Three repeated sessions of transcranial random noise stimulation (tRNS) leads to long-term effects on reaction time in the Go/No Go task

Objective. - We aimed to investigate whether the number of sessions delivered within one day influences the acute and long-term effects of transcranial random noise stimulation (tRNS) applied over the dorsolateral prefrontal cortex (DLPFC) on inhibitory control. Methods. -Thirty-six healthy participants were randomly assigned to receive either (i) 3 active (3A), (ii) 1 active and 2 sham (1A2S) or (iii) 3 sham (3S) tRNS sessions. The 3 tRNS were delivered consecutively in the same half-day separated by 30 min with the anode over the right and the cathode over the left DLPFC. The effects of tRNS on inhibitory control were assessed 5 times using a Go/No Go task: at baseline (T0), after one tRNS session (T1), after the 3 sessions (T3), 1 (D1) and 8 (D8) days after. Results. -As compared to sham, active tRNS did not acutely modulate accuracy in the Go/No Go task but decreased reaction times at Go trials. At D1, participants who received at least one active tRNS sessions (3A and 1A2S groups) were faster than those who received 3 sessions of sham. At D8, only the participants who received 3 active tRNS sessions were faster to successfully respond to Go trials as compared to sham. Discussion. -Three active tRNS sessions induced longer effects on reaction times than a single session of active tRNS, compared to sham. These findings suggested that delivering repeated tRNS sessions on the same day induces more sustained effects than delivering a single session. (C) 2018 Elsevier Masson SAS. All rights reserved.