Pain processing in multisensory environments

Abstract

Abstract“Don’t look and it won’t hurt” is common ad­vice heard before receiving an injection, but is there any truth in this statement? Pain pro­cessing can be separated into two major components: a sensory-discriminative com­ponent, which reflects the location and inten­sity of a painful event, and an affective-mo­tivational component that reflects the un­pleasantness of pain. The differentiation be­tween these components and the effects of additional sensory inputs on them becomes apparent if you watch a needle penetrating your skin: On the one hand, it may be some­what reassuring to know precisely when and where to expect the pinprick, on the other hand, you eye-witness damage inflicted on your body, which can increase personal dis­tress. Here we review recent studies, which demonstrate that a host of variables such as onset timing, spatial alignment, semantic meaning, and attention differentially affect how visual inputs influence pain processing. These studies also indicate that there is some truth in the opening statement.

A neuroimaging marker for predicting longitudinal changes in pain intensity of subacute back pain based on large-scale brain network interactions

“…Our large-scale functional network model outperformed previous studies, which used a single connection of mPFC–NAc 1 , 9 , in terms of predicting future pain intensity and distinguishing between the SBPp and SBPr group. Our findings involved large-scale connections regulating attentional modulation of pain perception 47 – 49 and multisensory integration 50 – 53 . The connections, which showed strong positive weights to predict changes in pain intensity involve lateral frontal region in the frontoparietal network and brainstem area, in particular periaqueductal gray matter (PAG).…”

“…Brain images were made using FSLeyes v.0.31.2 34 www.nature.com/scientificreports/ group. Our findings involved large-scale connections regulating attentional modulation of pain perception [47][48][49] and multisensory integration [50][51][52][53] . The connections, which showed strong positive weights to predict changes in pain intensity involve lateral frontal region in the frontoparietal network and brainstem area, in particular periaqueductal gray matter (PAG).…”

“…RSNs involve multiple overlapping brain regions, which might mix fMRI signals of pain-related and pain-independent regions. In addition, they do not include basal ganglia and brainstem, which are important regions for pain modulation [47][48][49][50][51][52][53] . Furthermore, RSNs were constructed using healthy controls, which may not reflect brain regions of pain modulation in patients.…”

Mechanical Pain Thresholds and the Rubber Hand Illusion

“…A similar experiment to the one of Höfle et al (2012) was performed by Valeriani et al (2008) , where subjects saw video clips of the hands of others pricked by a needle or touched by a cotton swab, while the subjects themselves received painful stimuli at their own corresponding hand induced by a laser. In those experiments, the video clips and the painful stimulation on the subjects’ own hands were obviously not synchronized ( Höfle et al, 2010 ), so that – similarly to our asynchronous RHI condition (control experiment 1) – “ownership” of the hand seen in the video clip could not fully occur. Accordingly, no effects of visual input on pain intensity and unpleasantness ratings were observed by Valeriani et al (2008) .…”

“…Nociception is known to be modulated by multisensory input (see Höfle et al, 2010 , or Senkowski et al, 2014 , for a review). For example, Pomper et al (2013) showed that spatiotemporally aligned, task-irrelevant visual stimuli enhanced the perception and processing of simultaneously induced pain in a manner as predicted by the known principle of inverse effectiveness in multisensory processing.…”