Processing the fine-grained features of tactile textures involves the primary somatosensory cortex.

Dynamic tactile perception and discrimination of textures require the ability to encode and differentiate complex vibration patterns elicited at the level of the skin when sliding against a surface. Whether the primary somatosensory cortex (S1) can encode the fine-grained spectrotemporal features distinguishing textures remains debated. To address this question, electroencephalography (EEG) frequency-tagging approach was used to characterize responses to vibrotactile oddball contrasts between two textures.

The effects of lacosamide, pregabalin, and tapentadol on peripheral nerve excitability: A randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects.

Background: Chronic pain is a leading cause of disability globally, with limited treatment options and frequent adverse effects. The IMI-PainCare-BioPain project aimed to enhance analgesic drug development by standardizing biomarkers. This study, IMI2-PainCare-BioPain-RCT1, evaluated the effects of lacosamide, pregabalin, and tapentadol on peripheral nerve excitability in healthy subjects through a randomized, double-blind, placebo-controlled crossover trial.

Repeated exposure to cutaneous high-frequency electrical stimulation prolongs the time course of secondary hyperalgesia.

Exposure to noxious stimuli induces secondary hyperalgesia (SH), likely due to long-term potentiation (LTP) in the dorsal horn or "central sensitization." Previous studies have suggested that repeated exposure to a sensitizing stimulus may promote a persistent form of potentiation. We tested this hypothesis by characterizing the time course and spatial spread of SH induced by repeated exposures to high-frequency electrical stimulation (HFS) in healthy volunteers.

Effect of Vagus Nerve Stimulation on Electroencephalogram Synchronization: A Longitudinal Study Using a Clinical-Research Response Scale.

Objectives: No reliable biomarkers exist for predicting and assessing vagus nerve stimulation (VNS) response. While VNS induces acute electroencephalography (EEG) desynchronization after implantation, longitudinal evaluations of EEG synchronization changes are lacking. This study constitutes the first prospective investigation evaluating EEG synchronization before and after VNS device implantation and correlating it with the clinical response to VNS.

Navigating the biopsychosocial landscape: A systematic review on the association between social support and chronic pain.

The biopsychosocial model is widely used to explain chronic pain conditions. Yet, the role of social aspects including social support is not clear. Literature on social support and chronic pain is still sparse and results inconsistent.

Strength, extent and duration of secondary hyperalgesia induced by high-frequency electrical stimulation of the foot compared to the volar forearm of healthy human volunteers.

High-frequency electrical stimulation (HFS) of the skin using a multi-pin electrode activating epidermal nociceptors is used to explore spinal central sensitization in humans. Most previous studies applied HFS to the volar forearm. To prepare for clinical applications in which HFS could be applied to different body sites, this study compared the secondary hyperalgesia induced by stimulation of the foot dorsum vs.

A pain research strategy for Europe: A European survey and position paper of the European Pain Federation EFIC.

Background: Pain is the leading cause of disability and reduced quality of life worldwide. Despite the increasing burden for patients and healthcare systems, pain research remains underfunded and under focused. Having stakeholders identify and prioritize areas that need urgent attention in the field will help focus funding topics, reduce 'research waste', improve the effectiveness of pain research and therapy and promote the uptake of research evidence.

Preoperative susceptibility to developing secondary hyperalgesia is associated with post-thoracotomy pain at 2 months.

Background: Identifying the subset of patients at risk for developing persistent pain after surgery is clinically important as they could benefit from targeted prevention measures. In this prospective study, we investigated if the preoperative assessment of the individual susceptibility to developing experimentally induced secondary hyperalgesia is associated with post-thoracotomy pain at 2 months.

Methods: Forty-one patients scheduled to undergo a posterolateral thoracotomy were recruited before surgery and followed prospectively for 2 months.

How visual experience shapes body representation.

We do not have a veridical representation of our body in our mind. For instance, tactile distances of equal measure along the medial-lateral axis of our limbs are generally perceived as larger than those running along the proximal-distal axis. This anisotropy in tactile distances reflects distortions in body-shape representation, such that the body parts are perceived as wider than they are.

Studying the Effect of Expectations on High-Frequency Electrical Stimulation-Induced Pain and Pinprick Hypersensitivity.

Negative expectations can increase pain, but can they promote the development of central sensitization? This study used an inert treatment and verbal suggestions to induce expectations of increased high-frequency electrical stimulation (HFS)-induced pain and assessed their effects on pain ratings during HFS and HFS-induced pinprick hypersensitivity. Fifty healthy volunteers were randomly allocated to either a control group (N = 25) or a nocebo group (N = 25). Participants in both groups received a patch containing water on the right forearm.

Systematic review and co-ordinate based meta-analysis to summarize the utilization of functional brain imaging in conjunction with human models of peripheral and central sensitization.

Background And Objective: Functional magnetic resonance imaging, in conjunction with models of peripheral and/or central sensitization, has been used to assess analgesic efficacy in healthy humans. This review aims to summarize the use of these techniques to characterize brain mechanisms of hyperalgesia/allodynia and to evaluate the efficacy of analgesics.

Databases And Data Treatment: Searches were performed (PubMed-Medline, Cochrane, Web of Science and Clinicaltrials.

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study.

Background: Decline in olfaction may occur after general anesthesia, but the exact incidence and underlying physiopathology remain scarcely investigated. Olfactory dysfunction arises with aging and is known to be linked to cognitive impairment. In this pilot study, we evaluated the incidence of immediate postoperative decline in olfaction and its association with a preoperative cognitive test, performance at Clock Drawing Test (CDT), in a group of older patients.

Intra-operative electroencephalogram frontal alpha-band spectral analysis and postoperative delirium in cardiac surgery: A prospective cohort study.

Background: Postoperative delirium (POD) remains a frequent complication after cardiac surgery, with pre-operative cognitive status being one of the main predisposing factors. However, performing complete pre-operative neuropsychological testing is challenging. The magnitude of frontal electroencephalographic (EEG) α oscillations during general anaesthesia has been related to pre-operative cognition and could constitute a functional marker for brain vulnerability.

Influence of skin type and laser wavelength on laser-evoked potentials.

Background: Infrared laser stimulation is a valuable tool in pain research, its primary application being the recording of laser-evoked brain potentials (LEPs). Different types of laser stimulators, varying in their skin penetrance, are likely to have a large influence on the LEPs, when stimulating different skin types. The aim of this study was to investigate how LEPs depend on laser type and skin location.

Comparison between pupillometry and numeric pain rating scale for pain assessments in communicating adult patients in the emergency department.

Objective: The adequate assessment of pain in the emergency department (ED) can be challenging. Two dynamic pupillary measures used in conscious subjects after a surgical procedure were previously shown to correlate to the magnitude of ongoing pain. The objective of this study was to test the ability of dynamic measures derived from pupillometry to evaluate pain intensity in conscious adult patients admitted to the ED.

Pain-free default mode network connectivity contributes to tonic experimental pain intensity beyond the role of negative mood and other pain-related factors.

Background: Alterations in the default mode network (DMN) connectivity across pain stages suggest a possible DMN involvement in the transition to persistent pain.

Aim: This study examined whether pain-free DMN connectivity at lower alpha oscillations (8-10 Hz) accounts for a unique variation in experimental peak pain intensity beyond the contribution of factors known to influence pain intensity.

Methods: Pain-free DMN connectivity was measured with electroencephalography prior to 1 h of capsaicin-evoked pain using a topical capsaicin patch on the right forearm.

Perceptual simultaneity between nociceptive and visual stimuli depends on their spatial congruence.

To protect our body against physical threats, it is important to integrate the somatic and extra-somatic inputs generated by these stimuli. Temporal synchrony is an important parameter determining multisensory interaction, and the time taken by a given sensory input to reach the brain depends on the length and conduction velocity of the specific pathways through which it is transmitted. Nociceptive inputs are transmitted through very slow conducting unmyelinated C and thinly myelinated Aδ nociceptive fibers.

The test-retest reliability of large and small fiber nerve excitability testing with threshold tracking.

Objective: Standard nerve excitability testing (NET) predominantly assesses Aα- and Aβ-fiber function, but a method examining small afferents would be of great interest in pain studies. Here, we examined the properties of a novel perception threshold tracking (PTT) method that preferentially activates Aδ-fibers using weak currents delivered by a novel multipin electrode and compared its reliability with NET.

Methods: Eighteen healthy subjects (mean age:34.

Confidence of probabilistic predictions modulates the cortical response to pain.

Pain typically evolves over time, and the brain needs to learn this temporal evolution to predict how pain is likely to change in the future and orient behavior. This process is termed temporal statistical learning (TSL). Recently, it has been shown that TSL for pain sequences can be achieved using optimal Bayesian inference, which is encoded in somatosensory processing regions.

Spatial summation of cold and warm detection: Evidence for increased precision when brisk stimuli are delivered over larger area.

Cold and warm stimuli delivered over a larger skin area tend to be more easily detected/elicit stronger sensations, a phenomenon referred to as spatial summation. The aim of the present study was to clarify how stimulation area affects thermal detection processes by evaluating whether increasing the stimulation area simply reduces the detection threshold or also reduces the uncertainty of the detection process. Psychometric functions were fitted to the detection performance of 16 healthy subjects.

Neural evidence for functional roles of tactile and visual feedback in the application of myoelectric prosthesis.

. The primary purpose of this study was to investigate the electrophysiological mechanism underlying different modalities of sensory feedback and multi-sensory integration in typical prosthesis control tasks..