47 research outputs found

    Kafkaesque Absurdity in the Aesthetics of Beckett and Giacometti

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    The complex zone of what I refer to as the aesthetical absurd is examined in the works of Modernists Kafka, Giacometti, and Beckett. This aesthetic zone, addressed through cognitive poetics, exists between artistic notion, the artist’s ideal cognitive image, and the actual performance or resulting image born in reality. Artistic ideal is evaluated as the aesthetic image or notion that exists in a tentative nascent and emotive state, but one that the artist strives to produce in the world—to reconstruct from the cognitive zone of creativity—but at times fails to bring to completion or fruition. This ever present bifurcation between these two conflictive states leads to a new view of the Sisyphean absurd. Kafka stands as the beginning point of the discussion. His fragmented, at times incomplete, writing serves as a touchstone to position the aesthetics of the later Beckett and Giacometti, a sculptor. Beckett mirrors Kafka’s sensibility, and relates his negative aesthetic, one lacking or hiding any visible scaffolding for the artistic process. Beckett and Giacometti were friends and collaborated on crafting props for a staging of his signature play Waiting for Godot, a failed attempt. An assessment of the aesthetics of these three artists advances the understanding of their works in terms of the aesthetical absurd

    In vivo neurophysiological recordings from geniculate ganglia: taste response properties of individual greater superficial petrosal and chorda tympani neurones

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    Coding of gustatory information is complex and unique among sensory systems; information is received by multiple receptor populations located throughout the oral cavity and carried to a single central relay by four separate nerves. The geniculate ganglion is the location of the somata of two of these nerves, the greater superficial petrosal (GSP) and the chorda tympani (CT). The GSP innervates taste buds on the palate and the CT innervates taste buds on the anterior tongue. To obtain requisite taste response profiles of GSP neurones, we recorded neurophysiological responses to taste stimuli of individual geniculate ganglion neurones in vivo in the rat and compared them to those from the CT. GSP neurones had a distinct pattern of responding compared to CT neurones. For example, a small subset of GSP neurones had high response frequencies to sucrose stimulation, whereas no CT neurones had high response frequencies to sucrose. In contrast, NaCl elicited high response frequencies in a small subset of CT neurones and elicited moderate response frequencies in a relatively large proportion of GSP neurones. The robust whole‐nerve response to sucrose in the GSP may be attributable to relatively few, narrowly tuned neurones, whereas the response to NaCl in the GSP may relate to proportionately more, widely tuned neurones. These results demonstrate the diversity in the initial stages of sensory coding for two separate gustatory nerves involved in the ingestion or rejection of taste solutions, and may have implications for central coding of gustatory quality and concentration as well as coding of information used in controlling energy, fluid and electrolyte homeostasis

    Injury-Induced Functional Plasticity in the Peripheral Gustatory System

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    Combining unilateral denervation of anterior tongue taste buds with a low-sodium diet in rats results in a rapid, dramatic, and selective attenuation of neurophysiological sodium taste responses from the intact side of the tongue. The transduction pathway responsible for the attenuated response is through the epithelial sodium channel (Hill and Phillips, 1994). Current experiments extend these findings by detailing the effects of experimentally induced injury on taste responses from anterior tongue taste receptors in sodium-restricted rats. Experiments focused on functional salt taste responses from the intact chorda tympani nerve in sodium-restricted rats in which a gustatory nerve was sectioned that innervates the anterior tongue (chorda tympani), the posterior tongue (glossopharyngeal), or palatal taste receptors (greater superficial petrosal) or in which a nongustatory nerve was sectioned that also has its target in the anterior tongue (trigeminal). An additional group was studied that received thermal injury to the anteroventral tongue. Substantial and selective suppression of sodium salt responses occurred in a graded manner generally related to the distance from the target field of the injury to anterior tongue taste buds. The order of effectiveness was: chorda tympani section \u3e trigeminal section \u3e thermal injury = glossopharyngeal section \u3e greater superficial petrosal section. These results support the hypothesis that local, diffusible factors liberated from immune-derived cells as a result of neural and/or epithelial damage are involved in regulating the transduction pathway responsible for sodium salt sensation, and that these factors may become evident through dietary sodium restriction

    Time course of morphological alterations of fungiform papillae and taste buds following chorda tympani transection in neonatal rats

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    The time course of structural changes in fungiform papillae was analyzed in rats that received unilateral chorda tympani nerve transection at 10 days of age. Morphological differences between intact and denervated sides of the tongue were first observed at 8 days postsection, with an increase in the number of fungiform papillae that did not have a pore. In addition, the first papilla with a filiform‐like appearance was noted on the denervated side at 8 days postsectioning. By 11 days after surgery, the total number of papillae and the number of papillae with a pore were significantly lower on the transected side of the tongue as compared to the intact side. At 50 days postsection, there was an average of 70.5 fungiform papillae on the intact side and a mean of only 20.8 fungiform papillae the denervated side. Of those few remaining papillae on the cut side, an average of 13.5 papillae were categorized as filiform‐like, while no filiform‐like papillae occurred on the intact side. Significant reduction in taste bud volume was noted at 4 days posttransection and further decrements in taste bud volume were noted at 8 and 30 days postsection. Electron microscopy of the lingual branch of the trigeminal nerve from adult rats that received neonatal chorda tympani transection showed normal numbers of both myelinated and unmyelinated fibers. Thus, in addition to the well‐characterized dependence of taste bud maintenance on the chorda tympani nerve, the present study shows an additional role of the chorda tympani nerve in papilla maintenance during early postnatal development. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 223–236, 2002

    Each sensory nerve arising from the geniculate ganglion expresses a unique fingerprint of neurotrophin receptor genes

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    Neurons in the geniculate ganglion, like those in other sensory ganglia, are dependent on neurotrophins for survival. Most geniculate ganglion neurons innervate taste buds in two regions of the tongue and two regions of the palate; the rest are cutaneous nerves to the skin of the ear. We investigated the expression of four neurotrophins, nerve growth factor (NGF), brain‐derived neurotrophic factor (BDNF), neurotrophin 3 (NT‐3), and NT‐4, and five neurotrophin receptors, trkA, trkB, trkC, p75, and truncated trkB (Trn‐B) in single sensory neurons of the adult rat geniculate ganglion associated with the five innervation fields. For fungiform papillae, a glass pipette containing biotinylated dextran was placed over the target papilla and the tracer was iontophoresed into the target papilla. For the other target fields, Fluoro‐Gold was microinjected. After 3 days, geniculate ganglia were harvested, sectioned, and treated histochemically (for biotinylated dextran) or immunohistochemically (for Fluoro‐Gold) to reveal the neurons containing the tracer. Single labeled neurons were harvested from the slides and subjected to RNA amplification and RT‐PCR to reveal the neurotrophin or neurotrophin receptor genes that were expressed. Neurons projecting from the geniculate ganglion to each of the five target fields had a unique expression profile of neurotrophin and neurotrophic receptor genes. Several individual neurons expressed more than one neurotrophin receptor or more than one neurotrophin gene. Although BDNF is significantly expressed in taste buds, its primary high affinity receptor, trkB, was not prominently expressed in the neurons. The results are consistent with the interpretation that at least some, perhaps most, of the trophic influence on the sensory neurons is derived from the neuronal somata, and the trophic effect is paracrine or autocrine, rather than target derived. The BDNF in the taste bud may also act in a paracrine or autocrine manner on the trkB expressed in taste buds, as shown by others. © 2004 Wiley‐Liss, Inc

    Intraretinal signaling by ganglion cell photoreceptors to dopaminergic amacrine neurons

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    Retinal dopaminergic amacrine neurons (DA neurons) play a central role in reconfiguring retinal function according to prevailing illumination conditions, yet the mechanisms by which light regulates their activity are poorly understood. We investigated the means by which sustained light responses are evoked in DA neurons. Sustained light responses were driven by cationic currents and persisted in vitro and in vivo in the presence of L-AP4, a blocker of retinal ON-bipolar cells. Several characteristics of these L-AP4-resistant light responses suggested that they were driven by melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), including long latencies, marked poststimulus persistence, and a peak spectral sensitivity of 478 nm. Furthermore, sustained DA neuron light responses, but not transient DA neuron responses, persisted in rod/cone degenerate retinas, in which ipRGCs account for virtually all remaining retinal phototransduction. Thus, ganglion-cell photoreceptors provide excitatory drive to DA neurons, most likely by way of the coramification of their dendrites and the processes of DA neurons in the inner plexiform layer. This unprecedented centrifugal outflow of ganglion-cell signals within the retina provides a novel basis for the restructuring of retinal circuits by light

    Imaging and Tissue Biomarkers of Choline Metabolism in Diffuse Adult Glioma: 18F-Fluoromethylcholine PET/CT, Magnetic Resonance Spectroscopy, and Choline Kinase α

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    The cellular and molecular basis of choline uptake on PET imaging and MRS-visible choline containing compounds is not well understood. Choline kinase alpha (ChoKa) is an enzyme that phosphorylates choline, an essential step in membrane synthesis. We investigate choline metabolism through 18F-fluoromethylcholine (18F-FMC) PET, MRS and tissue ChoKa in human glioma. 14 patients with suspected diffuse glioma underwent multimodal 3T MRI and dynamic 18F FMC PET/CT prior to surgery. Co-registered PET and MRI data were used to target biopsies to regions of high and low choline signal, and immunohistochemistry for ChoKa expression was performed. 18F-FMC/PET differentiated WHO grade IV from grade II and III tumours, whereas MRS differentiated grade III/IV from grade II tumours. Tumoural 18F-FMC/PET uptake was higher than in normal-appearing white matter across all grades and markedly elevated within regions of contrast enhancement. 18F-FMC/PET correlated weakly with MRS Cho ratios. ChoKa expression on IHC was negative or weak in all but one GBM sample, and did not correlate with tumour grade or imaging choline markers. MRS and 18F-FMC/PET provide complimentary information on glioma choline metabolism. Tracer uptake is, however, potentially confounded by blood-brain barrier permeability. ChoKa overexpression does not appear to be a common feature in diffuse glioma

    Towards a quality education for all

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    This document summarises the recommendations being proposed in the NCF and examines the implications of such recommendations. There can only be a meaningful strategy for the implementation of the NCF once the recommendations are debated and the full impact of their implications understood. This process of consultation needs to include all stakeholders in a professionally engaging manner. Moreover, the consultation and implementation strategies need to be based on the full understanding of a change management process. This document will therefore map out the way forward by presenting: ‱ a summary of the recommendations being proposed by the NCF; ‱ implications of these recommendations for implementation; ‱ ideas about the management of change which underpin the consultation and implementation strategies the NCF would like to promote; ‱ a strategy for the consultation process following the publication of the draft NCF; and ‱ a proposed timeline for the implementation process of the NCF, following consultation and agreement with the wider educational community about the way forward.peer-reviewe

    Natural Single-Nucleosome Epi-Polymorphisms in Yeast

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    Epigenomes commonly refer to the sequence of presence/absence of specific epigenetic marks along eukaryotic chromatin. Complete histone-borne epigenomes have now been described at single-nucleosome resolution from various organisms, tissues, developmental stages, or diseases, yet their intra-species natural variation has never been investigated. We describe here that the epigenomic sequence of histone H3 acetylation at Lysine 14 (H3K14ac) differs greatly between two unrelated strains of the yeast Saccharomyces cerevisiae. Using single-nucleosome chromatin immunoprecipitation and mapping, we interrogated 58,694 nucleosomes and found that 5,442 of them differed in their level of H3K14 acetylation, at a false discovery rate (FDR) of 0.0001. These Single Nucleosome Epi-Polymorphisms (SNEPs) were enriched at regulatory sites and conserved non-coding DNA sequences. Surprisingly, higher acetylation in one strain did not imply higher expression of the relevant gene. However, SNEPs were enriched in genes of high transcriptional variability and one SNEP was associated with the strength of gene activation upon stimulation. Our observations suggest a high level of inter-individual epigenomic variation in natural populations, with essential questions on the origin of this diversity and its relevance to gene x environment interactions

    Transient exposure to low levels of insecticide affects metabolic networks of honeybee larvae

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    The survival of a species depends on its capacity to adjust to changing environmental conditions, and new stressors. Such new, anthropogenic stressors include the neonicotinoid class of crop-protecting agents, which have been implicated in the population declines of pollinating insects, including honeybees (Apis mellifera). The low-dose effects of these compounds on larval development and physiological responses have remained largely unknown. Over a period of 15 days, we provided syrup tainted with low levels (2 ”g/L−1) of the neonicotinoid insecticide imidacloprid to beehives located in the field. We measured transcript levels by RNA sequencing and established lipid profiles using liquid chromatography coupled with mass spectrometry from worker-bee larvae of imidacloprid-exposed (IE) and unexposed, control (C) hives. Within a catalogue of 300 differentially expressed transcripts in larvae from IE hives, we detect significant enrichment of genes functioning in lipid-carbohydrate-mitochondrial metabolic networks. Myc-involved transcriptional response to exposure of this neonicotinoid is indicated by overrepresentation of E-box elements in the promoter regions of genes with altered expression. RNA levels for a cluster of genes encoding detoxifying P450 enzymes are elevated, with coordinated downregulation of genes in glycolytic and sugar-metabolising pathways. Expression of the environmentally responsive Hsp90 gene is also reduced, suggesting diminished buffering and stability of the developmental program. The multifaceted, physiological response described here may be of importance to our general understanding of pollinator health. Muscles, for instance, work at high glycolytic rates and flight performance could be impacted should low levels of this evolutionarily novel stressor likewise induce downregulation of energy metabolising genes in adult pollinators
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