Specific Reflexes Research Articles

Activation of select airway afferent subpopulations evokes cardiopulmonary reflexes

Activation of airway sensory nerves causes respiratory and autonomic reflexes. The majority of the sensory nerves are only sensitive to noxious stimuli, such as inflammation, infection, irritants and pollutants. Activation of these nociceptive sensory nerves evokes protective mechanisms such as apnea, cough and bradycardia that can contribute to disease morbidity. Airway nociceptive sensory nerves are heterogeneous with respect to gene expression and neuroanatomy, and our objective is to characterize the specific reflexes evoked by activation of specific afferent subsets. To selectively activate these vagal afferent subpopulations in vivo, mice were exposed to nebulized selective stimuli such as capsaicin (transient receptor potential (TRP) vanillin 1 (V1) agonist), allyl isothiocyanate (AITC, TRP ankyrin 1 (A1) agonist) and clozapine‐N‐oxide (CNO, selective agonist for the designer receptors exclusively activated by designer drugs (DREADD) stimulatory receptor hM3Dq). hM3Dq expression was selectively expressed in sensory subpopulations under the control of cre recombinase in TRPV1‐cre (all nociceptors) and Tac1‐cre (peptidergic nerves). ECGs were recorded via radiotelemetry following implantation of biopotential sensing modules, and respiration was measured via whole body plethysmography. Our data indicate that stimulation of nociceptive subpopulations selectively evokes bradypnea and bradycardia in freely moving wild type mice.

Chapter 14 - Neural control of the lower airways: Role in cough and airway inflammatory disease

Airway function is under constant neurophysiological control, in order to maximize airflow and gas exchange and to protect the airways from aspiration, damage, and infection. There are multiple sensory nerve subtypes, whose disparate functions provide a wide array of sensory information into the CNS. Activation of these subtypes triggers specific reflexes, including cough and alterations in autonomic efferent control of airway smooth muscle, secretory cells, and vasculature. Importantly, every aspect of these reflex arcs can be impacted and altered by local inflammation caused by chronic lung disease such as asthma, bronchitis, and infections. Excessive and inappropriate activity in sensory and autonomic nerves within the airways is thought to contribute to the morbidity and symptoms associated with lung disease.

Sensory modulation of gait characteristics in human locomotion: A neuromusculoskeletal modeling study.

The central nervous system of humans and other animals modulates spinal cord activity to achieve several locomotion behaviors. Previous neuromechanical models investigated the modulation of human gait changing selected parameters belonging to CPGs (Central Pattern Generators) feedforward oscillatory structures or to feedback reflex circuits. CPG-based models could replicate slow and fast walking by changing only the oscillation’s properties. On the other hand, reflex-based models could achieve different behaviors through optimizations of large dimensional parameter spaces. However, they could not effectively identify individual key reflex parameters responsible for gait characteristics’ modulation. This study investigates which reflex parameters modulate the gait characteristics through neuromechanical simulations. A recently developed reflex-based model is used to perform optimizations with different target behaviors on speed, step length, and step duration to analyze the correlation between reflex parameters and their influence on these gait characteristics. We identified nine key parameters that may affect the target speed ranging from slow to fast walking (0.48 and 1.71 m/s) as well as a large range of step lengths (0.43 and 0.88 m) and step duration (0.51, 0.98 s). The findings show that specific reflexes during stance significantly affect step length regulation, mainly given by positive force feedback of the ankle plantarflexors’ group. On the other hand, stretch reflexes active during swing of iliopsoas and gluteus maximus regulate all the gait characteristics under analysis. Additionally, the results show that the hamstrings’ group’s stretch reflex during the landing phase is responsible for modulating the step length and step duration. Additional validation studies in simulations demonstrated that the modulation of identified reflexes is sufficient to regulate the investigated gait characteristics. Thus, this study provides an overview of possible reflexes involved in modulating speed, step length, and step duration of human gaits.

Molecular identity, anatomy, gene expression and function of neural crest vs. placode-derived nociceptors in the lower airways

The lower airways (larynx to alveoli) are protected by a complex array of neural networks that regulate respiration and airway function. Harmful stimuli trigger defensive responses such as apnea, cough and bronchospasm by activating a subpopulation of sensory afferent nerves (termed nociceptors) which are found throughout the airways. Airway nociceptive fibers are projected from the nodose vagal ganglia, the jugular vagal ganglia and the dorsal root ganglia, which are derived from distinct embryological sources: the former from the epibranchial placodes, the latter two from the neural crest. Embryological source determines nociceptive gene expression of receptors and neurotransmitters and recent evidence suggests that placode- and neural crest-derived nociceptors have distinct stimuli sensitivity, innervation patterns and functions. Improved understanding of the function of each subset in specific reflexes has substantial implications for therapeutic targeting of the neuronal components of airway disease such as asthma, viral infections and chronic obstructive pulmonary disease.

Contribution of the Police Academy in Szczytno to Counter-terrorist Activities

One of the state entities which have the task of preventing and combating terrorism is the Police, while the Police Academy in Szczytno is their intellectual base. It is not only an organisational unit of the Police, but also a higher education institution with legal personality. This status entitles it to teach at different levels of civilian higher education, as well as conduct in-service training for police officers. Education in the area of terrorist threats and counteracting them is aimed, on the one hand, at making the students aware of the scale of such threats and their accurate identification, as well as the ways of responding to them by the state and its institutions, and, on the other hand, at learning specific reflexes that will allow anyone who finds themselves in an area threatened by a terrorist attack to quickly assess the resulting threat and to react immediately. The goals set in this way are reflected in the employment structure of the academy, which includes specialist organisational units, and among the scientific and teaching staff are experts, including practitioners, who in the past carried out the tasks of the state at different levels of the system for counteracting terrorist threats. They systematically participate in scientific undertakings, including research projects, scientific conferences and publication work, participate in the work of expert teams, both national and international, and cooperate extensively with external entities. The result of their multidimensional activities is shaping and deepening social awareness of terrorist threats and desired attitudes towards them, as well as appropriate preparation of police officers, but also other services, to safely perform tasks related to the elimination of terrorist threats.

High frequency impulse ground penetrating radar application in assessment of interlayer connections

Ground Penetrating Radar (GPR) technique is commonly used in the nondestructive evaluation of pavement structures. In particular, this method is used to estimate thicknesses of pavement layers as well as it can be utilized in advanced studies of pavement structures. The device presented in this paper comprise the high frequency impulse antennas that allow for investigating the interlayer zones in terms of their electromagnetic properties (e.g. dielectric constant). In some cases these electromagnetic responses can be suitable in the assessment of layer bonding in the pavement structure. This paper discusses the assessment of the quality of asphalt pavement interlayer bonding with the use of high frequency GPR techniques. The preliminary laboratory measurements were performed using an impulse antenna in the zero-offset configuration combined with the large-scale models simulating an idealized horizontal delamination. These measurements allowed to estimate the antenna sensitivity to detect interlayer connection under dry and wet conditions. Analysis of collected results led to formulating practical conclusions regarding critical limitations of the measuring system and adequate methods of signal processing and interpretation. The field investigations consisted of the GPR measurements along selected road sections and collection of the core samples at the locations associated with the specific reflexes. Inspection of the cores provided some real insights into the structure of different delaminations associated with characteristic reflexes. Analysis showed the reflection properties are able to expresses some important features of the interlayer zone, such as delaminations, presence of alien material at the interface, insufficient compaction occurring at the base of layer, and water penetration.

Biomechanics of aerial righting in wingless nymphal stick insects.

Numerous wingless arthropods as well as diverse vertebrates are capable of mid-air righting. We studied the biomechanics of the aerial righting reflex in first-instar nymphs of the stick insect Extatosoma tiaratum. After being released upside-down, insects reoriented dorsoventrally and stabilized body posture via active modulation of limb positions and associated aerodynamic torques. We identified specific reflexes for bilaterally asymmetric leg displacements which elicit body rotation and subsequently stabilize mid-air posture. Coordinated appendicular movements thus improve torsional manoeuvrability in the absence of wings, as may have characterized the initial origins of controlled aerial behaviour in arthropods. Design of small aerial or multimodal robotic vehicles may similarly benefit from use of such strategies for flight control.

Lucian Blaga Between Words and Silence

One of the most important Romanian writers of the interwar period, Lucian Blaga (1895 - 1961) has been well known as a poet and a philosopher, an exquisite translator, a subtle essayist and a beloved playwright. Had he been awarded the Nobel Prize for Literature in 1956, as it seemed likely at the time, his work would have been studied all over the world, as it deserves. Nevertheless, the situation was complicated by politics and the prize went instead to Juan Ramon Jimenez. Blaga remained relatively unknown to the Western reader and has since often been considered a marginal or peripheral author, his great accomplishments being ignored outside Romania. Believing mystery to be an integral part of human life, he used his poetry to illuminate its significance to individuals and society and his philosophic system proved to be, at least partially, a type of pantheism dominated by the search for an elusive metaphysical principle called the Great Anonymous.Discussing Lucian Blaga's place in the field of Romanian culture but also keeping in mind the general context of world literature, Marcel Cornis-Pop considers that this author holds a singular position in modern Romanian literature, comparable to that of Eliot and Pound in the English-speaking countries.2 In fact, Blaga was the first Romanian poet whose work synchronized with some essential European artistic forms, his most important achievement being, perhaps, that of adapting Expressionism to Romanian poetry3 but also reappraising the models and relieving the will to modernity in terms specific to Romanian culture.The period between the two World Wars was Romania's golden age of modernism4: Tudor Arghezi, Ion Barbu, Tristan Tzara, Eugen Ionescu, Mircea Eliade and E.M. Cioran are only some names representing a generation determined to change something in the Romanian culture. Some of them became more or less familiar to the Western world, especially after leaving their native country and established mainly in France. But mention should be made that, as Andrei Codrescu pointed out, twentieth-century ideas descended on our small Balkan country all at once and were quickly absorbed and transformed.5 Together with some of his contemporaries, Blaga represents a constructivist phase in Romanian modernism, mainly because, picking up the scattered pieces of Dadaism, futurism and Expressionism and avoiding the excess of the new French art (surrealism), their work participated, however indirectly, in a reconstruction of European art in a post-Dada age.6In addition to the aspects mentioned before, Blaga belongs to the family of modern creators destined to have a many-sided commanding influence over the culture they belong to, considers Edgar Papu, stressing that these types of scholars, heralded already by Nietzsche and who cannot be absent from a privileged place neither in the history of poetry nor in the history of thinking, have appeared in orderly succession from Miguel de Unamuno to Jean-Paul Sartre. Their fecund polyvalence cannot be separated from the unity of their own personality which, from all sides, radiates the same vivid originality and the same message.7 Blaga is somehow paradoxical within Romanian culture: very keen on penetrating deep into the of his native land and, at the same time, being eager to resonate with the modern ideas of his own time, the poet carried the resources of the Romanian spirit to a culminating convergence; he made up his own inner horizon and connected with the spiritual profile of his people in order to find all specific reflexes of the great horizons of this particular circuit. Unamuno surprised an essence of Spain and established its place in the world and Blaga did exactly the same for Romania. Besides, Blaga is the first to include the search for final traits in the philosophic register, by applying concepts and categories of the philosophy of culture especially to the Romanian subhistory, to the unrecorded strata of the visible known history. …

Mo1189 Severe Exocrine Pancreatic Dysfunction in Children With Severe Acute Malnutrition; A Comparison of Faecal Elastase-1 Levels in Children With Marasmus and Kwashiorkor

G A A b st ra ct s composite response. Graded-stimulus-volume response relationships are shown (Table 1). Conclusions: In infants with sBPD, mechano-, osmo-, and chemosensitive stimuli evoke volume-dependent specific peristaltic, UES contractile, and LES relaxation reflexes at 42 and 50 weeks PMA. Recruitment of these reflexes is also dependent on physiochemical properties of the stimuli. Although at these studied PMAs, the patterns of recruitment of reflexes during maturation in sBPD are similar, there was a significant increase in EDR with acidic stimulus at advanced maturation. *Supported in part by PPG-P01 DK 068051 (Jadcherla/Shaker) Table 1. Graded stimulus-response relationship across maturation in sBPD

Habituation and sensitization in primary headaches.

The phenomena of habituation and sensitization are considered most useful for studying the neuronal substrates of information processing in the CNS. Both were studied in primary headaches, that are functional disorders of the brain characterized by an abnormal responsivity to any kind of incoming innocuous or painful stimuli and it’s cycling pattern over time (interictal, pre-ictal, ictal). The present review summarizes available data on stimulus responsivity in primary headaches obtained with clinical neurophysiology. In migraine, the majority of electrophysiological studies between attacks have shown that, for a number of different sensory modalities, the brain is characterised by a lack of habituation of evoked responses to repeated stimuli. This abnormal processing of the incoming information reaches its maximum a few days before the beginning of an attack, and normalizes during the attack, at a time when sensitization may also manifest itself. An abnormal rhythmic activity between thalamus and cortex, namely thalamocortical dysrhythmia, may be the pathophysiological mechanism subtending abnormal information processing in migraine. In tension-type headache (TTH), only few signs of deficient habituation were observed only in subgroups of patients. By contrast, using grand-average responses indirect evidence for sensitization has been found in chronic TTH with increased nociceptive specific reflexes and evoked potentials. Generalized increased sensitivity to pain (lower thresholds and increased pain rating) and a dysfunction in supraspinal descending pain control systems may contribute to the development and/or maintenance of central sensitization in chronic TTH. Cluster headache patients are chrarcterized during the bout and on the headache side by a pronounced lack of habituation of the brainstem blink reflex and a general sensitization of pain processing. A better insight into the nature of these ictal/interictal electrophysiological dysfunctions in primary headaches paves the way for novel therapeutic targets and may allow a better understanding of the mode of action of available therapies.

Clinical Applications of Intraspinal Microstimulation

Intraspinal microstimulation is a neuroprosthetic approach for activating specific spinal reflexes using penetrating electrodes chronically implanted into spinal cord. Artificial control of spinally mediated functions, such as arm and leg movement or bladder voiding, may be necessary in spinal cord injury, multiple sclerosis, cerebral palsy, amyotrophic lateral sclerosis, and spina bifida, when the brain becomes disconnected from spinal cord and a person loses control over these functions. Animal studies indicate the feasibility of efficient control of bladder voiding and limb movement. Development of novel microstimulation electrodes focuses on reduction of electrode dimensions for improved targeting efficiency, decreased tissue trauma, improved biocompatibility, and long-term safety and reliability of applied stimulation. Clinical usefulness of existing devices is limited by a lack of highly integrated and biocompatible neuroprosthetic systems, comprising high-density electrode arrays and integrated electronics for pulse generation and stimulation site addressing. Future developments will require a coordinated effort in the areas of neural prosthetic engineering, applied neurophysiology, neurosurgery, physical therapy, and rehabilitation. In the long term, clinical applications of intraspinal microstimulation may include treatments of such spinal cord-related disabilities, such as bladder and bowel emptying, sexual function, hand and arm control, and even walking. These treatments can address the long-standing needs of paralyzed patients aimed at improving their medical, psychological, social, and work-related conditions.

Vector representation of associative learning.

I. P. Pavlov has shown that conditioned reflexes are selective both with respect to conditioned stimuli and to conditioned reflexes elicited by those conditioned stimuli. At the neuronal level, selective aspects of conditional stimuli are based on detectors selectively tuned to the respective stimuli. The selective aspects of conditioned reflexes are due to command neurons representing specific unconditioned reflexes. It can be assumed that conditioned reflexes result from association between selective detectors and specific command neurons. The detectors activated by a conditional stimulus constitute a combination of excitations--a detector excitation vector. The detector excitation vector acts on a command neuron via a set of plastic synapses--a synaptic weight vector. Plastic synapses are modified in the process of learning, making the command neuron selectively tuned to a specific conditioned stimulus. The selective tuning of a particular command neuron to a specific excitation vector referred to a conditioned stimulus is the basis of associative learning. The probabilities of conditioned reflexes elicited by conditional and differential stimuli implicitly contain information concerning excitation vectors that encode the respective stimuli. The contribution of the vector code to associative learning was explored combining differential color conditioning with intracellular recording from color-coding neurons. It is shown that colors in carps and monkeys are represented on a hypersphere in the four-dimensional space similar with human color space. The basis of the color space is constituted by red-green, blue-yellow, brightness, and darkness neurons.

Analysis of isokinetic and isometric muscle function after arthroscopic anterior cruciate ligament repair

Following anterior cruciate ligament replacement plasty performed via arthroscopy, isokinetic and isometric power data were measured at the beginning and end of a sports therapy treatment course. Evaluation yielded surprising results that were partly contradictory to those communicated in current literature. Besides the dependence of force values on preset velocities of motion in dynamic measurements (isokinetics) or in static measurements (isometrics), markedly lower losses of power than expected were measured in the involved extremity on repeated power application. Possible reasons are discussed on the basis of specific innervation criteria and polymodal reflexes. We assume that muscle potential is not yet fully available after surgical intervention, due to reflexive modulations of power realisation, so that the joint and especially the anterior cruciate ligament are thus protected from damage.

Modulation of unconditioned defensive reflexes by a putative emotive Pavlovian conditioned stimulus.

Four experiments showed differential modulation of defensive unconditioned responses (URs) in rabbits by contextual stimuli that Brandon and Wagner (1991) have shown similarly to modulate conditioned eyeblink responses. Two 30-s auditory cues, A and B, were differentially paired with shock. Tests were presentations of a response-eliciting probe stimulus within A, B, or a comparable blank interval, Experiments 1 and 2 demonstrated that A and B differentially facilitated eyeblink URs, and Experiments 3 and 4 showed that A and B similarly differentially facilitated startle responses elicited by airpuffs to the ear. These data are consistent with a characterization of Pavlovian conditioning that distinguishes between emotive and sensory conditioning and assumes that conditioned emotional responses similarly modulate specific conditioned and unconditioned defensive reflexes (Konorski, 1967; Wagner & Brandon, 1989).

Retinal transplants can drive a pupillary reflex in host rat brains.

Retinae taken from embryonic rats were transplanted over the midbrain of neonatal rats, from whom one eye had been removed. After 5 months, the optic nerve of the remaining eye was cut, and the transplant was exposed. Illumination of the transplant caused pupilloconstriction of the host eye, a response abolished by damaging the transplant. Thus neural transplants are capable of driving specific reflexes in response to natural stimuli.

Chemosensitive Spinal Afferents: Thresholds of Specific and Nociceptive Reflexes as Compared with Thresholds of Excitation for Receptors and Axons

Publisher Summary The reflex rise of arterial pressure is an extremely sensitive indicator of tissue receptor excitation that is caused by endogenic substances. There are two kinds of pressor reflexes. The first kind arises in response to stimulation by substances with concentrations several orders lower than the algogenic ones. These reflexes are termed as “specific.” The second kinds are evoked by substances in algogenic concentrations. They are large, and what is especially important, have a high rate of arterial pressure rise. This kind of reflex is nociceptive—that is, represents the circulatory component of the defence reaction. The effective concentrations for both, the second kind of reflex and for chemalgia, are the same. The non-algesic substances—for example, tryptophan, methacholine, and pilocarpine—evoke only specific reflexes on exciting sensory nerve endings in the organ. Potentially algogenic substances, when used in concentrations many orders lower than the algesic ones, have the same effect.

Area specific reflexes from normal and supernumerary hindlimbs of Xenopus laevis.

Two area specific reflexes elicited by natural stimulation of different regions of the hindlimbs of Xenopus laevis have been identified. Light or intense mechanical stimulation of the foot evokes reflex activity in the ipsilateral knee flexor nerve; moderate pressure applied to the calf evokes reflex activity predominantly in the ipsilateral knee extensor nerve. The reflex responses have been recorded electrophysiologically to overcome the limitations of behavioral observations for determining the presence of activity in particular muscles. Normal area specific reflexes are elicited in the normal ipsilateral hindlimb by stimulation of grafted supernumerary hindlimbs innervated either by hindlimb (lumbar) or by non-limb (thoracic) spinal cord segments. The area specific reflexes can be elicited only if the limb is grafted to a host younger than stage 54-55 of Nieuwkoop and Faber ('56), the stage at which reflex movements are first observed behaviorally. Abnormal reflex responses are evoked by stimulation of supernumerary limbs innervated by either thoracic or lumbar segments when the limb buds are grafted to older larvae. Supernumerary forelimbs grafted at early stages and innervated by either thoracic or lumbar spinal cord segments generally fail to elicit area specific reflex responses in the normal hindlimb. Single-unit recordings of afferent fibers supplying the normal and supernumerary hindlimbs show that each limb receives a separate nerve supply. No evidence for branched afferent fibers has been found. The implications of these results for theories of neuronal specification are discussed, particularly the hypothesis that peripheral tissues are able to specify the central actions of afferent fibers that innervate them.

Behavioural Aspects of Degeneration and Regeneration in Fish Brain: a Comparison with Higher Vertebrates

This chapter compares the behavioral aspects of degeneration and regeneration in fish brain with the higher vertebrates. The chapter focuses on the structure and functions of the telencephalon of higher teleosts. In bony fishes the endbrain is a centre for smell whereas it lacks several functions present in the telencephalon of higher vertebrates. Moreover, some functional analogies with the limbic system of mammals are present. The chapter also describes experiments concerned with locomotion, posture, and feeding. The telencephalon of bony fishes has a (1) function regarding the perception of odor, (2) integrative function in the perception of odor and some taste stimuli, and (3) function with regard to the threshold range of the brightness perception. The telencephalon of bony fishes gives a more spontaneous character to specific reflexes and facilitates aggressive behavior. In comparing fishes it appears difficult to discover homologies in telencephalic structure.

CONFINEMENT TO BED FOR ONLY TWENTY-FOUR HOURS AFTER OPERATION

As a result of getting patients out of bed on the first postoperative day and increasing their activity as tolerated (with respiratory exercises mentioned hereinafter), circulatory and pulmonary complications have been reduced to a minimum, intestinal function has been restored without enemas and the period of morbidity and disability has been diminished 50 per cent or more. A previous publication1on this subject precipitated editorial comments in several leading medical journals.2These comments enable me to correct erroneous impressions surgeons inexperienced with early rising have had regarding it. In addition I am presenting another series of 464 consecutive surgical cases in which practically all the patients were subjected to early rising. This article also brings to attention specific reflexes that initiate pathologic changes—changes that lead to complications—and presents evidence that early rising, with its modifying effect on these reflex reactions, should be instituted by the first postoperative day.

Of Psychological Elements

The list of psychological elements that have been proposed within the last three centuries includes innate ideas which served to justify the doctrines of the church while rejecting the authority of the scholastics. Innate ideas were opposed by the empiricists as undemonstrable, a revolutionary epoch finding support in the doctrine of associated ideas, received through the senses. When this theory seemed to lead the skepticism, separate faculties were advocated, thus providing an innate form to human mental and moral life which was independent of experience. Faculty psychology became top-heavy and was abandoned, only to reappear in our day in the form of abilities, whether of intelligence or of other skills. The experimental period produced the notion of sensations and feelings as elements, but this could not meet the difficulties of the mind-body problem. Other proposed elements include separate instincts, specific reflexes, innate structures of Gestalten, and wishes or desires. The disagreement about t...