Past Journal Clubs
Tuesday, May 11, 2021, 1 pm EST
Title: Physiological and Chemical Properties of C-Tactile Afferents in Man and Their Distribution Across the Body
Presented by: Dr. Line Löken, Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden
Abstract: Since the discovery that the skin of man is innervated with unmyelinated tactile (CT) afferents that convey social and emotional aspects of touch, extensive explorations of the physiology and function of these afferents have been made. In spite of this, aspects of the properties of CT afferents as well as their prevalence and density in different areas of the human body have remained elusive. Numerous microneurography studies in the human peroneal nerve, without reports of CT afferents, suggested that these afferents are lacking in the more distal parts of the limbs. Here we recorded from unmyelinated low-threshold mechanosensitive afferents in the peroneal, lateral antebrachial and radial nerves. The most distal receptive fields were located on the proximal phalanx of the third finger for the superficial branch of the radial nerve, and near the lateral malleolus for the peroneal nerve. We found that the physiological properties with regards to conduction velocity and mechanical threshold, as well as their tuning to brush velocity, was similar in CT units across the antebrachial, radial and peroneal nerves. Lastly, we explored the chemical sensitivity of these afferents and found that CT afferents were not activated by either the pruritogen histamine or the cooling agent menthol. In light of previous studies showing the combined effects that temperature and mechanical stimuli have on these neurons, including a lack of responsiveness to capsaicin, these findings add to the growing body of research suggesting that CT afferents constitute a unique sense organ with highly specialized mechanisms for transducing stimuli relevant to affective touch sensation.
Tuesday, April 20, 2021, 3 pm EST
Title: A picture is worth a thousand words: linking fibromyalgia pain widespreadness from digital pain drawings with pain catastrophizing and brain cross-network connectivity
Presented by: Dr. Vitaly Napadow, Professor in Radiology, Harvard Medical School, USA
Abstract: Pain catastrophizing is prominent in chronic pain conditions such as fibromyalgia, and has been proposed to contribute to the development of pain widespreadness. However, the brain mechanisms responsible for this association are unknown. We hypothesized that increased resting Salience Network (SLN) connectivity to nodes of the Default Mode Network (DMN), representing previously reported pain-linked cross-network enmeshment, would be associated with increased pain catastrophizing and widespreadness across body sites.We applied functional Magnetic Resonance Imaging (fMRI) and digital pain drawings (free-hand drawing over a body outline, analyzed using conventional software for multivoxel fMRI analysis) to investigate precisely-quantified measures of pain widespreadness and the associations between pain catastrophizing (Pain Catastrophizing Scale, PCS), resting brain network connectivity (Dual-regression Independent Component Analysis, 6-minute multiband accelerated fMRI), and pain widespreadness in fibromyalgia patients (N=79).Fibromyalgia patients reported pain in multiple body areas (most frequently the spinal region, from the lower back to the neck), with moderately high pain widespreadness (mean±SD: 26.1±24.1 percent of total body area), and high PCS scores (27.0±21.9, scale range: 0-52), which were positively correlated (r=0.26,p=0.02). A whole-brain regression analysis focused on SLN connectivity indicated that pain widespreadness was also positively associated with SLN connectivity to the Posterior Cingulate Cortex (PCC), a key node of the DMN. Moreover, we found that SLN-PCC connectivity statistically mediated the association between pain catastrophizing and pain widespreadness (p=0.01).In conclusion, we identified a putative brain mechanism underpinning the association between greater pain catastrophizing and a larger spatial extent of body pain in fibromyalgia, implicating a role for brain SLN-DMN cross-network enmeshment in mediating this association.
Relevant Paper: https://pubmed.ncbi.nlm.nih.gov/33230008/
Tuesday, March 30, 2021, 1 pm EST
Title: Forced choices reveal a trade-off between cognitive effort and physical pain
Presented by: Todd Vogel, PhD Candidate (PI: Dr. Mathieu Roy), Department of Psychology, McGill University, Montréal, Canada
Abstract: Cognitive effort is described as aversive, and people will generally avoid it when possible. This aversion to effort is believed to arise from a cost–benefit analysis of the actions available. The comparison of cognitive effort against other primary aversive experiences, however, remains relatively unexplored. Here, we offered participants choices between performing a cognitively demanding task or experiencing thermal pain. We found that cognitive effort can be traded off for physical pain and that people generally avoid exerting high levels of cognitive effort. We also used computational modelling to examine the aversive subjective value of effort and its effects on response behaviours. Applying this model to decision times revealed asymmetric effects of effort and pain, suggesting that cognitive effort may not share the same basic influences on avoidance behaviour as more primary aversive stimuli such as physical pain.
Wednesday, March 16, 2021
Title: Touch inhibits touch: sanshool-induced paradoxical tingling reveals perceptual interaction between somatosensory submodalities.
Presented by: Professor Patrick Haggard, Action & Body Group Leader, Institute of Cognitive Neuroscience, UCL, London, UK
Abstract: Human perception of touch is mediated by inputs from multiple channels. Classical theories postulate independent contributions of each channel to each tactile feature, with little or no interaction between channels. In contrast to this view, we show that inputs from two sub-modalities of mechanical input channels interact to determine tactile perception. The flutter-range vibration channel was activated anomalously using hydroxy-α-sanshool , a bioactive compound of Szechuan pepper, which chemically induces vibration-like tingling sensations. We tested whether this tingling sensation on the lips was modulated by sustained mechanical pressure. Across four experiments, we show that sustained touch inhibits sanshool tingling sensations in a location-specific, pressure-level and time-dependent manner. Additional experiments ruled out the mediation of this interaction by nociceptive or affective (C-tactile) channels. These results reveal novel inhibitory influence from steady pressure onto flutter-range tactile perceptual channels, consistent with early-stage interactions between mechanoreceptor inputs within the somatosensory pathway.
Relevant Paper: https://royalsocietypublishing.org/doi/10.1098/rspb.2020.2914
Wednesday, March 3, 2021
Title: Confidence in subjective pain is predicted by reaction time during decision making
Presented by: Troy Dildine, PhD Candidate (Atlas Lab), NCCIH/NIH and Karolinska Institute
Abstract: Self-report is the gold standard for measuring pain. However, decisions about pain can vary substantially within and between individuals. We measured whether self-reported pain is accompanied by metacognition and variations in confidence, similar to perceptual decision-making in other modalities. Eighty healthy volunteers underwent acute thermal pain and provided pain ratings followed by confidence judgments on continuous visual analogue scales. We investigated whether eye fixations and reaction time during pain rating might serve as implicit markers of confidence. Confidence varied across trials and increased confidence was associated with faster pain rating reaction times. The association between confidence and fixations varied across individuals as a function of the reliability of individuals’ association between temperature and pain. Taken together, this work indicates that individuals can provide metacognitive judgments of pain and extends research on confidence in perceptual decision-making to pain.
Relevant Paper: https://www.nature.com/articles/s41598-020-77864-8
Wednesday, February 17, 2021
Title: Chronic pain precedes disrupted eating behavior in back pain patients
Presented by: Dr. Paul Geha, Assistant Professor, University of Rochester, USA
Abstract: Chronic low-back pain (CLBP) and obesity are interrelated, but the mechanisms of this interaction are still poorly understood. We have previously shown that patients with CLBP exhibit blunted hedonic response to highly palatable fat-rich food and disrupted satiety signals. This observation is consistent with the reorganization of the nucleus accumbens observed in CLBP patients, and the role of this striatal area in the hedonic perception of highly palatable foods. Here we asked how eating behavior would be affected in back pain patients before and after they transition to chronic pain or recover from it, and how does hedonic perception of fat-rich food relate to the properties of the nucleus accumbens in this patients’ population. Therefore, we tested sub-acute back pain patients and healthy controls at baseline when back pain was 6-12 weeks old, and at approximately one-year follow-up using behavioral assays and structural brain imaging. Likewise, we tested a cohort of CLBP patients at one time point. CLBP patients and, surprisingly, sub-acute back pain patients who recovered at follow-up (SBPr) showed disrupted eating behavior while sub-acute back pain patients who persisted in having pain at follow-up (SBPp) had an intact eating behavior. However, only SBPp patients at baseline and follow-up, and CLBP patients, showed a direct relationship between hedonic perception of fat-rich food and nucleus accumbens volume. Our data reproduces our previous findings and suggest that disrupted eating behavior sets in after pain chronification and is directly related to the properties of nucleus accumbens.
Meeting ID: 834 7571 0509
Wednesday, January 27, 2021
Title: Sex differences in brain modular organization in chronic pain
Presented by: Dr. Camille Fauchon, Postdoctoral Fellow (PI: Karen Davis), Krembil Brain Institute, University Health Network, Canada
Abstract: Men and women can exhibit different pain sensitivities and many chronic pain conditions are more prevalent in one sex. Although there is evidence of sex differences in the brain, it is not known whether there are sex differences in the organization of large-scale functional brain networks in chronic pain. Here, we used graph theory with modular analysis and machine-learning of resting-state (RS)-fMRI data from 220 participants; 155 healthy controls and 65 individuals with chronic low back pain due to ankylosing spondylitis (AS), a form of arthritis.We found an extensive overlap in the graph partitions with the major brain intrinsic systems (i.e., default mode, central, visual and sensorimotor modules), but also sex-specific network topological characteristics in healthy people and those with chronic pain. People with chronic pain exhibited higher cross-network connectivity, and sex-specific nodal graph properties changes (i.e., Hubs disruption), some of which were associated with the severity of the chronic pain condition. Females exhibited atypically higher functional segregation in the mid- and subgenual cingulate cortex and lower connectivity in the network with the default mode and fronto-parietal modules; whereas males exhibited stronger connectivity with the sensorimotor module. Classification models on nodal graph metrics could classify an individuals' sex and whether they have chronic pain with high accuracies (77-92%). These findings highlight the organizational abnormalities of RS-brain networks in people with chronic pain and provide a framework to consider sex-specific pain therapeutics.
Wednesday, December 16, 2020
Title: Reward enhances pain discrimination in humans
Presented by: Dr. Susanne Becker, Research Group Leader, Integrative Spinal Research, Department of Chiropratic Research, University of Zurich, Switzerland
Abstract: The notion that reward inhibits pain is a well-supported observation in both humans and animals, allowing suppression of pain reflexes to acquired rewarding stimuli. However, a blanket inhibition of pain by reward would also impair pain discrimination. In contrast, early counterconditioning experiments implied that reward might actually spare pain discrimination. To test this hypothesis, we investigated whether discriminative performance was enhanced or inhibited by reward. We found in adult human volunteers (N = 25) that pain-based discriminative ability is actually enhanced by reward, especially when reward is directly contingent on discriminative performance. Drift-diffusion modeling shows that this relates to an augmentation of the underlying sensory signal strength and is not merely an effect of decision bias. This enhancement of sensory-discriminative pain-information processing suggests that whereas reward can promote reward-acquiring behavior by inhibition of pain in some circumstances, it can also facilitate important discriminative information of the sensory input when necessary.
Relevant Paper: CLICK HERE
Monday, November 23, 2020
Title: Striatal hypofunction as a neural correlate of mood alterations in chronic pain patients
Presented by: Ellie Minhae Kim, Senior Clinical Research Coordinator, Pain and Neuroinflammation Imaging Lab (Dr. Marco Loggia), A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA
Abstract: Chronic pain and mood disorders share common neuroanatomical substrates involving disruption of the reward system. Although increase in negative affect (NA) and decrease in positive affect (PA) are well-known factors complicating the clinical presentation of chronic pain patients, our understanding of the mechanisms underlying the interaction between pain and PA/NA remains limited. Here, we used a validated task probing behavioral and neural responses to monetary rewards and losses in conjunction with functional magnetic reso- nance imaging (fMRI) to test the hypothesis that dysfunction of the striatum, a key mesolimbic structure involved in the encoding of motivational salience, relates to mood alterations comorbid with chronic pain. Twenty-eight chronic musculoskeletal pain patients (chronic low back pain, n1⁄415; fibromyalgia, n1⁄413) and 18 healthy controls underwent fMRI while performing the Monetary Incentive Delay (MID) task. Behavioral and neural responses were compared across groups and correlated against measures of depression (Beck Depression Inventory) and hedonic capacity (Snaith-Hamilton Pleasure Scale). Compared to controls, patients demonstrated higher anhedonia and depression scores, and a dampening of striatal activation and incentive-related behavioral facilitation (reduction in reaction times) during reward and loss trials of the MID task (ps < 0.05). In all participants, lower activation of the right striatum during reward trials was correlated with lower incentive-related behavioral facilitation and higher anhedonia scores (ps < 0.05). Finally, among patients, lower bilateral striatal activation during loss trials was correlated with higher depression scores (ps < 0.05). In chronic pain, PA reduction and NA increase are accompanied by striatal hypofunction as measured by the MID task.
Thursday, October 22, 2020
Title: The Distributed Nociceptive System: A Framework for Understanding Pain
Presented by: Dr. Robert C. Coghill, Director, Center for Understanding Pediatric Pain (CUPP), Professor of Pediatrics Behavioral Medicine and Clinical Psychology, Cincinnati Children’s Hospital Medical Center
Abstract: Chronic pain remains challenging to both diagnose and treat. These challenges, in part, arise from limited systems-level understanding of the basic mechanisms that process nociceptive information and ultimately instantiate a subjectively available experience of pain. Here, I provide a framework, the distributed nociceptive system, for understanding nociceptive mechanisms at a systems level by integrat- ing the concepts of neural population coding with distributed processing. Within this framework, wide-spread engagement of populations of neurons produces representations of nociceptive information that are highly resilient to disruption. The distributed nociceptive system provides a foundation for understanding complex spatial aspects of chronic pain and provides an impetus for nonpharmacological cognitive and physical therapies that can effectively target the highly distributed system that gives rise to an experience of pain.
Relevant Paper: https://doi.org/10.1016/j.tins.2020.07.004
Wednesday, September 23, 2020
Title: Using fMRI hyperscanning to investigate the patient-clinician relationship in chronic pain: The role of therapeutic alliance, behavioral mirroring, and brain-to-brain concordance in therapeutic pain relief
Presented by: Dr. Dan-Mikael Ellingsen, Postdoctoral research fellow (Napadow Lab), Harvard Medical School and Martinos Center for Biomedical imaging, Boston, USA.
Abstract: The patient-clinician interaction can powerfully shape treatment outcomes such as pain, but is often considered an intangible “art-of-medicine”, and has largely eluded scientific inquiry. Although brain correlates of social processes such as em- pathy and theory-of-mind have been studied using single-subject designs, the spe- cific behavioral and neural mechanisms underpinning the patient-clinician interac- tion are unknown. Using a two-person interactive design, we simultaneously rec- orded functional MRI (i.e. hyperscanning) in patient-clinician dyads, who interacted via live video while clinicians treated evoked pain in chronic pain patients. Our re- sults show that patient analgesia is mediated by patient-clinician nonverbal behav- ioral mirroring and brain-to-brain concordance in circuitry implicated in theory-of- mind and social mirroring. Dyad-based analyses showed extensive dynamic cou- pling of these brain nodes with the partners’ brain activity, yet only in dyads where clinical rapport had been established prior to the interaction. These findings point to a putatively key brain-behavioral mechanism for therapeutic alliance and psycho- social analgesia.
Relevant Paper: https://www.biorxiv.org/content/10.1101/2020.08.05.237511v1
Thursday, August 6/11 2020
We have an outstanding lineup of trainees who will present at the DataBlitz.
We had 31 submissions (!!) that will be presented in three sessions. The first two sessions will be held in parallel on August 6 at 3pm EST and the third session will be held on August 11 at 6:30pm EST. All presenters have been contacted and assigned their timeslots. All trainees will get feedback on their presentations.
An overview of the DataBlitz, including instructions, judges panel, and timings is available here.
The Abstracts and Order of Presentations for each of the DataBlitz events can be found here:
DataBlitz 1 - Room 1
Prizes will be announced on August 15, 2020.
Prizes sponsored by:
Thursday, July 16, 2020
Title: “But for pain words are lacking”: using language features to predict placebo analgesia in chronic pain. (New Data; Unpublished work)
Presented by: Dr. Paulo Branco, Postdoctoral Fellow at Apkarian Pain and Passions lab, Northwestern University, Chicago, USA.
Abstract: “But for pain words are lacking”, writes Virginia Woolf in her Magnum Opus, The Waves. And indeed, even though language is rich in meaning and is seen as “a window to the soul”, the discourse of patients with chronic illness and pain – like Woolf herself – have long been neglected. Natural language processing (NLP) is a relatively popular technique that extracts languages features out of discourse reflecting the person’s personality, behavior and mood. In this study, we hypothesize that chronic back pain patients who respond to placebo will show specific language patterns that can be picked up, quantified, and used to classify and infer the extent of analgesia after placebo pill ingestion. We were able to classify placebo responders with high accuracy (79% cross-validated). Further, with just three language features (semantic proximity to stigma, identity, and text tags associated with achievement) we were able to explain 50% of the variance in the reported pain after treatment. Predictive language features were also associated with personality traits and are not explained by treatment effects alone. Together, these show high promise to the use of quantitative language features to study placebo analgesia and have important implications for both the design of clinical trials and, conceivably, for identifying subjects that can benefit from placebo as a treatment option for chronic pain.
Thursday, July 9, 2020
PANEL DISCUSSION: WHAT HAS IMAGING ADDED TO OUR UNDERSTANDING OF PAIN
A recent editorial in the journal Brain (https://academic.oup.com/brain/article-abstract/143/4/1045/5823483?redirectedFrom=fulltext) criticized brain imaging (in particular fMRI) and stated that it has offered little to our understanding of brain-based disease, and has little (if any) clinical utility.
I thought it would be a good exercise to have a discussion about fMRI/sMRI papers that have had a meaningful impact on our mechanistic understanding of pain, or that have had meaningful clinical impact. This is a useful exercise for us to pull back and to think about the work we do.
Several faculty members have offered to participate, including:
David A. Seminowicz, Associate Professor, University of Maryland School of Dentistry, USA
Flavia Mancini, MRC Career Development Fellow, Cambridge University, UK
Markus Ploner, Heisenberg Professor of Human Pain Research, TUM, Germany
Irene Tracey, Nuffield Chair in Anesthetic Science, Oxford University, UK
Marco Loggia, Associate Professor of Radiology, Harvard Medical School, USA
Ulrike Bingel, Professor in Clinical Neuroscience, University Hospital Essen, Germany
Tor Wager, Diana L. Taylor Distinguished Professor, Dartmouth, USA
Javeria Hashmi, Canada Research Chair (CRC) Tier II (Pain), Dalhousie University, Canada
Marina Lopez-Sola, Serra Hunter Lecturer Prof, University of Barcelona, Spain
DETAILS TO FOLLOW
Thursday, July 2, 2020
SYMPOSIUM: PAIN AND EMOTION—BRAIN, BODY, AND BEYOND
Pain and emotion are tightly linked, but are traditionally studied and treated separately. This symposium highlights conceptual, psychological, and neural intersections between these two constructs, emphasizing opportunity for collaborations across the pain and affective science research and clinical communities. Our diverse panel of speakers combine innovative experimental methodologies and conceptual models, from basic animal and human research, to clinical research in chronic pain patients
Gadi Gilam, firstname.lastname@example.org
Gregory Corder, email@example.com
Siri Leknes, firstname.lastname@example.org
Rachel Aaron, email@example.com
Thursday, June 18, 2020
Title: Multiple Brain Networks Mediating Stimulus-Pain Relationships in Humans.
Presented by: Prof. Tor Wager, Diana L. Taylor Distinguished Professor, Dartmouth, USA
Geuter et al. Multiple Brain Networks Mediating Stimulus-Pain Relationships in Humans. Cerebral Cortex 30(7): 4204–4219
Thursday, June 4, 2020
Guo et al. Ultralow-frequency neural entrainment to pain. PLoS Biology. 18(4): e3000491.
Presented by: Dr. Yifei Guo and Dr. Rory Bufacchi, Postdoctoral Fellow, Iannetti Lab, Italian Institute of Technology, Rome, Italy
Thursday, May 21, 2020
Title: "Mindfulness engages a novel pain modulatory neural pathway" - Preprint Talk
Presented by: Dr. Fadel Zeidan, Assistant Professor, Department of Anesthesiology, UCSD, USA
(This is new work from Fadel's lab)
Thursday, May 7, 2020
Makari et al. Loss of nucleus accumbens low-frequency fluctuations is a signature of chronic pain. Proceedings of the National Academy of Sciences, in press. DOI: 10.1073/pnas.1918682117
Presented by: Dr. Paul Geha, Assistant Professor, University of Rochester, USA
Thursday, May 21, 2020
Lim et al. Threat Prediction from Schemas as a Source of Bias in Pain Perception. Journal of Neuroscience 40 (7): 1538-1548, 2020.
Presented by: Dr. Javeria Hashmi, Canada Research Chair (CRC) Tier II (Pain), Department of Anesthesia, Pain Management & Perioperative Medicine, Dalhousie University, Canada
Thursday, April 16, 2020
Lettieri et al. Emotionotopy in the human right temporo-parietal cortex. Nature Communications 10: 5568 (2019).
Presented by: Massieh Moayedi, Assistant Professor and Co-Director of the Centre for Sensorimotor and Pain Research, University of Toronto, Canada
Furman et al. Sensorimotor peak alpha frequency is a reliable biomarker of pain sensitivity. BiorXiv (preprint).
Presented by: Andrew Furman, PhD Candidate, Seminowicz Lab, University of Maryland, USA
Thursday, April 2, 2020