The influence of visual training on predicting complex action sequences

Linking observed and executable actions appears to be achieved by an action observation network (AON), comprising parietal, premotor, and occipitotemporal cortical regions of the human brain. AON engagement during action observation is thought to aid in effortless, efficient prediction of ongoing movements to support action understanding. Here, we investigate how the AON responds when observing and predicting actions we cannot readily reproduce before and after visual training. During pre‐ and posttraining neuroimaging sessions, participants watched gymnasts and wind‐up toys moving behind an occluder and pressed a button when they expected each agent to reappear. Between scanning sessions, participants visually trained to predict when a subset of stimuli would reappear. Posttraining scanning revealed activation of inferior parietal, superior temporal, and cerebellar cortices when predicting occluded actions compared to perceiving them. Greater activity emerged when predicting untrained compared to trained sequences in occipitotemporal cortices and to a lesser degree, premotor cortices. The occipitotemporal responses when predicting untrained agents showed further specialization, with greater responses within body‐processing regions when predicting gymnasts' movements and in object‐selective cortex when predicting toys' movements. The results suggest that (1) select portions of the AON are recruited to predict the complex movements not easily mapped onto the observer's body and (2) greater recruitment of these AON regions supports prediction of less familiar sequences. We suggest that the findings inform both the premotor model of action prediction and the predictive coding account of AON function. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.     

Local and systemic humoral immune response to protein I of Neisseria gonorrhoeae]

Knowledge of the immune response to natural infection with Neisseria gonorrhoeae is presupposition for the development of a gonococcal vaccine. Pili and protein I have gained importance for a subunite vaccine. A pilus vaccine proved to be ineffective in a field trial due to extensive pilus variability. According to an alternative strategy protein I may represent an important vaccine candidate for a gonococcal vaccine. To study the local and systemic, humoral immune response to N. gonorrhoeae cervical secretion, vaginal fluid and serum from prostitutes and family planning patients were compared by the use of a protein I ELISA. In local secretions and in serum patients in the study group showed significantly higher anti-protein-I-IgA-levels than patients in the control group. In cervical secretion immune response to an acute gonococcal infection consisted of a short lived, significant increase of anti-protein-I-IgA, while anti-protein-I-IgG showed a lower, but longer lasting significant increase. The course of the immune response in vaginal fluid reflected the immune response of cervical secretion at a lower level. In serum antigenic stimulus of a local gonococcal infection resulted in a significant but short lived protein I specific IgG immune response. In local infection with N. gonorrhoeae protein I represents a target antigen of the local and systemic immune response. Clear differences exist between local and systemic humoral immune response in the protein I reactive immunoglobulin class and in the course of reactivity. In the future it may be possible to define epitopes on protein I which induce protective immunity.     

Detection of Papillary Thyroid Carcinoma by Analysis of BRAF and RET/PTC1 Mutations in Fine-needle Aspiration Biopsies of Thyroid Nodules

Background  

Activating mutations of the oncogene BRAF or rearrangements of the tyrosine kinase receptor RET are observed in up to 80% of papillary thyroid carcinomas (PTCs). The predominant BRAF V600E mutation has not been detected in benign thyroid tissue so far, so consequently, this assumedly pathognomonic alteration is qualified to improve the preoperative diagnosis of PTC.     

Assessment of cerebral autoregulation with transcranial Doppler sonography in poor bone windows using constant infusion of an ultrasound contrast agent

Cerebral autoregulation is an important pathophysiological and prognostic parameter for a variety of neurologic conditions. It can be assessed quickly and safely using transcranial Doppler sonography (TCD). In elderly patients, poor insonation conditions decrease the number of examinable patients and can cause a systematic bias in autoregulation parameters. The aim of this study was to investigate whether a constant infusion of an ultrasound contrast agent (Levovist((R))) can counteract these effects. We examined two cohorts of unselected neurologic patients. In 45 patients with good insonation windows (cohort 1), we used a thin aluminium foil between the skin and the TCD probe to artificially decrease the insonation quality. We determined two parameters of cerebral autoregulation (phase difference [PD] and a cross-correlation coefficient [Mx]) in native patients, with aluminium foil and with aluminium foil and a constant infusion of Levovist. In 30 patients with poor insonation windows (cohort 2), we measured the autoregulation twice, with and without an infusion of Levovist, to assess the reproducibility of the autoregulation parameters. In cohort 1, the foil model significantly decreased the Doppler signal quality, i.e., the mean spectrum energy decreased from 33.9 +/- 2.7 dB to 26.3 +/- 2.4 dB (p < 0.001). This introduced a significant bias to all autoregulation parameters (PD: decreased from 38.2 +/- 10.0 degrees to 27.9 +/- 12.5 degrees (p < 0.001); Mx: decreased from 0.308 +/- 0.170 to 0.254 +/- 0.162 (p < 0.01)). Both effects were compensated largely by a constant infusion of Levovist (300 mg/min). In cohort 2, infusion of the contrast agent at the same rate increased insonation quality, too, but to a lesser degree (27.4 +/- 2.4 dB to 32.0 +/- 3.7 dB, p < 0.001). This smaller increase did not cause a significant change in the autoregulation parameters, but the reproducibility of the PD was significantly improved (intraclass coefficient coefficient [ICC] 0.76, 95% confidence interval [0.59-0.87] in native poor bone window compared with ICC 0.90, 95% confidence interval [0.81-0.95] with infusion of the contrast agent). Our data show that constant infusion of an ultrasound contrast agent during the assessment of cerebral autoregulation can avoid potential bias introduced by poor insonation conditions. Furthermore, infusion of the contrast agent can improve reproducibility and contribute to the credibility of autoregulation assessment in the elderly. (E-mail: matthias.lorenz@em.uni-frankfurt.de).