Transcranial direct current stimulation of the motor cortex in waking resting state induces motor imagery

Abstract

This study investigates if anodal and cathodal transcranial direct current stimulation (tDCS) of areas above the motor cortex (C3) influences spontaneous motor imagery experienced in the waking resting state. A randomized triple-blinded design was used, combining neurophysiological techniques with tools of quantitative mentation report analysis from cognitive linguistics. The results indicate that while spontaneous motor imagery rarely occurs under sham stimulation, general and athletic motor imagery (classified as athletic disciplines), is induced by anodal tDCS. This insight may have implications beyond basic consciousness research. Motor imagery and corresponding motor cortical activation have been shown to benefit later motor performance. Electrophysiological manipulations of motor imagery could in the long run be used for rehabilitative tDCS protocols benefitting temporarily immobile clinical patients who cannot perform specific motor imagery tasks -such as dementia patients, infants with developmental and motor disorders, and coma patients.

As we fall asleep we forget about the future: A quantitative linguistic analysis of mentation reports from hypnagogia

“…An advantage of the quantitative linguistic analysis of mentation reports is that it presents a conservative measure in so far as it looks for differences in the mental events as they are expressed as pre-defined linguistic differences in the reports from different experimental conditions (Speth et al, 2013). The high agreement achieved by the report raters in the current study as well as in related studies (Speth, Speth et al, 2016;Speth, Harley et al, 2016;Speth & Speth, 2016b;Speth et al, 2013Speth et al, , 2015Speth & Speth, in press), despite the fact that they did not receive intense training or possess a psycholinguistic background, suggests.…”

“…note the challenges of using first-person ratings on mental activity, and the participants' differing understandings of episodic memories. Their observation resonates with the recent philosophical debate on the incommensurability of participants' potentially biased explicit assessments of their own mental events versus their implicit knowledge of their own mental events as displayed in their mentation reports (Speth, Speth, & Harley, 2015;Windt, 2013). The current study therefore …”

“…grammatical agencies connected to the semantic field of cognition, describing cognitive acts such as thinking, remembering, or planning. It has been used in different versions to successfully link degrees of linguistic references to motor imagery in mentation reports with motor cortical activation of the respective state of consciousness (Speth, Frenzel, & Voss, 2013), to investigate the effect of transcranial direct current stimulation (tDCS) on motor imagery (Speth et al, 2015;Speth & Speth, 2016a), and to measure the number of linguistic indications of auditory verbal hallucinations and inner speech in different states of consciousness (Speth, Harley, & Speth, 2016), as well as to investigate memory for the future across states of consciousness (Speth, Schloerscheidt, & Speth, submitted for publication). The second part of the current tool is based on the cognitive-semantic theory of mental spaces by Fauconnier and Turner (Fauconnier, 1994;Fauconnier & Turner, 1997): The method of analysing future, past, and present mental spaces was developed for this study in order to measure if instances of cognitive agency introduced references to future, past, or present scenarios that were imagined or recalled by the participants relative to the mentation time.…”

A New Measure of Hallucinatory States and a Discussion of REM Sleep Dreaming as a Virtual Laboratory for the Rehearsal of Embodied Cognition

“…It integrates two linguistic tools for the quantitative analysis of mentation reports: (a) the linguistic analysis of motor imagery and (b) the linguistic analysis of cognitive agency (Speth & Speth & Speth, 2017;Speth et al, 2013Speth et al, , 2015Speth, Harley, & Speth, 2016;. Brief descriptions of these tools are presented in the following, while the complete rating manual for our new MHS is included as supplementary material.…”

“…Linguistic indications of motor imagery were quantified by means of motor agency analysis (Speth & Speth, 2016b;Speth et al, 2013Speth et al, , 2015, a grammatical tool based on linguistic theta theory (Gruber, 2001;Reinhart, 2002;Reinhart & Siloni, 2005). References to motor imagery were quantified as grammatical (theta role) agencies that denote manner-of-motion verbs.…”