Action verbs and the primary motor cortex: a comparative TMS study of silent reading, frequency judgments, and motor imagery

Single pulse transcranial magnetic stimulation (TMS) was applied to the hand area of the left primary motor cortex or, as a control, to the vertex (STIMULATION: TMS(M1) vs. TMS(vertex)) while right-handed volunteers silently read verbs related to hand actions. We examined three different tasks and time points for stimulation within the same experiment: subjects indicated with their left foot when they (i) had finished reading, (ii) had judged whether the corresponding movement involved a hand rotation after simulating the hand movement, and (iii) had judged whether they would frequently encounter the action verb in a newspaper (TASK: silent reading, motor imagery, and frequency judgment). Response times were compared between TMS(M1) and TMS(vertex), both applied at different time points after stimulus onset (DELAY: 150, 300, 450, 600, and 750 ms). TMS(M1) differentially modulated task performance: there was a significant facilitatory effect of TMS(M1) for the imagery task only (about 88 ms), with subjects responding about 10% faster (compared to TMS(vertex)). In contrast, response times for silent reading and frequency judgments were unaffected by TMS(M1). No differential effect of the time point of TMS(M1) was observed. The differential effect of TMS(M1) when subjects performed a motor imagery task (relative to performing silent reading or frequency judgments with the same set of verbs) suggests that the primary motor cortex is critically involved in processing action verbs only when subjects are simulating the corresponding movement. This task-dependent effect of hand motor cortex TMS on the processing of hand-related action verbs is discussed with respect to the notion of embodied cognition and the associationist theory.     

Predictive force programming in the grip-lift task: the role of memory links between arbitrary cues and object weight

We tested the ability of healthy participants to learn an association between arbitrary sensory cues and the weight of an object to be lifted using a precision grip between the index finger and thumb. Right-handed participants performed a series of grip-lift tasks with each hand. In a first experiment, participants lifted two objects of equal visual appearance which unexpectedly and randomly changed their weight. In two subsequent experiments, the change in object weight was indicated by cues, which were presented (i) visually or (ii) auditorily. When no cue about the weight of the object to be lifted was presented, participants programmed grip force according to the most recent lift, regardless of the hand used. In contrast, participants were able to rapidly establish an association between a particular sensory cue with a given weight and scaled grip force precisely to the actual weight thereafter, regardless of the hand used or the sensory modality of the cue. We discuss our data within the theoretical concept of internal models.     

Differential processing of hierarchical visual stimuli in young and older healthy adults: implications for pathology

Hierarchical figures in which large (global) forms are constructed from smaller (local) forms (Navon, 1977) have proved valuable in studies of perceptual organisation and hemispheric specialisation in both healthy volunteers and a wide range of neurological and psychiatric patients. In studies using Navon figures, normal young adults typically identify global forms faster than local forms. When the global and local forms are incongruent (e.g., a large E made of smaller Rs), global forms often interfere with local form identification more than vice versa. In two conditions on the same subjects, we contrasted the performance of young (mean age 22 years) and older (mean age 58 years) healthy volunteers on global and local processing. In the directed attention task, subjects were instructed to detect a target letter that occurred at the prespecified local or global level. The young subjects showed, as expected, faster reaction times (RTs) to detect global targets. In contrast, the older subjects showed significantly faster RTs to the local targets. Likewise, in a divided attention task, in which subjects were instructed to detect a target letter that could occur at either the local or the global level, the young adults were slightly quicker to detect the global targets and the older subjects were significantly quicker to detect the local targets. Error rates were generally low and there was no significant speed/accuracy trade-off in either condition. The observed local precedence effects in healthy older subjects were unexpected and are discussed in reference to previous work on differential hemispheric aging. That work has suggested that the left hemisphere is preferentially biased toward local processing and ages relatively slowly while the right hemisphere is biased toward global processing and ages relatively quickly. The implications of such putative differential aging for the interpretation of pathological local/global processing in neurological and psychiatric diseases are also emphasised.     

Microwave Ablation Compared with Radiofrequency Ablation for The Treatment of Liver Cancer: a Systematic Review and Meta-analysis

BackgroundGuidelines have reported that although microwave ablation (MWA) has potential advantages over radiofrequency ablation (RFA), superiority in efficacy and safety remain unclear. Aim of the study is to compare MWA with RFA in the treatment of liver cancer.MethodsMeta-analysis was conducted according to the PRISMA guidelines for studies published from 2010 onwards. A random-effects model was used for the meta-analyses. Complete ablation (CA), local tumor progression (LTP), intrahepatic distant recurrence (IDR), and complications were analyzed.ResultsFour randomized trials and 11 observational studies with a total of 2,169 patients met the inclusion criteria. Although overall analysis showed no significant difference in LTP between MWA and RFA, subgroup analysis including randomized trials for patients with hepatocellular cancer (HCC) demonstrated statistically decreased rates of LTP in favor of MWA (OR, 0.40; 95% CI, 0.18–0.92; p = 0.03). No significant differences were found between the two procedures in CA, IDR, complications, and tumor diameter less or larger than 3 cm.ConclusionsMWA showed promising results and demonstrated better oncological outcomes in terms of LTP compared to RFA in patients with HCC. MWA can be utilized as the ablation method of choice in patients with HCC.Key words: liver, carcinoma hepatocellular, liver neoplasms, radiofrequency ablation, microwaves     

Developmental changes in neural activation and psychophysiological interaction patterns of brain regions associated with interference control and time perception

Interference control and time perception are mediated by common neural networks, including the frontal and parietal lobes, the cerebellum and the basal ganglia. Previous studies have shown that while time perception develops early in life, interference control seems to follow a protracted course of maturation into late adolescence. Thus, the current study examined developmental changes in neural activation and functional interaction between brain regions during a combined time discrimination and interference control task using fMRI. Thirty-four participants, aged 8-15 years, were scanned while performing a spatial stimulus response compatibility (SRC) task and a time discrimination (TD) task using identical stimuli. We found shared neural activation in a fronto-parieto-cerebellar network as well as task-specific patterns of psychophysiological interaction with positive coupling between the right inferior frontal gyrus (IFG), the superior parietal lobes bilaterally, the contralateral IFG and the thalamus during interference control and positive interactions between the right IFG and bilateral cerebellar activity and the thalamus during time discrimination. Developmental changes in task performance and brain activation patterns were only observed during the SRC task, with increased neural activity in the left inferior parietal gyrus and positive coupling between fronto-parietal brain regions that was only observed in the adolescents group. These results suggest that although both cognitive tasks rely on a shared neural network, distinct developmental curves of brain activation and connectivity could be observed associated with differential maturation patterns underlying cognitive development.     

Characterisation of NcGRA7 and NcSAG4 proteins: Immunolocalisation and their role in the host cell invasion by <Emphasis Type="Italic">Neospora caninum</Emphasis> tachyzoites

Neospora caninum negatively impacts bovine reproductive performance around the world. Addressing this problem requires a greater understanding of the parasite’s molecular biology. In this study, monoclonal antibodies against recombinant proteins were successfully developed and employed to characterise two different proteins of N. caninum: the acute phase-associated NcGRA7 and the chronic phase-associated NcSAG4. Immunofluorescence with the anti-rNcGRA7 monoclonal antibody suggested that NcGRA7 trafficks from tachyzoite dense granules to the matrix of the parasitophorous vacuole and parasite’s surroundings. Furthermore, NcGRA7 is also expressed in the bradyzoite stage and localised on the matrix of bradyzoite-positive vacuoles. NcGRA7 appears to be partially involved in the tachyzoite-invasion mechanisms, as an anti-rNcGRA7 monoclonal antibody partially inhibited in vitro tachyzoite-invasion. A monoclonal antibody specific for NcSAG4 confirmed this protein’s bradyzoitespecific expression both by western blot and immunofluorescence. However, some bradyzoite-positive vacuoles only weakly expressed NcSAG4, if it was expressed at all. The specificity of the anti-rNcSAG4 monoclonal antibody was confirmed by the recognition of the NcSAG4 in the membrane surface of Nc-1SAG4^c transgenic tachyzoites, which constitutively expresses NcSAG4. Blocking NcSAG4 of Nc-1SAG4^c tachyzoites with the monoclonal antibody did not affect host cell invasion. However, its implication on the host cell adhesion or host immune evasion should not be discarded.     

The neural basis of perceptual bias and response bias in the Landmark task

Spatial neglect as a multifaceted syndrome may consist of perceptual/attentional as well as motor/intentional components. The present study investigated the lesion anatomy underlying perceptual and response bias using a manual response Landmark task (Bisiach, Ricci, Lualdi, & Colombo, 1998) in 68 patients with right-hemispheric stroke. The two differential aspects of the neglect syndrome were assessed by measuring response tendencies resulting from underestimations of the length of left line segments and from hypometric movement execution towards contralesional space, respectively. Perceptual and response bias were orthogonal components of task performance in the Landmark task. Perceptual as well as response bias both explained variance in the performance of standard paper-and-pencil neglect tests. While lesions within middle frontal, inferior parietal and parieto-occipital brain regions were related to perceptual bias, subcortical lesions within the caudate were related to response bias in the Landmark task. Our data suggest that perceptual/attentional and motor/intentional aspects of neglect are independent components of the syndrome with differential neural underpinnings in fronto-parietal and subcortical brain regions.     

Unzureichende Validit?t eines Blutschnelltests zur Diagnose der Helicobacter-pylori-Infektion

Zusammenfassung Hintergrund und Ziel: Blutschnelltests zur Diagnose der Helicobacter-(H.-) pylori-Infektion ermöglichen den Nachweis von Antikörpern gegen H. pylori ohne zeitlichen und apparativen Aufwand. Primäres Ziel: Validierung eines Blutschnelltests, des Helisal™ Rapid Whole Blood Test (HRBT), mit endoskopisch-bioptischen Methoden als Referenz. Sekundäres Ziel: Vergleich des HRBT mit ELISA-IgG-Serologie. Patienten und Methoden: Der HRBT wurde bei 145 konsekutiven Patienten (medianes Alter 59 Jahre) durchgeführt, bevor sie sich wegen Dyspepsie einer Ösophagogastroduodenoskopie mit Antrum- und Korpusbiopsien unterzogen. Ein positiver H.-pylori-Status wurde definiert durch eine positive Kultur oder die Kombination von positivem Ureaseschnelltest mit positiver Histologie. Bei 92 Patienten stand Serum für einen IgG-ELISA-Test zur Verfügung. Ergebnisse: Der H.-pylori-Status war in 66% positiv. Die Sensitivität des HRBT lag bei 80%, die Spezifität bei 82%. Die Sensitivität des HRBT für einen positiven ELISA-Test betrug 87%, die Spezifität 96%. Schlussfolgerungen Die diagnostische Validität des HRBT reicht für die klinische Anwendung nicht aus. Falsche Testergebnisse summieren sich durch die Diskrepanz zwischen serologischen und bioptischen Methoden allgemein und durch eine gegenüber der ELISA-Serologie verminderte Sensitivität. Abstract Background and Aim: Rapid blood tests for diagnosis of Helicobacter (H.) pylori infection enable to detect antibodies against H. pylori instantly without laboratory equipment. Primary aim: to validate the Helisal™ Rapid Whole Blood Test (HRBT) with endoscopic bioptic methods as reference. Secondary aim: to compare the HRBT with ELISA IgG serology. Patients and Methods: The HRBT was performed in 145 consecutive dyspeptic patients (Median age 59 years) before undergoing esophago-gastroduodenoscopy including biopsies from gastric antrum and corpus. A positive H. pylori status was defined by a positive culture or the combination of a positive rapid urease test and a positive histology. Serum from ELISA IgG testing was available from 92 patients. Results: The H. pylori status was positive in 66% of the patients. The sensitivity of the HRBT resulted at 80%, the specificity at 82%. The sensitivity of the HRBT for a positive ELISA test amounted to 87%, the specificity to 96%. Conclusions: The diagnostic validity of the HRBT is insufficient for clinical application. False test results add up by the general discrepancy between serological and bioptic methods and by diminished sensitivity compared to ELISA serology.     

Dysfunctional attentional networks in children with attention deficit/hyperactivity disorder: evidence from an event-related functional magnetic resonance imaging study.

BACKGROUND: Although there is evidence for attentional dysfunction in children with attention deficit/hyperactivity disorder (ADHD), the neural basis of these deficits remains poorly understood. METHODS: We used event-related functional magnetic resonance imaging (fMRI) to investigate brain activations related to three particular aspects of attention: alerting, reorienting, and executive control. Sixteen medication-naive boys with ADHD and 16 healthy boys, aged 8 to 12 years, were studied. RESULTS: Behaviorally, children with ADHD showed a significant impairment only in their executive control system compared to healthy subjects. Neurally, children with ADHD (relative to controls) recruited deviant brain regions for all three attentional networks: less right-sided activation in the anterior cingulate gyrus during alerting, more fronto-striatal-insular activation during reorienting, and less fronto-striatal activation for executive control. ADHD symptom severity was associated with dysregulation of the blood oxygen level dependent (BOLD) signal within the putamen during reorienting and executive control. CONCLUSIONS: Our results demonstrated altered brain mechanism in ADHD associated with all three attentional networks investigated. For alerting and executive attention, our data indicate a deviant mechanism of cortical control, while ADHD children may have adopted altered strategies for reorienting of attention. Our results also stress the etiological role of functional abnormalities in the putamen in medication-naive ADHD.