Functional Imaging and Pain: Behavior, Perception, and Modulation

Wellness of patients with chronic pain is not only about pain intensity

OBJECTIVE

Attaining good outcomes in the management of chronic pain remains a clinical challenge. This study aimed to investigate the relationships between - and the contribution of - pain and related conditions to the wellness of these patients.

DESIGN

A secondary analysis of database of patients with chronic pain treated with medical cannabis (MC) to carry out a one-year prospective follow-up study was conducted. Questionnaires were completed before (T₀ ), six (T₆ ), and twelve (T₁₂ ) months after MC initiation. Data included patients' demographics and questionnaires related to three latent factors: pain intensity measures, related conditions (catastrophizing, sleep disturbance, anxiety, and depression), and wellness parameters (quality-of-life, disability, subjective-health-state). Weighted average of the observed variables (WOBs) were calculated for each latent factor. Longitudinal structural equation modeling (SEM) and mediation analyses were performed to identify predictors and interrelations between the WOBs, respectively.

RESULTS

Participants included 510 patients. All variables were significantly improved from T₀ to T₆ and T₁₂ . SEM revealed that related conditions, and to a lesser extent pain, predicted wellness at T₀ , T₆ , and T₁₂ (related conditions: β₀  = 0.55, p < 0.001; β₆  = 0.54, p < 0.001; and β₁₂  = 0.51, p < 0.001; pain: β₀  = 0.42, p < 0.001; β₆  = 0.18, p < 0.001; and β₁₂  = 0.25, p < 0.001). Mediation analyses demonstrated that the effect of WOB-related conditions was greater than WOB-pain on wellness.

CONCLUSION

Wellness of patients with chronic pain can be determined not only by pain itself but even more so by the severity of related conditions. Thus, considering a broad spectrum of pain measures and related conditions seems relevant for improving the wellness of patients with chronic pain.

Supraspinal Mechanisms Underlying Ocular Pain

Supraspinal mechanisms of pain are increasingly understood to underlie neuropathic ocular conditions previously thought to be exclusively peripheral in nature. Isolating individual causes of centralized chronic conditions and differentiating them is critical to understanding the mechanisms underlying neuropathic eye pain and ultimately its treatment. Though few functional imaging studies have focused on the eye as an end-organ for the transduction of noxious stimuli, the brain networks related to pain processing have been extensively studied with functional neuroimaging over the past 20 years. This article will review the supraspinal mechanisms that underlie pain as they relate to the eye.

Gray matter alteration in medication overuse headache: a coordinates-based activation likelihood estimation meta-analysis

Medication overuse headache (MOH) is a prevalent secondary headache, bringing heavy economic burden and neuropsychological damage. Neuroimaging studies on the disease reported divergent results. To merge the reported neuroimaging alterations in MOH patients and explore a pathophysiological mechanism of this disorder. A meta-analytic activation likelihood estimation (ALE) analysis method was used. We systematically searched English and Chinese databases for both morphological and functional neuroimaging studies published before Nov 18, 2021. Reported altered brain regions and the stereotactic coordinates of their peaks were extracted and pooled by GingerALE using Gaussian probability distribution into brain maps, illustrating converged regions of alteration among studies. We identified 927 articles, of which five studies on gray matter changes, using voxel-based morphometry (VBM) were eventually included for ALE analysis, with 344 subjects and 54 coordinates put into GingerALE. No functional magnetic resonance imaging (fMRI) or positron emission topography (PET) studies were included for pooling. Compared with healthy controls (HCs), MOH featured increased gray matter density in midbrain, striatum, cingulate, inferior parietal cortex and cerebellum (P < 0.001 uncorrected), whereas decreased gray matter density in orbitofrontal cortex (P < 0.05, family-wise error), frontal, insular and parietal cortices (P < 0.001 uncorrected). Withdrawal of analgesics led to decreased gray matter density in superior temporal gyrus, cuneus, midbrain and cerebellum (P < 0.001 uncorrected). This meta-analysis confirmed that medication overuse headache is associated with morphologic alteration in the reward system, the prefrontal cortex and a reversible modification in the pain network. Further functional imaging paradigms and longitudinal studies are required for a more definite conclusion and a causal mechanism.

Grieving over the past and struggling forward - a qualitative study of women's experiences of chronic pain one year after childbirth

OBJECTIVE

To describe women's experiences of chronic pain related to childbirth approximately one year after labour.

DESIGN

A qualitative design with face-to-face interviews analysed using inductive qualitative content analysis.

PARTICIPANTS

Twenty women who reported chronic pain, with onset during pregnancy and/or following labour, approximately one year after childbirth.

FINDINGS

The analysis revealed an essential theme, "Grieving over the past and struggling forward", and three categories "Mourning the losses", "Struggling with the present" and "Managing the future".

CONCLUSIONS

This study provides new knowledge about women's experiences of chronic pain one year after childbirth. The pain severely reduced women´s previous ability to perform physical and social activities, negatively impacted psychological well-being and altered their self-image. Most of the women adopted a positive attitude and hoped for improved health in the future, although constantly struggling with the pain and its consequences.

IMPLICATIONS FOR PRACTICE

This knowledge is particularly important as chronic pain may not diminish with time in predisposed individuals who may need help and support from health professionals in their endeavour to manage their pain. Healthcare providers, i.e. midwives, gynaecologists and general practitioners need to understand women´s experiences of chronic pain from their own perspective to improve identification and treatment of pain following childbirth, thus preventing women's suffering and potential long-term health problems. Future studies are warranted to further explore and discuss women's coping strategies, health seeking behaviour and experiences of health care.

Neuropsychopharmacological effects of midazolam on the human brain

As a commonly used anesthetic agent, midazolam has the properties of water-soluble, rapid onset, and short duration of action. With the rapid development in the field of neuroimaging, numerous studies have investigated how midazolam acts on the human brain to induce the alteration of consciousness. However, the neural bases of midazolam-induced sedation or anesthesia remain beginning to be understood in detail. In this review, we summarize findings from neuroimaging studies that have used midazolam to study altered consciousness at different levels and content. We also compare the results to those of neuroimaging studies using diverse anesthetic agents and describe the common neural correlates of anesthetic-induced alteration of consciousness.

Childhood and adult attention deficit hyperactivity disorder symptoms in fibromyalgia: associations with depression, anxiety and disease impact

Objective: The first aim of this study was to determine the prevalence of childhood and current attention deficit hyperactivity disorder (ADHD) symptoms in patients with fibromyalgia. The second aim is to assess the role of depression and anxiety on the relationship between childhood and adult ADHD symptoms with disease impact in this population.Methods: Sixty-four patients with fibromyalgia were compared to matched 58 healthy controls. All participants completed the Wender Utah Rating Scale (WURS), Adult ADHD Self-Report Scale (ASRS), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Fibromyalgia Impact Questionnaire (FIQ).Results: Patients with fibromyalgia had significantly higher mean scores of depression (BDI), anxiety (BAI), childhood ADHD symptoms (WURS) and adult ADHD symptoms (ASRS total, ASRS hyperactivity/impulsivity subscale and ASRS attention deficit subscale) than the control group. Fibromyalgia impact (FIQ) was significantly correlated with depression (BDI; r = 0.57, p < .001), anxiety (BAI; r = 0.56, p < .001) and childhood ADHD symptoms (WURS; r = 0.41, p < .001) in fibromyalgia group. There was no significant correlation between fibromyalgia impact (FIQ) and adult ADHD symptoms (ASRS total or sub-scale scores). Hierarchical multiple regression indicated that childhood ADHD symptoms (WURS), anxiety (BAI) and depression (BDI) predicted fibromyalgia impact. Both anxiety (BAI) and depression (BDI) mediated the relationship between childhood ADHD symptoms (WURS) and fibromyalgia impact (FIQ).Conclusion: Childhood ADHD symptoms may be a contributory factor to poorer functioning in the patients with fibromyalgia. The relationship was more pronounced in the presence of depression and anxiety symptoms. Evaluation of childhood and adult ADHD symptoms in patients with fibromyalgia is important for recognition and treatment of ADHD comorbidity and also for attenuating the severity of the disease.

Pain-Evoked Reorganization in Functional Brain Networks

Recent studies indicate that a significant reorganization of cerebral networks may occur in patients with chronic pain, but how immediate pain experience influences the organization of large-scale functional networks is not yet well characterized. To investigate this question, we used functional magnetic resonance imaging in 106 participants experiencing both noxious and innocuous heat. Painful stimulation caused network-level reorganization of cerebral connectivity that differed substantially from organization during innocuous stimulation and standard resting-state networks. Noxious stimuli increased somatosensory network connectivity with (a) frontoparietal networks involved in context representation, (b) "ventral attention network" regions involved in motivated action selection, and (c) basal ganglia and brainstem regions. This resulted in reduced "small-worldness," modularity (fewer networks), and global network efficiency and in the emergence of an integrated "pain supersystem" (PS) whose activity predicted individual differences in pain sensitivity across 5 participant cohorts. Network hubs were reorganized ("hub disruption") so that more hubs were localized in PS, and there was a shift from "connector" hubs linking disparate networks to "provincial" hubs connecting regions within PS. Our findings suggest that pain reorganizes the network structure of large-scale brain systems. These changes may prioritize responses to painful events and provide nociceptive systems privileged access to central control of cognition and action during pain.

Daily Anxiety and Depressive Symptoms in Couples Coping With Vulvodynia: Associations With Women's Pain, Women's Sexual Function, and Both Partners' Sexual Distress

Vulvodynia is a idiopathic vulvovaginal pain condition that interferes with the sexual and mental health of affected couples. Research has underscored that psychological factors, such as anxiety and depression, are associated with its development and maintenance and related sexual impairment. However, the daily role of anxiety and depressive symptoms in the pain and sexuality outcomes of couples coping with vulvodynia is not well understood. Using a dyadic daily experience method, 127 women (mean age = 26.21, SD = 6.24 years) diagnosed with vulvodynia and their partners (mean age = 27.44, SD = 7.29 years) reported on anxiety and depressive symptoms, pain, sexual function, and sexual distress over a period of 8 weeks. Multilevel modeling was used to examine how daily deviations in anxiety and depressive symptoms from a participant's own mean were associated with pain, sexual function, and sexual distress. On days of sexual activity, when women reported higher anxiety and depressive symptoms (compared with their average), they reported greater pain and lower sexual function. On days of sexual activity, when women reported higher depressive symptoms, they reported greater levels of sexual distress, and when partners reported higher anxiety and depressive symptoms, women as well as partners reported greater levels of sexual distress. Results suggest that daily anxiety and depressive symptoms play a role in women's experience of vulvodynia-related pain, women's sexual function, and the couple's sexual distress. Targeting daily anxiety and depressive symptoms could enhance the efficacy of psychological interventions for vulvodynia.

PERSPECTIVE

This article examines the daily associations between anxiety and depressive symptoms, women's pain, sexual function, and sexual distress among couples coping with vulvodynia. Findings contribute to refine the biopsychosocial model of pain, showing that daily affective factors are associated with pain and sexual well-being.

Dynamic Changes in Nociception and Pain Perception After Spinal Cord Stimulation in Chronic Neuropathic Pain Patients

OBJECTIVES

Patients with an implanted spinal cord stimulation (SCS) system for pain management present an opportunity to study dynamic changes in the pain system in a situation where patients are not stimulated (ie, experiencing severe pain) compared with a situation in which patients have just been stimulated (ie, pain free or greatly reduced pain). The aims of this study were (1) to determine if there are differences in nociceptive withdrawal reflex thresholds (NWR-T) and electrical pain thresholds (EP-T) before and after SCS; and (2) to establish if these differences are related to psychological factors associated with chronic pain.

METHODS

Seventeen volunteers with chronic neuropathic pain participated in the experiment. Electrical stimuli were applied to assess the NWR-T and the EP-T. In addition, psychological factors (ie, pain characteristics, depression, anxiety, and disability indexes) were also recorded. The NWR-T and EP-T were assessed with the SCS system off (at least 8 h before the experiment), and then reassessed 1 hour after the SCS system was turned on.

RESULTS

Ongoing pain intensity ratings decreased (P=0.018), whereas the NWR-T increased (P=0.028) after the SCS was turned on, whereas no significant difference was found for EP-T (P=0.324). Psychological factors were significant predictors for EP-T but not for NWR-T.

DISCUSSION

The results of this study suggest that pain relief after SCS is partially mediated by a decrease in the excitability of dorsal horn neurons in the spinal cord.

Increased cortical activation upon painful stimulation in fibromyalgia syndrome

BACKGROUND

Fibromyalgia syndrome (FMS) is a chronic condition characterized by widespread pain and associated symptoms. We investigated cerebral activation in FMS patients by functional near-infrared spectroscopy (fNIRS).

METHODS

Two stimulation paradigms were applied: a) painful pressure stimulation at the dorsal forearm; b) verbal fluency test (VFT). We prospectively recruited 25 FMS patients, ten patients with unipolar major depression (MD) without pain, and 35 healthy controls. All patients underwent neurological examination and all subjects were investigated with questionnaires (pain, depression, FMS, empathy).

RESULTS

FMS patients had lower pressure pain thresholds than patients with MD and controls (p <  .001) and reported higher pain intensity (p < 0.001). Upon unilateral pressure pain stimulation fNIRS recordings revealed increased bilateral cortical activation in FMS patients compared to controls (p < 0.05). FMS patients also displayed a stronger contralateral activity over the dorsolateral prefrontal cortex in direct comparison to patients with MD (p < 0.05). While all three groups performed equally well in the VFT, a frontal deficit in cortical activation was only found in patients with depression (p < 0.05). Performance and cortical activation correlated negatively in FMS patients (p < 0.05) and positively in patients with MD (p < 0.05).

CONCLUSION

Our data give further evidence for altered central nervous processing in patients with FMS and the distinction between FMS and MD.

TRIAL REGISTRATION

ISRCTN registry ID ISRCTN15015327 (24.09.2015).

Transcranial direct current stimulation on the autonomic modulation and exercise time in individuals with spinal cord injury. A case report

PURPOSE

To report the effect of the transcranial direct current stimulation (tDCS) applied over the primary motor cortex (M1) of an individual, a sedentary male subject with complete chronic spinal cord injury at the T11-T12 levels.

METHODS

The individual underwent three experimental sessions: control, sham and anodal tDCS. Before, during and after exercise sessions, the following variables were recorded: heart rate variability, Rating of Perceived Exertion (RPE), power and glucose (this one only before and after the exercise).

RESULTS

The anodal tDCS provided greater exercise time and power, lower perceived exertion, greater reduction in glucose, and an increase in time to reach the threshold of heart rate variability.

CONCLUSIONS

tDCS caused an improvement in the exercise tolerance, probably due to the modulation of the autonomic nervous system and the pain, characterized by reduced RPE.

Pain Processing after Social Exclusion and Its Relation to Rejection Sensitivity in Borderline Personality Disorder

OBJECTIVE

There is a general agreement that physical pain serves as an alarm signal for the prevention of and reaction to physical harm. It has recently been hypothesized that "social pain," as induced by social rejection or abandonment, may rely on comparable, phylogenetically old brain structures. As plausible as this theory may sound, scientific evidence for this idea is sparse. This study therefore attempts to link both types of pain directly. We studied patients with borderline personality disorder (BPD) because BPD is characterized by opposing alterations in physical and social pain; hyposensitivity to physical pain is associated with hypersensitivity to social pain, as indicated by an enhanced rejection sensitivity.

METHOD

Twenty unmedicated female BPD patients and 20 healthy participants (HC, matched for age and education) played a virtual ball-tossing game (cyberball), with the conditions for exclusion, inclusion, and a control condition with predefined game rules. Each cyberball block was followed by a temperature stimulus (with a subjective pain intensity of 60% in half the cases). The cerebral responses were measured by functional magnetic resonance imaging. The Adult Rejection Sensitivity Questionnaire was used to assess rejection sensitivity.

RESULTS

Higher temperature heat stimuli had to be applied to BPD patients relative to HCs to reach a comparable subjective experience of painfulness in both groups, which suggested a general hyposensitivity to pain in BPD patients. Social exclusion led to a subjectively reported hypersensitivity to physical pain in both groups that was accompanied by an enhanced activation in the anterior insula and the thalamus. In BPD, physical pain processing after exclusion was additionally linked to enhanced posterior insula activation. After inclusion, BPD patients showed reduced amygdala activation during pain in comparison with HC. In BPD patients, higher rejection sensitivity was associated with lower activation differences during pain processing following social exclusion and inclusion in the insula and in the amygdala.

DISCUSSION

Despite the similar behavioral effects in both groups, BPD patients differed from HC in their neural processing of physical pain depending on the preceding social situation. Rejection sensitivity further modulated the impact of social exclusion on neural pain processing in BPD, but not in healthy controls.

Longitudinal associations between depression, anxiety, pain, and pain-related disability in chronic pain patients

OBJECTIVE

The current study sets out to examine the longitudinal relationship between pain, pain-related disability, and symptoms of depression and anxiety. The latter symptoms are highly prevalent in chronic pain and seriously impede functioning and quality of life. Nevertheless, the direction of the relationship involving these variables among individuals with chronic pain is still unclear.

METHODS

Four-hundred twenty-eight individuals with chronic pain (238 women, mean age 54.84 years, mean pain duration 85.21 months) treated at two pain clinics completed questionnaires regarding their pain (Short-Form McGill Pain Questionnaire), depression (Center for Epidemiological Studies-Depression Scale), state anxiety (State-Trait Anxiety Inventory), and pain-related disability (Pain Disability Index) at four time points, with an average of 5 months between measurements. Cross-lagged, structural equation modeling analyses were performed, enabling the examination of longitudinal associations between the variables.

RESULTS

Significant symptoms of both depression and anxiety were reported by more than half of the sample on all waves. A latent depression/anxiety variable longitudinally predicted pain (β = .27, p < .001) and pain-related disability (β = .38, p < .001). However, neither pain (β = .10, p = .126) nor pain-related disability (β = -.01, p = .790) predicted depression/anxiety.

CONCLUSIONS

Among adult patients with chronic pain treated at specialty pain clinics, high levels of depression and anxiety may worsen pain and pain-related disability.

Assessing pain objectively: the use of physiological markers

Pain diagnosis and management would benefit from the development of objective markers of nociception and pain. Current research addressing this issue has focused on five main strategies, each with its own advantages and disadvantages. These encompass: (i) monitoring changes in the autonomic nervous system; (ii) biopotentials; (iii) neuroimaging; (iv) biological (bio-) markers; and (v) composite algorithms. Although each strategy has shown areas of promise, there are currently no validated objective markers of nociception or pain that can be recommended for clinical use. This article introduces the most important developments in the field and highlights shortcomings, with the aim of allowing the reader to make informed decisions about what trends to watch in the future.

The perception of pain and its management in disorders of consciousness

One of the most controversial issues in the management of patients in a vegetative state or a minimally conscious state concerns their hypothetical capacity to continue to experience pain despite an apparent absence of self- and environmental awareness. Recent functional neuroimaging studies have shown a greater perception of pain in patients in minimally conscious state compared with patients in vegetative state, suggesting the possible involvement of preserved cognitive mechanisms in the process of pain modulation in the former. In addition, a subgroup of patients might continue to experience some elementary emotional and affective feelings, as suggested by the reported activation of specific cerebral areas in response to situations, which commonly generate empathy. However, the available evidence is not sufficient to draw conclusions about the presence or absence of pain experience in patients with disorders of consciousness. Future studies should contribute to a better understanding of which central neural pathways are involved in the perception and modulation of pain in healthy subjects and in patients with severe brain injuries. Such studies should thus also improve our know-how about pain management in this particularly challenging group of patients.

Ranking brain areas encoding the perceived level of pain from fMRI data

Pain perception is thought to emerge from the integrated activity of a distributed brain system, but the relative contribution of the different network nodes is still incompletely understood. In the present functional magnetic resonance imaging (fMRI) study, we aimed to identify the more relevant brain regions to explain the time profile of the perceived pain intensity in healthy volunteers, during noxious chemical stimulation (ascorbic acid injection) of the left hand. To this end, we performed multi-way partial least squares regression of fMRI data from twenty-two a-priori defined brain regions of interest (ROI) in each hemisphere, to build a model that could efficiently reproduce the psychophysical pain profiles in the same individuals; moreover, we applied a novel three-way extension of the variable importance in projection (VIP) method to summarize each ROI contribution to the model. Brain regions showing the highest VIP scores included the bilateral mid-cingulate, anterior and posterior insular, and parietal operculum cortices, the contralateral paracentral lobule, bilateral putamen and ipsilateral medial thalamus. Most of these regions, with the exception of medial thalamus, were also identified by a statistical analysis on mean ROI beta values estimated using the time course of the psychophysical rating as a regressor at the voxel level. Our results provide the first rank-ordering of brain regions involved in coding the perceived level of pain. These findings in a model of acute prolonged pain confirm and extend previous data, suggesting that a bilateral array of cortical areas and subcortical structures is involved in pain perception.

Altered spontaneous brain activity in patients with Parkinson's disease accompanied by depressive symptoms, as revealed by regional homogeneity and functional connectivity in the prefrontal-limbic system

As patients with Parkinson’s disease (PD) are at high risk for comorbid depression, it is hypothesized that these two diseases are sharing common pathogenic pathways. Using regional homogeneity (ReHo) and functional connectivity approaches, we characterized human regional brain activity at resting state to examine specific brain networks in patients with PD and those with PD and depression (PDD). This study comprised 41 PD human patients and 25 normal human subjects. The patients completed the Hamilton Depression Rating Scale and were further divided into two groups: patients with depressive symptoms and non-depressed PD patients (nD-PD). Compared with the non-depressed patients, those with depressive symptoms exhibited significantly increased regional activity in the left middle frontal gyrus and right inferior frontal gyrus, and decreased ReHo in the left amygdala and bilateral lingual gyrus. Brain network connectivity analysis revealed decreased functional connectivity within the prefrontal-limbic system and increased functional connectivity in the prefrontal cortex and lingual gyrus in PDD compared with the nD-PD group. In summary, the findings showed regional brain activity alterations and disruption of the mood regulation network in PDD patients. The pathogenesis of PDD may be attributed to abnormal neural activity in multiple brain regions.

Relief of depression and pain improves daily functioning and quality of life in patients with major depressive disorder

OBJECTIVE

The objective of this study was to investigate the effects of depression relief and pain relief on the improvement in daily functioning and quality of life (QOL) for depressed patients receiving a 6-week treatment of fluoxetine.

METHOD

A total of 131 acutely ill inpatients with major depressive disorder (MDD) were enrolled to receive 20mg of fluoxetine daily for 6 weeks. Depression severity, pain severity, daily functioning, and health-related QOL were assessed at baseline and again at week 6. Depression severity, pain severity, and daily functioning were assessed using the 17-item Hamilton Depression Rating Scale, the Short-Form 36 (SF-36) Body Pain Index, and the Work and Social Adjustment Scale. Health-related QOL was assessed by three primary domains of the SF-36, including social functioning, vitality, and general health perceptions. Pearson's correlation and structural equation modeling were used to examine relationships among the study variables. Five models were proposed. In model 1, depression relief alone improved daily functioning and QOL. In model 2, pain relief alone improved daily functioning and QOL. In model 3, depression relief, mediated by pain relief, improved daily functioning and QOL. In model 4, pain relief, mediated by depression relief, improved daily functioning and QOL. In model 5, both depression relief and pain relief improved daily functioning and QOL.

RESULTS

One hundred and six patients completed all the measures at baseline and at week 6. Model 5 was the most fitted structural equation model (χ(2) = 8.62, df = 8, p = 0.376, GFI = 0.975, AGFI = 0.935, TLI = 0.992, CFI = 0.996, RMSEA = 0.027).

CONCLUSION

Interventions which relieve depression and pain improve daily functioning and QOL among patients with MDD. The proposed model can provide quantitative estimates of improvement in treating patients with MDD.

Anxiety but not social stressors predict 12-month depression and pain severity

OBJECTIVES

To determine whether baseline anxiety and social stressors as well their early change (first 3 months) predict 12-month depression and pain severity.

METHODS

We analyzed data from the Stepped Care for Affective Disorders and Musculoskeletal Pain study, a randomized clinical trial of a combined medication-behavioral intervention for primary care patients with chronic musculoskeletal pain and depression. Using multivariable linear regression modeling, we examined the independent association of baseline anxiety and social stressors with depression and pain severity at 12 months. In addition, we modeled whether changes in anxiety and social stressors predicted 12-month depression and pain severity.

RESULTS

Overall, the sample (N=250) was 52.8% women with a mean age of 55.5 years, and a racial distribution of 60.4% white, 36.4% black, and 3.2% other. Depression and pain were moderately severe at baseline (mean SCL-20 depression=1.9 and Brief Pain Inventory pain severity=6.15) and similar across intervention and usual care arms. Baseline anxiety symptoms predicted both depression (t score=2.13, P=0.034) and pain severity (t score=2.75, P=0.007) at 12 months. Also, early change in anxiety predicted 12-month depression (t score=-2.47, P=0.014), but not pain. Neither baseline nor early change in social stressors predicted depression or pain severity.

CONCLUSIONS

Anxiety, but not social stressors predict 12-month depression and pain severity. The presence of comorbid anxiety should be considered in the assessment and treatment of patients with musculoskeletal pain and depression, particularly as a factor that may adversely affect treatment response.

Evidence-based pain management: is the concept of integrative medicine applicable?

This article is dedicated to the concept of predictive, preventive, and personalized (integrative) medicine beneficial and applicable to advance pain management, overviews recent insights, and discusses novel minimally invasive tools, performed under ultrasound guidance, enhanced by model-guided approach in the field of musculoskeletal pain and neuromuscular diseases. The complexity of pain emergence and regression demands intellectual-, image-guided techniques personally specified to the patient. For personalized approach, the combination of the modalities of ultrasound, EMG, MRI, PET, and SPECT gives new opportunities to experimental and clinical studies. Neuromuscular imaging should be crucial for emergence of studies concerning advanced neuroimaging technologies to predict movement disorders, postural imbalance with integrated application of imaging, and functional modalities for rehabilitation and pain management. Scientific results should initiate evidence-based preventive movement programs in sport medicine rehabilitation. Traditional medicine and mathematical analytical approaches and education challenges are discussed in this review. The physiological management of exactly assessed pathological condition, particularly in movement disorders, requires participative medical approach to gain harmonized and sustainable effect.

Pharmacological modulation of brain activity in a preclinical model of osteoarthritis

The earliest stages of osteoarthritis are characterized by peripheral pathology; however, during disease progression chronic pain emerges-a major symptom of osteoarthritis linked to neuroplasticity. Recent clinical imaging studies involving chronic pain patients, including osteoarthritis patients, have demonstrated that functional properties of the brain are altered, and these functional changes are correlated with subjective behavioral pain measures. Currently, preclinical osteoarthritis studies have not assessed if functional properties of supraspinal pain circuitry are altered, and if these functional properties can be modulated by pharmacological therapy either by direct or indirect action on brain systems. In the current study, functional connectivity was first assessed in order to characterize the functional neuroplasticity occurring in the rodent medial meniscus tear (MMT) model of osteoarthritis-a surgical model of osteoarthritis possessing peripheral joint trauma and a hypersensitive pain state. In addition to knee joint trauma at week 3 post-MMT surgery, we observed that supraspinal networks have increased functional connectivity relative to sham animals. Importantly, we observed that early and sustained treatment with a novel, peripherally acting broad-spectrum matrix metalloproteinase (MMP) inhibitor (MMPi) significantly attenuates knee joint trauma (cartilage degradation) as well as supraspinal functional connectivity increases in MMT animals. At week 5 post-MMT surgery, the acute pharmacodynamic effects of celecoxib (selective cyclooxygenase-2 inhibitor) on brain function were evaluated using pharmacological magnetic resonance imaging (phMRI) and functional connectivity analysis. Celecoxib was chosen as a comparator, given its clinical efficacy for alleviating pain in osteoarthritis patients and its peripheral and central pharmacological action. Relative to the vehicle condition, acute celecoxib treatment in MMT animals yielded decreased phMRI infusion responses and decreased functional connectivity, the latter observation being similar to what was detected following chronic MMPi treatment. These findings demonstrate that an assessment of brain function may provide an objective means by which to further evaluate the pathology of an osteoarthritis state as well as measure the pharmacodynamic effects of therapies with peripheral or peripheral and central pharmacological action.

Psychophysical and cerebral responses to heat stimulation in patients with central pain, painless central sensory loss, and in healthy persons

Patients with central pain (CP) typically have chronic pain within an area of reduced pain and temperature sensation, suggesting an impairment of endogenous pain modulation mechanisms. We tested the hypothesis that some brain structures normally activated by cutaneous heat stimulation would be hyperresponsive among patients with CP but not among patients with a central nervous system lesion causing a loss of heat or nociceptive sensation with no pain (NP). We used H(2)(15)O positron emission tomography to measure, in 15 healthy control participants, 10 NP patients, and 10 CP patients, increases in regional cerebral blood flow among volumes of interest (VOI) from the resting (no stimulus) condition during bilateral contact heat stimulation at heat detection, heat pain threshold, and heat pain tolerance levels. Both patient groups had a reduced perception of heat intensity and unpleasantness on the clinically affected side and a bilateral impairment of heat detection. Compared with the HC group, both NP and CP patients had more hyperactive and hypoactive VOI in the resting state and more hyperresponsive and hyporesponsive VOI during heat stimulation. Compared with NP patients, CP patients had more hyperresponsive VOI in the intralaminar thalamus and sensory-motor cortex during heat stimulation. Our results show that focal CNS lesions produce bilateral sensory deficits and widespread changes in the nociceptive excitability of the brain. The increased nociceptive excitability within the intralaminar thalamus and sensory-motor cortex of our sample of CP patients suggests an underlying pathophysiology for the pain in some central pain syndromes.

Tracing Toothache Intensity in the Brain

Identification of brain regions that differentially respond to pain intensity may improve our understanding of trigeminally mediated nociception. This report analyzed cortical responses to painless and painful electrical stimulation of a right human maxillary canine tooth. Functional magnetic resonance images were obtained during the application of five graded stimulus strengths, from below, at, and above the individually determined pain thresholds. Study participants reported each stimulus on a visual rating scale with respect to evoked sensation. Based on hemodynamic responses of all pooled stimuli, a cerebral network was identified that largely corresponds to the known lateral and medial nociceptive system. Further analysis of the five graded stimulus strengths revealed positive linear correlations for the anterior insula bilaterally, the contralateral (left) anterior mid-cingulate, as well as contralateral (left) pregenual cingulate cortices. Cerebral toothache intensity coding on a group level can thus be attributed to specific subregions within the cortical pain network.

Cerebral activation and catastrophizing during pain anticipation in patients with fibromyalgia

OBJECTIVE

Anticipation of pain influences its cerebral processing and dysfunctional cognitive style like catastrophizing correlates with the severity of pain. Patients with fibromyalgia syndrome (FMS) exhibit higher levels of catastrophizing, increased attention to pain, and augmented cerebral pain processing. Therefore, alteration in cerebral processing during anticipation of experimental pain and its relation to catastrophizing are the main focus of the study.

METHODS

Functional magnetic resonance imaging of the brain was acquired during the time of pain anticipation with announcement of its intensity or not in 12 patients with FMS and 14 healthy controls. Within a two-factorial model (factors "group" and "session"), the main effect of group and the interaction effect were tested in a whole-brain analysis. In addition, activation of the periaqueductal gray (PAG) was analyzed in a region-of-interest analysis.

RESULTS

Patients with FMS generally displayed greater catastrophizing behavior (p = .003) but not during the anticipation of the experimental pain (p > .16). Furthermore, patients showed greater activation of the dorsolateral prefrontal cortex (p = .05), the PAG (p = .04), and the posterior parietal cortex (p = .03) during the anticipation of pain, independent of the pain coping behavior during anticipation.

CONCLUSIONS

The lack of difference in catastrophizing during the experimental pain suggests independent coping mechanisms during experimental and clinical pain. Regarding the importance of the frontal cortex and the PAG in the descending pain modulation system, it seems reasonable to assume that these functional changes related to the context of stimulus presentation may contribute to central sensitization in FMS.

Influence of body position on cortical pain-related somatosensory processing: an ERP study

BACKGROUND

Despite the consistent information available on the physiological changes induced by head down bed rest, a condition which simulates space microgravity, our knowledge on the possible perceptual-cortical alterations is still poor. The present study investigated the effects of 2-h head-down bed rest on subjective and cortical responses elicited by electrical, pain-related somatosensory stimulation.

METHODOLOGY/PRINCIPAL FINDINGS

Twenty male subjects were randomly assigned to two groups, head-down bed rest (BR) or sitting control condition. Starting from individual electrical thresholds, Somatosensory Evoked Potentials were elicited by electrical stimuli administered randomly to the left wrist and divided into four conditions: control painless condition, electrical pain threshold, 30% above pain threshold, 30% below pain threshold. Subjective pain ratings collected during the EEG session showed significantly reduced pain perception in BR compared to Control group. Statistical analysis on four electrode clusters and sLORETA source analysis revealed, in sitting controls, a P1 component (40-50 ms) in the right somatosensory cortex, whereas it was bilateral and differently located in BR group. Controls' N1 (80-90 ms) had widespread right hemisphere activation, involving also anterior cingulate, whereas BR group showed primary somatosensory cortex activation. The P2 (190-220 ms) was larger in left-central locations of Controls compared with BR group.

CONCLUSIONS/SIGNIFICANCE

Head-down bed rest was associated to an overall decrease of pain sensitivity and an altered pain network also outside the primary somatosensory cortex. Results have implications not only for astronauts' health and spaceflight risks, but also for the clinical aspects of pain detection in bedridden patients at risk of fatal undetected complications.

Parallel processing of nociceptive and non-nociceptive somatosensory information in the human primary and secondary somatosensory cortices: evidence from dynamic causal modeling of functional magnetic resonance imaging data

Several studies have suggested that, in higher primates, nociceptive somatosensory information is processed in parallel in the primary (S1) and secondary (S2) somatosensory cortices, whereas non-nociceptive somatosensory input is processed serially from S1 to S2. However, evidence suggesting that both nociceptive and non-nociceptive somatosensory inputs are processed in parallel in S1 and S2 also exists. Here, we aimed to clarify whether or not the hierarchical organization of nociceptive and non-nociceptive somatosensory processing in S1 and S2 differs in humans. To address this question, we applied dynamic causal modeling and Bayesian model selection to functional magnetic resonance imaging (fMRI) data collected during the selective stimulation of nociceptive and non-nociceptive somatosensory afferents in humans. This novel approach allowed us to explore how nociceptive and non-nociceptive somatosensory information flows within the somatosensory system. We found that the neural activities elicited by both nociceptive and non-nociceptive somatosensory stimuli are best explained by models in which the fMRI responses in both S1 and S2 depend on direct thalamocortical projections. These observations indicate that, in humans, both nociceptive and non-nociceptive information are processed in parallel in S1 and S2.

A regularization algorithm for decoding perceptual temporal profiles from fMRI data

In several biomedical fields, researchers are faced with regression problems that can be stated as Statistical Learning problems. One example is given by decoding brain states from functional magnetic resonance imaging (fMRI) data. Recently, it has been shown that the general Statistical Learning problem can be restated as a linear inverse problem. Hence, new algorithms were proposed to solve this inverse problem in the context of Reproducing Kernel Hilbert Spaces. In this paper, we detail one iterative learning algorithm belonging to this class, called ν-method, and test its effectiveness in a between-subjects regression framework. Specifically, our goal was to predict the perceived pain intensity based on fMRI signals, during an experimental model of acute prolonged noxious stimulation. We found that, using a linear kernel, the psychophysical time profile was well reconstructed, while pain intensity was in some cases significantly over/underestimated. No substantial differences in terms of accuracy were found between the proposed approach and one of the state-of-the-art learning methods, the Support Vector Machines. Nonetheless, adopting the ν-method yielded a significant reduction in computational time, an advantage that became more evident when a relevant feature selection procedure was implemented. The ν-method can be easily extended and included in typical approaches for binary or multiple classification problems, and therefore it seems well-suited to build effective brain activity estimators.

The pain matrix reloaded: a salience detection system for the body

Neuroimaging and neurophysiological studies have shown that nociceptive stimuli elicit responses in an extensive cortical network including somatosensory, insular and cingulate areas, as well as frontal and parietal areas. This network, often referred to as the "pain matrix", is viewed as representing the activity by which the intensity and unpleasantness of the perception elicited by a nociceptive stimulus are represented. However, recent experiments have reported (i) that pain intensity can be dissociated from the magnitude of responses in the "pain matrix", (ii) that the responses in the "pain matrix" are strongly influenced by the context within which the nociceptive stimuli appear, and (iii) that non-nociceptive stimuli can elicit cortical responses with a spatial configuration similar to that of the "pain matrix". For these reasons, we propose an alternative view of the functional significance of this cortical network, in which it reflects a system involved in detecting, orienting attention towards, and reacting to the occurrence of salient sensory events. This cortical network might represent a basic mechanism through which significant events for the body's integrity are detected, regardless of the sensory channel through which these events are conveyed. This function would involve the construction of a multimodal cortical representation of the body and nearby space. Under the assumption that this network acts as a defensive system signaling potentially damaging threats for the body, emphasis is no longer on the quality of the sensation elicited by noxious stimuli but on the action prompted by the occurrence of potential threats.

Neural bases of conditioned placebo analgesia

Despite growing interest in the placebo effect, the neural correlates of conditioned analgesia are still incompletely understood. We investigated herein on brain activity during the conditioning and post-conditioning phases of a placebo experimental paradigm, using event-related fMRI in 31 healthy volunteers. Brief laser heat stimuli delivered to one foot (either right or left) were preceded by different visual cues, signalling either painful stimuli alone, or painful stimuli accompanied by a (sham) analgesic procedure. Cues signalling the analgesic procedure were followed by stimuli of lower intensity in the conditioning session, whereas in the test session both cues were followed by painful stimuli of the same intensity. During the first conditioning trials, progressive signal increases over time were found during anticipation of analgesia compared to anticipation of pain, in a medial prefrontal focus centered on medial area BA8, and in bilateral lateral prefrontal foci. These frontal foci were adjacent to, and partially overlapped, those active during anticipation of analgesia in the test session, whose signal changes were related to the magnitude of the placebo behavioral response, and those active during placebo analgesia. Specifically, a large focus in the right prefrontal cortex showed activity related to analgesia, irrespective of the expected side of stimulation. Analgesia was also related to decreased activity, detectable immediately following noxious stimulation, in parietal, insular and cingulate pain-related clusters. Our findings of dynamic changes in prefrontal areas during placebo conditioning, and of direct placebo effects on cortical nociceptive processing, add new insights into the neural bases of conditioned placebo analgesia.

From the neuromatrix to the pain matrix (and back)

Pain is a conscious experience, crucial for survival. To investigate the neural basis of pain perception in humans, a large number of investigators apply noxious stimuli to the body of volunteers while sampling brain activity using different functional neuroimaging techniques. These responses have been shown to originate from an extensive network of brain regions, which has been christened the Pain Matrix and is often considered to represent a unique cerebral signature for pain perception. As a consequence, the Pain Matrix is often used to understand the neural mechanisms of pain in health and disease. Because the interpretation of a great number of experimental studies relies on the assumption that the brain responses elicited by nociceptive stimuli reflect the activity of a cortical network that is at least partially specific for pain, it appears crucial to ascertain whether this notion is supported by unequivocal experimental evidence. Here, we will review the original concept of the "Neuromatrix" as it was initially proposed by Melzack and its subsequent transformation into a pain-specific matrix. Through a critical discussion of the evidence in favor and against this concept of pain specificity, we show that the fraction of the neuronal activity measured using currently available macroscopic functional neuroimaging techniques (e.g., EEG, MEG, fMRI, PET) in response to transient nociceptive stimulation is likely to be largely unspecific for nociception.

Individual differences in prefrontal cortex function and the transition from drug use to drug dependence

Several neuropsychological hypotheses have been formulated to explain the transition to addiction, including hedonic allostasis, incentive salience, and the development of habits. A key feature of addiction that remains to be explored is the important individual variability observed in the propensity to self-administer drugs, the sensitivity to drug-associated cues, the severity of the withdrawal state, and the ability to quit. In this review, we suggest that the concept of self-regulation, combined with the concept of modularity of cognitive function, may aid in the understanding of the neural basis of individual differences in the vulnerability to drugs and the transition to addiction. The thesis of this review is that drug addiction involves a failure of the different subcomponents of the executive systems controlling key cognitive modules that process reward, pain, stress, emotion, habits, and decision-making. A subhypothesis is that the different patterns of drug addiction and individual differences in the transition to addiction may emerge from differential vulnerability in one or more of the subcomponents.

Central nervous system findings on functional magnetic resonance imaging in patients before and after treatment with anticholinergic medication

PURPOSE

Anticholinergic medications are commonly used to treat urinary urgency and frequency. Muscarinic receptors are located in areas beyond the detrusor muscle. In this study we measured changes in central nervous system activity in patients with lower urinary tract symptoms treated with tolterodine or a placebo.

MATERIALS AND METHODS

A total of 20 female patients with urinary frequency were randomized to 4 weeks of treatment with tolterodine or a placebo. Functional magnetic resonance imaging based on blood oxygenation level dependant imaging of the brain during bladder filling was performed before and after treatment. For each patient the bladder was filled by a urethral catheter and emptied 5 times.

RESULTS

Multiple brain areas showed significant activation with bladder filling compared to the empty state and many areas also showed deactivation. Overall brain activation with bladder filling was decreased after treatment in both groups. After treatment 2 areas of the parietal cortex (precuneus and postcentral gyrus) showed significantly greater activity in patients treated with tolterodine vs placebo. Two areas of the cerebellum (anterior lobe and culmen) showed significantly greater activity in the placebo group, and these were also areas of significant deactivation in the tolterodine group.

CONCLUSIONS

Brain activity changes as well as the areas of activation after treatment of lower urinary tract symptoms in patients with an anticholinergic medication or placebo are different in the 2 groups. Whether this finding represents action at the central nervous system or the bladder level is not known.

Brain networks responsive to aversive visual stimuli in humans

The neural mechanisms subserving recognition of noxious stimuli and empathy for pain appear to involve at least in part the cortical regions associated with the processing of pain affect. An important issue concerns the specificity of brain networks associated with observing and representing painful conditions, in comparison with other unpleasant stimuli. Recently, we found both similarities and differences between the brain patterns of activity related to the observation of noxious or disgusting stimuli delivered to one hand or foot. Overlap regions included the perigenual anterior cingulate (pACC), whose activity was related to the perceived unpleasantness. We aimed here at revealing how pACC functional connectivity changes in relationship to the different experimental conditions, using a psychophysiological interaction model. Activity in pACC during the observation of painful stimuli was specifically and positively related to regions in the right hemisphere, including portions of the prefrontal, midcingulate and insular cortex. On the other hand, positive changes in pACC connectivity during the vision of disgusting stimuli were present in the right basal ganglia. These data suggest that pACC activity is part of different networks involved in the recognition of painful or disgusting stimuli.

Decreased gray matter volumes in the cingulo-frontal cortex and the amygdala in patients with fibromyalgia

OBJECTIVE

Studies in fibromyalgia syndrome with functional neuroimaging support the hypothesis of central pain augmentation. To determine whether structural changes in areas of the pain system are additional preconditions for the central sensitization in fibromyalgia we performed voxel based morphometry in patients with fibromyalgia and healthy controls.

METHODS

We performed 3 Tesla magnetic resonance imaging of the brain in 14 patients with fibromyalgia and 14 healthy controls. Regional differences of the segmented and normalized gray matter volumes in brain areas of the pain system between both groups were determined. In those areas in which patients structurally differed from healthy controls, the correlation of disease-related factors with gray matter volumes was analyzed.

RESULTS

Patients presented a decrease in gray matter volume in the prefrontal cortex, the amygdala, and the anterior cingulate cortex (ACC). The duration of pain or functional pain disability did not correlate with gray matter volumes. A trend of inverse correlation of gray matter volume reduction in the ACC with the duration of pain medication intake has been detected.

CONCLUSIONS

Our results suggest that structural changes in the pain system are associated with fibromyalgia. As disease factors do not correlate with reduced gray matter volume in areas of the cingulo-frontal cortex and the amygdala in patients, one possible interpretation is that volume reductions might be a precondition for central sensitization in fibromyalgia.

Initial evidence of a failure to activate right anterior insula during affective set shifting in posttraumatic stress disorder

OBJECTIVE

Interoception is the sense of one's internal physiological, sensory, and emotional status. Extensive evidence supports a link between interoception and subjective experience. An altered ability to monitor or modulate interoception as it relates to subjective experience may provide a mechanistic explanation for the development of some forms of psychiatric illness.

METHODS

We investigated which neural networks are activated when anticipating a change in affective (and thus interoceptive) state, which we term "affective set-shifting," in 15 women with posttraumatic stress disorder (PTSD) related to intimate partner violence, and in 15 nontraumatized healthy volunteers.

RESULTS

Although both groups activated the dorsolateral prefrontal cortex during affective set shifting, the PTSD group showed significantly less activation in the right anterior insula than did the controls.

CONCLUSIONS

These findings may suggest that although individuals with PTSD are cognitively aware of the impending shift in interoceptive state, they fail to appropriately activate neural circuitry involved in modulating interoceptive responses.

Nociceptive laser-evoked brain potentials do not reflect nociceptive-specific neural activity

Brief radiant laser pulses can be used to activate cutaneous Adelta and C nociceptors selectively and elicit a number of transient brain responses [laser-evoked potentials (LEPs)] in the ongoing EEG. LEPs have been used extensively in the past 30 years to gain knowledge about the cortical mechanisms underlying nociception and pain in humans, by assuming that they reflect at least neural activities uniquely or preferentially involved in processing nociceptive input. Here, by applying a novel blind source separation algorithm (probabilistic independent component analysis) to 124-channel event-related potentials elicited by a random sequence of nociceptive and non-nociceptive somatosensory, auditory, and visual stimuli, we provide compelling evidence that this assumption is incorrect: LEPs do not reflect nociceptive-specific neural activity. Indeed, our results indicate that LEPs can be entirely explained by a combination of multimodal neural activities (i.e., activities also elicited by stimuli of other sensory modalities) and somatosensory-specific, but not nociceptive-specific, neural activities (i.e., activities elicited by both nociceptive and non-nociceptive somatosensory stimuli). Regardless of the sensory modality of the eliciting stimulus, the magnitude of multimodal activities correlated with the subjective rating of saliency, suggesting that these multimodal activities are involved in stimulus-triggered mechanisms of arousal or attentional reorientation.

A randomized, double-blind, placebo-controlled study of preemptively administered intravenous parecoxib: effect on anxiety levels and procedural pain during epidural catheter placement for surgical operations or for chronic pain therapy

BACKGROUND

The effect of parecoxib, when used perioperatively or during interventional techniques, is well demonstrated in the literature. Little is known about its effects on anxiety levels before the analgesic technique application. The aim of this prospective, randomized, double-blind, placebo-controlled, clinical study is to investigate whether parecoxib, preemptively administrated, has an effect on anxiety levels reported prior to an epidural puncture, and if it influences the reported pain of the interventional technique itself.

MATERIAL AND METHODS

The study protocol involved 110 patients, scheduled for epidural catheter placement for chronic pain therapy--Group I, as well as 112 patients scheduled for orthopedic operations under epidural anesthesia--Group II. Patients in each group were randomly allocated into two subgroups in relation to parecoxib/placebo administration before epidural catheter placement: Group Ia, parecoxib 40 mg i.v. (n = 54), Group Ib, placebo (n = 56), Group IIa, parecoxib 40 mg i.v. (n = 57), Group IIb, placebo (n = 55). Patients were given a self-administered inventory to measure the anxiety level of the presurgical/preprocedural state (State-Trait Spielberger Anxiety Inventory) and anxiety levels were recorded 1 hour before epidural puncture, 20 minutes postdosing, and 1 hour after epidural catheter placement. Anxiety levels were also measured and recorded using visual analog scale (VAS). One hour after epidural puncture, reported procedural pain was recorded (VAS). One hour and 6 hours postepidural, patients' satisfaction was also recorded, on a 4-point scale.

RESULTS

All four subgroups were similar regarding demographic, operative/procedural data, and coexisting diseases. Preprocedural anxiety levels were significantly decreased with parecoxib administration in comparison with placebo in both groups (P < 0.05). Reported VAS regarding pain from epidural puncture was lower in Groups IA and Ib. Patients' satisfaction was greater with parecoxib in comparison with placebo.

CONCLUSION

The levels of anxiety have been investigated in several medical procedures and early, in the study of pain. The higher the expectation of pain and the anxiety are, the higher the intensity of the pain. Parecoxib seems to exert positive influence on pain and anxiety levels of interventional procedure. Further studies are needed to elucidate the actual mechanisms that are involved.

The Relationship Between Pain Perception and Interoception

The question of whether the perception of externally applied pain stimuli and the perception of interoceptive stimuli are based upon similar neuronal or behavioral processes is still open to debate. If such a similarity exists, one would expect that persons who are highly sensitive to visceral stimuli would also exhibit a higher sensitivity to pain stimuli. The present study investigated the sensitivity to heat pain of individuals with high vs. low cardiac interoceptive sensitivity. Pain threshold and pain tolerance were assessed using a testing-the-limits procedure. Furthermore, participants rated the subjective intensity and unpleasantness of tonic heat stimuli on visual analog scales and in a questionnaire. The results show that pain experience did not differ between participants with high and low interoceptive sensitivity, nor did correlation analyses reveal significant relationships between pain experience and cardiac interoceptive sensitivity. These findings suggest that the pathway of peripheral pain processing is at least partially independent of the pathway of interoceptive sensations.

Functional activation and neural networks in women with posttraumatic stress disorder related to intimate partner violence

BACKGROUND

Intimate partner violence (IPV) is one of the most common causes of posttraumatic stress disorder (PTSD) in women. Victims of IPV are often preoccupied by the anticipation of impending harm. This investigation tested the hypothesis that IPV-related PTSD individuals show exaggerated insula reactivity to the anticipation of aversive stimuli.

METHODS

Fifteen women with a history of IPV and consequent PTSD (IPV-PTSD) and 15 non-traumatized control (NTC) women performed a task involving cued anticipation to images of positive and negative events during functional magnetic resonance imaging.

RESULTS

Both groups showed increased activation of bilateral anterior insula during anticipation of negative images minus anticipation of positive images. Activation in right anterior/middle insula was significantly greater in the IPV-PTSD relative to the NTC group. Functional connectivity analysis revealed that changes in activation in right middle insula and bilateral anterior insula were more strongly associated with amygdala activation changes in NTC than in IPV-PTSD subjects.

CONCLUSIONS

This study revealed increased activation in the anterior/middle insula during negative anticipation in women with IPV-related PTSD. These findings in women with IPV could be a consequence of the IPV exposure, reflect pre-existing differences in insular function, or be due to the development of PTSD. Thus, future longitudinal studies need to examine these possibilities.

Association of depression and anxiety alone and in combination with chronic musculoskeletal pain in primary care patients

OBJECTIVE

To assess the relationship between depression and anxiety comorbidity on pain intensity, pain-related disability, and health-related quality of life (HRQL).

METHODS

Analysis of baseline data from the Stepped Care for Affective Disorders and Musculoskeletal Pain (SCAMP) study. All patients (n = 500) had chronic pain (>or=3-month duration) of the low back, hip, or knee. Patients with depression were oversampled for the clinical trial component of SCAMP and thus represented 50% of the study population. Patients were categorized according to pain comorbid with depression, anxiety, or both. We used analysis of variance and multivariate analysis of variance models to assess the relationships between independent and dependent variables.

RESULTS

Participants had a mean age of 59 years; they were 55% women, 56% White, and 40% Black. Fifty-four percent (n = 271) reported pain only, 20% (n = 98) had pain and depression, 3% (n = 15) had pain and anxiety, and 23% (n = 116) had pain, depression, and anxiety. Patients with pain and both depression and anxiety experienced the greatest pain severity (p < .0001) and pain-related disability (p < .0001). Psychiatric comorbidity was strongly associated with disability days in the past 3 months (p < .0001), with 18.1 days reported by patients with pain only, 32.2 days by those with pain and anxiety, 38.0 days by those with pain and depression, and 42.6 days in those with all three conditions. We found a similar pattern of poorer HRQL (p < .0001) in those with pain, depression, and anxiety.

CONCLUSIONS

The added morbidity of depression and anxiety with chronic pain is strongly associated with more severe pain, greater disability, and poorer HRQL.