Cortical excitability and the shape of the haemodynamic response

Individual differences in the temporal dynamics of the haemodynamic response can reflect cortical excitation and can reveal underlying cortical physiology. Here, we show differences in the shape of the haemodynamic response that are dependent on stimulus parameters. Two sets of visual stimuli were used varying in parameters that are known to manipulate the haemodynamic response in the visual cortex. We measured the oxyhaemoglobin response using near infrared spectroscopy. The first set of stimuli comprised chromatic square-wave gratings that varied with respect to the separation in the CIE UCS chromaticities of the alternating bars. The gratings with large separations in chromaticity evoked an oxyhaemoglobin response with greater amplitude, consistent with greater activation of the visual cortex. The second set of stimuli comprised horizontal achromatic gratings that (1) were static, (2) drifted at a constant velocity towards fixation, or (3) reversed direction every half spatial cycle to create a vertical vibrating motion. Although the three types of grating had a similar effect on the amplitude of the oxyhaemoglobin response, the moving gratings (2 and 3) evoked a steeper decrease in oxyhaemoglobin concentration after stimulus-offset. The steeper slope appears to reflect the post-stimulus undershoot and the slope may provide a correlate of cortical excitability when the amplitude of the haemodynamic response has saturated

Photophobia in migraine: A symptom cluster?

Photophobia is one of the most common symptoms in migraine, and the underlying mechanism is uncertain. The discovery of the intrinsically-photosensitive retinal ganglion cells which signal the intensity of light on the retina has led to discussion of their role in the pathogenesis of photophobia. In the current review, we discuss the relationship between pain and discomfort leading to light aversion (traditional photophobia) and discomfort from flicker, patterns, and colour that are also common in migraine and cannot be explained solely by the activity of intrinsically-photosensitive retinal ganglion cells. We argue that, at least in migraine, a cortical mechanism provides a parsimonious explanation for discomfort from all forms of visual stimulation, and that the traditional definition of photophobia as pain in response to light may be too restrictive. Future investigation that directly compares the retinal and cortical contributions to photophobia in migraine with that in other conditions may offer better specificity in identifying biomarkers and possible mechanisms to target for treatment

Using coloured filters to reduce the symptoms of visual stress in children with reading delay

Background: Meares Irlen Syndrome (MIS), otherwise known as “visual stress”, is one condition that can cause difficulties with reading. Aim: This study aimed to compare the effect of two coloured-filter systems on the symptoms of visual stress in children with reading delay. Methods: The study design was a pre-test, post-test, randomized head-to-head comparison of two filter systems on the symptoms of visual stress in school children. A total of 68 UK mainstream schoolchildren with significant impairment in reading ability completed the study. Results: The filter systems appeared to have a large effect on the reported symptoms between pre and post three-month time points (d = 2.5, r = 0.78). Both filter types appeared to have large effects (Harris d = 1.79, r = 0.69 and DRT d = 3.22, r = 0.85). Importantly, 35% of participants’ reported that their symptoms had resolved completely; 72% of the 68 children appeared to gain improvements in three or more visual stress symptoms. Conclusion and significance: The reduction in symptoms, which appeared to be brought about by the use of coloured filters, eased the visual discomfort experienced by these children when reading. This type of intervention therefore has the potential to facilitate occupational engagement

RNA-Seq analysis and comparison of corneal epithelium in keratoconus and myopia patients

© 2017 The Author(s). Keratoconus is a common degenerative corneal disease that can lead to significant visual morbidity, and both genetic and environmental factors have been implicated in its pathogenesis. We compared the transcriptome of keratoconus and control epithelium using RNA-Seq. Epithelial tissues were obtained prior to surgery from keratoconus and myopia control patients, undergoing collagen cross-linking and photorefractive keratectomy, respectively. We identified major differences in keratoconus linked to cell-cell communication, cell signalling and cellular metabolism. The genes associated with the Hedgehog, Wnt and Notch1 signaling pathways were down-regulated in keratoconus. We also identified plasmolipin and Notch1 as being significantly reduced in keratoconus for both gene and protein expression (p < 0.05). Plasmolipin is a novel protein identified in human corneal epithelium, and has been demonstrated to have a key role in epithelial cell differentiation in other tissues. This study shows altered gene and protein expression of these three proteins in keratoconus, and further studies are clearly warranted to confirm the functional role of these proteins in the pathogenesis of keratoconus

Author Correction: RNA-Seq analysis and comparison of corneal epithelium in keratoconus and myopia patients.

In the original version of this Article, a relevant paper on the detection of PLLP in human corneal epithelium during KC pathogenesis was not cited. This article is now cited as Ref 56 and discussed. As a result, in the Conclusion, "Notch1 and PLLP have not previously been linked to KC pathogenesis. PLLP has not been previously reported to be expressed in human corneal epithelium, although its roles in other tissues suggests it could play a critical role in normal corneal epithelial cellular activities, and interact with the Notch1 signaling pathway." now reads: "Notch1 has not previously been linked to KC pathogenesis. PLLP was reported to be upregulated in KC corneal epithelium compared to normal through proteomic analysis56. Both previous finding and our paper suggested an abnormal expression of PLLP in KC, however our study showed PLLP was down-regulated in KC. The difference can be attributed to the sample types and preparation. Myopia rather than normal corneal samples were used as control in this study. We measured and compared PLLP expression in each sample, whereas the previous study used pooled sample56 and therefore may mask the individual differences. The role of PLLP in human corneal epithelium is unclear, however findings from studies in other tissues suggest that it could be important in maintaining normal corneal epithelial cellular activities and interact with the Notch 1 signalling pathway." Subsequent references in the Article have been renumbered accordingly. The original Article has been corrected

INFERRED H alpha FLUX AS A STAR FORMATION RATE INDICATOR AT z similar to 4-5: IMPLICATIONS FOR DUST PROPERTIES, BURSTINESS, AND THE z=4-8 STAR FORMATION RATE FUNCTIONS

We derive Hα fluxes for a large spectroscopic and photometric-redshift-selected sample of sources over GOODS-North and South in the redshift range z = 3.8–5.0 with deep Hubble Space Telescope (HST), Spitzer/IRAC, and ground-based observations. The Hα flux is inferred based on the offset between the IRAC 3.6 μm flux and that predicted from the best-fit spectral energy distribution (SED). We demonstrate that the Hα flux correlates well with dust-corrected UV star formation rate (SFR) and therefore can serve as an independent SFR indicator. However, we also find a systematic offset in the ${\mathrm{SFR}}_{{\rm{H}}\alpha }/{\mathrm{SFR}}_{\mathrm{UV}+\beta }$ ratios for z ~ 4–5 galaxies relative to local relations (assuming the same dust corrections for nebular regions and stellar light). We show that we can resolve the modest tension in the inferred SFRs by assuming bluer intrinsic UV slopes (increasing the dust correction), a rising star formation history, or assuming a low-metallicity stellar population with a hard ionizing spectrum (increasing the ${L}_{{\rm{H}}\alpha }/\mathrm{SFR}$ ratio). Using Hα as an SFR indicator, we find a normalization of the star formation main sequence in good agreement with recent SED-based determinations and also derive the SFR functions at z\sim 4\mbox{--}8. In addition, we assess for the first time the burstiness of star formation in $z\sim 4$ galaxies on <100 Myr timescales by comparing UV and Hα-based sSFRs; their one-to-one relationship argues against significantly bursty star formation histories

A Cross-Sectional Study of People with Epilepsy and Neurocysticercosis in Tanzania: Clinical Characteristics and Diagnostic Approaches.

Neurocysticercosis (NCC) is a major cause of epilepsy in regions where pigs are free-ranging and hygiene is poor. Pork production is expected to increase in the next decade in sub-Saharan Africa, hence NCC will likely become more prevalent. In this study, people with epilepsy (PWE, n=212) were followed up 28.6 months after diagnosis of epilepsy. CT scans were performed, and serum and cerebrospinal fluid (CSF) of selected PWE were analysed. We compared the demographic data, clinical characteristics, and associated risk factors of PWE with and without NCC. PWE with NCC (n=35) were more likely to be older at first seizure (24.3 vs. 16.3 years, p=0.097), consumed more pork (97.1% vs. 73.6%, p=0.001), and were more often a member of the Iraqw tribe (94.3% vs. 67.8%, p=0.005) than PWE without NCC (n=177). PWE and NCC who were compliant with anti-epileptic medications had a significantly higher reduction of seizures (98.6% vs. 89.2%, p=0.046). Other characteristics such as gender, seizure frequency, compliance, past medical history, close contact with pigs, use of latrines and family history of seizures did not differ significantly between the two groups. The number of NCC lesions and active NCC lesions were significantly associated with a positive antibody result. The electroimmunotransfer blot, developed by the Centers for Disease Control and Prevention, was more sensitive than a commercial western blot, especially in PWE and cerebral calcifications. This is the first study to systematically compare the clinical characteristics of PWE due to NCC or other causes and to explore the utility of two different antibody tests for diagnosis of NCC in sub-Saharan Africa

Oral Contraceptives and Periodontal Diseases: Rethinking the Association Based Upon Analysis of National Health and Nutrition Examination Survey Data

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141450/1/jper1374.pd

Sea level: measuring the bounding surfaces of the ocean

The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea level change, this paper focuses on contributions from geodesy and the role of the ocean’s bounding surfaces: the sea surface and the Earth’s crust

The Experience of Quality in Higher Education in the United Arab Emirates: In Times of Rapid Change and Complexities

In less than five decades, from offering formal education only in a few schools to a small tribal community to providing a selection of three public and approximately 100 private higher education institutions to the citizens of seven emirates creates a unique context in the United Arab Emirates (UAE). It is an evolution that corresponds with its remarkable economic growth. Quality assurance of diverse higher educational institutions requires complex schemes to ensure their fitness for purpose, while perhaps development and enhancement aspects need time to mature. The quality of the education is especially important because the UAE yearns for the diversified and knowledge-based economy; one that is led by its own citizens whose contribution to the workforce is currently less than 10%. This chapter highlights contextual complexities in the UAE that might have direct and/or indirect impacts on the quality experiences in the higher education sector, with proposed recommendations