interactions with MPH only, a 3 (MPH none, half and full dose) x 3 (CRT) x 6 (ISI) analysis of variance revealed significant two-way interactions for MPH x ISI (P = 0.040) and condition x ISI (P < 0.001, n = 18). Effects observed for MPH were strongest on facilitatory processes, weaker for intracortical inhibition. In sum, MPH seems to interact via striato-thalamo-cortical pathways with original motorcortical processes (ISI), to a lesser extent with task-dependent or behavioral parameters (CRT).
Buchmann
Johannes
J
Department of Psychiatry, Neurology, Psychosomatics and Psychotherapy in Childhood and Adolescence, Center of Nerve Diseases, University of Rostock, Rostock, Germany. johannes.buchmann@med.uni-rostock.de
Dueck
A
A
Gierow
W
W
Zamorski
H
H
Heinicke
S
S
Heinrich
H
H
Hoeppner
J
J
Klauer
T
T
Reis
O
O
Haessler
F
F
D000704:Analysis of Variance; D001288:Attention / Q000187:drug effects / Q000502:physiology; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019054:Evoked Potentials, Motor / Q000187:drug effects; D056344:Executive Function / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008774:Methylphenidate / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D009433:Neural Inhibition / Q000187:drug effects; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D013647:Task Performance and Analysis; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation; D014836:Volition
D018765:Dopamine Uptake Inhibitors; D008774:Methylphenidate