Subthalamic nucleus activity in the processing of body and mental action verbs in people with Parkinson's disease.

Local field potentials evoked by body action and mental action verbs were recorded in the subthalamic nucleus (STN) of 18 patients with Parkinson's disease through the electrodes implanted for deep brain stimulation. Compared with the medication on-condition, the medication off-condition showed a difference in activity in the early time segments, mainly in the right STN, with larger amplitudes for body action verbs. In the on-condition a similar pattern was detected in the left STN. These patterns of early differences in activity evoked by different types of verbs might indicate the potential of the STN to rapidly detect relevant behavioural clues in verbal content and to integrate these in subsequent cortico-subcortical interactions. In addition, these lateralizations allow speculations about shifts in processing activity correlating with dopaminergic denervation. Whether this detection relies on phonological, semantic or grammatical clues remains an open question.

The white matter architecture underlying semantic processing: A systematic review.

From a holistic point of view, semantic processes are subserved by large-scale subcortico-cortical networks. The dynamic routing of information between grey matter structures depends on the integrity of subcortical white matter pathways. Nonetheless, controversy remains on which of these pathways support semantic processing. Therefore, a systematic review of the literature was performed with a focus on anatomo-functional correlations obtained from direct electrostimulation during awake tumor surgery, and conducted between diffusion tensor imaging metrics and behavioral semantic performance in healthy and aphasic individuals. The 43 included studies suggest that the left inferior fronto-occipital fasciculus contributes to the essential connectivity that allows semantic processing. However, it remains uncertain whether its contributive role is limited to the organization of semantic knowledge or extends to the level of semantic control. Moreover, the functionality of the left uncinate fasciculus, inferior longitudinal fasciculus and the posterior segment of the indirect arcuate fasciculus in semantic processing has to be confirmed by future research.

Electrophysiological registration of phonological perception in the subthalamic nucleus of patients with Parkinson's Disease.

Phonological processing is usually associated with the activation of cortical areas, especially in the left cerebral hemisphere. This study examined if phonologically elicited evoked potentials can be recorded directly from the subthalamic nucleus in patients with Parkinson's Disease (PD). Seven PD patients who had undergone implantation of deep brain electrodes for the stimulation of the subthalamic nucleus were included. Local field potentials were recorded in a pre-attentive auditory phonological task, an attentive auditory phonological discrimination task, and a word recognition task. Auditory evoked potentials related to phonological, but not lexical processing, could be demonstrated in the subthalamic nucleus for all three tasks. Only minor changes were found after levodopa administration. This study demonstrates that the subthalamic nucleus is involved in early phonological perception, which puts the subthalamic nucleus in a position to modify phonological perception in a larger cortico-subcortical network.

Risk factors for the development of polyneuropathy and myopathy in critically ill patients.

BACKGROUND: Previously, mainly retrospective and a few important prospective studies postulated the role of sepsis or systemic inflammatory response syndrome (SIRS), multiple organ failure, and the use of medication as causative factors for the development of critical illness polyneuropathy and myopathy (CIPNM). This study aimed to identify the risk factors in the development of CIPNM. METHODS: Prospectively, we studied 98 patients who were on artificial respirators for the development of CIPNM. The Acute Physiology and Chronic Health Evaluation (APACHE) III score, presence of SIRS, and sepsis severity score at entry; the dosage of midazolam, vecuronium, and steroids at entry and day 7 of artificial respiration; and the use of aminoglycosides at entry were related with time to CIPNM or time of last follow-up. The Kaplan-Meier method and log-rank test were used. RESULTS: Thirty-two patients (33%) developed CIPNM. After multivariate analysis, it was found that the APACHE III score and the presence of SIRS were significantly related with risk for the development of CIPNM. No significant relation was found for the use of midazolam, vecuronium, or steroids. Based on a risk index from a Cox regression model with APACHE III score and presence of SIRS as outcomes, three groups could be constructed with low-, medium-, and high-risk patients for the development of CIPNM. CONCLUSIONS: The APACHE III score, a quantitative index of disease severity based on clinical and laboratory physiologic data, is a valuable predictor for the development of CIPNM in patients in the intensive care unit. Together with the presence of SIRS, it can be used to estimate the risk of developing CIPNM for patients on artificial respirators.

["Critical-illness" polyneuropathy and -myopathy]. / 'Critical-illness'-polyneuropathie en -myopathie.

Critical-illness polyneuropathy and myopathy (CIPNM) can be considered a part of the syndrome of multiple organ dysfunction. CIPNM is the commonest cause of muscle weakness acquired in the intensive care unit. Its incidence is 35-80% during prolonged mechanical ventilation. For a (differential) diagnosis, electrophysiological investigations are usually necessary, and sometimes a muscle biopsy. CIPNM may be induced by triggering of the immune response leading to increased vascular permeability with tissue invasion of inflammatory cells and local damage. There is a relation between myopathy and medication, notably corticosteroids. Clinical improvement usually follows when the CIPNM patient survives the underlying disease, but weaning from artificial ventilation is often difficult, and rehabilitation prolonged.

Critical illness polyneuropathy and myopathy (CIPNM): evidence for local immune activation by cytokine-expression in the muscle tissue.

In a longitudinal prospective study a muscle biopsy was taken from 30/32 (33%) of the 98 patients who developed critical illness polyneuropathy and myopathy (CIPNM). Neuropathic changes were found in 37%, myopathic in 40%, and a combination in 23% of the biopsies. The immunohistopathology showed macrophages and Th-cells in 40% and 60% of the muscle biopsies respectively. Small mainly perivascular infiltrates contained macrophages and Th-cells. ICAM-1, VCAM and MAC were found on the vascular endothelium in 58%, 53% and 79% respectively. In all biopsies there was an upregulation of both HLA-I and HLA-DR. Proinflammatory cytokines and TNFalphaR75 were also produced locally (IL-1beta in 71%, IFN-gamma in 40%, IL-12 in 73%, TNFalphaR75 in 90%). The anti-inflammatory cytokine IL-10 was simultaneously expressed in 96% of the biopsies. HLA-DR, TNFalphaR75 and IL-10 differed significantly when compared with control muscle biopsies. Our data provide evidence that small numbers of activated leukocytes producing both pro- and anti-inflammatory cytokines infiltrate skeletal muscle of CIPNM patients. We propose that the local balance of leukocyte activities is of importance in the pathophysiology of muscle weakness in CIPNM.

Cytokines in the muscle tissue of idiopathic inflammatory myopathies: implications for immunopathogenesis and therapy.

The inflammatory myopathies (IM), dermatomyositis (DM), polymyositis (PM) and idiopathic inclusion body myositis (IBM) are acquired immune-mediated myopathies. About their pathogenesis and etiology no definitive insights are available yet. Here we present a review of cytokine studies in IM. Combined with cellular immunohistochemical findings a model is presented describing a common mechanism of immune activation in IM. This model is based on a "hit" triggering local cytokine production with dominance of pro-inflammatory cytokines, like IFN-gamma and Th1-mediated activities. The altered Th1-Th2 balance necessitates detection of the anti-inflammatory arm of immune activation, which includes Th2-derived IL-4, IL-1, and Th3/Tr1 derived IL-10 and TGF-beta. Redirection of the ratio provides targets for novel immunotherapy by direct inhibition of the IFN-gamma-mediated Th1 response, stimulation of Th3/Tr1, or IL-4-secreting Th2-cells, negative feedback inhibition with IFN-beta and IFN-gamma and inactivation of MHC molecules.