Article

Effects of an acute D2-dopaminergic blockade on the somatosensory cortical responses in healthy humans: evidence from evoked magnetic fields.

BioMag Laboratory, Medical Engineering Centre Department of Clinical Neurophysiology, Helsinki University Central Hospital, P.O. Box 340, FIN-00029 HUS.
Neuroreport (impact factor: 1.66). 08/2003; 14(12):1609-12. DOI:10.1097/01.wnr.0000085689.46774.53 pp.1609-12
Source: PubMed

ABSTRACT We tested the possible role of dopaminergic activity in the processing of somatosensory afferent information in healthy humans. Somatosensory evoked magnetic fields (SEFs) were recorded in seven subjects in response to left median nerve stimulation. SEFs were obtained in all subjects after oral administration of 2 mg haloperidol, an antagonist to dopaminergic D2 receptors, and placebo, which were given in a randomized, double-blind cross-over design. SEFs were analyzed using a multiple equivalent current dipole (ECD) model, with one dipole at the right primary somatosensory cortex (SI) and at both left and right secondary somatosensory cortices (SII). The earliest responses from SI, peaking at about 20 ms (N20m) and 35 ms (P35m), were not affected by haloperidol. A later deflection peaking at about 75 ms (P60m), however, was slightly reduced (p < 0.05). Responses arising from SII were not significantly changed. The results suggest that dopaminergic activity may be involved in modulating somatosensory processing after the initial stages of cortical activation.

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Keywords

2 mg haloperidol
 
antagonist
 
deflection peaking
 
dopaminergic D2 receptors
 
double-blind cross-over design
 
earliest responses
 
healthy humans
 
initial stages
 
median nerve stimulation
 
modulating somatosensory processing
 
multiple equivalent current dipole
 
oral administration
 
peaking
 
possible role
 
secondary somatosensory cortices
 
SEFs
 
SI
 
SII