Coxsackievirus infection induces direct pancreatic β cell killing but poor antiviral CD8+ T cell responses

Coxsackievirus B (CVB) infection of pancreatic β cells is associated with β cell autoimmunity and type 1 diabetes. We investigated how CVB affects human β cells and anti-CVB T cell responses. β cells were efficiently infected by CVB in vitro, down-regulated human leukocyte antigen (HLA) class I, and presented few, selected HLA-bound viral peptides. Circulating CD8+ T cells from CVB-seropositive individuals recognized a fraction of these peptides; only another subfraction was targeted by effector/memory T cells that expressed exhaustion marker PD-1. T cells recognizing a CVB epitope cross-reacted with β cell antigen GAD. Infected β cells, which formed filopodia to propagate infection, were more efficiently killed by CVB than by CVB-reactive T cells. Our in vitro and ex vivo data highlight limited CD8+ T cell responses to CVB, supporting the rationale for CVB vaccination trials for type 1 diabetes prevention. CD8+ T cells recognizing structural and nonstructural CVB epitopes provide biomarkers to differentially follow response to infection and vaccination.

Coxsackievirus infection induces direct pancreatic β-cell killing but poor anti-viral CD8+ T-cell responses

Coxsackievirus B (CVB) infection of pancreatic β cells is associated with β-cell autoimmunity. We investigated how CVB impacts human β cells and anti-CVB T-cell responses. β cells were efficiently infected by CVB in vitro, downregulated HLA Class I and presented few, selected HLA-bound viral peptides. Circulating CD8+ T cells from CVB-seropositive individuals recognized only a fraction of these peptides, and only another sub-fraction was targeted by effector/memory T cells that expressed the exhaustion marker PD-1. T cells recognizing a CVB epitope cross-reacted with the β-cell antigen GAD. Infected β cells, which formed filopodia to propagate infection, were more efficiently killed by CVB than by CVB-reactive T cells. Thus, our in-vitro and ex-vivo data highlight limited T-cell responses to CVB, supporting the rationale for CVB vaccination trials for type 1 diabetes prevention. CD8+ T cells recognizing structural and non-structural CVB epitopes provide biomarkers to differentially follow response to infection and vaccination.

Coxsackievirus and type 1 diabetes: diabetogenic mechanisms and implications for prevention

The evidence for an association between Coxsackievirus B (CVB) infection, pancreatic islet autoimmunity and clinical type 1 diabetes is increasing. Results from prospective cohorts and pancreas histopathology studies have provided a compelling case. However, the demonstration of a causal relationship is missing, and is likely to remain elusive until tested in humans by avoiding exposure to this candidate viral trigger. To this end, CVB vaccines have been developed and are entering clinical trials. However, the progress made in understanding the biology of the virus and in providing tools to address the long-standing question of causality contrasts with the scarcity of information about the anti-viral immune responses triggered by infection. Beta-cell death may be primarily induced by CVB itself, possibly in the context of poor immune protection, or secondarily provoked by T-cell responses against CVB-infected beta cells. The possible involvment of epitope mimicry mechanisms skewing the physiological anti-viral response toward autoimmunity has also been suggested. We here review the available evidence for each of these three non-mutually exclusive scenarios. Understanding which ones are at play is critical to maximize the odds of success of CVB vaccination, and to develop suitable tools to monitor the efficacy of immunization and its intermingling with autoimmune onset or prevention.

Exocrine pancreas function is impaired in adult relatives of patients with type 1 diabetes

AIMS

Alterations of the exocrine pancreas have been reported in type 1 diabetes, but their contribution to the pathogenesis of the disease is poorly understood. Here, we investigated markers of exocrine pancreas dysfunction in individuals at-risk of developing type 1 diabetes.

METHODS

Serum P-amylase and lipase levels were assessed in samples obtained from healthy controls, patients with new onset type 1 diabetes, relatives participating to the TrialNet Pathway to Prevention who were, at blood collection, autoantibody negative or positive for a single autoantibody (low-risk individuals), and positive for multiple autoantibodies (high-risk individuals). Linear mixed models were adopted to estimate variation of pancreatic enzymes among the groups and to evaluate the influence of high-risk HLA genotypes and residual beta cell function on exocrine pancreas function.

RESULTS

In adults, but not children, reduced levels of P-amylase and lipase were shown in at-risk individuals, including (for P-amylase levels only) those at low-risk, and in T1Dnew. Furthermore, while high-risk HLA genotypes negatively affected P-amylase levels in autoantibody negative adult individuals, fasting C-peptide levels did not correlate with pancreatic enzyme levels.

CONCLUSIONS

Exocrine pancreas dysfunction precedes the onset of type 1 diabetes in adult at-risk individuals and may be unrelated to fasting C-peptide levels.

Circulating platelet-neutrophil aggregates characterize the development of type 1 diabetes in humans and NOD mice

Platelet-neutrophil aggregates (PNAs) facilitate neutrophil activation and migration and could underpin the recruitment of neutrophils to the pancreas during type 1 diabetes (T1D) pathogenesis. PNAs, measured by flow cytometry, were significantly elevated in the circulation of autoantibody-positive (Aab⁺) children and new-onset T1D children, as well as in pre-T1D (at 4 weeks and 10–12 weeks) and T1D-onset NOD mice, compared with relevant controls, and PNAs were characterized by activated P-selectin⁺ platelets. PNAs were similarly increased in pre-T1D and T1D-onset NOD isolated islets/insulitis, and immunofluorescence staining revealed increased islet-associated neutrophil extracellular trap (NET) products (myeloperoxidase [MPO] and citrullinated histones [CitH3]) in NOD pancreata. In vitro, cell-free histones and NETs induced islet cell damage, which was prevented by the small polyanionic drug methyl cellobiose sulfate (mCBS) that binds to histones and neutralizes their pathological effects. Elevated circulating PNAs could, therefore, act as an innate immune and pathogenic biomarker of T1D autoimmunity. Platelet hyperreactivity within PNAs appears to represent a previously unrecognized hematological abnormality that precedes T1D onset. In summary, PNAs could contribute to the pathogenesis of T1D and potentially function as a pre-T1D diagnostic.

New Evidence of Exocrine Pancreatopathy in Pre-symptomatic and Symptomatic Type 1 Diabetes

PURPOSE OF REVIEW

Type 1 diabetes (T1D) is one of the most frequent chronic autoimmune diseases in humans, characterized by the lack of insulin production resulting in high blood glucose levels and lifelong requirement of exogenous insulin administration for survival. It is now recognized that the autoimmune process begins years before the clinical onset, in a stage called pre-symptomatic T1D, in which the presence of β-cell-specific autoantibodies is detectable. Our aim is to review evidence for T1D as a "whole-pancreas disease," featured by both endocrine and exocrine pancreas alterations already at early disease stages.

RECENT FINDINGS

In this review, we discuss a series of recent observations indicating that in genetically predisposed individuals, structural and functional abnormalities as well as immune cell infiltration of the exocrine pancreas are already present in the pre-symptomatic stages of the disease. Despite T1D being considered a β-cell-specific disease, numerous reports point to the presence of exocrine pancreas subclinical abnormalities occurring during disease development. These observations challenge the long-standing idea that T1D exocrine damage exists as a mere consequence of disease progression and provide further explanation of mechanisms underlying T1D pathogenesis.

Neutrophils and type 1 diabetes: current knowledge and suggested future directions

PURPOSE OF REVIEW

Purpose of this review is to describe the most recent human studies on neutrophils in type 1 diabetes (T1D) and to focus on the key questions that still need to be addressed.

RECENT FINDINGS

Recent evidences demonstrate that neutrophils have marked abnormalities in phenotype and function and play a central role in initiation and perpetuation of aberrant immune responses and organ damage in various systemic autoimmune diseases such as lupus erythematosus and rheumatoid arthritis. In T1D, we have recently demonstrated that reduced circulating neutrophil numbers precede and accompany the disease and that neutrophils infiltrate the pancreas and extrude neutrophil extracellular traps already before the onset of clinical symptoms. However, few other evidences of alterations in neutrophil phenotype and function have been reported in humans, especially in the T1D presymptomatic phases.

SUMMARY

Dissecting the pathogenic role of these cells in human T1D is crucial for a better understanding of the disease and to open new therapeutic opportunities.

Abnormal neutrophil signature in the blood and pancreas of presymptomatic and symptomatic type 1 diabetes

BACKGROUND

Neutrophils and their inflammatory mediators are key pathogenic components in multiple autoimmune diseases, while their role in human type 1 diabetes (T1D), a disease that progresses sequentially through identifiable stages prior to the clinical onset, is not well understood. We previously reported that the number of circulating neutrophils is reduced in patients with T1D and in presymptomatic at-risk subjects. The aim of the present work was to identify possible changes in circulating and pancreas-residing neutrophils throughout the disease course to better elucidate neutrophil involvement in human T1D.

METHODS

Data collected from 389 subjects at risk of developing T1D, and enrolled in 4 distinct studies performed by TrialNet, were analyzed with comprehensive statistical approaches to determine whether the number of circulating neutrophils correlates with pancreas function. To obtain a broad analysis of pancreas-infiltrating neutrophils throughout all disease stages, pancreas sections collected worldwide from 4 different cohorts (i.e., nPOD, DiViD, Siena, and Exeter) were analyzed by immunohistochemistry and immunofluorescence. Finally, circulating neutrophils were purified from unrelated nondiabetic subjects and donors at various T1D stages and their transcriptomic signature was determined by RNA sequencing.

RESULTS

Here, we show that the decline in β cell function is greatest in individuals with the lowest peripheral neutrophil numbers. Neutrophils infiltrate the pancreas prior to the onset of symptoms and they continue to do so as the disease progresses. Of interest, a fraction of these pancreas-infiltrating neutrophils also extrudes neutrophil extracellular traps (NETs), suggesting a tissue-specific pathogenic role. Whole-transcriptome analysis of purified blood neutrophils revealed a unique molecular signature that is distinguished by an overabundance of IFN-associated genes; despite being healthy, said signature is already present in T1D-autoantibody-negative at-risk subjects.

CONCLUSIONS

These results reveal an unexpected abnormality in neutrophil disposition both in the circulation and in the pancreas of presymptomatic and symptomatic T1D subjects, implying that targeting neutrophils might represent a previously unrecognized therapeutic modality.

FUNDING

Juvenile Diabetes Research Foundation (JDRF), NIH, Diabetes UK.

Can HLA-DRB4 Help to Identify Asthmatic Patients at Risk of Churg-Strauss Syndrome?

HLA-DRB4 gene is associated with Churg-Strauss syndrome (CSS), a systemic eosinophilic vasculitis with a prodromal phase characterized by severe asthma, eosinophilia, nasal polyposis, and sinusitis. Aim of this study was to evaluate if the presence of HLA-DRB4 in asthmatic patients is associated with a clinical picture resembling that of the prodromal phase of CSS. HLA-DRB1 was determined in a cohort of 159 asthmatic patients and its frequency was compared with that of 1808 blood donors. HLA-DRB4 presence/absence was correlated with clinical features, including sinusitis, nasal polyposis, eosinophils, antiasthmatic drugs, asthma severity, and pulmonary function tests. HLA-DRB4 gene was associated with severe persistent asthma before treatment (P < 0.02), near fatal or severe hypoxemic asthma (P < 0.01), sinusitis (P < 0.01), nasal polyposis (P < 0.01), number of patients with eosinophils >1000/ μ l: (P < 0.05), need of beclomethasone >1000-2000  μ g/daily (P < 0.001), use of a third controller (P < 0.05), and oral prednisone (P < 0.02). HLA-DRB4 gene is associated in asthmatic patients with a clinical picture characterized by asthma severity, sinusitis, nasal polyposis, and eosinophilia closely resembling that of the prodromal phase of CSS and might be useful to suspect corticosteroids-masked cases of CSS.

Functional coupling of parietal α rhythms is enhanced in athletes before visuomotor performance: a coherence electroencephalographic study

It has been shown that elite pistol shooters are characterized by a power increase of wide cortical electroencephalographic (EEG) alpha (about 8-12 Hz) and beta (about 14-35 Hz) rhythms during the preparation of air pistol shots, possibly related to selective attentional and "neural efficiency" processes [Del Percio C, Babiloni C, Bertollo M, Marzano N, Iacoboni M, Infarinato F, Lizio R, Stocchi M, Robazza C, Cibelli G, Comani S, Eusebi F (2009a) Hum Brain Mapp 30(11):3527-3540; Del Percio C, Babiloni C, Marzano N, Iacoboni M, Infarinato F, Vecchio F, Lizio R, Aschieri P, Fiore A, Toràn G, Gallamini M, Baratto M, Eusebi F (2009b) Brain Res Bull 79(3-4):193-200]. Here, we tested the hypothesis that such processes are associated with an enhanced functional coupling of posterior cortical regions involved in task-relevant attentional processes and visuo-motor transformations. To this aim, between-electrodes spectral coherence was computed from spatially enhanced EEG data collected during a previous study (i.e. right handed 18 elite air pistol shooters and 10 matched non-athletes; augmented 10-20 system; surface Laplacian estimation). Theta (about 4-6 Hz), low-frequency alpha (about 8-10 Hz), high-frequency alpha (about 10-12 Hz), low-frequency beta (14-22 Hz), high-frequency beta (23-35 Hz), and gamma (36-44 Hz) bands were considered. Statistical results showed that intra-hemispheric low-frequency alpha (parietal-temporal and parietal-occipital regions), high-frequency alpha (parietal-temporal and parietal-occipital regions), high-frequency beta, and gamma (parietal-temporal regions) coherence values were stable in amplitude in the elite athletes but not in the non-athletes during the preparation of pistol shots. The same applies to inter-hemispheric low-frequency alpha (parietal regions), high-frequency alpha (parietal regions), high-frequency beta and gamma coherence values. These findings suggest that under the present experimental conditions, elite athletes are characterized by the stabilization of functional coupling of preparatory EEG rhythms between "visuo-spatial" parietal area and other posterior cortical areas.

Human equilibrative nucleoside transporter 1 (hENT1) protein is associated with short survival in resected ampullary cancer

BACKGROUND

Gemcitabine is an acceptable alternative to best supportive care in the treatment of advanced biliary tract cancers. The human equilibrative nucleoside transporter 1 (hENT1) is a ubiquitous protein and is the major means by which gemcitabine enters human cells. Moreover, recent reports indicate a significant correlation between immunohistochemical variations of hENT1 in tumor samples and survival after gemcitabine therapy in patients with solid tumors.

MATERIALS AND METHODS

We used immunohistochemistry to assess the abundance and distribution of hENT1 in tumor samples from radically resected cancer of the ampulla, and sought correlations between immunohistochemical results and clinical parameters including disease outcomes.

RESULTS

In the 41 individual tumors studied, 12 (29.3%) had uniformly high hENT1 immunostaining. Statistical analysis showed a significant correlation between hENT1 and Ki-67 (P = 0.04). No statistical significant differences were found between immunohistochemical findings and patient characteristics (sex, age, and tumor-node-metastasis). On univariate analysis, hENT1 and Ki-67 expression were associated with overall survival (OS). Specifically, those patients with overexpression of hENT1 showed a shorter OS (P = 0.022) and those with high Ki-67 staining showed a shorter survival (P = 0.05).

CONCLUSIONS

hENT1 expression is a molecular prognostic marker for patients with resected ampullary cancer and holds promise as a predictive factor to assist in chemotherapy decisions.

The common allergens in the Churg-Strauss syndrome

BACKGROUND

The asthmatic-prodromal phase of Churg-Strauss syndrome (CSS) is usually considered allergic, but data about the involved allergens are scarce. The aim of our work was to examine the prevalence of allergy in a group of CSS patients and in two control groups of persistent asthmatic subjects selected for eosinophilia >10% [first control group patients (CGP1)] and eosinophils <6% [second control group patients (CGP2)].

METHODS

The respiratory symptoms, and the results of prick test and/or RAST for the common allergens, performed before the vasculitic phase in 51 CSS, were retrospectively evaluated and compared with those of 46 CGP1 and 50 CGP2.

RESULTS

31.4% of CSS vs 67.4% of CGP1 (P = 0.0004) and vs 58.0% CGP2 (P = 0.007) were allergic. The number of subjects with seasonal allergies was lower in CSS vs CGP1 (P = 0.0069) and vs CGP2 (P = 0.0002). The number of perennial allergies was significantly higher in CSS than in both control groups (CSS vs CGP1, P = 0.0108; CSS vs CGP2, P = 0.0079). The subjects allergic to Dermatophagoides were prevalent in CSS vs CGP1 (P = 0.0045) but not vs CGP2.

CONCLUSIONS

The evidence of allergy, considered as the demonstration of specific IgE consistent with the clinical history, is present in less than one-third of CSS and the higher prevalence of seasonal allergies in the controls disagrees with persistent asthma. Allergy may be only one of several mechanisms triggering exacerbation of asthma or supporting chronic airway inflammation as in asthma in general. Alternatively, unidentified allergens may play a role.

Conversion from mild cognitive impairment to Alzheimer's disease is predicted by sources and coherence of brain electroencephalography rhythms

Objective. Can quantitative electroencephalography (EEG) predict the conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD)? Methods. Sixty-nine subjects fulfilling criteria for MCI were enrolled; cortical connectivity (spectral coherence) and (low resolution brain electromagnetic tomography) sources of EEG rhythms (delta=2-4 Hz; theta=4-8 Hz; alpha 1=8-10.5 Hz; alpha 2=10.5-13 Hz: beta 1=13-20 Hz; beta 2=20-30 Hz; and gamma=30-40) were evaluated at baseline (time of MCI diagnosis) and follow up (about 14 months later). At follow-up, 45 subjects were still MCI (MCI Stable) and 24 subjects were converted to AD (MCI Converted). Results. At baseline, fronto-parietal midline coherence as well as delta (temporal), theta (parietal, occipital and temporal), and alpha 1 (central, parietal, occipital, temporal, limbic) sources were stronger in MCI Converted than stable subjects (P<0.05). Cox regression modeling showed low midline coherence and weak temporal source associated with 10% annual rate AD conversion, while this rate increased up to 40% and 60% when strong temporal delta source and high midline gamma coherence were observed respectively. Interpretation. Low-cost and diffuse computerized EEG techniques are able to statistically predict MCI to AD conversion.

Use of high-dose acyclovir in pityriasis rosea

BACKGROUND

The association of human herpesvirus 6 (HHV-6) and HHV-7 with pityriasis rosea suggests that systemic drugs directed against HHV may hasten recovery of patients with pityriasis rosea.

OBJECTIVE

The purpose of this study was to verify the efficacy of oral acyclovir in the treatment of pityriasis rosea.

METHODS

Eighty-seven consecutive patients were treated for 1 week with either oral acyclovir (800 mg 5 times daily) or placebo. In all patients, the time of lesion clearing and the number of new lesions appearing during treatment were recorded.

RESULTS

On the 14th day of treatment, 79% of treated patients fully regressed compared with 4% of the placebo group. The lesions cleared in 18.5 days in treated patients and in 37.9 days in the placebo group. Clearance was achieved in 17.2 days in patients treated in the first week from onset and in 19.7 days in the patients treated later. On the 7th day, there were significantly fewer new lesions in patients treated in the first week than in those treated later.

LIMITATIONS

This trial was neither randomized nor double blind. Objectivity was achieved by counting the lesions.

CONCLUSION

Acyclovir may be effective in the treatment of pityriasis rosea, especially in patients treated in the first week from onset, when replicative viral activity of HHV is probably very high.

COX-2 expression in ampullary carcinoma: correlation with angiogenesis process and clinicopathological variables

BACKGROUND

There is evidence that the anti-neoplastic effect of non-steroidal anti-inflammatory drugs is attributable to cyclooxygenase-2 (COX-2) inhibition, but the exact mechanisms whereby COX-2 can promote tumour cell growth remain unclear. One hypothesis is the stimulation of tumour angiogenesis by the products of COX-2 activity. To data, there have been few clinicopathological studies on COX-2 expression in human ampullary carcinoma and no data have been reported about its relation with tumour angiogenesis.

OBJECTIVE

To investigate by immunohistochemistry the expression of COX-2 and the angiogenesis process in a series of primary untreated ampullary carcinomas.

METHODS

Tissue samples from 40 archival ampullary carcinomas were analysed for COX-2, vascular endothelial growth factor (VEGF), and an endothelial cell marker von Willebrand factor (vWF) by immunohistochemistry, using specific antibodies.

RESULTS

COX-2 expression was detected in 39 tissue samples (97.5%), of which two (5%) were graded as weak, 26 (65%) as moderate, and 11 (27.5%) as strong. Only one lesion (2.5%) was negative for COX-2 expression. VEGF expression was detected in 36 tissue samples (90%). A significant positive correlation was found between COX-2 and VEGF expression. No statistic correlation was found between COX-2 expression and microvessel density.

CONCLUSIONS

COX-2 is highly expressed in ampullary carcinomas. This suggests an involvement of the COX-2 pathway in ampullary tumour associated angiogenesis, providing a rationale for targeting COX-2 in the treatment of ampullary cancer.

Distinguishing androgenetic alopecia from chronic telogen effluvium when associated in the same patient: a simple noninvasive method

BACKGROUND

Distinguishing chronic telogen effluvium (CTE) from androgenetic alopecia (AGA) may be difficult especially when associated in the same patient.

OBSERVATIONS

One hundred consecutive patients with hair loss who were clinically diagnosed as having CTE, AGA, AGA + CTE, or remitting CTE. Patients washed their hair in the sink in a standardized way. All shed hairs were counted and divided "blindly" into 5 cm or longer, intermediate length (>3 to <5 cm), and 3 cm or shorter. The latter were considered telogen vellus hairs, and patients having at least 10% of them were classified as having AGA. We assumed that patients shedding 200 hairs or more had CTE. The kappa statistic revealed, however, that the best concordance between clinical and numerical diagnosis (kappa = 0.527) was obtained by setting the cutoff shedding value at 100 hairs or more. Of the 100 patients, 18 with 10% or more of hairs that were 3 cm or shorter and who shed fewer than 100 hairs were diagnosed as having AGA; 34 with fewer than 10% of hairs that were 3 cm or shorter and who shed at least 100 hairs were diagnosed as having CTE; 34 with 10% or more of hairs that were 3 cm or shorter and who shed at least 100 hairs were diagnosed as having AGA + CTE; and 14 with fewer than 10% of hairs that were 3 cm or shorter and who shed fewer than 100 hairs were diagnosed as having CTE in remission.

CONCLUSION

This method is simple, noninvasive, and suitable for office evaluation.

Fibromyxoid sarcoma in a 4-year-old boy: case report and review of the literature

The authors report on the case of a low-grade fibromyxoid sarcoma (LGFMS) with giant rosettes in a 4-year-old boy. The tumor arose in the paravertebral region and had infiltrated the vertebral canal between L2 and S1. A review of the literature indicates that this is one of the youngest patients diagnosed with a tumor of this type, and spinal involvement had never been reported with LGFMS.

Decrease of functional coupling between left and right auditory cortices during dichotic listening: An electroencephalography study

The present study focused on functional coupling between human bilateral auditory cortices and on possible influence of right over left auditory cortex during dichotic listening of complex non-verbal tones having near (competing) compared with distant non-competing fundamental frequencies. It was hypothesized that dichotic stimulation with competing tones would induce a decline of functional coupling between the two auditory cortices, as revealed by a decrease of electroencephalography coherence and an increase of directed transfer function from right (specialized for the present stimulus material) to left auditory cortex. Electroencephalograph was recorded from T3 and T4 scalp sites, overlying respectively left and right auditory cortices, and from Cz scalp site (vertex) for control purposes. Event-related coherence between T3 and T4 scalp sites was significantly lower for all electroencephalography bands of interest during dichotic listening of competing than non-competing tone pairs. This was a specific effect, since event-related coherence did not differ in a monotic control condition. Furthermore, event-related coherence between T3 and Cz and between T4 and Cz scalp sites showed no significant effects. Conversely, the directed transfer function results showed negligible influence at group level of right over left auditory cortex during dichotic listening. These results suggest a decrease of functional coupling between bilateral auditory cortices during competing dichotic stimuli as a possible neural substrate for the lateralization of auditory stimuli during dichotic listening.

Coupling Between "Hand" Primary Sensorimotor Cortex and Lower Limb Muscles After Ulnar Nerve Surgical Transfer in Paraplegia

Previous neuroimaging evidence revealed an "invasion" of "hand" over "lower limb" primary sensorimotor cortex in paraplegic subjects, with the exception of a rare patient who received a surgical motor reinnervation of hip-thigh muscles by the ulnar nerve. Here, the authors show that a functional reorganization of cortico-muscular and cortico-cortical oscillatory coupling was related to the recovery of the rare patient, as a paradigmatic case of long-term plasticity in human sensorimotor cortex after motor reinnervation of paraplegic muscles. This conclusion was based on electroencephalographic and electromyographic data collected while the patient and normal control subjects performed isometric muscle contraction of the left hand or lower limb. Cortico-muscular and cortico-cortical coupling was estimated by electroencephalographic-electromyographic coherence and directed transfer function of a multivariate autoregressive model.