Neuromatrix

Presents an obituary of Ronald Melzack (1929-2019). Melzack died on Sunday, December 22, 2019, at 10:00 p.m. News of his death spread like wildfire through the network of long-time friends and colleagues who had heard of his imminent passing. At that moment, the world lost a compassionate and caring soul, an advocate for chronic pain sufferers around the globe, and a giant in the international pain community. He is survived by his wife of 59 years, Lucy (née Birch), their son, Joel, and daughter, Lauren. Ron is known for four major accomplishments: establishing Canada's first multidisciplinary pain center at the Montreal General Hospital with neurosurgeon colleague and friend the late Joseph Stratford; the 1965 publication, in Science , of the gate control theory of pain with the late Patrick Wall; development of the McGill Pain Questionnaire and its derivatives; and later in his career, at 60 years of age, publication of the neuromatrix theory of pain, moving the field beyond the spinal gating mechanism into the brain...

AIM: The aim of this study was to assess the effectiveness of a primary care-based group educational intervention about concepts of pain neuroscience for the management of migraine compared to the routine medical care delivered to patients with this condition. BACKGROUND: The way pain is understood has been radically changed in recent decades, thanks to developments in the field of neuroscience. Thus, migraine may develop as a result of an exaggerated perception of threat that activates the pain neuromatrix, which might be modifiable, from a learning perspective, by adjusting the beliefs and behaviours that favour the onset of an attack...

Since early work attempting to characterize the brain's role in pain, it has been clear that pain is not generated by a specific brain region, but rather by coordinated activity across a network of brain regions, the "neuromatrix." The advent of noninvasive whole-brain neuroimaging, including functional magnetic resonance imaging, has provided insight on coordinated activity in the pain neuromatrix and how correlations in activity between regions, referred to as "functional connectivity," contribute to pain and its modulation...

BACKGROUND: Spinal cord injury (SCI) persons with chronic neuropathic pain (NP) demonstrate maladaptive autonomic profiles compared to SCI counterparts without NP (SCI - NP) or able-bodied (AB) controls. These aberrations may be secondary to maladaptive neuroplasticity in the shared circuitry of the pain neuromatrix-central autonomic network interface (PNM-CAN). In this study, we explored the proposed PNM-CAN mechanism in SCI + NP and AB cohorts following centrally-directed neuromodulation to assess if the PNM and CAN are capable of being differentially modulated...

Lateral ankle sprains (LASs) are among the most common injuries incurred during participation in sport and physical activity, and it is estimated that up to 40% of individuals who experience a first-time LAS will develop chronic ankle instability (CAI). Chronic ankle instability is characterized by a patient's being more than 12 months removed from the initial LAS and exhibiting a propensity for recurrent ankle sprains, frequent episodes or perceptions of the ankle giving way, and persistent symptoms such as pain, swelling, limited motion, weakness, and diminished self-reported function...

Lateral ankle sprains are the most common injuries sustained during physical activity. The epidemiologic trends associated with chronic ankle instability (CAI) suggest that current rehabilitation approaches may be inadequate. We sought to synthesize best-practices evidence for the rehabilitation of patients with acute ankle sprains and CAI through the integration of emerging paradigms in perception, the dynamics of skill acquisition, and the biopsychosocial model of function, disability, and health. From the best available evidence, 4 key factors emerged for effective treatment and rehabilitation strategies: pain reduction, external ankle support for up to 1 year, progressive return to motion, and coordination training...

Why does the brain choose pain? Why does an organ that is able to mask pain, even when intense as in fractures or in fighting wounds, decide to let pain pass and begin conscious, such as that of migraine, when there is no noxa patogena and there is no threat to the integrity of the organism, failing in the main function of pain, that of protection? In this brief review, we retrace the journey that led to the identification of the first complex mechanism of regulation of painful input, the spinal gate control system, through the identification of the predominantly thalamocortical supraspinal centers of the neuromatrix, up to the recognition of a pain matrix extremely articulate and sophisticated that integrates elementary sensations with much more complex functions, related to memory, affectivity, emotion, autonomic self-regulation, and homeostasis systems and so on...

Chronic pain is described as a manifestation of real or potential tissue damage. It is identified as a perception influenced by the complex interactions of biological, psychological, and social factors. Different types of pain and their comorbidities dramatically affect patients' quality of life and their families. Due to diverse etiology and pathogenesis, pain management represents a controversial issue in clinical practice. In 1986, the WHO developed a three-step ladder model based on the use of analgesics for pain management according to pain intensity in a linear up or down movement...

Background:Lysergic acid diethylamide (LSD) has agonist activity at various serotonin (5-HT) and dopamine receptors. Despite the therapeutic and scientific interest in LSD, specific receptor contributions to its neurobiological effects remain unknown. Methods: We therefore conducted a double-blind, randomized, counterbalanced, cross-over study (ClinicalTrials.gov, NCT02451072) during which 24 healthy human participants received either (i) placebo+placebo, (ii) placebo+LSD (100 µg po), or (iii) Ketanserin, a selective 5-HT2A receptor antagonist,+LSD...

Background: Recent findings have implicated supraspinal origins from the pain neuromatrix- central autonomic network (PNM-CAN) in the generation of neuropathic pain (NP) after spinal cord injury (SCI). The aim of this study was to further investigate the theorized PNM-CAN mechanisms in persons with SCI by using a centrally directed pain intervention, provided by breathing-controlled electrical stimulation (BreEStim), to measure resultant autonomic changes measured by time and frequency domain heart rate variability (HRV) analysis...

BACKGROUND: Somatoform disorders (SDs) are a heterogeneous group of psychiatric syndromes characterized by common symptoms, which may mimic a physical condition but they are not explained by a medical condition. Although the biologic nature of this disorder has been widely accepted, the neuroanatomical correlates characterizing SDs are still inconclusive. OBJECTIVE: This study aims to explore gray matter (GM) volume alterations in SD patients compared to healthy controls and their possible association with clinical and cognitive measures...

Background and aims In functional chest pain (FCP) of presumed esophageal origin central nervous system hyperexcitability is generally believed to play an important role in pain pathogenesis. However, this theory has recently been challenged. Using magnetic resonance diffusion tensor imaging, the aim was to characterize any microstructural reorganization of the pain neuromatrix in FCP patients. Methods 13 FCP patients and 20 matched healthy controls were studied in a 3T MR scanner. Inclusion criteria were relevant chest pain, normal coronary angiogram and normal upper gastrointestinal evaluation...

BACKGROUND: Neurodynamics is a clinical medium for testing the mechanical sensitivity of peripheral nerves which innervate the tissues of both the upper and lower limb. Currently, there is paucity in the literature of neurodynamic testing in osteopathic research, and where there is research, these are often methodologically flawed, without the appropriate comparators, blinding and reliability testing. AIMS: This study aimed to assess the physiological effects (measured through Range of Motion; ROM), of a commonly utilized cervical mobilization treatment during a neurodynamic test, with the appropriate methodology, i...

BACKGROUND: Chronic pain conditions are associated with neuroplasticity within the central nervous system. In most patients the maladaptive consequence of neuroplasticity supports prolonged course of chronic pain, despite the absence of a commensurate etiology. From a pain neuromatrix perspective it can involve three different circuits within the central nervous system; the classical sensory pathway, the limbic system pathway, and the associative pathways involving the parietal cortical connections...

The neuromatrix, or "pain matrix", is a network of cortical brain areas which is activated by noxious as well as salient somatosensory stimulation. This has been studied in mice and humans using blood oxygenation level-dependent (BOLD) fMRI. Here we demonstrate that BOLD effects observed in the murine neuromatrix in response to salient somatosensory stimuli are prone to reflect mean arterial blood pressure (MABP) changes, rather than neural activity. We show that a standard electrostimulus typically used in murine somatosensory fMRI can induce substantial elevations in MABP...

Background Cluster headache is a disorder characterized by intermittent, severe unilateral head pain accompanied by cranial autonomic symptoms. Most cases of CH are episodic, manifesting as "in-bout" periods of frequent headache separated by month-to-year-long "out-of-bout" periods of remission. Previous imaging studies have implicated the hypothalamus and pain matrix in the pathogenesis of episodic CH. However, the pathophysiology driving the transition between in- and out-of-bout periods remains unclear...

PURPOSE: Burning mouth syndrome (BMS) is a chronic intraoral pain syndrome featuring idiopathic oral pain and burning discomfort despite clinically normal oral mucosa. The etiology of chronic pain syndrome is unclear, but preliminary neuroimaging research has suggested the alteration of volume, metabolism, blood flow, and diffusion at multiple brain regions. According to the neuromatrix theory of Melzack, pain sense is generated in the brain by the network of multiple pain-related brain regions...

BACKGROUND: Rapid gastric balloon distension to discomfort threshold activates the "pain neuromatrix" and deactivates exteroceptive sensory and "default mode network" regions. However, little is known about brain mechanisms underlying tolerance of meal-induced gastric distension. We aimed to directly compare brain responses to gradual balloon distension and intragastric nutrient infusion and to explore the role of differential gut peptide release in these responses...

Hypnosis is a physiological mind activity characterized by focused attention, absorption, dissociation and plastic imagination. In the early 19th century, several hundred surgical interventions were described with hypnosis as the sole anesthetic, in an epoch when no anesthetic drugs were available; then hypnosis was prejudicially abandoned and forgotten after its introduction. In the past two decades, an increasing number of studies on hypnosis has shown its capacity to modify the activity of the prefrontal cortex, default mode network and pain neuromatrix (including the anterior cingulate cortex, amygdala, thalamus, insula and somatosensory cortex) and increase pain threshold up to the level of surgical anesthesia...

Pain is a complex and multidimensional perception, embodied in our daily experiences through interoceptive appraisal processes. The article reviews the recent literature about interoception along with predictive coding theories and tries to explain a missing link between the sense of the physiological condition of the entire body and the perception of pain in chronic conditions, which are characterized by interoceptive deficits. Understanding chronic pain from an interoceptive point of view allows us to better comprehend the multidimensional nature of this specific organic information, integrating the input of several sources from Gifford's Mature Organism Model to Melzack's neuromatrix...