Brain dopamine and kinematics of graphomotor functions.
Three experiments were performed in an attempt to achieve a better understanding of the effect of dopamine on handwriting. In the first experiment, kinematic aspects of handwriting movements were compared between healthy participants and patients with Parkinson's disease (PD) on their usual dopaminergic treatment and following withdrawal of dopaminergic medication. In the second experiment, the writing performance of healthy participants with a hyperechogenicity of the substantia nigra as detected by transcranial sonography (TCS) was compared with the performance of healthy participants with low echogenicity of the substantia nigra. The third experiment examined the effect of central dopamine reduction on kinematic aspects of handwriting movements in healthy adults using acute phenylalanine and tyrosine depletion (APTD). A digitising tablet was used for the assessment of handwriting movements. Participants were asked to perform a simple writing task. Movement time, distance, velocity, acceleration and measures of fluency of handwriting movements were measured. The kinematic analysis of handwriting movements revealed that alterations of central dopaminergic neurotransmission adversely affect movement execution during handwriting. In comparison to the automatic processing of handwriting movements displayed by control participants, participants with an altered dopaminergic neurotransmission shifted from an automatic to a controlled processing of movement execution. Central dopamine appears to be of particular importance with regard to the automatic execution of well-learned movements.
Lange
Klaus W
KW
Department of Experimental Psychology, University of Regensburg, 93040 Regensburg, Germany. klaus.lange@psychologie.uni-regensburg.de
Mecklinger
Lara
L
Walitza
Susanne
S
Becker
Georg
G
Gerlach
Manfred
M
Naumann
Markus
M
Tucha
Oliver
O
D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001696:Biomechanical Phenomena; D001921:Brain / Q000187:drug effects / Q000503:physiopathology*; D003196:Computer Graphics; D018592:Cross-Over Studies; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000627:therapeutic use; D004311:Double-Blind Method; D004453:Echoencephalography; D005260:Female; D006236:Handwriting; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology; D010649:Phenylalanine / Q000172:deficiency; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D013378:Substantia Nigra / Q000187:drug effects / Q000503:physiopathology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014443:Tyrosine / Q000172:deficiency
D000978:Antiparkinson Agents; D018491:Dopamine Agonists; D014443:Tyrosine; D010649:Phenylalanine; D004298:Dopamine