Organization of sensory feature selectivity in the whisker system

Our sensory receptors are faced with an onslaught of different environmental inputs. Each sensory event or encounter with an object involves a distinct combination of physical energy sources impinging upon receptors. In the rodent whisker system, each primary afferent neuron located in the trigeminal ganglion innervates and responds to a single whisker and encodes a distinct set of physical stimulus properties – features – corresponding to changes in whisker angle and shape and the consequent forces acting on the whisker follicle. Here we review the nature of the features encoded by successive stages of processing along the whisker pathway. At each stage different neurons respond to distinct features, such that the population as a whole represents diverse properties. Different neuronal types also have distinct feature selectivity. Thus, neurons at the same stage of processing and responding to the same whisker nevertheless play different roles in representing objects contacted by the whisker. This diversity, combined with the precise timing and high reliability of responses, enables populations at each stage to represent a wide range of stimuli. Cortical neurons respond to more complex stimulus properties – such as correlated motion across whiskers – than those at early subcortical stages. Temporal integration along the pathway is comparatively weak: neurons up to barrel cortex are sensitive mainly to fast (tens of milliseconds) fluctuations in whisker motion. The topographic organization of whisker sensitivity is paralleled by systematic organization of neuronal selectivity to certain other physical features, but selectivity to touch and to dynamic stimulus properties is distributed in “salt-and-pepper” fashion

Impact of promoting self-care in nursing workload

Abstract OBJECTIVES To assess the impact of promoting self-care in nursing workload and associate it to the variables: age, gender, socioeconomic status, education, marital status and number of children of caregivers. METHODS Prospective study with 31 children and their caregivers. Participants were assessed at two moments, 1st and 2nd hospitalization, the nursing workload was measured by the Nursing Activities Score (NAS). RESULTS The mean NAS in the 1st hospitalization was 60.9% and in the 2nd hospitalization was 41.6%, that is, 14.6 and 9.9 hours of nursing, respectively. The nursing workload on the first day of hospitalization was higher compared to the last day, both for the 1st (p<0.001) and for the 2nd hospitalization (p<0.001), and higher in the first (p<0.001) and in the last day (p=0.025) in the 1st hospitalization. Comparing the 1st hospitalization to the 2nd hospitalization, the first was higher (p<0.001), and NAS items related to the training of self-care was influenced (p<0.001). CONCLUSION The nursing workload associated to self-care promotion corresponded to 14.6 hours and was higher than determined by the existing legislation

Malnutrition and Disability: A Retrospective Study on 2258 Adult Patients Undergoing Elective Spine Surgery.

Background and Objectives: Malnutrition's prevalence and its relationship with functional ability in patients with end-stage spine pathologies, i.e., any disease of the vertebral bodies, intervertebral discs, and associated joints requiring surgical intervention, are yet to be explored. This retrospective study aimed to investigate the association between malnutrition, disability, and physical health in patients undergoing elective spine surgery in our Italian hospital. Materials and Methods: Data between 2016 and 2019, recorded at pre-admission visits, were extracted from our institutional spine registry (ClinicalTrials.gov number: NCT03644407), excluding minor patients or those undergoing emergency or oncological surgery. The measures were the Oswestry disability index (ODI) and the physical health (PH) summary of the 36-item Short-Form Health Survey. Clinical data were linked to nine laboratory parameters from pre-operative routine blood tests, and equations to ascertain the risk of malnutrition and its diagnosis were attributed. Results: The study sample included 2258 spine patients (58.15% females) who underwent surgery in our Italian hospital. The ODI and PH significantly varied across body weight difference (BWd) strata in younger adults (adjusted-p = 0.046, η2 = 0.04; adjusted-p = 0.036, η2 = 0.06) and adults (adjusted-p = 0.001, η2 = 0.02; adjusted-p = 0.004, η2 = 0.02). Protein malnutrition with acute/chronic inflammation (PMAC) in both adults (adjusted-p < 0.001, η2 = 0.04; adjusted-p < 0.001, η2 = 0.04) and older adults (adjusted-p = 0.010, η2 = 0.04; adjusted-p = 0.009, η2 = 0.05) had also a discernible impact in determining the ODI and PH. In older adults, the ODI was associated with iron deficit malnutrition (IDM) (adjusted-p = 0.005, η2 = 0.06) and both the ODI and PH were associated with vitamin B deficit (VBD) (adjusted-p = 0.037, η2 = 0.01; adjusted-p = 0.049, η2 = 0.01). Trend monotonicity was diagnosis- and sex-specific, with meaningful ordered patterns being observed mostly in young males and older females. Conclusions: Functional ability showed an association with malnutrition in younger adults and adults when using BWd, in adults and older adults when using PMAC, and in older adults when using IDM and VBD. The authors advocate for the inclusion of nutritional management in the pre-operative evaluation to potentially enhance recovery after spine surgery

What can whiskers tell us about mammalian evolution, behaviour, and ecology?

Most mammals have whiskers; however, nearly everything we know about whiskers derives from just a handful of species, including laboratory rats Rattus norvegicus and mice Mus musculus, as well as some species of pinniped and marsupial. We explore the extent to which the knowledge of the whisker system from a handful of species applies to mammals generally. This will help us understand whisker evolution and function, in order to gain more insights into mammalian behaviour and ecology. This review is structured around Tinbergen’s four questions, since this method is an established, comprehensive, and logical approach to studying behaviour. We ask: how do whiskers work, develop, and evolve? And what are they for? While whiskers are all slender, curved, tapered, keratinised hairs that transmit vibrotactile information, we show that there are marked differences between species with respect to whisker arrangement, numbers, length, musculature, development, and growth cycles. The conservation of form and a common muscle architecture in mammals suggests that early mammals had whiskers. Whiskers may have been functional even in therapsids. However, certain extant mammalian species are equipped with especially long and sensitive whiskers, in particular nocturnal, arboreal species, and aquatic species, which live in complex environments and hunt moving prey. Knowledge of whiskers and whisker use can guide us in developing conservation protocols and designing enriched enclosures for captive mammals. We suggest that further comparative studies, embracing a wider variety of mammalian species, are required before one can make large-scale predictions relating to evolution and function of whiskers. More research is needed to develop robust techniques to enhance the welfare and conservation of mammals

Microsecond-scale Timing Precision in Rodent Trigeminal Primary Afferents

Communication in the nervous system occurs by spikes: the timing precision with which spikes are fired is a fundamental limit on neural information processing. In sensory systems, spike-timing precision is constrained by first-order neurons. We found that spike-timing precision of trigeminal primary afferents in rats and mice is limited both by stimulus speed and by electrophysiological sampling rate. High-speed video of behaving mice revealed whisker velocities of at least 17,000°/s, so we delivered an ultrafast “ping” (>50,000°/s) to single whiskers and sampled primary afferent activity at 500 kHz. Median spike jitter was 17.4 μs; 29% of neurons had spike jitter < 10 μs. These results indicate that the input stage of the trigeminal pathway has extraordinary spike-timing precision and very high potential information capacity. This timing precision ranks among the highest in biology

Prediction of Primary Somatosensory Neuron Activity During Active Tactile Exploration

ABSTRACTPrimary sensory neurons form the interface between world and brain. Their function is well-understood during passive stimulation but, under natural behaving conditions, sense organs are under active, motor control. In an attempt to predict primary neuron firing under natural conditions of sensorimotor integration, we recorded from primary mechanosensory neuronsof awake, head-fixed mice as they explored a pole with their whiskers, and simultaneously measured both whisker motion and forces with high-speed videography. Using Generalised Linear Models, we found that primary neuron responses were poorly predicted by kinematics but well-predicted by rotational forces acting on the whisker: both during touch and free-air whisker motion. These results are discrepant with previous studies of passive stimulation, but could be reconciled by differences in the kinematics-force relationship between active and passive conditions. Thus, simple statistical models can predict rich neural activity elicited by natural, exploratory behaviour involving active movement of the sense organs.</jats:p

Microbiological evaluation of different strategies for management of snakes in captivity

Keeping snakes in captivity to produce venom for scientific research and production of inputs is now a worldwide practice. Maintaining snakes in captivity involves capture, infrastructure investments, management techniques, and appropriate qualified personnel. Further, the success of the project requires knowledge of habitat, nutrition, and reproduction, and control of opportunistic infections. This study evaluated the management of snakes in three types of captivity (quarantine, intensive, and semiextensive) and diagnosed bacterial and fungal contaminants. A bacteriological profile was obtained by swabbing the oral and cloacal cavities, scales, and venoms of healthy adult snakes from Bothrops jararaca (Bj) and Crotalus durissus terrificus (Cdt). There was predominance of Enterobacteriaceae, especially non-fermenting Gram-negative bacilli excluding Pseudomonas spp and Gram- positive bacteria. Statistically, intensive captivity resulted in the highest number of bacterial isolates, followed by recent capture (quarantine) and by semiextensive captivity. No statistical difference was found between Bj and Cdt bacterial frequency. In vitro bacterial susceptibility testing found the highest resistance against the semisynthetic penicillins (amoxicillin and ampicillin) and highest sensitivity to amicacin and tobramycin aminoglycosides. To evaluate mycological profile of snakes from intensive captivity, samples were obtained from two healthy Bj and one B. moojeni, one B. pauloensis, and one Cdt showing whitish lesions on the scales suggestive of ringworm. Using conventional methods and DNA-based molecular procedures, five samples of Trichosporon asahii were identified. Despite the traditional role of intense captivity in ophidian venom production, semiextensive captivity was more effective in the present study by virtue of presenting superior control of bacterial and fungal transmission, easier management, lowest cost, and decreased rate of mortality; therefore, it should be considered as a good alternative for tropical countries.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Feature Reduction in Superset Learning Using Rough Sets and Evidence Theory

Supervised learning is an important branch of machine learning (ML), which requires a complete annotation (labeling) of the involved training data. This assumption, which may constitute a severe bottleneck in the practical use of ML, is relaxed in weakly supervised learning. In this ML paradigm, training instances are not necessarily precisely labeled. Instead, annotations are allowed to be imprecise or partial. In the setting of superset learning, instances are assumed to be labeled with a set of possible annotations, which is assumed to contain the correct one. In this article, we study the application of rough set theory in the setting of superset learning. In particular, we consider the problem of feature reduction as a mean for data disambiguation, i.e., for the purpose of figuring out the most plausible precise instantiation of the imprecise training data. To this end, we define appropriate generalizations of decision tables and reducts, using information-theoretic techniques based on evidence theory. Moreover, we analyze the complexity of the associated computational problems