904 resultados para Sensory
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MEG directly measures the neuronal events and has greater temporal resolution than fMRI, which has limited temporal resolution mainly due to the larger timescale of the hemodynamic response. On the other hand fMRI has advantages in spatial resolution, while the localization results with MEG can be ambiguous due to the non-uniqueness of the electromagnetic inverse problem. Thus, these methods could provide complementary information and could be used to create both spatially and temporally accurate models of brain function. We investigated the degree of overlap, revealed by the two imaging methods, in areas involved in sensory or motor processing in healthy subjects and neurosurgical patients. Furthermore, we used the spatial information from fMRI to construct a spatiotemporal model of the MEG data in order to investigate the sensorimotor system and to create a spatiotemporal model of its function. We compared the localization results from the MEG and fMRI with invasive electrophysiological cortical mapping. We used a recently introduced method, contextual clustering, for hypothesis testing of fMRI data and assessed the the effect of neighbourhood information use on the reproducibility of fMRI results. Using MEG, we identified the ipsilateral primary sensorimotor cortex (SMI) as a novel source area contributing to the somatosensory evoked fields (SEF) to median nerve stimulation. Using combined MEG and fMRI measurements we found that two separate areas in the lateral fissure may be the generators for the SEF responses from the secondary somatosensory cortex region. The two imaging methods indicated activation in corresponding locations. By using complementary information from MEG and fMRI we established a spatiotemporal model of somatosensory cortical processing. This spatiotemporal model of cerebral activity was in good agreement with results from several studies using invasive electrophysiological measurements and with anatomical studies in monkey and man concerning the connections between somatosensory areas. In neurosurgical patients, the MEG dipole model turned out to be more reliable than fMRI in the identification of the central sulcus. This was due to prominent activation in non-primary areas in fMRI, which in some cases led to erroneous or ambiguous localization of the central sulcus.
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This study aimed to investigate the morphology and function of corneal sensory nerves in 1) patients after corneal refractive surgery and 2) patients with dry eye due to Sjögren's syndrome. A third aim was to explore the possible correlation between cytokines detected in tears and development of post-PRK subepithelial haze. The main methods used were tear fluid ELISA analysis, corneal in vivo confocal microscopy, and noncontact esthesiometry. The results revealed that after PRK a positive correlation exists between the regeneration of subbasal nerves and the thickness of regenerated epithelium. Pre- or postoperative levels of the tear fluid cytokines TGF-β1, TNF-α, or PDGF-BB did not correlate with the development of corneal haze objectively estimated by in vivo confocal microscopy 3 months after PRK. After high myopic LASIK, a discrepancy between subjective dry eye symptoms and objective signs of dry eye was observed. The majority of patients reported ongoing dry eye symptoms even 5 years after LASIK, although no objective clinical signs of dry eye were apparent. In addition, no difference in corneal sensitivity was observed between these patients and controls. Primary Sjögren's syndrome patients presented with corneal hypersensitivity, although their corneal subbasal nerve density was normal. However, alterations in corneal nerve morphology (nerve sprouting and thickened stromal nerves) and an increased number of antigen-presenting cells among subbasal nerves were observed, implicating the presence of an ongoing inflammation. Based on these results, the relationship between nerve regeneration and epithelial thickness 3 months after PRK appears to reflect the trophic effect of corneal nerves on epithelium. In addition, measurement of tear fluid cytokines may not be suitable for screening patients for risk of scar (haze) formation after PRK. Presumably, at least part of the symptoms of "LASIK-associated dry eye" are derived from aberrantly regenerated and abnormally functioning corneal nerves. Thus, they may represent a form of corneal neuropathy or "phantom pain" rather than conventional dry eye. Corneal nerve alterations and inflammatory findings in Sjögren's syndrome offer an explanation for the corneal hypersensitivity or even chronic pain or hyperalgesia often observed in these patients. In severe cases of disabling chronic pain in patients with dry eye or after LASIK, when conventional therapeutic possibilities fail to offer relief, consultation of a physician specialized in pain treatment is recommended.
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Crickets have two tympanal membranes on the tibiae of each foreleg. Among several field cricket species of the genus Gryllus (Gryllinae), the posterior tympanal membrane (PTM) is significantly larger than the anterior membrane (ATM). Laser Doppler vibrometric measurements have shown that the smaller ATM does not respond as much as the PTM to sound. Hence the PTM has been suggested to be the principal tympanal acoustic input to the auditory organ. In tree crickets (Oecanthinae), the ATM is slightly larger than the PTM. Both membranes are structurally complex, presenting a series of transverse folds on their surface, which are more pronounced on the ATM than on the PTM. The mechanical response of both membranes to acoustic stimulation was investigated using microscanning laser Doppler vibrometry. Only a small portion of the membrane surface deflects in response to sound. Both membranes exhibit similar frequency responses, and move out of phase with each other, producing compressions and rarefactions of the tracheal volume backing the tympanum. Therefore, unlike field crickets, tree crickets may have four instead of two functional tympanal membranes. This is interesting in the context of the outstanding question of the role of spiracular inputs in the auditory system of tree crickets.
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Speech has both auditory and visual components (heard speech sounds and seen articulatory gestures). During all perception, selective attention facilitates efficient information processing and enables concentration on high-priority stimuli. Auditory and visual sensory systems interact at multiple processing levels during speech perception and, further, the classical motor speech regions seem also to participate in speech perception. Auditory, visual, and motor-articulatory processes may thus work in parallel during speech perception, their use possibly depending on the information available and the individual characteristics of the observer. Because of their subtle speech perception difficulties possibly stemming from disturbances at elemental levels of sensory processing, dyslexic readers may rely more on motor-articulatory speech perception strategies than do fluent readers. This thesis aimed to investigate the neural mechanisms of speech perception and selective attention in fluent and dyslexic readers. We conducted four functional magnetic resonance imaging experiments, during which subjects perceived articulatory gestures, speech sounds, and other auditory and visual stimuli. Gradient echo-planar images depicting blood oxygenation level-dependent contrast were acquired during stimulus presentation to indirectly measure brain hemodynamic activation. Lip-reading activated the primary auditory cortex, and selective attention to visual speech gestures enhanced activity within the left secondary auditory cortex. Attention to non-speech sounds enhanced auditory cortex activity bilaterally; this effect showed modulation by sound presentation rate. A comparison between fluent and dyslexic readers' brain hemodynamic activity during audiovisual speech perception revealed stronger activation of predominantly motor speech areas in dyslexic readers during a contrast test that allowed exploration of the processing of phonetic features extracted from auditory and visual speech. The results show that visual speech perception modulates hemodynamic activity within auditory cortex areas once considered unimodal, and suggest that the left secondary auditory cortex specifically participates in extracting the linguistic content of seen articulatory gestures. They are strong evidence for the importance of attention as a modulator of auditory cortex function during both sound processing and visual speech perception, and point out the nature of attention as an interactive process (influenced by stimulus-driven effects). Further, they suggest heightened reliance on motor-articulatory and visual speech perception strategies among dyslexic readers, possibly compensating for their auditory speech perception difficulties.
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Caveolae have been linked to diverse cellular functions and to many disease states. In this study we have used zebrafish to examine the role of caveolin-1 and caveolae during early embryonic development. During development, expression is apparent in a number of tissues including Kupffer's vesicle, tailbud, intersomite boundaries, heart, branchial arches, pronephric ducts and periderm. Particularly strong expression is observed in the sensory organs of the lateral line, the neuromasts and in the notochord where it overlaps with expression of caveolin-3. Morpholino-mediated downregulation of Cav1α caused a dramatic inhibition of neuromast formation. Detailed ultrastructural analysis, including electron tomography of the notochord, revealed that the central regions of the notochord has the highest density of caveolae of any embryonic tissue comparable to the highest density observed in any vertebrate tissue. In addition, Cav1α downregulation caused disruption of the notochord, an effect that was enhanced further by Cav3 knockdown. These results indicate an essential role for caveolin and caveolae in this vital structural and signalling component of the embryo.
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Background Interest in the use of healing gardens in healthcare settings to provide therapeutic benefits is increasing, however insight is needed to determine whether patients, patient families and friends, and staff who spend time in these gardens use these in the manner for which they were designed, and experience the benefits suggested by broader research in this field. Objective(s) Visitors to four of the LCCH gardens have left comments in ‘bench diaries’ (visitors books). Analysis of these comments yields valuable insights into the use of the gardens, enabling reflection on the design intent and outcomes and guidance regarding how the gardens might be better utilised, as well as a basis for further investigation into the use and value of the gardens. Method(s) Comments have been coded and analysed using a thematic analysis approach to identify patterns relating to the reasons for which people appear to come to the healing gardens; benefits they appear to receive from spending time there; and features and aspects of the gardens that they appear to appreciate in particular. Only comments related to the gardens have been used in this analysis, with all comments being deidentified. Outcome/Conclusion Comments left in the Adventure Garden and Secret Garden bench diaries were used for the analysis, as Staff Garden and Babies Garden bench diary comments did not relate to the garden. There were no negative comments relating to the gardens, other than one comment requesting additional benches. The vast majority of comments expressed gratitude for the space. The four most frequently observed themes from the comments left in the Secret Garden Bench Diary indicated that they were seeking ‘time out’ from their experiences of being at the hospital, a desire for a ‘dose of nature’ (greenery, beautiful garden, etc), and fresh air, and that the garden space provided a restorative experience to them in some manner. Comments in the Adventure Garden Bench Diary related predominately to the view. Analysis of the comments emphasises the importance of gardens providing multi-sensory experiences that significantly differentiate the space from the hospital ward and provide visitors with a sense of being away, of peacefulness, and of familiarity with the outside world. Positioning gardens with prospect, and solar aspect, appears important in these regards, as does the presence of visible greenery. Adequate seating in locations that provide pleasing views appears particularly important for staff and adult visitors. Whilst comments in the Bench Diaries did not indicate direct awareness of the stress and anxiety-reducing effects that research elsewhere has found from viewing plants and nature, however these effects may underpin many of these experiences that visitors did share.
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In a reverse Stroop task, observers respond to the meaning of a color word irrespective of the color in which the word is printed—for example, the word red may be printed in the congruent color (red), an incongruent color (e.g., blue), or a neutral color (e.g., white). Although reading of color words in this task is often thought to be neither facilitated by congruent print colors nor interfered with incongruent print colors, this interference has been detected by using a response method that does not give any bias in favor of processing of word meanings or processing of print colors. On the other hand, evidence for the presence of facilitation in this task has been scarce, even though this facilitation is theoretically possible. By modifying the task such that participants respond to a stimulus color word by pointing to a corresponding response word on a computer screen with a mouse, the present study investigated the possibility that not only interference but also facilitation would take place in a reverse Stroop task. Importantly, in this study, participants’ responses were dynamically tracked by recording the entire trajectories of the mouse. Arguably, this method provided richer information about participants’ performance than traditional measures such as reaction time and accuracy, allowing for more detailed (and thus potentially more sensitive) investigation of facilitation and interference in the reverse Stroop task. These trajectories showed that the mouse’s approach toward correct response words was significantly delayed by incongruent print colors but not affected by congruent print colors, demonstrating that only interference, not facilitation, was present in the current task. Implications of these findings are discussed within a theoretical framework in which the strength of association between a task and its response method plays a critical role in determining how word meanings and print colors interact in reverse Stroop tasks.
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Synchronising bushcricket males achieve synchrony by delaying their chirps in response to calling neighbours. In multi-male choruses, males that delay chirps in response to all their neighbours would remain silent most of the time and be unable to attract mates. This problem could be overcome if the afferent auditory system exhibited selective attention, and thus a male interacted only with a subset of neighbours. We investigated whether individuals of the bushcricket genus Mecopoda restricted their attention to louder chirps neurophysiologically, behaviourally and through spacing. We found that louder leading chirps were preferentially represented in the omega neuron but the representation of softer following chirps was not completely abolished. Following chirps that were 20 dB louder than leading chirps were better represented than leading chirps. During acoustic interactions, males synchronised with leading chirps even when the following chirps were 20 dB louder. Males did not restrict their attention to louder chirps during interactions but were affected by all chirps above a particular threshold. In the field, we found that males on average had only one or two neighbours whose calls were above this threshold. Selective attention is thus achieved in this bushcricket through spacing rather than neurophysiological filtering of softer signals.
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"Body and Iron: Essays on the Socialness of Objects" focuses on the bodily-material interaction of human subjects and technical objects. It poses a question, how is it possible that objects have an impact on their human users and examines the preconditions of active efficacy of objects. In this theoretical task the work relies on various discussions drawing from realistic ontology, phenomenology of body, neurophysiology of Antonio Damasio and psychoanalysis to establish both objects and bodies as material entities related in a causal interaction with each other. Out of material interaction emerge a symbolic field, psyche and culture that produce representations of interactions with material world they remain dependent on and conditioned by. Interaction with objects informs the human body via its somatosensory systems: interoseptive and proprioseptive (or kinesthetic) systems provide information to central nervous system of the internal state of the body and muscle tensions and motor activity of the limbs. Capability to control the movements of one's body by the internal "feel" of being a body turns out to be a precondition to the ability to control artificial extensions of the body. Motor activity of the body is involved in every perception of environment as the feel of one's own body is constitutive of any perception of external objects. Perception of an object cause changes in the internal milieu of the body and these changes in the organism form a bodily representation of an external object. Via these "muscle images" the subject can develop a feel for an instrument. Bodily feel for an object is pre-conceptual, practical knowledge that resists articulation but allows sensing the world through the object. This is what I would call sensual knowledge. Technical objects intervene between body and environment, transforming the relation of perception and motor activity. Once connected to a vehicle, human subject has to calibrate visual information of his or her position and movement in space to the bodily actions controlling the machine. It is the machine that mediates the relation of human actions to the relation of her body to its environment. Learning to use the machine necessarily means adjusting his or her bodily actions to the responses of the machine in relation to environmental changes it causes. Responsiveness of the machine to human touch "teaches" its subject by providing feedback of the "correctitude" of his or her bodily actions. Correct actions form a body technique of handling the object. This is the way of socialness of objects. While responding to human actions they generate their subjects. Learning to handle a machine means accepting the position of the user in the program of action materialized in the construction of the object. Objects mediate, channel and transform the relation of the body to its environment and via environment to the body itself according to their material and technical construction. Objects are sensory media: they channel signals and information from the environment thus constituting a representation of environment, a virtual or artificial reality. They also feed the body directly with their powers equipping their user with means of regulating somatic and psychic states of her self. For these reasons humans look for the company of objects. Keywords: material objects, material culture, sociology of technology, sociology of body, mobility, driving
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The Disability Standards for Education (2005) and the Australian Curriculum, Assessment and Reporting Authority relevant standards underscore the right of students with disability to access the curriculum on the same basis as students without disability. Students with disability are entitled to rigorous, relevant and engaging learning opportunities drawn from the Australian curriculum content. Taking this context into account, this paper provides a work-in-progress report on a two-year mathematics intervention project conducted in 12 special schools (Preparatory-Year 12) in Queensland, Australia. The project aims to build the capacity of teachers to teach mathematics to their students and to identify and make sense of the intervention program’s impact. It combines two approaches—appreciative inquiry and action research to monitor schools’ change processes. The interim findings demonstrated that teachers were concerned about their students’ underachievement in mathematics and that the multi-sensory forms of teaching advocated in the program increased student engagement and performance.
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Kirjallisuuskatsauksessa käsiteltiin viiliä hapanmaitotuotteena, viilin arviointimenetelmiä sekä viilihapatteissa käytettyjen hapatekantojen vaikutuksia maidossa ja niiden vuorovaikutuksia toisiinsa. Lisäksi pohdittiin viilihapatteiden bakteriofaageja, niiden ehkäisyä sekä solunsisäisiä että -ulkoisia faagiresistenssimekanismeja. Kokeellisessa osassa tutkittiin, onko nykyisten tuotantohapatteiden koostaminen yksittäiskannoista mahdollista, sekä koostettiin uusista Lactococcus lactis ssp. cremoris -kannoista varahapate. Hapatteiden käyttökelpoisuutta tutkittiin rakennemittauksin ja aistinvaraisin menetelmin. Varahapatteen faagikestävyyttä testattiin valmistamalla viiliä ja infektoimalla viilit faaginäytteillä. Hapatekannat viljeltiin fermentorissa, konsentroitiin sentrifugoimalla ja pakastettiin –75 °C:ssa. Hapatteet koostettiin noin 1 päivä ennen viilin valmistusta. Viilit arvioitiin aistinvaraisesti 3–6 hengen ryhmässä ja viileille tehtiin rakennemittaukset (kiinteys, sakeus ja koossapysyvyys) sekä kemialliset analyysit. Aistinvaraisen arvioinnin tulokset käsiteltiin tilastollisesti ja tulosten perusteella tehtiin uudet kantakombinaatiot ja viilit. Tuotantohapatekannoilla valmistetut viilit arvioitiin kolmitestillä (n = 10–11) ja uusilla kannoilla valmistetut viilit arvioitiin profiilitestillä (n = 8). Lisäksi viileille tehtiin rakennemittaukset ja kemialliset analyysit. Varahapatekoosteilla valmistettujen viilien pH laski 4,5:een faagin läsnäollessa 0–10 tunnin viiveellä verrattuna faagivapaisiin viileihin, kun taas tuotantohapatteet eivät hapantuneet faagin läsnäollessa. Aromintuottajat eivät kasvaneet viileissä kunnolla, kun hapate koostettiin yksittäiskannoista. Kolmitestissä ei erotettu nykyisillä tuotantohapatteilla valmistettua viiliä yksittäin koostetusta hapatteesta, eli hapatteita on mahdollista koostaa yksittäiskannoista. Varahapatteilla koostetut viilit poikkesivat profiilitestissä tuotantohapatteella koostetusta viilistä ulkonäkö- ja rakenneominaisuuksiltaan. Makuominaisuuksien suhteen ei viilien välille saatu eroa.
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The nutritional quality of the product as well as other quality attributes like microbiological and sensory quality are essential factors in baby food industry, and therefore different alternative sterilizing methods for conventional heating processes are of great interest in this food sector. This report gives an overview on different sterilization techniques for baby food. The report is a part of the work done in work package 3 ”QACCP Analysis Processing: Quality – driven distribution and processing chain analysis“ in the Core Organic ERANET project called Quality analysis of critical control points within the whole food chain and their impact on food quality, safety and health (QACCP). The overall objective of the project is to optimise organic production and processing in order to improve food safety as well as nutritional quality and increase health promoting aspects in consumer products. The approach will be a chain analysis approach which addresses the link between farm and fork and backwards from fork to farm. The objective is to improve product related quality management in farming (towards testing food authenticity) and processing (towards food authenticity and sustainable processes. The articles in this volume do not necessarily reflect the Core Organic ERANET’s views and in no way anticipate the Core Organic ERANET’s future policy in this area. The contents of the articles in this volume are the sole responsibility of the authors. The information contained here in, including any expression of opinion and any projection or forecast, has been obtained from sources believed by the authors to be reliable but is not guaranteed as to accuracy or completeness. The information is supplied without obligation and on the understanding that any person who acts upon it or otherwise changes his/her position in reliance thereon does so entirely at his/her own risk. The writers gratefully acknowledge the financial support from the Core Organic Funding Body: Ministry of Agriculture and Forestry, Finland, Swiss Federal Office for Agriculture, Switzerland and Federal Ministry of Consumer Protection, Food and Agriculture, Germany.
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P>1Organisms with low mobility, living within ephemeral environments,need to find vehicles that can disperse them reliably to new environments. The requirement for specificity in this passenger-vehicle relationship is enhanced within a tritrophic interaction when the environment of passenger and vehicle is provided by a third organism. Such relationships pose many interesting questions about specificity within a tritrophic framework. 2. Central to understanding how these tritrophic systems have evolved, is knowing how they function now. Determining the proximal cues and sensory modalities used by passengers to find vehicles and to discriminate between reliable and non-reliable vehicles is, therefore, essential to this investigation. 3. The ancient, co-evolved and highly species-specific nursery pollination mutualism between figs and fig wasps is host to species-specific plant-parasitic nematodes which use fig wasps to travel between figs. Since individual globular fig inflorescences, i.e. syconia, serve as incubators for hundreds of developing pollinating and parasitic wasps, a dispersal-stage nematode within such a chemically,complex and physically crowded environment is faced with the dilemma of choosing the right vehicle for dispersal into a new fig. Such a system therefore affords excellent opportunities to investigate mechanisms that contribute to the evolution of specificity between the passenger and the vehicle. 4. In this study of fig-wasp-nematode tritrophic interactions in Ficus racemosa within which seven wasp species can breed, we demonstrate using two-choice as well as cafeteria assays that plant-parasitic nematodes (Schistonchus racemosa) do not hitch rides randomly on available eclosing wasps within the fig syconium, but are specifically attracted, at close range, i.e. 3 mm distance, to only that vehicle which can quickly, within a few hours, reliably transfer it to another fig. This vehicle is the female pollinating wasp. Male wasps and female parasitic wasps are inappropriate vehicles since the former are wingless and die within the fig, while the latter never enter another fig. Nematodes distinguished between female pollinating wasps and other female parasitic wasps using volatiles and cuticular hydrocarbons. Nematodes could not distinguish between cuticular hydrocarbons of male and female pollinators but used other cues, such as volatiles, at close range, to find female pollinating wasps with which they have probably had a long history of chemical adaptation. 5. This study opens up new questions and hypotheses about the evolution and maintenance of specificity in fig-wasp-nematode tritrophic interactions.
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The Hodgkin and Huxley (HH) model of action potential has become a central paradigm of neuroscience. Despite its ability to predict action potentials with remarkable accuracy, it fails to explain several biophysical findings related to the initiation and propagation of the nerve impulse. The isentropic heat release and optical phenomena demonstrated by various experiments suggest that action potential is accompanied by a transient phase change in the axonal membrane. In this study a method was developed for preparing a giant axon from the crayfish abdominal cord for studying the molecular mechanisms of action potential simultaneously by electrophysiological and optical methods. Also an alternative setup using a single-cell culture of an Aplysia sensory neuron is presented. In addition to the description of the method, the preliminary results on the effect of phloretin, a dipole potential lowering compound, on the excitability of a crayfish giant axon are presented.
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The overlapping sound pressure waves that enter our brain via the ears and auditory nerves must be organized into a coherent percept. Modelling the regularities of the auditory environment and detecting unexpected changes in these regularities, even in the absence of attention, is a necessary prerequisite for orientating towards significant information as well as speech perception and communication, for instance. The processing of auditory information, in particular the detection of changes in the regularities of the auditory input, gives rise to neural activity in the brain that is seen as a mismatch negativity (MMN) response of the event-related potential (ERP) recorded by electroencephalography (EEG). --- As the recording of MMN requires neither a subject s behavioural response nor attention towards the sounds, it can be done even with subjects with problems in communicating or difficulties in performing a discrimination task, for example, from aphasic and comatose patients, newborns, and even fetuses. Thus with MMN one can follow the evolution of central auditory processing from the very early, often critical stages of development, and also in subjects who cannot be examined with the more traditional behavioural measures of auditory discrimination. Indeed, recent studies show that central auditory processing, as indicated by MMN, is affected in different clinical populations, such as schizophrenics, as well as during normal aging and abnormal childhood development. Moreover, the processing of auditory information can be selectively impaired for certain auditory attributes (e.g., sound duration, frequency) and can also depend on the context of the sound changes (e.g., speech or non-speech). Although its advantages over behavioral measures are undeniable, a major obstacle to the larger-scale routine use of the MMN method, especially in clinical settings, is the relatively long duration of its measurement. Typically, approximately 15 minutes of recording time is needed for measuring the MMN for a single auditory attribute. Recording a complete central auditory processing profile consisting of several auditory attributes would thus require from one hour to several hours. In this research, I have contributed to the development of new fast multi-attribute MMN recording paradigms in which several types and magnitudes of sound changes are presented in both speech and non-speech contexts in order to obtain a comprehensive profile of auditory sensory memory and discrimination accuracy in a short measurement time (altogether approximately 15 min for 5 auditory attributes). The speed of the paradigms makes them highly attractive for clinical research, their reliability brings fidelity to longitudinal studies, and the language context is especially suitable for studies on language impairments such as dyslexia and aphasia. In addition I have presented an even more ecological paradigm, and more importantly, an interesting result in view of the theory of MMN where the MMN responses are recorded entirely without a repetitive standard tone. All in all, these paradigms contribute to the development of the theory of auditory perception, and increase the feasibility of MMN recordings in both basic and clinical research. Moreover, they have already proven useful in studying for instance dyslexia, Asperger syndrome and schizophrenia.