Boosting focally-induced brain plasticity by dopamine.

Full Abstract

Dopamine (DA) simultaneously produces both excitation and inhibition in the human cortex. In order to shed light on the functional significance of these seemingly opposing effects, we administered the DA precursor levodopa (L-dopa) to healthy subjects in conjunction with 2 neuroplasticity-inducing motor cortex stimulation protocols. Transcranial direct current stimulation (tDCS) induces cortical excitability enhancement by anodal and depression by cathodal brain polarization, which is not restricted to specific subgroups of synapses. In contrast, paired associative stimulation (PAS) induces focal excitability enhancements of somatosensory and motor cortical neuronal synaptic connections. Here, we show that administering L-dopa turns the unspecific excitability enhancement caused by anodal tDCS into inhibition and prolongs the cathodal tDCS-induced excitability diminution. Conversely, it stabilizes the PAS-induced synapse-specific excitability increase. Most importantly, it prolongs all of these aftereffects by a factor of about 20. Hereby, DA focuses synapse-specific excitability-enhancing neuroplasticity in human cortical networks.

Author information

Author/s: Kuo, Min-Fang (MF); Paulus, Walter (W); Nitsche, Michael A (MA);

Affiliation: Department of Clinical Neurophysiology, Georg-August-University Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't

Journal: Cerebral cortex (New York, N.Y. : 1991) (Cereb Cortex), published in United States. (Language: eng)

Reference: 2008-Mar; vol 18 (issue 3) : pp 648-51

Dates: Created 2008/02/18; Completed 2008/04/17;

PMID: 17591596, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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