Premium
Parietal transcranial direct current stimulation modulates primary motor cortex excitability
Author(s) -
RiveraUrbina Guadalupe Nathzidy,
Batsikadze Giorgi,
MoleroChamizo Andrés,
Paulus Walter,
Kuo MinFang,
Nitsche Michael A.
Publication year - 2015
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12840
Subject(s) - transcranial direct current stimulation , transcranial magnetic stimulation , neuroscience , primary motor cortex , posterior parietal cortex , motor cortex , psychology , neuroplasticity , motor learning , stimulation , brain stimulation
Abstract The posterior parietal cortex is part of the cortical network involved in motor learning and is structurally and functionally connected with the primary motor cortex (M1). Neuroplastic alterations of neuronal connectivity might be an important basis for learning processes. These have however not been explored for parieto‐motor connections in humans by transcranial direct current stimulation ( tDCS ). Exploring tDCS effects on parieto‐motor cortical connectivity might be functionally relevant, because tDCS has been shown to improve motor learning. We aimed to explore plastic alterations of parieto‐motor cortical connections by tDCS in healthy humans. We measured neuroplastic changes of corticospinal excitability via motor evoked potentials ( MEP ) elicited by single‐pulse transcranial magnetic stimulation ( TMS ) before and after tDCS over the left posterior parietal cortex (P3), and 3 cm posterior or lateral to P3, to explore the spatial specificity of the effects. Furthermore, short‐interval intracortical inhibition/intracortical facilitation ( SICI / ICF ) over M1, and parieto‐motor cortical connectivity were obtained before and after P3 tDCS . The results show polarity‐dependent M1 excitability alterations primarily after P3 tDCS . Single‐pulse TMS ‐elicited MEP s, M1 SICI / ICF at 5 and 7 ms and 10 and 15 ms interstimulus intervals ( ISI s), and parieto‐motor connectivity at 10 and 15 ms ISI s were all enhanced by anodal stimulation. Single pulse‐ TMS ‐elicited MEP s, and parieto‐motor connectivity at 10 and 15 ms ISI s were reduced by cathodal tDCS . The respective corticospinal excitability alterations lasted for at least 120 min after stimulation. These results show an effect of remote stimulation of parietal areas on M1 excitability. The spatial specificity of the effects and the impact on parietal cortex–motor cortex connections suggest a relevant connectivity‐driven effect.