Regulation of anterior insular cortex activity using real-time fMRI

Recent advances in functional magnetic resonance imaging (fMRI) data acquisition and processing techniques have made real-time fMRI (rtfMRI) of localized brain areas feasible, reliable and less susceptible to artefacts. Previous studies have shown that healthy subjects learn to control local brain activity with operant training by using rtfMRI-based neurofeedback. In the present study, we investigated whether healthy subjects could voluntarily gain control over right anterior insular activity. Subjects were provided with continuously updated information of the target ROI's level of activation by visual feedback. All participants were able to successfully regulate BOLD-magnitude in the right anterior insular cortex within three sessions of 4 min each. Training resulted in a significantly increased activation cluster in the anterior portion of the right insula across sessions. An increased activity was also found in the left anterior insula but the percent signal change was lower than in the target ROI. Two different control conditions intended to assess the effects of non-specific feedback and mental imagery demonstrated that the training effect was not due to unspecific activations or non feedback-related cognitive strategies. Both control groups showed no enhanced activation across the sessions, which confirmed our main hypothesis that rtfMRI feedback is area-specific. The increased activity in the right anterior insula during training demonstrates that the effects observed are anatomically specific and self-regulation of right anterior insula only is achievable. This is the first group study investigating the volitional control of emotionally relevant brain region by using rtfMRI training and confirms that self-regulation of local brain activity with rtfMRI is possible.     

Temporal classification of multichannel near-infrared spectroscopy signals of motor imagery for developing a brain-computer interface

There has been an increase in research interest for brain-computer interface (BCI) technology as an alternate mode of communication and environmental control for the disabled, such as patients suffering from amyotrophic lateral sclerosis (ALS), brainstem stroke and spinal cord injury. Disabled patients with appropriate physical care and cognitive ability to communicate with their social environment continue to live with a reasonable quality of life over extended periods of time. Near-infrared spectroscopy is a non-invasive technique which utilizes light in the near-infrared range (700 to 1000 nm) to determine cerebral oxygenation, blood flow and metabolic status of localized regions of the brain. In this paper, we describe a study conducted to test the feasibility of using multichannel NIRS in the development of a BCI. We used a continuous wave 20-channel NIRS system over the motor cortex of 5 healthy volunteers to measure oxygenated and deoxygenated hemoglobin changes during left-hand and right-hand motor imagery. We present results of signal analysis indicating that there exist distinct patterns of hemodynamic responses which could be utilized in a pattern classifier towards developing a BCI. We applied two different pattern recognition algorithms separately, Support Vector Machines (SVM) and Hidden Markov Model (HMM), to classify the data offline. SVM classified left-hand imagery from right-hand imagery with an average accuracy of 73% for all volunteers, while HMM performed better with an average accuracy of 89%. Our results indicate potential application of NIRS in the development of BCIs. We also discuss here future extension of our system to develop a word speller application based on a cursor control paradigm incorporating online pattern classification of single-trial NIRS data.     

Impact of an educational tool on young women’s knowledge of cervical cancer screening recommendations

Cancer Causes & Control - Current cervical cancer screening guidelines recommend 3-year screening intervals, in contrast to the previous recommendation of annual screening, to prevent over...     

Using real-time fMRI to learn voluntary regulation of the anterior insula in the presence of threat-related stimuli

Previous studies have shown that healthy participants learn to control local brain activity with operant training by using real-time functional magnetic resonance imaging (rt-fMRI). Very little data exist, however, on the dynamics of interaction between critical brain regions during rt-fMRI-based training. Here, we examined self-regulation of stimulus-elicited insula activation and performed a psychophysiological interaction (PPI) analysis of real-time self-regulation data. During voluntary up-regulation of the left anterior insula in the presence of threat-related pictures, differential activations were observed in the ventrolateral prefrontal cortex, the frontal operculum, the middle cingulate cortex and the right insula. Down-regulation in comparison to no-regulation revealed additional activations in right superior temporal cortex, right inferior parietal cortex and right middle frontal cortex. There was a significant learning effect over sessions during up-regulation, documented by a significant improvement of anterior insula control over time. Connectivity analysis revealed that successful up-regulation of the activity in left anterior insula while viewing aversive pictures was directly modulated by dorsomedial and ventrolateral prefrontal cortex. Down-regulation of activity was more difficult to achieve and no learning effect was observed. More extensive training might be necessary for successful down-regulation. These findings illustrate the functional interactions between different brain areas during regulation of anterior insula activity in the presence of threat-related stimuli.     

A comparison of human smooth muscle and mesenchymal stem cells as potential cell sources for tissue-engineered vascular patches

In pediatric patients requiring vascular reconstruction, the development of a cell-based tissue-engineered vascular patch (TEVP) has great potential to overcome current issues with nonliving graft materials. Determining the optimal cell source is especially critical to TEVP success. In this study, we compared the ability of human aortic smooth muscle cells (HuAoSMCs) and human mesenchymal stem cells (hMSCs) to form cell sheets on thermoresponsive poly(N-isopropylacrylamide) (PIPAAm) substrates. hMSCs treated with transforming growth factor beta 1 (TGFβ1) and ascorbic acid (AA) had higher expression of SMC-specific proteins compared to HuAoSMCs. hMSCs also had larger cell area and grew to confluence more quickly on PIPAAm than did HuAoSMCs. hMSCs typically formed cell sheets in 2-3 weeks and had greater wet tissue weight and collagen content compared with HuAoSMC sheets, which generally required growth for up to 5 weeks. Assays for calcification and alkaline phosphatase activity revealed that the osteogenic potential of TGFβ1+AA-treated hMSCs was low; however, Alcian Blue staining suggested high chondrogenic behavior of TGFβ1+AA-treated hMSCs. Although hMSCs are promising for cell-based TEVPs in their ability to form robust tissue with significant extracellular matrix content, improved control over hMSC behavior will be required for long-term TEVP success.     

Extraovarian primary peritoneal papillary serous carcinoma

Objective  

To identify an unusual histologic entity, extraovarian primary peritoneal carcinoma (EOPPC) along with a review of the recent literature.     

Observations on the metabolism of the psychotomimetic indolealkylamines: implications for future clinical studies

Although the psychotomimetic indolealkylamines N,N-dimethyltryptamine, 5-methoxy-N,N-dimethyltryptamine, and 5-hydroxy-N,N-dimethyltryptamine have been unequivocally identified in human body fluids, evidence relating their concentration to the presence of psychotic illness in humans remains controversial. A series of studies on the metabolism of the compounds in the rat have highlighted the rapidity and with which these are metabolized and renally excreted. The implications of our observation for the interpretation of past clinical studies and the design of future ones is discussed.     

Formation and repair of DNA lesions in kidneys of male mice after acute exposure to methyl chloride

The time-course of DNA lesions (DNA-protein cross-links, single-strand breaks) induced by high concentrations of methyl chloride (1000 ppm) was measured in renal tissue of male mice by means of the alkaline elution assay in order to gain an insight into repair processes. DNA-protein cross-links were removed at a fast rate, whereas single-strand breaks appeared to accumulate, even during repair of DNA-protein cross-links. However, 48 h after exposure to methyl chloride, neither of these lesions were detectable in mouse kidney. Both types of DNA damage were ascribed to the action of formaldehyde, an intermediate in methyl chloride metabolism which may react with nucleic acids and protein and interfere with DNA repair.This paper is compiled from the thesis of C. Ristau submitted to the Faculty of Biology of the Ruhr-Universität Bochum (Ristau 1989). The detailed data and statistical assessment are contained in the appendix of this thesis