TY - JOUR
T1 - The effect of dual-hemisphere transcranial direct current stimulation over the parietal operculum on tactile orientation discrimination
AU - Fujimoto, Shuhei
AU - Tanaka, Satoshi
AU - Laakso, Ilkka
AU - Yamaguchi, Tomofumi
AU - Kon, Noriko
AU - Nakayama, Takeo
AU - Kondo, Kunitsugu
AU - Kitada, Ryo
PY - 2017/9
Y1 - 2017/9
N2 - The parietal operculum (PO) often shows ipsilateral activation during tactile object perception in neuroimaging experiments. However, the relative contribution of the PO to tactile judgment remains unclear. Here, we examined the effect of transcranial direct current stimulation (tDCS) over bilateral PO to test the relative contributions of the ipsilateral PO to tactile object processing. Ten healthy adults participated in this study, which had a double-blind, sham-controlled, cross-over design. Participants discriminated grating orientation during three tDCS and sham conditions. In the dual-hemisphere tDCS conditions, anodal and cathodal electrodes were placed over the left and right PO. In the uni-hemisphere tDCS condition, anodal and cathodal electrodes were applied over the left PO and contralateral orbit, respectively. In the tDCS and sham conditions, we applied 2 mA for 15 min and for 15 s, respectively. Computational models of electric fields (EFs) during tDCS indicated that the strongest electric fields were located in regions in and around the PO. Compared with the sham condition, dual-hemisphere tDCS improved the discrimination threshold of the index finger contralateral to the anodal electrode. Importantly, dual-hemisphere tDCS with the anodal electrode over the left PO yielded a decreased threshold in the right finger compared with the uni-hemisphere tDCS condition. These results suggest that the ipsilateral PO inhibits tactile processing of grating orientation, indicating interhemispheric inhibition (IHI) of the PO.
AB - The parietal operculum (PO) often shows ipsilateral activation during tactile object perception in neuroimaging experiments. However, the relative contribution of the PO to tactile judgment remains unclear. Here, we examined the effect of transcranial direct current stimulation (tDCS) over bilateral PO to test the relative contributions of the ipsilateral PO to tactile object processing. Ten healthy adults participated in this study, which had a double-blind, sham-controlled, cross-over design. Participants discriminated grating orientation during three tDCS and sham conditions. In the dual-hemisphere tDCS conditions, anodal and cathodal electrodes were placed over the left and right PO. In the uni-hemisphere tDCS condition, anodal and cathodal electrodes were applied over the left PO and contralateral orbit, respectively. In the tDCS and sham conditions, we applied 2 mA for 15 min and for 15 s, respectively. Computational models of electric fields (EFs) during tDCS indicated that the strongest electric fields were located in regions in and around the PO. Compared with the sham condition, dual-hemisphere tDCS improved the discrimination threshold of the index finger contralateral to the anodal electrode. Importantly, dual-hemisphere tDCS with the anodal electrode over the left PO yielded a decreased threshold in the right finger compared with the uni-hemisphere tDCS condition. These results suggest that the ipsilateral PO inhibits tactile processing of grating orientation, indicating interhemispheric inhibition (IHI) of the PO.
KW - Cortical plasticity
KW - Inter-hemispheric inhibition (IHI)
KW - Somatosensory cortex
KW - Tactile
KW - Transcranial direct current stimulation (tDCS)
KW - Transcranial magnetic stimulation (TMS)
U2 - 10.3389/fnbeh.2017.00173
DO - 10.3389/fnbeh.2017.00173
M3 - Journal article
C2 - 28979197
AN - SCOPUS:85041966956
SN - 1662-5153
VL - 11
JO - Frontiers in Behavioral Neuroscience
JF - Frontiers in Behavioral Neuroscience
M1 - 173
ER -