Neurocognitive Mechanisms of Synesthesia

SummarySynesthesia is a condition in which stimulation of one sensory modality causes unusual experiences in a second, unstimulated modality. Although long treated as a curiosity, recent research with a combination of phenomenological, behavioral, and neuroimaging methods has begun to identify the cognitive and neural basis of synesthesia. Here, we review this literature with an emphasis on grapheme-color synesthesia, in which viewing letters and numbers induces the perception of colors. We discuss both the substantial progress that has been made in the past fifteen years and some open questions. In particular, we focus on debates in the field relating to the neural basis of synesthesia, including the relationship between synesthesia and attention and the role of meaning in synesthetic colors. We propose that some, but probably not all, of these differences can be accounted for by differences in the synesthetes studied and discuss some methodological implications of these individual differences

The role of Botanic Gardens in the Conservation of Wild and Native Flora

The present study highlights the role of botanic gardens in the conservation of wild and native floristic elements. It is observed that, there is a total of 33 species of plants belonging to 26 families and 28 genera. Out of 33 species, 19-species are conserved asex-situ and 14-species by in-situ methods

An “off-the shelf” Synthetic Membrane to Simplify Regeneration of Damaged Corneas

yesOur overall aim is to develop a synthetic off-the-shelf alternative to human amniotic membrane which is currently used for delivering cultured limbal stem cells to the cornea in patients who suffer scarring of the cornea because of the loss of limbal stem cells. We have recently reported that both cultured cells and limbal explants grow well on electrospun Poly(D,L-lactide-co-glycolide) (PLGA) (44 kg/mol) with a 50:50 ratio of lactide and glycolide and sterilized with γ-irradiation. Prior to undertaking a clinical study our immediate aim now is to achieve long term storage of the membranes in convenient to use packaging. Membranes were electrospun from Poly(D,L-lactide-co-glycolide) (44 kg/mol) with a 50:50 ratio of lactide and glycolide and sterilized with γ-irradiation and then stored dry (with desiccant) for several months at -80°C and -20°C , Room temperature (UK and India), 37°C and 50°C. We explored the contribution of vacuum sealing and the use of a medical grade bag (PET/Foil/LDPE) to achieve a longer shelf life. Confirmation of membranes being suitable for clinical use was obtained by culturing tissue explants on membranes post storage. When scaffolds were stored dry the rate of breakdown was both temperature and time dependent. At -20°C and -80°C there was no change in fiber diameter over 18 months of storage, and membranes were stable for 12 months at 4°C while at 50°C (above the transition temperature for PLGA) scaffolds lost integrity after several weeks. The use of vacuum packaging and a medical grade bag both improved the storage shelf-life of the scaffolds. The impact of temperature on storage is summarized beneath. We report that this synthetic membrane can be used as an off-the-shelf or-out-of-the freezer alternative to the amniotic membrane for corneal regeneration

Motion integration using competitive priors

Psychophysical experiments show that humans are better at perceiving rotation and expansion than translation [5][9]. These findings are inconsistent with standard models of motion integration which predict best performance for translation. To explain this discrepancy, our theory formulates motion perception at two levels of inference: we first perform model selection between the competing models (e.g. translation, rotation, and expansion) and then estimate the velocity using the selected model. We define novel prior models for smooth rotation and expansion using techniques similar to those in the slow-and-smooth model [23] (e.g. Green functions of differential operators). The theory gives good agreement with the trends observed in four human experiments

Synthetic biodegradable alternatives to the use of the amniotic membrane for corneal regeneration: assessment of local and systemic toxicity in rabbits.

AIM: The aim of this study was to assess the local and systemic response to poly-lactic co-glycolic acid (PLGA) 50:50 membranes, developed as synthetic biodegradable alternatives to the use of human donor amniotic membrane in the treatment of limbal stem cell deficiency. METHODS: PLGA membranes of 2  cm diameter and 50  µm thickness were placed on one eye of rabbits and secured in place using fibrin glue and a bandage contact lens, suturing the eye close with a single stitch. Control animals were treated identically, with the absence of the membranes. Plain and microfabricated electrospun membranes (containing micropockets which roughly emulate the native limbal niche) were examined over 29 days. All animals were subjected to a detailed gross and histopathological observation as well as a detailed examination of the eye. RESULTS: Application of the membranes both with and without microfabricated pockets did not adversely affect animal welfare. There was complete degradation of the membranes by day 29. The membranes did not induce any significant local or systemic toxicity. Conjunctival congestion and corneal vascularisation were noted in a few control and PLGA-treated animals. Intraocular pressure was normal and the retinal status was unaltered. The ocular surface was clear and intact in all animals by the end of 29  days. CONCLUSION: Membranes of 50:50 PLGA can be safely applied to rabbit corneas without inducing any local or systemic toxicity and these break down completely within 29 days