Perspective-dependent activation of frontoparietal circuits during the observation of a static body effector.

The perspective from which body-related stimuli are observed plays a fundamental role in modulating cerebral activity during the processing of others' bodies and actions. Previous research has shown perspective-dependent cerebral responses during the observation of both ongoing actions and static images of an acting body with implied motion information, with an advantage for the egocentric viewpoint. The present high-density EEG study assessed event-related potentials triggered by the presentation of a forearm at rest before reach-to-grasp actions, shown from four different viewpoints. Through a spatiotemporal analysis of the scalp electric field and the localization of cortical generators, our study revealed overall different processing for the third-person perspective relative to other viewpoints, mainly due to a later activation of motor-premotor regions. Since observing a static body effector often precedes action observation, our results integrate previous evidence of perspective-dependent encoding, with cascade implications on the design of neurorehabilitative or motor learning interventions based on action observation.

Perspective-dependent reactivity of sensorimotor mu rhythm in alpha and beta ranges during action observation: an EEG study.

During action observation, several visual features of observed actions can modulate the level of sensorimotor reactivity in the onlooker. Among possibly relevant parameters, one of the less investigated in humans is the visual perspective from which actions are observed. In the present EEG study, we assessed the reactivity of alpha and beta mu rhythm subcomponents to four different visual perspectives, defined by the position of the observer relative to the moving agent (identifying first-person, third-person and lateral viewpoints) and by the anatomical compatibility of observed effectors with self- or other individual's body (identifying ego- and allo-centric viewpoints, respectively). Overall, the strongest sensorimotor responsiveness emerged for first-person perspective. Furthermore, we found different patterns of perspective-dependent reactivity in rolandic alpha and beta ranges, with the former tuned to visuospatial details of observed actions and the latter tuned to action-related parameters (such as the direction of actions relative to the observer), suggesting a higher recruitment of beta motor rhythm in face-to-face interactions. The impact of these findings on the selection of most effective action stimuli for "Action Observation Treatment" neurorehabilitative protocols is discussed.

"Embodied Body Language": an electrical neuroimaging study with emotional faces and bodies.

To date, most investigations in the field of affective neuroscience mainly focused on the processing of facial expressions, overlooking the exploration of emotional body language (EBL), its capability to express our emotions notwithstanding. Few electrophysiological studies investigated the time course and the neural correlates of EBL and the integration of face and body emotion-related information. The aim of the present study was to investigate both the time course and the neural correlates underlying the integration of affective information conveyed by faces and bodies. We analysed EEG activities evoked during an expression matching task, requiring the judgment of emotional congruence between sequentially presented pairs of stimuli belonging to the same category (face-face or body-body), and between stimuli belonging to different categories (face-body or body-face). We focused on N400 time window and results showed that incongruent stimuli elicited a modulation of the N400 in all comparisons except for body-face condition. This modulation was mainly detected in the Middle Temporal Gyrus and within regions related to the mirror mechanism. More specifically, while the perception of incongruent facial expressions activates somatosensory-related representations, incongruent emotional body postures also require the activation of motor and premotor representations, suggesting a strict link between emotion and action.

Correction: Proactive Control Strategies for Overt and Covert Go/NoGo Tasks: an Electrical Neuroimaging Study.

[This corrects the article DOI: 10.1371/journal.pone.0152188.].

Proactive Control Strategies for Overt and Covert Go/NoGo Tasks: An Electrical Neuroimaging Study.

Proactive and reactive inhibition are generally intended as mechanisms allowing the withholding or suppression of overt movements. Nonetheless, inhibition could also play a pivotal role during covert actions (i.e., potential motor acts not overtly performed, despite the activation of the motor system), such as Motor Imagery (MI). In a previous EEG study, we analyzed cerebral activities reactively triggered during two cued Go/NoGo tasks, requiring execution or withholding of overt or covert imagined actions, respectively. This study revealed activation of pre-supplementary motor area (pre-SMA) and right inferior frontal gyrus (rIFG), key nodes of the network underpinning reactive inhibition of overt responses in NoGo trials, also during MI enactment, enabling the covert nature of the imagined motor response. Taking into account possible proactive engagement of inhibitory mechanisms by cue signals, for an exhaustive interpretation of these previous findings in the present study we analyzed EEG activities elicited during the preparatory phase of our cued overt and covert Go/NoGo tasks. Our results demonstrate a substantial overlap of cerebral areas activated during proactive recruitment and subsequent reactive implementation of motor inhibition in both overt and covert actions; also, different involvement of pre-SMA and rIFG emerged, in accord with the intended type (covert or overt) of incoming motor responses. During preparation of the overt Go/NoGo task, the cue is encoded in a pragmatic mode, as it primes the possible overt motor response programs in motor and premotor cortex and, through preactivation of a pre-SMA-related decisional mechanism, it triggers a parallel preparation for successful response selection and/or inhibition during the response phase. Conversely, the preparatory strategy for the covert Go/NoGo task is centered on priming of an inhibitory mechanism in rIFG, tuned to the instructed covert modality of motor performance and instantiated during subsequent MI, which allows the imagined response to remain a potential motor act.

A prospective study of the cumulative incidence and course of restless legs syndrome in de novo patients with Parkinson's disease during chronic dopaminergic therapy.

The authors report the cumulative incidence of Restless Legs Syndrome (RLS) over a 3 years follow-up period in 92 de novo Parkinson's disease patients under chronic dopaminergic therapy and the clinical course of the sensory-motor disorder over 12 months as from its onset. The overall cumulative incidence of RLS was found by 15.3%, i.e. 14 incident cases, and by 11.9%, i.e. 11 incident cases, after the exclusion of possible "secondary" forms of the disorder. These figures are higher than those reported in general population in Germany (Study of Health in Pomerania), confirming our previous findings of incidence rate of the disorder. At the end of the 3 years follow-up period the prevalence of "current" RLS was significantly higher than that previously found in drug naïve Parkinson's disease patients and in controls, supporting the view that RLS emerging in the course of chronic dopaminergic therapy is the main determinant of the co-morbid association with Parkinson's disease. During the 12 months period of observation the RLS showed a frequency of occurrence of 6.08 episodes per month on average and a remittent clinical course was prevailing in the 11 incident cases, with a significant frequency decrease in the second as compared to the first 6 months, i.e. 3.26 versus 8.9 episodes per month, and none of the patients developed augmentation in the same period. It is hypothesized that the remittent course could be due to long-term adaptation (downregulation) of the hypersensitive post-synaptic dopamine receptors in the spinal cord to a continuous dopaminergic stimulation, possibly coupled with compensatory up-regulation of pre-synaptic dopamine re-uptake mechanism, in the patients in which the hypothalamic A11 area, site of origin of the dopamine-mediated diencephalo-spinal pathway, is involved in the neurodegenerative process.

Motor Inhibition during Overt and Covert Actions: An Electrical Neuroimaging Study.

Given ample evidence for shared cortical structures involved in encoding actions, whether or not subsequently executed, a still unsolved problem is the identification of neural mechanisms of motor inhibition, preventing "covert actions" as motor imagery from being performed, in spite of the activation of the motor system. The principal aims of the present study were the evaluation of: 1) the presence in covert actions as motor imagery of putative motor inhibitory mechanisms; 2) their underlying cerebral sources; 3) their differences or similarities with respect to cerebral networks underpinning the inhibition of overt actions during a Go/NoGo task. For these purposes, we performed a high density EEG study evaluating the cerebral microstates and their related sources elicited during two types of Go/NoGo tasks, requiring the execution or withholding of an overt or a covert imagined action, respectively. Our results show for the first time the engagement during motor imagery of key nodes of a putative inhibitory network (including pre-supplementary motor area and right inferior frontal gyrus) partially overlapping with those activated for the inhibition of an overt action during the overt NoGo condition. At the same time, different patterns of temporal recruitment in these shared neural inhibitory substrates are shown, in accord with the intended overt or covert modality of action performance. The evidence that apparently divergent mechanisms such as controlled inhibition of overt actions and contingent automatic inhibition of covert actions do indeed share partially overlapping neural substrates, further challenges the rigid dichotomy between conscious, explicit, flexible and unconscious, implicit, inflexible forms of motor behavioral control.

A long-term prospective follow-up study of incident RLS in the course of chronic DAergic therapy in newly diagnosed untreated patients with Parkinson's disease.

It is currently controversial if and in which terms Parkinson's disease (PD) and restless legs syndrome (RLS) are linked in co-morbid association. In a cohort of 106 de novo PD patients (67 male and 39 female, aged 42-83 years), 15 of them developed RLS, which was prospectively assessed at 6-month intervals from the starting of dopamine(DA)ergic therapy. The incidence rate of total RLS was 47 per 1,000 case/person per year and 37 per 1,000 case/person per year after the exclusion of possible "secondary" forms of the disorder (n = 3). These figures are higher than those reported in an incidence study conducted in German general population (Study of Health in Pomerania), in which the method of ascertainment of RLS similar to ours has been used. An incidence rate of total RLS significantly higher than that reported in the above-mentioned study was found in the age ranges 55-64 years and in the age range 45-74 years standardized to European general population 2013  (70 and 53 per 1,000 case/person per year, respectively, p < 0.01). Ten out of 12 patients (83.3 %) developed RLS within 24 months from the starting of DAergic medication (median latency 7.5 months). These findings support the view that sustained DAergic therapy could represent the critical factor inducing an increased incidence of RLS in patients with PD and that the latter disease should be regarded as the condition predisposing to the occurrence of the former and not viceversa as previously hypothesized. The mechanism underlying the increased incidence of RLS remains unclear and deserves further investigation.

A study of the prevalence of restless legs syndrome in previously untreated Parkinson's disease patients: absence of co-morbid association.

OBJECTIVE: The co-morbidity between Parkinson's disease (PD) and restless legs syndrome (RLS) is currently controversial, mainly because in most of the studies so far conducted, the patients were already on therapy with dopamine(DA)ergic drugs. This study has been carried out to assess the prevalence of RLS in de novo PD patients previously unexposed to DAergic drugs. METHODS: One hundred nine cognitively unimpaired outpatients with PD (70M/39F), mean age 66.89 years±9.37 SD were included in the study. The mean duration of PD was 15.81 months±11.24 SD, and the median Hoehn and Yahr (H&Y) stage was 2 (range 1.5-3). All patients underwent interview to assess the occurrence of overall life-time and current "primary" form of RLS according to the criteria of the International RLS Study Group (IRLSSG). One hundred sixteen age and sex matched subjects (74M/42F, mean age 66.52.years±8.65 SD) free from a history of neurological diseases, were taken as controls and likewise interviewed. "Secondary" forms of RLS in both patients and controls were subsequently excluded. RESULTS: No significant difference was found (chi-square test) in the frequency of overall life-time and of current "primary" RLS between PD patients and controls (6 out of 109 versus 5 out of 116 and 3 out of 109 versus 3 out of 116, respectively). CONCLUSIONS: This survey does not support the concept of a co-morbid association between the two conditions and confirm indirectly the findings of previous studies reporting the onset of RLS after diagnosis of PD has been made in the great majority of patients and so likely on ongoing DAergic treatment. Therefore, we speculate that RLS occurring in these patients could be related to DAergic therapy for PD.

Dry mouth as an initial sign of food-borne botulism: a case report and review of the literature.

Botulism is a rare neuroparalytic disease caused by a potent neurotoxin produced by Clostridium botulinum. There are different clinical types of botulism. Early diagnosis of the condition is essential for effective treatment. We report a case of food-borne botulism in identical twins characterized by severe initial oral involvement and a review of the literature about the condition.

Unexplained dyspnea in an old patient with recurrent stroke: platypnea-orthodeoxia syndrome and evidence of patent foramen ovale.

Platypnea-orthodeoxia is a syndrome characterized by dyspnea and hypoxemia in orthostatism relieved by supine position. This phenomenon is frequently associated with interatrial communication, mainly patent foramen ovale. The association of platypnea-orthodeoxia syndrome with recurrent stroke and patent foramen ovale is extremely uncommon. A 73-year-old woman experienced recurrent attacks of dyspnea after an ischemic stroke. Arterial blood gas analysis changes in upright and supine position confirmed the diagnosis of platypnea-orthodeoxia syndrome. Contrast-enhanced transthoracic echocardiography showed patent foramen ovale with atrial septal aneurysm and right-to-left shunt. Percutaneous closure of patent foramen ovale led to stabilization of blood oxygen saturation and resolution of dyspnea. Platypnea-orthodeoxia syndrome should be considered in patients with stroke and unexplained dyspnea. The diagnosis could lead to correction of an unknown cardiac defect and of potential risk factor for stroke.

Absence of co-morbidity of Parkinson disease and restless legs syndrome: a case-control study in patients attending a movement disorders clinic.

We have carried out a case-control survey of the prevalence of restless legs syndrome (RLS) in 118 Parkinson's disease out-patients with different stage of disease severity by using the International restless legs syndrome Study Group clinical criteria. This study failed to demonstrate a significantly augmented prevalence of either primary and secondary restless legs syndrome pooled together or primary restless legs syndrome alone among Parkinson's disease patients as compared to age and gender matched controls. The results of our survey do not confirm a significant co-morbid occurrence of the two disorders. However, an unavoidable limitation of this and all previous studies is that most of the patients examined were already treated with dopaminomimetic drugs, which could have abolished a mild unrecognized RLS anteceding the diagnosis of Parkinson's disease or possibly masked the subsequent emergence of the sensory-motor disorder following the onset of Parkinson's disease.