Chronic pain

Join the Hadjab laboratory to investigate chronic pain and headache using single-cell RNA and chromatin-accessibility data, spatial transcriptomics and integration across datasets. The scholarship supports postdoctoral research in Solna, connecting computational methods with molecular and cellular neuroscience. The award is intended for eligible researchers coming from outside Sweden and is tax-exempt; no amount is advertised. Scholarships are normally set for twelve months at a time, up to two years. Apply by 26 October 2026.

Chronic pain is a serious clinical and scientific problem, affecting 1 in 5 people worldwide, yet its mechanisms and ways to treat it remain poorly understood. Pain is modulated by endogenous pain modulatory pathways that connect the brain to the spinal cord, up- and down-regulating the transmission of nociceptive information. The most important region when such modulation occurs is the Rostral Ventromedial Medulla (Fields et al., 1983; Chen and Heinricher, 2022). Despite extensive work characterising the responses of RVM cells during pharmacological interventions, little is currently known ab

The management of chronic pain remains one of the greatest challenges of the 21st century, affecting over a third of the world’s population, and yet it is often not treated appropriately. To address this important public health issue, dual-target ligands that can engage more than one receptor and exert complementary analgesic actions represent a promising avenue for the treatment of acute and chronic pain. Therefore, ligands acting on the neurotensin receptor type 2 (NTSR2), which exert non-opioid antinociceptive effects and a synergistic effect when co-administered with opioids, offer an attr

Pain is an adaptive and primordial aspect of mammal’s physiology whose role is to warn against potential harmful situations and prevent aggravation of actual physical damages. However, many patients suffer from chronic pain, which overpasses pain’s adaptive trait becoming pathological. Nociceptive signal transmission is first relayed by the spinal cord before reaching the brain through ascending pathways. The control of spinal integration descending pathway is orchestrated by the periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). In the RVM, ON, OFF and neutral cells, are respec

Chronic pain is a major public health issue, often accompanied by comorbidities such as anxiety and depression. Thanks to the work of our team, we now know that the development of these disorders are linked to a dysregulation of the excitatory/inhibitory (EI) balance in cortical structures, such as the anterior cingulate cortex (ACC) and basolateral amygdala (BLA). An essential actor for the EI balance are the fast-spiking interneurons expressing parvalbumin (INPV). These neurons are surrounded by a specialized extracellular matrix, the perineuronal nets (PNNs) which regulate their functions a

Chronic pain affects nearly 20% of the Canadian population and is now recognized as a disease by the World Health Organization. Moderate to severe pain is currently treated with opioids which are known to cause various side effects (constipation, nausea, respiratory depression, drowsiness) and strong dependence. A promising alternative is neurotensin, an endogenous neuromodulator peptide which induces analgesia by interacting with its two G-protein coupled receptors NTS1 and NTS2. However, NTS1 activation is also associated with hypotension and hypothermia. Selectivity towards NTS2 is, therefo

Phantom limb pain (PLP) is a condition where pain is perceived as arising from a missing limb. Despite the high prevalence of PLP among individuals with amputation, the underlying mechanisms of this painful condition are poorly understood. The aim of the research presented here is to analyse high-resolution EEG data to differentiate oscillatory patterns in amputees who experience PLP from two control groups, amputees without PLP and individuals without amputation, and generate novel insights into the pathophysiology of PLP. This work expands on a previous investigation on the use of common spa

…indicated that PCOS accelerates pain perception in patients, yet the underlying mechanism remains elusive.In this

Pain is a complex sensory and emotion experience that typically facilitates a learning event so that an individual may avoid future harm. However, in a chronic pain context, pain that is experienced at inappropriate times no longer provides a useful function and may impair learning. Cognitive deficits including difficulties with learning and memory recall have been well documented in the clinic but pre-clinical data is lacking and the neural basis remains poorly understood. Using a chronic constriction injury (CCI) model of neuropathic pain in mice, combined with ex vivo electrophysiology and

Chronic pain is often secondary to medical conditions such as cancer or diabetes or surgery (ICD-11). One of the major puzzles in the field is why some people with seemingly identical conditions do not suffer from pain. Psychosocial predictors determine the pain severity. The aim of this study was to investigate factorial structure of predictor variables in a population without the confounder of coexisting chronic pain.This study is a follow-up of the studies conducted with the BioPain subproject of the IMI-PainCare project. Here we analyzed data collected in 6 different countries.During a scr

Chronic pain is a major concern in public health. Opioids are effective analgesics, but they may lead to severe adverse effects, including dependence. Non-pharmacological interventions, such as music listening, can be used as adjuvants to analgesics. However, the underlying mechanisms are insufficiently understood. Here, we aimed at assessing whether music exposure can modulate opioid adverse effects by influencing dopamine dynamics in the brain. First, mice underwent surgery to inject a dopamine biosensor (Dlight 1.3b) and to implant a fiberoptic in the nucleus accumbens (NAcc). After allowin

Affecting around 10% of world population, chronic pain and its related psychiatric comorbidities are major health issues. Implication of neuropeptides in modulation of pain remains poorly described in the brain. The relaxin-3 (RLN3) neuropeptide displays antidepressant and anxiolytic effects, and our preliminary results indicate an analgesic role in rodents. RLN3 is expressed by nucleus incertus (NI) neurons that project to different cortical (e.g. anterior cingulate cortex (ACC)) and subcortical (e.g. amygdala) areas of pain matrix.We aim at studying the pain modulatory effects of RLN3/RXFP3

…and a recognized association with chronic pain. Current evidence suggests that astrocytes play a key role in both disorders. Consequently, we investigated the effect of olfactory bulbectomy (OBX), a well-known model of depression-related behavior, on nociceptive behaviors and the number and morphology of astrocytes within the basolateral amygdala (BLA) in male rats. We conducted behavioral test, including the von Frey assessment of mechanical allodynia and acetone test of thermal cold allodynia,

While normal pain perception is necessary for increasing survival possibility of organisms, chronic pain is a great source of disability and is a serious social problem. On pain perception, dorsal root ganglion (DRG) neurons generate electrical activity by nociceptive stimuli, and transmit signals toward spinal cord. Alteration in pain processing circuit of spinal cord network can cause a type of chronic pain called nociplastic pain. Conventional studies using model animals are limited to investigate the complex mechanisms of functional changes in neural networks. In this study, we aimed to re

Chronic pain affects 20% of the adult population, particularly the elderly, and worsens cognitive impairment. Chronic pain includes conditions such as arthritis, neuropathic pain, or certain sexual dysfunctions. Based on this clinical relationship with vulvodynia, we conducted a study on CGRPergic innervation in the dorsal horn of the spinal cord and the female external genitalia in different age groups.Immunohistochemistry was performed against calcitonin gene-related peptide (CGRP) in the lumbosacral enlargement and vulva of adult (60, 70 years) and elderly (84, 85 years) human cadaveric don

Activity of the insular cortex had been consistently suggested to be related with chronic pain. Of the sub-regions in the insular cortex, the posterior insular cortex (pIC) receives inputs from brain regions that receive primary sensory inputs. Anatomical changes of the pIC were reported in neuropathic pain conditions. However, how the activity of pIC neurons may be related with neuropathic pain remain to be investigated. We, therefore, investigated the role of pIC pyramidal neurons and neuropathic pain using optogenetics and fiberphotometry using male mice. We found that inhibiting the activi

Chronic pain is a major disease burden with high incidence compared to other chronic diseases and with high persistence among affected individuals over many years.Satellite glial cells (SGCs) is a supportive cell type that ensheath the body of sensory neurons in the peripheral nervous system and in health SGCs are believed to contribute to neuronal homeostasis. However, evidence suggests that in certain disease states such as a traumatic nerve injury, satellite glial cells contribute to the development of chronic pain. Recent advances in single-cell RNA sequencing (scRNAseq) have prompted the

Neuromodulation techniques offer drug-free management of chronic pain. However, electrical stimulation does not discriminate between sensory and motor fibres, nor between their functional subtypes, and can therefore result in off-target effects (e.g., motor activation). One way to alter nociceptive fibre activity alone is through the selective expression of light sensitive opsins within nociceptive fibres. Thus, light may be used to alter nociceptive activity whilst leaving neighbouring fibres unaffected. We selectively expressed either excitatory (channelrhodopsin; ChR2) or inhibitory (halorh

…hypersensitivity and reducing chronic pain. Besides the well-characterized effects of prostacyclin (PGI2) in the vasculature, there is a general recognition that PGI2 is also involved in nociception, as it induces pain sensitivity and increase inflammatory responses. These biological effects are mediated by the prostacyclin receptor (IP-R) expres

Despite the pervasiveness of chronic pain worldwide, few effective strategies for long-term pain management exist. The development of new, non-addictive pain interventions hinges upon a deeper understanding of the changes in neural activity and circuitry that drive the development of chronic pain states. Recent studies have implicated the basolateral amygdala (BLA) as a critical hub in the encoding of negative valence to nociceptive information. Using immediate early gene mapping in combination with an activity-based rabies viral tracing screen, we identified several brain regions that synapse

Chronic pain is a leading cause of morbidity, common to patients with gastrointestinal diseases such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Most pain killers are largely ineffective against this type of pain or restricted for use in these patients due to gut related complications and risk of addition. A significant unmet clinical need therefore exists to develop novel non-opioid based visceral analgesics.

…with both mental health disorders and chronic pain. However, we currently lack tools to quantify aversive learning at scale. We have developed a suite of game-like cognitive tests which helps us tease apart individual differences in aversive learning, which can be performed by anyone, in the comfort of their home, using a touch based

Across species, survival depends on harvesting essential rewards such as food in the face of potential, occasionally catastrophic, dangers (such as serious injuries). This presents the challenge as to how to remain as efficient as possible when it comes to reward acquisition, whilst avoiding accrual of damage, especially during early exploration of new environments. This safety-efficiency dilemma is a special case of the exploration-exploitation dilemma, which typically collapses punishment and reward into a single scalar signal, whereby early losses can be overcome by later gains. However, th

Nowadays, 1.5 billion people suffer from chronic pain. Current neuropharmacology and neurostimulation treatments are associated with suboptimal efficacy, due to a lack of understanding of the pain system. A major contributor to many persistent clinical pain states is the phenomenon of central sensitization---a state of hyperexcitability of the pain system resulting from changes in the properties of neurons and circuits within the dorsal horns of the spinal cord. Although spinal cord circuits and their plasticity are challenging to study experimentally, only a handful of computational studies