Impact de la cécité sur le système nociceptif

La vision joue un rôle très important dans la prévention du danger. La douleur a aussi pour fonction de prévenir les lésions corporelles. Nous avons donc testé l’hypothèse qu’une hypersensibilité à la douleur découlerait de la cécité en guise de compensation sensorielle. En effet, une littérature exhaustive indique qu’une plasticité intermodale s’opère chez les non-voyants, ce qui module à la hausse la sensibilité de leurs sens résiduels. De plus, plusieurs études montrent que la douleur peut être modulée par la vision et par une privation visuelle temporaire. Dans une première étude, nous avons mesuré les seuils de détection thermique et les seuils de douleur chez des aveugles de naissance et des voyants à l’aide d’une thermode qui permet de chauffer ou de refroidir la peau. Les participants ont aussi eu à quantifier la douleur perçue en réponse à des stimuli laser CO2 et à répondre à des questionnaires mesurant leur attitude face à des situations douloureuses de la vie quotidienne. Les résultats obtenus montrent que les aveugles congénitaux ont des seuils de douleur plus bas et des rapports de douleur plus élevés que leurs congénères voyants. De plus, les résultats psychométriques indiquent que les non-voyants sont plus attentifs à la douleur. Dans une deuxième étude, nous avons mesuré l’impact de l'expérience visuelle sur la perception de la douleur en répliquant la première étude dans un échantillon d’aveugles tardifs. Les résultats montrent que ces derniers sont en tous points similaires aux voyants quant à leur sensibilité à la douleur. Dans une troisième étude, nous avons testé les capacités de discrimination de température des aveugles congénitaux, car la détection de changements rapides de température est cruciale pour éviter les brûlures. Il s’est avéré que les aveugles de naissance ont une discrimination de température plus fine et qu’ils sont plus sensibles à la sommation spatiale de la chaleur. Dans une quatrième étude, nous avons examiné la contribution des fibres A∂ et C au traitement nociceptif des non-voyants, car ces récepteurs signalent la première et la deuxième douleur, respectivement. Nous avons observé que les aveugles congénitaux détectent plus facilement et répondent plus rapidement aux sensations générées par l’activation des fibres C. Dans une cinquième et dernière étude, nous avons sondé les changements potentiels qu’entrainerait la perte de vision dans la modulation descendante des intrants nociceptifs en mesurant les effets de l’appréhension d’un stimulus nocif sur la perception de la douleur. Les résultats montrent que, contrairement aux voyants, les aveugles congénitaux voient leur douleur exacerbée par l’incertitude face au danger, suggérant ainsi que la modulation centrale de la douleur est facilitée chez ces derniers. En gros, ces travaux indiquent que l’absence d’expérience visuelle, plutôt que la cécité, entraine une hausse de la sensibilité nociceptive, ce qui apporte une autre dimension au modèle d’intégration multi-sensorielle de la vision et de la douleur.

Functions of the SLC36 transporter Pathetic in growth control of Drosophila sensory neurons

Thesis (Ph.D.)--University of Washington, 2016-08

Comparison of Objectively and Subjectively Measured Sedentary Behavior in Men with Prostate Cancer and a History of Androgen-Deprivation Therapy Use

Thesis (Master's)--University of Washington, 2016-08

Die Plastizität des Nervensystems. Konsequenzen für die Pädagogik

Die Rolle von Umwelteinflüssen auf den Erwerb von Sinnesleistungen und Sprachkompetenz wird anhand von Deprivationsexperimenten aufgezeigt. Die so erläuterte Plastizität des Nervensystems beschränkt sich für Teilfunktionen auf kritische Phasen der Kindheit. Nach diesen ist das Gehirn für diese Funktion nicht mehr lernfähig. Neuroanatomische Studien stützen die Feststellung, daß Potentialitäten des Gehirns genetisch vorgegeben, aber teilweise in ihrer selektiven Ausprägung umweltabhängig sind. Daraus werden Schlußfolgerungen für die pädagogische Verantwortung in kritischen Phasen der Erziehung gezogen. Werden diese Phasen nicht genutzt, so sind sie unwiederbringlich vertan. (DIPF/Orig.)

Sensory work of diagnosis : a crisis of legitimacy

The Janus-faced City: A Sensory History of the London Blitz 1940–1941

The city of London was, during the years of 1940–1941, a city under fire. The metropolis seemed to have two faces, like the Roman deity Janus: the face of the daylight hours, so normal, and yet so deceiving in its false quietness – and at nightfall, the city turned, and the face of it was the face of the devil himself, transforming London into a living inferno. This thesis examines the sensescapes of the Blitz, through the diaries and memoirs written of that time. The primary sources consist of seven different diaries, two autobiographies, and four research volumes that contain multiple diary- and memoire entries, mostly from the Mass Observation Archives and from the Imperial War Museum. The sensory approach is a new orientation in the field of history – it studies the five senses in their cultural contexts, interpreting the often subtle ways in which the senses affect into society, politics, culture, and class hierarchies, to name only but few. The subject of the sensory history of war is a theme widely unexamined: this thesis contributes to this frontier field by unveiling the sensorium of the London bombings, comparing the differences between the halves of nychtemeron, and examining how the Blitz was communicated by the writers as a lived, bodily experience. This study reveals the very different sensory worlds in which the Londoners lived, during a time that is often described with the mythical solidarity that was thought to exist between the people. The reality of the homeless, working class, and poor were in the foul smelling tubes, poor law -dated rations, and in the smoking ruins of East End – the contrast was massive reflecting it to the luxury hotels and restaurants of the upper classes, opportunities for evacuation, sheltering possibilities, and overall comforts of life.

Effects of unilateral visual deprivation on the developing avian brain

The effect of varying states of visual deprivation on the development of the optic lobes and cerebral hemispheres has been studied in the chick where the visual pathways are totally crossed over. Unilateral eye extirpation of the new hatched chick resulted in arrested development of the contralateral but not ipsilateral lobe, as measured by weight, protein content and acetylcholinesterase activity. Similar effects but of smaller magnitude were observed in the cerebral hemispheres. Histologic and enzymic evidence revealed the absence of significant degeneration in the optic lobe contralateral to an eye removed 17 days previously. These results were observed in the optic lobes of operated animals maintained either in light of in darkness between 3 and 17 days after hatch. However, in the inpaired cerebral hemispheres, differences could only be detected in birds kept the light. The effects of unilateral eyelid suturing on the development of chick brain regions were also examined. In this group, all asymmetrical differences observed within paired brain regions were totally light dependent and confined to the cerebral hemispheres. The hemisphere contralateral to the sutured eye weighed less and had less acetylcholinesterase activity than its paired hemisphere. The cerebral hemispheres of monocularly treated birds manifested effects of similar magnitude whether the treatment was enucleation or suturing. This suggests that the complete development of the associative centers in avian cerebral hemispheres is dependent on both intact innervation and on the information content of the visual input. © 1969.

Quantitative phosphoproteomics reveals the role of the AMPK plant ortholog SnRK1 as a metabolic master regulator under energy deprivation

Since years, research on SnRK1, the major cellular energy sensor in plants, has tried to define its role in energy signalling. However, these attempts were notoriously hampered by the lethality of a complete knockout of SnRK1. Therefore, we generated an inducible amiRNA::SnRK1α2 in a snrk1α1 knock out background (snrk1α1/α2) to abolish SnRK1 activity to understand major systemic functions of SnRK1 signalling under energy deprivation triggered by extended night treatment. We analysed the in vivo phosphoproteome, proteome and metabolome and found that activation of SnRK1 is essential for repression of high energy demanding cell processes such as protein synthesis. The most abundant effect was the constitutively high phosphorylation of ribosomal protein S6 (RPS6) in the snrk1α1/α2 mutant. RPS6 is a major target of TOR signalling and its phosphorylation correlates with translation. Further evidence for an antagonistic SnRK1 and TOR crosstalk comparable to the animal system was demonstrated by the in vivo interaction of SnRK1α1 and RAPTOR1B in the cytosol and by phosphorylation of RAPTOR1B by SnRK1α1 in kinase assays. Moreover, changed levels of phosphorylation states of several chloroplastic proteins in the snrk1α1/α2 mutant indicated an unexpected link to regulation of photosynthesis, the main energy source in plants.

The Role of Cannabinoids in the Neurobiology of Sensory Gating: A firing rate model study

Gating of sensory (e.g. auditory) information has been demonstrated as a reduction in the auditory-evoked potential responses recorded in the brain of both normal animals and human subjects. Auditory gating is perturbed in schizophrenic patients and pharmacologically by drugs such as amphetamine, phencyclidine or ketamine, which precipitate schizophrenic-like symptoms in normal subjects. The neurobiological basis underlying this sensory gating can be investigated using local field potential recordings from single electrodes. In this paper we use such technology to investigate the role of cannabinoids in sensory gating. Cannabinoids represent a fundamentally new class of retrograde messengers which are released postsynaptically and bind to presynaptic receptors. In this way they allow fine-tuning of neuronal response, and in particular can lead to so-called depolarization-induced suppression of inhibition (DSI). Our experimental results show that application of the exogenous cannabinoid WIN55, 212-2 can abolish sensory gating as measured by the amplitude of local field responses in rat hippocampal region CA3. Importantly we develop a simple firing rate population model of CA3 and show that gating is heavily dependent upon the presence of a slow inhibitory (GABAB) pathway. Moreover, a simple phenomenological model of cannabinoid dynamics underlying DSI is shown to abolish gating in a manner consistent with our experimental findings.

Effects of various salt purity levels on lipid oxidation and sensory characteristics of ground turkey and pork

Salt use in meat products is changing. Consumers desire sea salt which may also contain trace metals and the government is demanding a reduction in sodium. Therefore a need exists to understand how varying impurity levels in salt affect meat quality. This study evaluated the effects of various salt preparations on lipid oxidation, sensory characteristics, protein extractability, and bind strength of ground turkey and pork. This study was a completely randomized design with 5 treatment groups and 6 replications in 2 species. Ground, turkey and pork meat was formulated into one hundred and fifty gram patties with sodium chloride (1%) containing varying amounts of metal impurities (copper, iron, and manganese). Samples were randomly assigned to frozen storage periods of 0, 3, 6, and 9 weeks. After storage, samples were packaged in PVC overwrap and stored under retail display for 5 days. Samples were evaluated for proximate analysis to ensure the fat content was similar for all of the starting material.Thiobarbituric acid reactive substances (TBARS) were determined on raw and cooked samples to evaluate lipid oxidation. A trained six member sensory panel evaluated the samples at each storage period for saltiness, off flavor, and oxidized odor. Break strength was conducted using a Texture Analyzer and compared with salt soluble proteins (increasing salt concentrations) to evaluate protein extractability characteristics. Statistical analyses were conducted using the MIXED procedure of SAS within repeated measures over time where appropriate. No significant differences were observed among the salt treatments for raw and cooked TBARS when the control group was removed (P>0.05). Sensory panelists detected increased levels of off flavor and oxidized odor over the entire storage duration. Less force was required to break the patties from the control group when compared with the salt treatments (P<0.05). As salt concentration increased salt-soluble protein extraction increased, but there was no effect of salt type. Overall, no meaningful statistical differences among the various salt treatments were observed for all of the parameters evaluated for turkey and pork. Salt at a 1% inclusion rate containing varying levels of copper, iron, and manganese impurities in ground turkey thigh meat and ground pork served as a prooxidant. However, if a meat processor uses a 1% inclusion rate of salt in turkey and pork regardless of impurities included, it is unlikely that differences in shelf life or protein functionality would be observed.

Effect of grape seed extract on oxidative, color and sensory stability of pre-cooked, frozen, re-heated beef sausage model system

The processing of meats at the factory level can trigger the onset of lipid oxidation, which can lead to meat quality deterioration. Warmed over flavor is an off-flavor, which is associated with oxidative deterioration in meat. To avoid or delay the auto-oxidation process in meat products, synthetic and natural antioxidants have been successfully used. Grape (Vitis Vinifera) is of special interest due to its high content of phenolic compounds. Grape seed extract sold commercially as a dietary supplement, has the potential to reduce lipid oxidation and WOF in cooked ground beef when added at 1%. The objective of study 1 was to compare the antioxidant activity of natural antioxidants including grape seed extract and some herbs belonging to the Lamiaciae family: rosemary (Rosmarinus Officinalis), sage (Salvia Officinalis) and oregano (Origanum Vulgare) with commercial synthetic antioxidants like BHT, BHA, propyl gallate and ascorbic acid using the ORAC assay. All sample solutions were prepared to contain 1.8 gm sample/10 ml solvent. The highest antioxidant activity was observed for the grape seed extract sample (359.75 µM TE), while the lowest was observed for BHA, propyl gallate and rosemary also showed higher antioxidant potential with ORAC values above 300 μmol TE/g. ORAC values obtained for ascorbic acid and Sage were between 250-300μ mol TE/g while lowest values were obtained for Butylated Hydroxytoluene (28.50 µM TE). Based on the high ORAC values obtained for grape seed extract, we can conclude that byproducts of the wine/grape industry have antioxidant potential comparable to or better than those present in synthetic counterparts. The objective of study 2 was to compare three levels of grape seed extract (GSE) to commonly used antioxidants in a pre-cooked, frozen, stored beef and pork sausage model system. Antioxidants added for comparison with control included grape seed extract (100, 300, 500 ppm), ascorbic acid (AA, 100 ppm of fat) and propyl gallate (PG, 100 ppm of fat). Product was formed into rolls, frozen, sliced into patties, cooked on a flat griddle to 70C, overwrapped in PVC, and then frozen at –18C for 4 months. GSE- and PG-containing samples retained their fresh cooked beef odor and flavor longer (p<0.05) than controls during storage. Rancid odor and flavor scores of GSE-containing samples were lower (p<0.05) than those of controls after 4 months of storage. The L* value of all samples increased (p<0.05) during storage. Thiobarbituric acid reactive substances (TBARS) of the control and AA-containing samples increased (p<0.05); those of GSE-containing samples did not change significantly (p>0.05) over the storage period.

Viability of probiotic bacteria and some chemical and sensory characteristics in cornelian cherry juice during cold storage

Background: Increased popularity of vegetarianism, lactose intolerance, and the high cholesterol content in dairy products, are all factors that have recently increased the demand for nondairy probiotic products. The objective of this study is to evaluate the effect of refrigeration on the viability of probiotics and asses someof the chemical and sensory characteristics in cornelian cherry juice. Results: The Iranian native probiotic strain (L. casei T4) showed greater viability compared to industrial types (viable count of 8.67 log cfu/mL versus <6.0 log cfu/mL at d 28). However, this most tolerant Iranian strain, could not withstand the conditions of ‘Natural juice’ at pH 2.6 for more than 7 d. Following a pH adjusted treatment (to pH ~3.5), the viability of the strain was improved to 28 d with some evidence of increased growth of the probiotic. However, the level of antioxidant activity, anthocyanin and phenolic compounds, revealed a slight decrease during cold storage. The changes in the chemical profile of the sample containing L. casei T4 indicated fermentation activity during cold storage. Sensory evaluation results showed significant differences between samples containing L. casei TD4 and other samples in taste, odor and overall acceptance in a complimentary way. Conclusions: The results showed that low pH and presence of inhibitor phenolic compounds of cornelian cherry juice have negative effect on viability of probiotics, especially industrial strains during refrigerated storage.

Sensory gating and its modulation by cannabinoids: electrophysiological, computational and mathematical analysis

Gating of sensory information can be assessed using an auditory conditioning-test paradigm which measures the reduction in the auditory evoked response to a test stimulus following an initial conditioning stimulus. Recording brainwaves from specific areas of the brain using multiple electrodes is helpful in the study of the neurobiology of sensory gating. In this paper, we use such technology to investigate the role of cannabinoids in sensory gating in the CA3 region of the rat hippocampus. Our experimental results show that application of the exogenous cannabinoid agonist WIN55,212-2 can abolish sensory gating. We have developed a phenomenological model of cannabinoid dynamics incorporated within a spiking neural network model of CA3 with synaptically interacting pyramidal and basket cells. Direct numerical simulations of this model suggest that the basic mechanism for this effect can be traced to the suppression of inhibition of slow GABAB synapses. Furthermore, by working with a simpler mathematical firing rate model we are able to show the robustness of this mechanism for the abolition of sensory gating.