Pedro Montoya

Background: Sequential application of repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS) may induce neurophysiological changes within sensorimotor and pain-related networks. However, the resting-state EEG effects of this combined approach in fibromyalgia remain unknown. Methods: In this exploratory randomized controlled pilot study, 10 adults with fibromyalgia were assigned to active stimulation (n = 5) or a no-stimulation control group (n = 5). Active participants received one or two sessions of 10-Hz rTMS over the left primary motor cortex (1,000 pulses/session), followed by 10 daily sessions of bilateral 10-Hz tACS (1 mA, 20 min). Six-minute eyes-closed resting-state EEG recordings were obtained before and after the intervention or an equivalent control interval. Power spectral density was quantified in the delta, theta, alpha, and beta bands and analyzed using mixed repeated-measures ANOVAs across central-centroparietal and posterior regions of interest. Results: Theta power increased significantly in the active group but not in controls, yielding significant Time × Group (F(1,8)=8.70, p=.018, ηp²=.521) and Time × ROI × Group (F(1,8)=5.53, p=.047, ηp²=.409) interactions. Follow-up analyses showed increased theta power in both central-centroparietal (p=.004) and posterior (p=.012) regions, with a larger increase observed posteriorly. No significant interaction effects were found for delta, alpha, or beta power. Conclusions: Sequential motor-cortex rTMS followed by repeated bilateral 10-Hz tACS was associated with increased resting-state theta activity in fibromyalgia. Given the small sample size, post hoc ROI selection, lack of sham stimulation, and absence of component-specific control conditions, these findings should be considered hypothesis-generating and require replication in adequately powered sham-controlled studies.

Body perception refers to the capacity to perceive internal and external bodily stimuli via brain somatosensory processing. Research on body perception has focused on specific dimensions rather than in a multidimensional way. Body perception levels were assessed in 120 adults through two self-reported questionnaires. Some domains of self-reported body perception (body awareness, public consciousness, body competence) were notably affected by age and sex. Subsequently, sensitivity to exteroceptive and interoceptive stimuli was assessed in the 55 participants with higher and lower body perception. Self-reported body perception was associated with pain sensitivity, but not to interoception. Individuals with high body perception exhibited higher pain sensitivity. Body awareness, a subdimension of the Scale of Body Connection, was a key domain distinguishing individual with high versus low body perception. An additional analysis of tactile somatosensory event-related potentials (SEPs) was conducted in the 42 participants with higher and lower body awareness. Individuals with heightened body awareness displayed increased amplitudes in SEPs associated with attention processes. In conclusion, body awareness appears to be an essential element for exploring body perception and its connections with physiological mechanisms. Evaluating body awareness in clinical environments would be relevant for recognizing dysfunctional body perception and creating modulatory interventions.

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Introduction: Several studies have demonstrated a reduced habituation to redundant somatosensory stimulation (sensory gating) in Fibromyalgia Syndrome. Furthermore, anodal transcranial direct current stimulation has been shown to modulate somatosensory processing. The aim of this study was to examine the modulatory effects of anodal transcranial direct current stimulation applied over the left primary somatosensory cortex on sensory gating in Fibromyalgia Syndrome.Methods: Thirty-nine female Fibromyalgia Syndrome patients (43–71 years, mean 55.56 ± 7.85) participated in the study and were randomly assigned to the active transcranial direct current stimulation (n = 17) or non-electrical stimulation (sham; n = 22). Before and after transcranial direct current stimulation, somatosensory evoked potentials were recorded during a paired-pulse paradigm, consisting of two identical somatosensory stimuli (S1 and S2) applied in the right forefinger in rapid succession.Results: Whereas P50 and N100 components were unaltered, a significant modulatory effect on the difference S1 – S2-which is commonly considered an index of sensory gating-in the Late Positive Complex component was found. This modulation manifested as an increased difference in the right hemisphere (contralateral to the stimulation) and a decreased difference in the left hemisphere (ipsilateral).Discussion: Although this lateralizing pattern remains to be clarified, present results suggest brain excitability and somatosensory processing modulation by using anodal transcranial direct current stimulation in Fibromyalgia Syndrome patients.

Background: Fibromyalgia syndrome (FMS) is linked to central sensitization and neuroplastic alterations that contribute to chronic pain, fatigue, cognitive, sleep, and affective disturbances. Conventional treatments offer limited benefit. Non-invasive transcranial electrical stimulation (tES), particularly transcranial direct current stimulation (tDCS), may modulate brain function and relieve symptoms, but findings remain inconsistent.Objective: To systematically review and meta-analyze the effects of tES on clinical, neurophysiological, neuropsychological, and neurochemical outcomes in FMS.Methods: Seven databases were searched for studies published between April 2013 and April 2023. Eligible designs included randomized controlled trials, cross-over, one-arm, and case studies involving adult FMS patients. Data extraction followed Cochrane Collaboration guidelines and used RevMan 6.6.0.Results: Anodal tDCS produced short- to mid-term reductions in pain and mood symptoms, especially when applied over M1 or DLPFC. Longer interventions and repeated sessions enhanced effects, though protocol heterogeneity limited comparability. Both subjective (VAS, NRS) and objective (QST) measures confirmed pain reduction. Cognitive improvements were inconsistent, and quality of life effects were limited. Neurophysiological and neurochemical changes suggested possible mechanisms, though findings varied. Study quality was mixed, with small sample sizes and methodological inconsistencies. Meta-analysis revealed statistically significant but small effects on pain (Hedges' g < 0.2), with limited evidence on clinical relevance.Conclusions: Anodal tDCS may offer short-term relief of pain and mood symptoms in FMS, potentially through modulation of cortical excitability and neuroplasticity. However, due to variability in findings and methodological limitations, its clinical relevance remains unclear. Future trials should use standardized protocols, assess long-term effects, and include clinically meaningful outcome measures.Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42023412332, PROSPERO CRD42023412332.

Purpose: Aging is accompanied by various changes in pain perception and modulation. However, the influence of older age – and associated neurocognitive changes – on placebo hypoalgesia has not been systematically investigated. Findings to date are inconclusive, ranging from a reduced, to a preserved or even an amplified response in older adults. The aim of this study was to examine age-related changes in the placebo hypoalgesic response magnitude, and the potential modulating effect of executive functions, namely working memory, cognitive flexibility and inhibitory control. Methods: Thirty-nine younger (18– 36 years) and 42 healthy older adults (60– 82 years) completed a series of executive functioning tests. Placebo hypoalgesic responding was assessed via a sham transcutaneous electrical nerve stimulation (TENS) intervention while participants received moderately painful electrical stimuli to their arm. An electroencephalogram (EEG) was recorded during the placebo paradigm and pain ratings were collected. Results: Overall, both age groups showed similar robust placebo hypoalgesic effects: pain ratings and pain-related brain potentials were significantly reduced in response to the sham treatment. Interestingly, worse executive functions in older adults (in particular, working memory and cognitive flexibility) were associated with reduced placebo responses. Moreover, executive functions also moderated the overall age group difference in placebo hypoalgesia: when cognitive flexibility and inhibitory control scores were low, older adults showed a smaller placebo response than younger adults. Conclusion: We demonstrated an age-related reduction in placebo hypoalgesia in older adults showing a decline in executive functioning. This is an important finding, considering the fact that placebo effects contribute to positive treatment outcomes. Our results advocate the assessment of executive functions when investigating the influence of aging on placebo effects, as variable aging trajectories of decline may influence overall group comparisons. Plain Language Summary: As people age, their pain experience and pain coping skills change. This study explores how aging, and related changes in brain function, affect the ability to experience pain relief from a placebo treatment (placebo hypoalgesia). Previous research has been unclear, showing reduced, unchanged, or even increased placebo responses in older adults. We investigated if aging affects the strength of the placebo effect and whether executive functions (like working memory, flexible thinking, ignoring distractions and controlling impulsive reactions) play a role. We studied 39 younger adults (18-36 years) and 42 older adults (60-82 years). They took tests measuring their executive functions and then received a fake electrical nerve stimulation treatment while experiencing moderately painful electrical stimuli on their arm. We recorded their brain activity and pain ratings. Both younger and older adults reported less pain and showed reduced brain responses to pain after the fake treatment, indicating a clear placebo effect in both groups. Older adults with better executive functions, particularly in working memory and cognitive flexibility, had stronger placebo responses. Moreover, when older adults had good cognitive flexibility and inhibitory control, their placebo responses were as large as those of younger adults. In conclusion, when executive functions are intact, normal placebo pain relief can be experienced in older age. This finding is relevant because placebo effects contribute considerably to treatment outcomes. Our results suggest that assessing a potential decline in executive functions is important when studying the impact of aging on pain (coping).

Background/Objectives: Chronic low back pain (CLBP) is highly prevalent and relevant in all medical fields. This study evaluated the safety and effectiveness of interdisciplinary fascia therapy (IFT) for CLBP, focusing on its potential to reduce pain intensity, disability, and regulate autonomic nervous system (ANS) activity. Methods: Nine participants with CLBP each underwent nine sessions of IFT, twice weekly. The intervention involved a 12-grip manual sequence targeting deep paravertebral myofascial structures, complemented by heart rate variability (HRV) biofeedback training twice daily for 15 min. Pain and quality-of-life measures were assessed using the Brief Pain Inventory (BPI) questionnaire at baseline, mid-treatment (4th session), and post-treatment (9th session). HRV metrics were monitored with a 24 h ECG Holter device before and after the treatment period. Statistical analyses included paired t-tests, Wilcoxon signed-rank tests, and Cohen’s d for effect size. Results: Significant reductions in pain levels were observed across all subjective BPI measures, including momentary, strongest, minimal, and average pain scores (p < 0.001), with 83% and 87% reductions in pain intensity and disability, respectively. Quality-of-life indicators such as mood, sleep, and enjoyment of life showed significant improvements (p < 0.001). While only one HRV metric (rMSSD) achieved statistical significance, other HRV measures indicated medium to large effect sizes, suggesting favorable trends in ANS regulation. Conclusions: IFT demonstrated significant effects on subjective BPI pain reduction and quality of life, alongside potential regulatory impacts on ANS activity in individuals with CLBP. These results support the use of IFT as an effective intervention for pain management in CLBP and ANS regulation, meriting further exploration.

BACKGROUND: Chronic pain is one of the most common symptoms of temporomandibular disorders (TMD). Although its pathophysiology is still a challenge, TMD has been associated with changes in central nervous system activity related to pain modulatory capacity. OBJECTIVE: To assess the cortical activity of patients with temporomandibular disorders and chronic pain of myofascial origin using quantitative electroencephalography (qEEG) in different mental states. METHOD: This study consists of a cross-sectional study. Individuals with TMD and chronic pain and healthy controls were evaluated using qEEG in four consecutive conditions, all with closed eyes: 1) initial resting condition; 2) non-painful motor imagery task of hand movement; 3) painful motor imagery task of clenching the teeth; 4) final resting condition. RESULTS: Participants with TMD and chronic pain overall presented decreased alpha power density during baseline at rest, non-painful and painful motor imagery tasks when compared to healthy controls. Furthermore, functional brain connectivity was distinct between groups, with TMD and chronic pain showing lower small-world values for the delta (all conditions), theta (painful and non-painful motor imagery task), and alpha bands (painful motor imagery task), and an increase in the beta band (all conditions). CONCLUSION: These results suggest that TMD and chronic pain could be associated with maladaptive plasticity in the brain, which may correspond to a reduced ability to modify brain activity during different mental tasks, including painful and non-painful motor imagery.

INTRODUCTION: Despite being considered least important for clinical practice in the pyramid of evidence for recommendations, sometimes scientists' expert opinions could help to better understand the summarization of updated publications. OBJECTIVE: To provide a major summarized update about brain imaging and stimulation of the nervous system in health and disease. METHODS: Comprehensive review developed by experts in each subarea of knowledge in neuroimaging and non-invasive stimulation of the nervous system. A team of researchers and clinic experts was invited to present an update on their area of expertise. RESULTS: In basics on brain imaging techniques, we approach general and quantitative electroencephalography, functional magnetic resonance imaging, functional near-infrared spectroscopy, and experimental paradigms in brain imaging studies. Were included associations between transcranial magnetic stimulation and electromyography, electroencephalography, and functional near-infrared stimulation to evaluate brain activity. Furthermore, we showed several actualized central and peripheral neuromodulation techniques. And finally, we presented different clinical and performance uses of non-invasive neuromodulation. CONCLUSION: To our knowledge, this is a major summarized and concentrated update about brain imaging and stimulation that can benefit neuroscience researchers and clinicians from different levels of experience.

Proprioception has long been linked with emotional dysregulation in neurotypical adults. Neuropediatric disorders such as autism spectrum disorder (ASD) and cerebral palsy (CP) are distinct entities and yet both present with deficits and challenges in sensory processing and the regulation of emotions. This study aimed to explore the relationship between proprioception and emotional–social performance in children and to compare proprioception and emotional–social performance in different underlying neurodevelopmental conditions. For this purpose, this cross-sectional study included 42 children with ASD, 34 children with CP and 50 typically developing peers. Proprioceptive acuity, proprioceptive reactive behavior as well as emotion regulation and social responsiveness were assessed. The results show a significant correlation between proprioceptive deficits and emotional difficulties in this pediatric sample, with distinct proprioceptive impairment patterns according to the underlying neurological disorder. Children with CP showed significant emotional knowledge deficits, while children with ASD predominantly showed challenges in social responsiveness. These data thus suggest a differentiated impact of proprioception on emotional–social performance in neurodevelopmental disorders and highlight proprioception as a potential therapeutic target for balancing emotion regulation in children with neurodevelopmental conditions.