Exploring attention in vr:Effects of visual and auditory modalities

Attention requires the ability to stay concentrated and alert to stimuli over prolonged periods of time. Virtual reality (VR) can be used in various training situations where attention plays a major role (e.g. system operators). Here, we investigate the effects of visual and auditory stimuli on attention performance in a VR aquarium (Nesplora Aquarium). Participants pay attention to the main fish tank and respond by pressing a button. The stimuli are different species of fish that are delivered either via visual or auditory channels. Thirty-seven participants completed the VR test and paper questionnaires. We found that attention is influenced differently by sensory modalities. Attention performance measured by the reaction time to correct targets and the number of errors of omission were better in the visual condition, while the number of errors of commission were lower in the auditory condition. The human factors’ role in attention tasks is also discussed.</p

Identification of the molecular signatures integral to regenerating photoreceptors in the retina of the zebra fish

Investigating neuronal and photoreceptor regeneration in the retina of zebra fish has begun to yield insights into both the cellular and molecular means by which this lower vertebrate is able to repair its central nervous system. However, knowledge about the signaling molecules in the local microenvironment of a retinal injury and the transcriptional events they activate during neuronal death and regeneration is still lacking. To identify genes involved in photoreceptor regeneration, we combined light-induced photoreceptor lesions, laser-capture microdissection of the outer nuclear layer (ONL) and analysis of gene expression to characterize transcriptional changes for cells in the ONL as photoreceptors die and are regenerated. Using this approach, we were able to characterize aspects of the molecular signature of injured and dying photoreceptors, cone photoreceptor progenitors, and microglia within the ONL. We validated changes in gene expression and characterized the cellular expression for three novel, extracellular signaling molecules that we hypothesize are involved in regulating regenerative events in the retina

The Teleost Retina as a Model for Developmental and Regeneration Biology

Retinal development in teleosts can broadly be divided into three epochs. The first is the specification of cellular domains in the larval forebrain that give rise to the retinal primordia and undergo early morphogenetic movements. The second is the neurogenic events within the retina proper—proliferation, cell fate determination, and pattern formation—that establish neuronal identities and form retinal laminae and cellular mosaics. The third, which is unique to teleosts and occurs in the functioning eye, is stretching of the retina and persistent neurogenesis that allows the growth of the retina to keep pace with the growth of the eye and other tissues. The first two events are rapid, complete by about 3 days postfertilization in the zebrafish embryo. The third is life-long and accounts for the bulk of retinal growth and the vast majority of adult retinal neurons. In addition, but clearly related to the retina's developmental history, lesions that kill retinal neurons elicit robust neuronal regeneration that originates from cells intrinsic to the retina. This paper reviews recent studies of retinal development in teleosts, focusing on those that shed light on the genetic and molecular regulation of retinal specification and morphogenesis in the embryo, retinal neurogenesis in larvae and adults, and injury-induced neuronal regeneration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63365/1/zeb.2004.1.257.pd

Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients

The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator. Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1–18 months, with a median follow-up of 6 months. Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3–18 months) with no in-field failures and were able to obtain encouraging toxicity profiles. Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity

Widespread Contribution of Gdf7 Lineage to Cerebellar Cell Types and Implications for Hedgehog-Driven Medulloblastoma Formation

The roof plate is a specialized embryonic midline tissue of the central nervous system that functions as a signaling center regulating dorsal neural patterning. In the developing hindbrain, roof plate cells express Gdf7 and previous genetic fate mapping studies showed that these cells contribute mostly to non-neural choroid plexus epithelium. We demonstrate here that constitutive activation of the Sonic hedgehog signaling pathway in the Gdf7 lineage invariably leads to medulloblastoma. Lineage tracing analysis reveals that Gdf7-lineage cells not only are a source of choroid plexus epithelial cells, but are also present in the cerebellar rhombic lip and contribute to a subset of cerebellar granule neuron precursors, the presumed cell-of-origin for Sonic hedgehog-driven medulloblastoma. We further show that Gdf7-lineage cells also contribute to multiple neuronal and glial cell types in the cerebellum, including glutamatergic granule neurons, unipolar brush cells, Purkinje neurons, GABAergic interneurons, Bergmann glial cells, and white matter astrocytes. These findings establish hindbrain roof plate as a novel source of diverse neural cell types in the cerebellum that is also susceptible to oncogenic transformation by deregulated Sonic hedgehog signaling

Medical school faculty discontent: prevalence and predictors of intent to leave academic careers

<p>Abstract</p> <p>Background</p> <p>Medical school faculty are less enthusiastic about their academic careers than ever before. In this study, we measured the prevalence and determinants of intent to leave academic medicine.</p> <p>Methods</p> <p>A 75-question survey was administered to faculty at a School of Medicine. Questions addressed quality of life, faculty responsibilities, support for teaching, clinical work and scholarship, mentoring and participation in governance.</p> <p>Results</p> <p>Of 1,408 eligible faculty members, 532 (38%) participated. Among respondents, 224 (40%; CI95: 0.35, 0.44) reported that their careers were not progressing satisfactorily; 236 (42%; CI95: 0.38, 0.46) were "seriously considering leaving academic medicine in the next five years." Members of clinical departments (OR = 1.71; CI95: 1.01, 2.91) were more likely to consider leaving; members of inter-disciplinary centers were less likely (OR = 0.68; CI95: 0.47, 0.98). The predictors of "serious intent to leave" included: Difficulties balancing work and family (OR = 3.52; CI95: 2.34, 5.30); inability to comment on performance of institutional leaders (OR = 3.08; CI95: 2.07, 4.72); absence of faculty development programs (OR = 3.03; CI95: 2.00, 4.60); lack of recognition of clinical work (OR = 2.73; CI95: 1.60, 4.68) and teaching (OR = 2.47; CI95: 1.59, 3.83) in promotion evaluations; absence of "academic community" (OR = 2.67; CI95: 1.86, 3.83); and failure of chairs to evaluate academic progress regularly (OR = 2.60; CI95: 1.80, 3.74).</p> <p>Conclusion</p> <p>Faculty are a medical school's key resource, but 42 percent are seriously considering leaving. Medical schools should refocus faculty retention efforts on professional development programs, regular performance feedback, balancing career and family, tangible recognition of teaching and clinical service and meaningful faculty participation in institutional governance.</p

Biophysical Studies of the Membrane-Embedded and Cytoplasmic Forms of the Glucose-Specific Enzyme II of the E. coli Phosphotransferase System (PTS)

The glucose Enzyme II transporter complex of the Escherichia coli phosphotransferase system (PTS) exists in at least two physically distinct forms: a membrane-integrated dimeric form, and a cytoplasmic monomeric form, but little is known about the physical states of these enzyme forms. Six approaches were used to evaluate protein-protein and protein-lipid interactions in this system. Fluorescence energy transfer (FRET) using MBP-IIGlc-YFP and MBP-IIGlc-CFP revealed that the homodimeric Enzyme II complex in cell membranes is stable (FRET-) but can be dissociated and reassociated to the heterodimer only in the presence of Triton X100 (FRET+). The monomeric species could form a heterodimeric species (FRET+) by incubation and purification without detergent exposure. Formaldehyde cross linking studies, conducted both in vivo and in vitro, revealed that the dimeric MBP-IIGlc activity decreased dramatically with increasing formaldehyde concentrations due to both aggregation and activity loss, but that the monomeric MBP-IIGlc retained activity more effectively in response to the same formaldehyde treatments, and little or no aggregation was observed. Electron microscopy of MBP-IIGlc indicated that the dimeric form is larger than the monomeric form. Dynamic light scattering confirmed this conclusion and provided quantitation. NMR analyses provided strong evidence that the dimeric form is present primarily in a lipid bilayer while the monomeric form is present as micelles. Finally, lipid analyses of the different fractions revealed that the three lipid species (PE, PG and CL) are present in all fractions, but the monomeric micellar structure contains a higher percentage of anionic lipids (PG & CL) while the dimeric bilayer form has a higher percentage of zwitterion lipids (PE). Additionally, evidence for a minor dimeric micellar species, possibly an intermediate between the monomeric micellar and the dimeric bilayer forms, is presented. These results provide convincing evidence for interconvertible physical forms of Enzyme-IIGlc

Descriptive epidemiology of selected birth defects, areas of Lombardy, Italy, 1999

<p>Abstract</p> <p>Background</p> <p>Birth defects are a leading cause of neonatal and infant mortality in Italy, however little is known of the etiology of most defects. Improvements in diagnosis have revealed increasing numbers of clinically insignificant defects, while improvements in treatment have increased the survival of those with more serious and complex defects. For etiological studies, prevention, and management, it is important to have population-based monitoring which provides reliable data on the prevalence at birth of such defects.</p> <p>Methods</p> <p>We recently initiated population-based birth defect monitoring in the Provinces of Mantova, Sondrio and Varese of the Region of Lombardy, northern Italy, and report data for the first year of operation (1999). The registry uses all-electronic source files (hospital discharge files, death certificates, regional health files, and pathology reports) and a proven case-generation methodology, which is described.</p> <p>The data were checked manually by consulting clinical records in hospitals. Completeness was checked against birth certificates by capture-recapture. Data on cases were coded according to the four-digit malformation codes of the International Classification of Diseases, Ninth Revision (ICD-9). We present data only on selected defects.</p> <p>Results</p> <p>We found 246 selected birth defects in 12,008 live births in 1999, 148 among boys and 98 among girls. Congenital heart defects (particularly septal defects) were the most common (90.8/10,000), followed by defects of the genitourinary tract (34.1/10, 000) (particularly hypospadias in boys), digestive system (23.3/10,000) and central nervous system (14.9/10,000), orofacial clefts (10.8/10,000) and Down syndrome (8.3/10,000). Completeness was satisfactory: analysis of birth certificates resulted in the addition of two birth defect cases to the registry.</p> <p>Conclusion</p> <p>This is the first population-based analysis on selected major birth defects in the Region. The high birth prevalences for septal heart defect and hypospadias are probably due to the inclusion of minor defects and lack of coding standardization; the latter problem also seems important for other defects. However the data produced are useful for estimating the demands made on the health system by babies with birth defects.</p

The bed nucleus of stria terminalis and the amygdala as targets of antenatal glucocorticoids: implications for fear and anxiety responses

Rationale: Several human and experimental studies have shown that early life adverse events can shape physical and mental health in adulthood. Stress or elevated levels of glucocorticoids (GCs) during critical periods of development seem to contribute for the appearance of neurospyschiatric conditions such as anxiety and depression, albeit the underlying mechanisms remain to be fully elucidated. Objectives: The aim of the present study was to determine the long-term effect of prenatal erxposure to dexamethasone- DEX (synthetic GC widely used in clinics) in fear and anxious behavior and identify the neurochemical, morphological and molecular correlates. Results: Prenatal exposure to DEX triggers a hyperanxious phenotype and altered fear behavior in adulthood. These behavioral traits were correlated with increased volume of the bed nucleus of the stria terminalis (BNST), particularly the anteromedial subivision which presented increased dendritic length; in parallel, we found an increased expression of synapsin and NCAM in the BNST of these animals. Remarkably, DEX effects were opposite in the amygdala, as this region presented reduced volume due to significant dendritic atrophy. Albeit no differences were found in dopamine and its metabolite levels in the BNST, this neurotransmitter was substantially reduced in the amygdala, which also presented an up-regulation of dopamine receptor 2. Conclusions: Altogether our results show that in utero DEX exposure can modulate anxiety and fear behavior in parallel with significant morphological, neurochemical and molecular changes; importantly, GCs seem to differentially affect distinct brain regions involved in this type of behaviors.This study was supported by a grant from the Institute for the Study of Affective Neuroscience (ISAN). AJR is supported by a Fundação para a Ciência e Tecnologia (FCT) grant

Genetics of photoreceptor degeneration and regeneration in zebrafish

Zebrafish are unique in that they provide a useful model system for studying two critically important problems in retinal neurobiology, the mechanisms responsible for triggering photoreceptor cell death and the innate stem cell–mediated regenerative response elicited by this death. In this review we highlight recent seminal findings in these two fields. We first focus on zebrafish as a model for studying photoreceptor degeneration. We summarize the genes currently known to cause photoreceptor degeneration, and we describe the phenotype of a few zebrafish mutants in detail, highlighting the usefulness of this model for studying this process. In the second section, we discuss the several different experimental paradigms that are available to study regeneration in the teleost retina. A model outlining the sequence of gene expression starting from the dedifferentiation of Müller glia to the formation of rod and cone precursors is presented