Could placebo or nocebo effects have an impact on implicit motor learning?

Abstract Background: Motor learning (ML) can be defined as “any experience-dependent improvement in performance”. Behavioral evidence showed that placebo and nocebo modulate ML, but the neurophysiological underpinnings influence of their effect on implicit processes are still unknown. Objective: The aim this study is to understand if how manipulations could probabilistic sequence explore whether manipulation-induced changes might neuroplasticity (LTP-like plasticity) primary motor cortex (M1) evaluated with Transcranial Magnetic Stimulation Paired Associative (PAS) protocol. Methods: 21 healthy young subjects performed SRTT tasks following conditions random order: 1) no manipulation, 2) Placebo (subjects were manipulated into believing sham tDCS, would increase ML), 3) Nocebo tDCS decrease ML). Reaction Time (RT) was computed evaluate behavioral changes. PAS after each task, Occlusion Index (OI) neuroplastic Following last experimental session, patient’s awareness assessed by Recognition (REC) Test, aimed at evaluating they able recognize frames should have learned. Results: RT data didn’t show any significant induced compared manipulation condition. Statistical analysis OI during higher (OI=0.45) condition (OI=0.19). Even though REC test reach statistical significance, ended sessions seem better identify sequence. Conclusions: Both Neurophysiological results had highest long-term potentiation M1. One possible explanation being inhibited participants’ arousal inducing a “paradoxical effect” M1 plasticity. Research Category Technology Methods Clinical Research: 10. (TMS) Keywords: Implicit learning, Probabilistic sequence, & Nocebo, Neuroplasticity