Attentional modulation of somatosensory processing during the anticipation of movements accompanying pain : an event-related potential study

Attending to pain-relevant information is crucial to protect us from physical harm. Behavioral studies have already suggested that during anticipation of pain somatosensory input at the body location under threat is prioritized. However, research using daily life cues for pain, especially movements, is lacking. Furthermore, to our knowledge, no studies have investigated cortical processing associated with somatosensory processing during threatened movements. The current study aims to investigate whether movements accompanying pain automatically steer attention toward somatosensory input at the threatened location, affecting somatosensory evoked potentials (SEPs). Healthy volunteers were cued to perform movements with the left or the right hand, and one of these movements could be accompanied by pain on the moving hand. During movement anticipation, a task-irrelevant tactile stimulus was presented to the threatened or pain-free hand to evoke SEPs. During anticipation of movements accompanying pain, the N120 component was increased for tactile stimuli at the threatened relative to the hand without pain. Moreover, the P200 SEP was enhanced during anticipation of movements accompanying pain relative to movements without pain, irrespective of which hand was stimulated. These findings show that the anticipation of pain-accompanying movements may affect the processing of somatosensory input, and that this is likely to be driven by attentional processes. PERSPECTIVE: This study shows that the anticipation of pain-related movements automatically biases attention toward stimuli at a pain-related location, measured according to SEPs. The present study provides important new insights in the interplay between pain and attention, and its consequences at the cortical level

Beyond the “Pain Matrix,” inter-run synchronization during mechanical nociceptive stimulation

Pain is a complex experience that is thought to emerge from the activity of multiple brain areas, some of which are inconsistently detected using traditional fMRI analysis. One hypothesis is that the traditional analysis of pain-related cerebral responses, by relying on the correlation of a predictor and the canonical hemodynamic response function (HRF)- the general linear model (GLM)- may under-detect the activity of those areas involved in stimulus processing that do not present a canonical HRF. In this study, we employed an innovative data-driven processing approach- an inter-run synchronization (IRS) analysis- that has the advantage of not establishing any pre-determined predictor definition. With this method we were able to evidence the involvement of several brain regions that are not usually found when using predictor-based analysis. These areas are synchronized during the administration of mechanical punctate stimuli and are characterized by a BOLD response different from the canonical HRF. This finding opens to new approaches in the study of pain imaging

Is it a painful error?:The effect of unpredictability and intensity of punishment on the error-related negativity, and somatosensory evoked potentials

We examined how predictable and unpredictable punishment intensity contingent on error commission modulated ERN amplitudes. We recorded the ERN in 35 healthy volunteers performing the Eriksen flanker task. Errors were punished with predictable nonpainful, painful or unpredictable electrical stimulation. Furthermore, we investigated trait anxiety. We observed that ERN amplitudes did not differ across conditions, nor were there significant effects of anxiety. In contrast, we found that predictable painful punishments led to smaller Error Positivity (Pe). The effects of predictability and intensity were present in Somatosensory Evoked Potentials elicited by the punishments. N1 amplitudes were increased for painful compared to nonpainful stimulation, and P2/P3 amplitudes for painful compared to nonpainful, and for unpredictable compared to predictable stimulation. We suggest that unpredictability and increased painfulness of punishments enhance the potential motivational significance of the errors, but do not potentiate ERN amplitudes beyond the ones elicited by errors punished with predictable nonpainful stimulation

Perceptual correlates of homosynaptic long-term potentiation in human nociceptive pathways: A replication study

Animal studies have shown that high-frequency stimulation (HFS) of peripheral C-fibres induces long-term potentiation (LTP) within spinal nociceptive pathways. The aim of this replication study was to assess if a perceptual correlate of LTP can be observed in humans. In 20 healthy volunteers, we applied HFS to the left or right volar forearm. Before and after applying HFS, we delivered single electrical test stimuli through the HFS electrode while a second electrode at the contra-lateral arm served as a control condition. Moreover, to test the efficacy of the HFS protocol, we quantified changes in mechanical pinprick sensitivity before and after HFS of the skin surrounding both electrodes. The perceived intensity was collected for both electrical and mechanical stimuli. After HFS, the perceived pain intensity elicited by the mechanical pinprick stimuli applied on the skin surrounding the HFS-treated site was significantly higher compared to control site (heterotopic effect). Furthermore, we found a higher perceived pain intensity for single electrical stimuli delivered to the HFS-treated site compared to the control site (homotopic effect). Whether the homotopic effect reflects a perceptual correlate of homosynaptic LTP remains to be elucidated.Fil: van de Broeke, Emanuel N.. Université Catholique de Louvain; BélgicaFil: Vanmaele, Tessa. Katholikie Universiteit Leuven; BélgicaFil: Mouraux, André. Université Catholique de Louvain; BélgicaFil: Stouffs, Alexandre. Université Catholique de Louvain; BélgicaFil: Biurrun Manresa, José Alberto. Universidad Nacional de Entre Ríos. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática; ArgentinaFil: Torta, Diana M.. Katholikie Universiteit Leuven; Bélgic

Objective and self-reported cognitive dysfunction in breast cancer women treated with chemotherapy: a prospective study

The objective of this study is to investigate if changes in cognitive functions can be recognised in patients undergoing chemotherapy for breast cancer. Forty women with breast cancer and without depression underwent cognitive evaluation before and after 6 months of chemotherapy; emotional evaluation was performed before and after 1, 3 and 6 months of chemotherapy. Self-reported cognitive deficit evaluation was included. Global cognitive functioning before starting chemotherapy was good. After 6 months of treatment there was a significant decline in some cognitive functions, particularly involving the attention subdomain. Objective cognitive deficit resulted independent from the emotional status. On the contrary, self-perceived mental dysfunction was unrelated to the objective cognitive decline, but it was associated with depression and anxiety. Breast cancer chemotherapy can induce domain-specific cognitive dysfunction. Patients' self-perception of mental decline is unrelated to objective cognitive deficit. Breast cancer patients negatively judge their cognitive performances if they have a negative emotional functioning.status: publishe

Body, space and pain

There is growing interest in understanding how the perception of pain (and touch) is influenced by the way we represent our body and the space surrounding it. Recent views argue that pain can only be understood in a larger framework of body perception and action. This attention is driven by accumulating research in experimental and clinical domains, indicating that pain perception depends largely on cognitive factors and multisensory integration. The interest is also boosted by studies on chronic pain conditions suggesting a tight link between body perception and the maintenance of pain. Many aspects remain yet to be elucidated. We welcomed submissions from researchers in cognitive neuroscience and pain to increase our understanding of the interplay among body, space, pain, touch and movement. We aimed to gather insights from different theoretical frameworks and encouraged investigators using a broad range of methods including (but not limited to) behavioural and neuropsychological approaches, imaging techniques, electrophysiology, psychophysiology and TMS to present their results in this Research Topic. In the attempt to go from bench- to bedside we also strongly encouraged submissions from clinicians and physiotherapist whose contribution may help rising some future key questions. Qualitative and phenomenological approaches were also welcome

The impact of the social context on the development of secondary hyperalgesia:an experimental study

Social support has been shown to reduce pain ratings and physiological responses to acute pain stimuli. Furthermore, this relationship is moderated by adult attachment styles. However, these effects have not been characterized in experimentally induced symptoms of chronic pain, such as secondary hyperalgesia (SH) which is characterized by an increased sensitivity of the skin surrounding an injury. We aimed to examine whether social support by handholding from a romantic partner can attenuate the development of experimentally induced SH. Thirty-seven women, along with their partners, participated in 2 experimental sessions 1 week apart. In both sessions, SH was induced using an electrical stimulation protocol. In the support condition, the partner was seated across from the participant holding the participant's hand during the electrical stimulation, whereas in the alone condition, the participant went through the stimulation alone. Heart rate variability was measured for both the participant as well as the partner before, during, and after the stimulation. We found that the width of the area of hyperalgesia was significantly smaller in the support condition. Attachment styles did not moderate this effect of social support on the area width. Increasing attachment avoidance was associated with both a smaller width of hyperalgesia and a smaller increase in the sensitivity on the stimulated arm. For the first time, we show that social support can attenuate the development of secondary hyperalgesia and that attachment avoidance may be associated with an attenuated development of secondary hyperalgesia

Dishabituation of laser-evoked EEG responses: dissecting the effect of certain and uncertain changes in stimulus spatial location

The repetition of nociceptive stimuli of identical modality, intensity and location at short (1 s) and constant inter-stimulus interval (ISI) determines a strong habituation of the corresponding electroencephalographic (EEG) responses. To understand what determines this response habituation, we (1) examined the effect of introducing a selective change in the spatial location of the repeated stimulus (i.e., without altering its modality, intensity and timing), and (2) dissected the relative contribution of bottom-up, stimulus-driven spatial changes and top-down, cognitive expectations of such a change. Multichannel EEG was recorded while participants received a triplet of stimuli (S1-S2-S3) delivered to the hand dorsum at 1-s ISI. S3 was delivered either to the same hand as S1 and S2 or to the other hand, and participants were either explicitly informed or not informed of the location of S3. We found that, unlike the introduction of a change in the sensory modality of the repeated stimulus (Valentini et al. in J Cogn Neurosci 23:2822-2837, 2011), introducing a change in its spatial location did not produce a significant dishabituation of the laser-evoked N1, N2 and P2 peaks, but only a small amplitude increase following the P2 peak, maximal on the hemisphere contralateral to the stimulated hand. Furthermore, the magnitude of the elicited responses was not significantly affected by cognitive expectations. Altogether, these results indicate that bottom-up, stimulus-driven novelty resulting from a change in stimulus spatial location does not revert the habituation caused by repetition suppression, but determines a small increase of neural activity over the contralateral central-parietal cortex, likely reflecting shifts in spatial attention.status: publishe

Error Processing and Pain:A New Perspective

Errors put organisms in danger. Upon error commission, error processing allows for the updating of behavior that proved ineffective in light of the current context and goals, and for the activation of behavioral defensive systems. Pain, on the other hand, signals actual or potential danger to one's physical integrity and, likewise, motivates protective behavior. These parallels suggest the existence of cross-links between pain and error processing but so far their relationship remains elusive. In this review, we tie together findings from the field of pain research with those from electroencephalography studies on error processing [specifically the Error Related Negativity (ERN) and Positivity (Pe)]. More precisely, we discuss three plausible associations: Firstly, pain may enhance error processing as it increases error salience. Secondly, persons fearful of pain may be particularly vigilant towards painful errors and thus show a stronger neural response to them. Thirdly, the ERN as a component of the neural response to error commission is considered an endophenotype of threat sensitivity. As high sensitivity to pain threats is known to incite avoidance behavior, this raises the intriguing possibility that neural signatures of error processing predict pain-related protective behaviors, such as avoidance. We propose an integration of these findings into a common framework to inspire future research. Perspectives Inspired by research in anxiety disorders, we discuss the potential bi-directional relationships between error processing and pain, and identify future directions to examine the neural and psychological processes involved in acute and chronic pain and respective avoidance behavior