Cognitive response control in writer's cramp

Disturbances of the motor and sensory system as well as an alteration of the preparation of movements have been reported to play a role in the pathogenesis of dystonias. However, it is unclear whether higher aspects of cortical – like cognitive – functions are also involved. Recently, the NoGo-anteriorization (NGA) elicited with a visual continuous performance test (CPT) during recording of a 21-channel electroencephalogram has been proposed as an electrophysiological standard-index for cognitive response control. The NGA consists of a more anterior location of the positive area of the brain electrical field associated with the inhibition (NoGo-condition) compared with that of the execution (Go-condition) of a prepared motor response in the CPT. This response control paradigm was applied in 16 patients with writer’s cramp (WC) and 14 age matched healthy controls. Topographical analysis of the associated event-related potentials revealed a significant (P < 0.05) NGA effect for both patients and controls. Moreover, patients with WC showed a significantly higher global field power value (P < 0.05) in the Go-condition and a significantly higher difference-amplitude (P < 0.05) in the NoGo-condition. A source location analysis with the low resolution electromagnetic tomography (LORETA) method demonstrated a hypoactivity for the Go-condition in the parietal cortex of the right hemisphere and a hyperactivity in the NoGo-condition in the left parietal cortex in patients with WC compared with healthy controls. These results indicate an altered response control in patients with WC in widespread cortical brain areas and therefore support the hypothesis that the pathogenesis of WC is not restricted to a pure sensory-motor dysfunction.

Nondermatomal somatosensory deficits in chronic pain are associated with cerebral grey matter changes

OBJECTIVES Widespread sensory deficits occur in 20-40% of chronic pain patients on the side of pain, independent of pain aetiology, and are known as nondermatomal sensory deficits (NDSDs). NDSDs can occur in absence of central or peripheral nervous system lesions. We hypothesised that NDSDs were associated with cerebral grey matter changes in the sensory system and in pain processing regions, detectable with voxel-based morphometry. METHODS Twenty-five patients with NDSDs, 23 patients without NDSDs ("pain-only"), and 29 healthy controls were studied with high resolution structural MRI of the brain. A comprehensive clinical and psychiatric evaluation based on Diagnostic and Statistical Manual was performed in all patients. RESULTS Patients with NDSDs and "pain-only" did not differ concerning demographic data and psychiatric diagnoses, although anxiety scores (HADS-A) were higher in patients with NDSDs. In patients with NDSDs, grey matter increases were found in the right primary sensory cortex, thalamus, and bilaterally in lateral temporal regions and the hippocampus/fusiform gyrus. "Pain-only" patients showed a bilateral grey matter increase in the posterior insula and less pronounced changes in sensorimotor cortex. CONCLUSIONS Dysfunctional sensory processing in patients with NDSDs is associated with complex changes in grey matter volume, involving the somatosensory system and temporal regions.

UNDERSTANDING INTERRUPTIONS IN HEALTHCARE: DEVELOPING A MODEL

Developing a Model Interruption is a known human factor that contributes to errors and catastrophic events in healthcare as well as other high-risk industries. The landmark Institute of Medicine (IOM) report, To Err is Human, brought attention to the significance of preventable errors in medicine and suggested that interruptions could be a contributing factor. Previous studies of interruptions in healthcare did not offer a conceptual model by which to study interruptions. As a result of the serious consequences of interruptions investigated in other high-risk industries, there is a need to develop a model to describe, understand, explain, and predict interruptions and their consequences in healthcare. Therefore, the purpose of this study was to develop a model grounded in the literature and to use the model to describe and explain interruptions in healthcare. Specifically, this model would be used to describe and explain interruptions occurring in a Level One Trauma Center. A trauma center was chosen because this environment is characterized as intense, unpredictable, and interrupt-driven. The first step in developing the model began with a review of the literature which revealed that the concept interruption did not have a consistent definition in either the healthcare or non-healthcare literature. Walker and Avant’s method of concept analysis was used to clarify and define the concept. The analysis led to the identification of five defining attributes which include (1) a human experience, (2) an intrusion of a secondary, unplanned, and unexpected task, (3) discontinuity, (4) externally or internally initiated, and (5) situated within a context. However, before an interruption could commence, five conditions known as antecedents must occur. For an interruption to take place (1) an intent to interrupt is formed by the initiator, (2) a physical signal must pass a threshold test of detection by the recipient, (3) the sensory system of the recipient is stimulated to respond to the initiator, (4) an interruption task is presented to recipient, and (5) the interruption task is either accepted or rejected by v the recipient. An interruption was determined to be quantifiable by (1) the frequency of occurrence of an interruption, (2) the number of times the primary task has been suspended to perform an interrupting task, (3) the length of time the primary task has been suspended, and (4) the frequency of returning to the primary task or not returning to the primary task. As a result of the concept analysis, a definition of an interruption was derived from the literature. An interruption is defined as a break in the performance of a human activity initiated internal or external to the recipient and occurring within the context of a setting or location. This break results in the suspension of the initial task by initiating the performance of an unplanned task with the assumption that the initial task will be resumed. The definition is inclusive of all the defining attributes of an interruption. This is a standard definition that can be used by the healthcare industry. From the definition, a visual model of an interruption was developed. The model was used to describe and explain the interruptions recorded for an instrumental case study of physicians and registered nurses (RNs) working in a Level One Trauma Center. Five physicians were observed for a total of 29 hours, 31 minutes. Eight registered nurses were observed for a total of 40 hours 9 minutes. Observations were made on either the 0700–1500 or the 1500-2300 shift using the shadowing technique. Observations were recorded in the field note format. The field notes were analyzed by a hybrid method of categorizing activities and interruptions. The method was developed by using both a deductive a priori classification framework and by the inductive process utilizing line-byline coding and constant comparison as stated in Grounded Theory. The following categories were identified as relative to this study: Intended Recipient - the person to be interrupted Unintended Recipient - not the intended recipient of an interruption; i.e., receiving a phone call that was incorrectly dialed Indirect Recipient – the incidental recipient of an interruption; i.e., talking with another, thereby suspending the original activity Recipient Blocked – the intended recipient does not accept the interruption Recipient Delayed – the intended recipient postpones an interruption Self-interruption – a person, independent of another person, suspends one activity to perform another; i.e., while walking, stops abruptly and talks to another person Distraction – briefly disengaging from a task Organizational Design – the physical layout of the workspace that causes a disruption in workflow Artifacts Not Available – supplies and equipment that are not available in the workspace causing a disruption in workflow Initiator – a person who initiates an interruption Interruption by Organizational Design and Artifacts Not Available were identified as two new categories of interruption. These categories had not previously been cited in the literature. Analysis of the observations indicated that physicians were found to perform slightly fewer activities per hour when compared to RNs. This variance may be attributed to differing roles and responsibilities. Physicians were found to have more activities interrupted when compared to RNs. However, RNs experienced more interruptions per hour. Other people were determined to be the most commonly used medium through which to deliver an interruption. Additional mediums used to deliver an interruption vii included the telephone, pager, and one’s self. Both physicians and RNs were observed to resume an original interrupted activity more often than not. In most interruptions, both physicians and RNs performed only one or two interrupting activities before returning to the original interrupted activity. In conclusion the model was found to explain all interruptions observed during the study. However, the model will require an even more comprehensive study in order to establish its predictive value.

Design of a training tool for improving the use of hand-held detectors in humanitarian demining

Purpose – The purpose of this paper is to introduce the design of a training tool intended to improve deminers' technique during close-in detection tasks. Design/methodology/approach – Following an introduction that highlights the impact of mines and improvised explosive devices (IEDs), and the importance of training for enhancing the safety and the efficiency of the deminers, this paper considers the utilization of a sensory tracking system to study the skill of the hand-held detector expert operators. With the compiled information, some critical performance variables can be extracted, assessed, and quantified, so that they can be used afterwards as reference values for the training task. In a second stage, the sensory tracking system is used for analysing the trainee skills. The experimentation phase aims to test the effectiveness of the elements that compose the sensory system to track the hand-held detector during the training sessions. Findings – The proposed training tool will be able to evaluate the deminers' efficiency during the scanning tasks and will provide important information for improving their competences. Originality/value – This paper highlights the need of introducing emerging technologies for enhancing the current training techniques for deminers and proposes a sensory tracking system that can be successfully utilised for evaluating trainees' performance with hand-held detectors.

The site of action of neuronal acidic fibroblast growth factor is the organ of Corti of the rat cochlea.

Here we show that the mature cochlear neurons are a rich source of acidic fibroblast growth factor (aFGF), which is expressed in the neuronal circuitry consisting of afferent and efferent innervation. The site of action of neuronal aFGF is likely to reside in the organ of Corti, where one of the four known FGF receptor (FGFR) tyrosine kinases--namely, FGFR-3 mRNA--is expressed. Following acoustic overstimulation, known to cause damage to the organ of Corti, a rapid up-regulation of FGFR-3 is evident in this sensory epithelium, at both mRNA and protein levels. The present results provide in vivo evidence for aFGF being a sensory neuron-derived, anterogradely transported factor that may exert trophic effects on a peripheral target tissue. In this sensory system, aFGF, rather than being a neurotrophic factor, seems to promote maintenance of the integrity of the organ of Corti. In addition, aFGF, released from the traumatized nerve endings, may be one of the first signals initiating protective recovery and repair processes following damaging auditory stimuli.

Calibración de cámaras de tiempo de vuelo: ajuste adaptativo del tiempo de integración y análisis de la frecuencia de modulación

La percepción de profundidad se hace imprescindible en muchas tareas de manipulación, control visual y navegación de robots. Las cámaras de tiempo de vuelo (ToF: Time of Flight) generan imágenes de rango que proporcionan medidas de profundidad en tiempo real. No obstante, el parámetro distancia que calculan estas cámaras es fuertemente dependiente del tiempo de integración que se configura en el sensor y de la frecuencia de modulación empleada por el sistema de iluminación que integran. En este artículo, se presenta una metodología para el ajuste adaptativo del tiempo de integración y un análisis experimental del comportamiento de una cámara ToF cuando se modifica la frecuencia de modulación. Este método ha sido probado con éxito en algoritmos de control visual con arquitectura ‘eye-in-hand’ donde el sistema sensorial está compuesto por una cámara ToF. Además, la misma metodología puede ser aplicada en otros escenarios de trabajo.

Behavioural and histopathological alterations in mice with cerebral malaria.

Different features of sensorimotor function and behaviour were studied in murine cerebral malaria (CM) and malaria without cerebral involvement (non-CM) applying the primary screen of the SHIRPA protocol. Histopathological analysis of distinct brain regions was performed and the relative size of haemorrhages and plugging of blood cells to brain vasculature was analysed. Animals suffering from CM develop a wide range of behavioural and functional alterations in the progressive course of the disease with a statistically significant impairment in all functional categories assessed 36 h prior to death when compared with control animals. Early functional indicators of cerebral phenotype are impairments in reflex and sensory system and in neuropsychiatric state. Deterioration in function is paralleled by the degree of histopathological changes with a statistically significant correlation between the SHIRPA score of CM animals and the mean size of brain haemorrhage. Furthermore, image analysis yielded that the relative area of the brain lesions was significantly larger in the forebrain and brainstem compared with the other regions of interest. Our results indicate that assessment of sensory and motor tasks by the SHIRPA primary screen is appropriate for the early in vivo discrimination of cerebral involvement in experimental murine malaria. Our findings also suggest a correlation between the degree of functional impairment and the size of the brain lesions as indicated by parenchymal haemorrhage. Applying the SHIRPA protocol in the functional characterization of animals suffering from CM might prove useful in the preclinical assessment of new antimalarial and potential neuroprotective therapies.

Pain and motor control of the lumbopelvic region: effect and possible mechanisms

Many authors report changes in the control of the trunk muscles in people with low back pain (LBP). Although there is considerable disagreement regarding the nature of these changes, we have consistently found differential effects on the deep intrinsic and superficial muscles of the lumbopelvic region. Two issues require consideration; first, the potential mechanisms for these changes in control, and secondly, the effect or outcome of changes in control for lumbopelvic function. Recent data indicate that experimentally induced pain may replicate some of the changes identified in people with LBP. While this does not exclude the possibility that changes in control of the trunk muscles may lead to pain, it does argue that, at least in some cases, pain may cause the changes in control. There are many possible mechanisms, including changes in excitability in the motor pathway, changes in the sensory system, and factors associated. with the attention demanding, stressful and fearful aspects of pain. A new hypothesis is presented regarding the outcome from differential effects of pain on the elements of the motor system. Taken together these data argue for strategies of prevention and rehabilitation of LBP (C) 2003 Elsevier Science Ltd. All rights reserved.

The functional roles of passive electroreception in non-electric fishes

Passive electroreception is a complex and specialised sense found in a large range of aquatic vertebrates primarily designed for the detection of weak bioelectric fields. Particular attention has traditionally focused on cartilaginous fishes, but a range of teleost and non-teleost fishes from a diversity of habitats have also been examined. As more species are investigated, it has become apparent that the role of electroreception in fishes is not restricted to locating prey, but is utilised in other complex behaviours. This paper presents the various functional roles of passive electroreception in non-electric fishes, by reviewing much of the recent research on the detection of prey in the context of differences in species' habitat (shallow water, deep-sea, freshwater and saltwater). A special case study on the distribution and neural groupings of ampullary organs in the omnihaline bull shark, Carcharhinus leucas, is also presented and reveals that prey-capture, rather than navigation, may be an important determinant of pore distribution. The discrimination between potential predators and conspecifics and the role of bioelectric stimuli in social behaviour is discussed, as is the ability to migrate over short or long distances in order to locate environmentally favourable conditions. The various theories proposed regarding the importance and mediation of geomagnetic orientation by either an electroreceptive and/or a magnetite-based sensory system receives particular attention. The importance of electroreception to many species is emphasised by highlighting what still remains to be investigated, especially with respect to the physical, biochemical and neural properties of the ampullary organs and the signals that give rise to the large range of observed behaviours.

Brain morphology in large pelagic fishes: A comparison between sharks and teleosts

A quantitative comparison was made of both relative brain size (encephalization) and the relative development of five brain area of pelagic sharks and teleosts. Two integration areas (the telencephalon and the corpus cerebellum) and three sensory brain areas (the olfactory bulbs, optic tectum and octavolateralis area, which receive primary projections from the olfactory epithelium, eye and octavolateralis senses, respectively), in four species of pelagic shark and six species of pelagic teleost were investigated. The relative proportions of the three sensory brain areas were assessed as a proportion of the total 'sensory brain', while the two integration areas were assessed relative to the sensory brain. The allometric analysis of relative brain size revealed that pelagic sharks had larger brains than pelagic teleosts. The volume of the telencephalon was significantly larger in the sharks, while the corpus cerebellum was also larger and more heavily foliated in these animals. There were also significant differences in the relative development of the sensory brain areas between the two groups, with the sharks having larger olfactory bulbs and octavolateralis areas, whilst the teleosts had larger optic tecta. Cluster analysis performed on the sensory brain areas data confirmed the differences in the composition of the sensory brain in sharks and teleosts and indicated that these two groups of pelagic fishes had evolved different sensory strategies to cope with the demands of life in the open ocean.

Enhanced information transmission with signal dependent noise in an array of LIF neurons

Sensory cells usually transmit information to afferent neurons via chemical synapses, in which the level of noise is dependent on an applied stimulus. Taking into account such dependence, we model a sensory system as an array of LIF neurons with a common signal. We show that information transmission is enhanced by a nonzero level of noise. Moreover, we demonstrate a phenomenon similar to suprathreshold stochastic resonance with additive noise. We remark that many properties of information transmission found for the LIF neurons was predicted by us before with simple binary units [Phys. Rev. E 75, 021121 (2007)]. This confirmation of our predictions allows us to point out identical roots of the phenomena found in the simple threshold systems and more complex LIF neurons.

Spectral sensitivity of cone photoreceptors and opsin expression in two colour-divergent lineages of the lizard Ctenophorus decresii

Intraspecific differences in sensory perception are rarely reported but may occur when a species range extends across varying sensory environments, or there is coevolution between the sensory system and a varying signal. Examples in colour vision and colour signals are rare in terrestrial systems. The tawny dragon lizard Ctenophorus decresii is a promising candidate for such intraspecific variation, because the species comprises two geographically and genetically distinct lineages in which throat colour (a social signal used in intra- and inter-specific interactions) is locally adapted to the habitat and differs between lineages. Male lizards from the southern lineage have UV-blue throats, whereas males from the northern lineage are polymorphic with four discrete throat colours that all show minimal UV reflectance. Here, we determine the cone photoreceptor spectral sensitivities and opsin expression of the two lineages, to test whether they differ, particularly in the UV wavelengths. Using microspectrophotometry on retinal cone photoreceptors, we identified a long-wavelength-sensitive (LWS) visual pigment, a 'short' and 'long' medium-wavelength-sensitive (MWS) pigment and a short-wavelength-sensitive (SWS) pigment, all of which did not differ in λmax between lineages. Through transcriptome analysis of opsin genes we found that both lineages express four cone opsin genes, including the SWS1 opsin with peak sensitivity in the UV range, and that amino acid sequences did not differ between lineages with the exception of a single leucine to valine substitution in the RH2 opsin. Counts of yellow and transparent oil droplets associated with LWS+MWS and SWS+UVS cones, respectively, showed no difference in relative cone proportions between lineages. Therefore, contrary to predictions, we find no evidence of differences between lineages in single cone photoreceptor spectral sensitivity or opsin expression. However, we confirm the presence of four single cone classes, suggesting tetrachromacy in C. decresii, and we also provide the first evidence of UV sensitivity in agamid lizards.

Navite: A Neural Network System For Sensory-Based Robot Navigation

A neural network system, NAVITE, for incremental trajectory generation and obstacle avoidance is presented. Unlike other approaches, the system is effective in unstructured environments. Multimodal inforrnation from visual and range data is used for obstacle detection and to eliminate uncertainty in the measurements. Optimal paths are computed without explicitly optimizing cost functions, therefore reducing computational expenses. Simulations of a planar mobile robot (including the dynamic characteristics of the plant) in obstacle-free and object avoidance trajectories are presented. The system can be extended to incorporate global map information into the local decision-making process.

A new sensory organ in "primitive" molluscs (Polyplacophora Lepidopleurida), and its context in the nervous system of chitons

Introduction: Chitons (Polyplacophora) are molluscs considered to have a simple nervous system without cephalisation. The position of the class within Mollusca is the topic of extensive debate and neuroanatomical characters can provide new sources of phylogenetic data as well as insights into the fundamental biology of the organisms. We report a new discrete anterior sensory structure in chitons, occurring throughout Lepidopleurida, the order of living chitons that retains plesiomorphic characteristics.

Results: The novel "Schwabe organ" is clearly visible on living animals as a pair of streaks of brown or purplish pigment on the roof of the pallial cavity, lateral to or partly covered by the mouth lappets. We describe the histology and ultrastructure of the anterior nervous system, including the Schwabe organ, in two lepidopleuran chitons using light and electron microscopy. The oesophageal nerve ring is greatly enlarged and displays ganglionic structure, with the neuropil surrounded by neural somata. The Schwabe organ is innervated by the lateral nerve cord, and dense bundles of nerve fibres running through the Schwabe organ epithelium are frequently surrounded by the pigment granules which characterise the organ. Basal cells projecting to the epithelial surface and cells bearing a large number of ciliary structures may be indicative of sensory function. The Schwabe organ is present in all genera within Lepidopleurida (and absent throughout Chitonida) and represents a novel anatomical synapomorphy of the clade.

Conclusions: The Schwabe organ is a pigmented sensory organ, found on the ventral surface of deep-sea and shallow water chitons; although its anatomy is well understood, its function remains unknown. The anterior commissure of the chiton oesophagial nerve ring can be considered a brain. Our thorough review of the chiton central nervous system, and particularly the sensory organs of the pallial cavity, provides a context to interpret neuroanatomical homology and assess this new sense organ.