Effects of co-activation on cortical organization and discrimination performance

Abstract

We used fMRI to investigate the effects of tactile co-activation on the topographic organization of the human primary somatosensory cortex (SI). Behavioral consequences of co-activation were studied in a psychophysical task assessing the mislocalization of tactile stimuli. Co-activation was applied to the index, middle and ring fingers of the right hand either synchronously or asynchronously. Cortical representations for synchronously co-activated fingers moved closer together, whereas cortical representations for asynchronously co-activated fingers became segregated. Behaviorally, this pattern coincided with an increased and reduced number of mislocalizations between synchronously and asynchronously co-activated fingers, respectively. Thus, both synchronous and asynchronous coupling of passive tactile stimulation is able to induce short-term cortical reorganization associated with functionally relevant changes.

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

“…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).…”

“…These measures were used to compare cortical PARAMETER CHOICE AND EFFECTIVENESS OF TACTILE STIMULATION 10 excitability and organization before and after rTS. They included functional magnetic resonance imaging (fMRI) Pilz et al, 2004;Pleger et al, 2003), electroencephalography (EEG) (Pleger et al, 2001), magnetoencephalography (MEG) Godde et al, 2003) and TMS . Also behavioral studies were used to assess the effect of rTS on sensory perception PARAMETER CHOICE AND EFFECTIVENESS OF TACTILE STIMULATION 11 Topography.…”

“…By comparison, after burst stimulation the polar angle changed by 3.61 degrees and dipole strength increased by 36.94 %, indicating a comparable change as after single pulse stimulation . (Pilz et al, 2004). An experiment by Braun and colleagues (2001) showed that this change in dipole can be task related.…”

“…After synchronous single pulse stimulation of index and middle or middle and ring finger mislocalization between these fingers increased by approximately 37.5 %. On the contrary, asynchronous stimulation led to improved localization performance of approximately 22% (Pilz et al, 2004). Stimulating all fingers of one hand synchronously resulted in mislocalization also on more distant fingers (Kalisch et al, 2007).…”

Reproducibility of functional MRI localization within the human somatosensory cortex

“…Recently human based studies such as Pilz et al (11) and Godde et al (12), have built on the rich history of animal evidence showing measurable plasticity in the somatosensory cortex. This study consisted of four key aims.…”