Differential effects of synchronous and asynchronous multifinger coactivation on human tactile performance

Abstract

Background: Repeated execution of a tactile task enhances task performance. In the present study we sought to improve tactile performance with unattended activation-based learning processes (i.e., focused stimulation of dermal receptors evoking neural coactivation (CA)). Previous studies show that the application of CA to a single finger reduced the stationary two-point discrimination threshold and significantly increased tactile acuity. These changes were accompanied by an expansion of the cortical finger representation in primary somatosensory cortex (SI). Here we investigated the effect of different types of multifinger CA on the tactile performance of each finger of the right hand.

Tactile stimulation interventions: Influence of stimulation parameters on sensorimotor behavior and neurophysiological correlates in healthy and clinical samples

“…However, if more than one finger is stimulated synchronously, the strength of effects increases especially for burst stimulation, rendering it more effective. While single pulse stimulation of multiple fingers results in a 15-20 % decrease of 2PD (Höffken et al, 2007;Kalisch et al, 2007), An even bigger improvement of up to 26 % was found after burst stimulation of two fingers (Kowalewski, Kattenstroth, Kalisch, & Dinse, 2012). We did not find a general difference between the strength of effects induced by either electrical or mechanical stimulation.…”

“…Since then, many studies that used different variants of tactile stimulation interventions, revealed supportive evidence that induced cortical changes rely on hebbian like processes (Beste & Dinse, 2013;Ragert, Kalisch, Bliem, Franzkowiak, & Dinse, 2008). Furthermore it could be shown that, as for the induction of LTD and LTP, the temporal pattern and frequency of tactile stimulation protocols were decisive for the found effects in terms of neural excitability, cortical topography, as well as tactile performance (Beste & Dinse, 2013;Dinse et al, 1996;Kalisch, Tegenthoff, & Dinse, 2007). Also the duration of the induced effects was similar for the effects induced by cellular stimulation and those induced by tactile stimulation (Kalisch et al, 2007).…”

“…Dinse et al, 2006;Höffken et al, 2007;Kalisch et al, 2007;Kalisch et al, 2008;Pilz, Veit, Braun, & Godde, 2004), or rather stimulation of the whole hand simultaneously with a specific glove to maximize the effect of coactivation (Christova et al, 2011;Golaszewski et al, 1999;Golaszewski et al, 2004;Golaszewski et al, 2010;Golaszewski et al, 2012). Few studies also stimulated other body parts, such as the palm or foot (Christova, Rafolt, Mayr, Wilfling, & Gallasch, 2010;Christova et al, 2012;Peurala et al, 2002).…”

“…Here, burst stimuli, with inter-burst intervals of about 5 seconds were used (Freyer, Reinacher, Nolte, Dinse, & Ritter, 2012;Freyer, Becker, Dinse, & Ritter, 2013;Kalisch et al, 2007;Tossi, Stude, Schwenkreis, Tegenthoff, & Dinse, 2013).…”

“…Furthermore it could be shown that, as for the induction of LTD and LTP, the temporal pattern and frequency of tactile stimulation protocols were decisive for the found effects in terms of neural excitability, cortical topography, as well as tactile performance (Beste & Dinse, 2013;Dinse et al, 1996;Kalisch, Tegenthoff, & Dinse, 2007). Also the duration of the induced effects was similar for the effects induced by cellular stimulation and those induced by tactile stimulation (Kalisch et al, 2007). At last, pharmaceutical research showed that drugs supporting LTP induction, can boost the behavioral and neurophysiological effects of rTS , while drugs blocking NMDA receptors involved in LTP induction prevented stimulation effects .…”