Reflex Changes Research Articles

Blink reflex changes and sensory perception in infraorbital nerve-innervated areas following zygomaticomaxillary complex fractures.

BackgroundInfraorbital nerve dysfunction is commonly reported after zygomaticomaxillary complex fractures. We evaluated sensory changes in four designated areas (eyelid, nose, zygoma, and lip) innervated by the infraorbital nerve. This evaluation was conducted using the static two-point discrimination test and the vibration threshold test. We assessed the diagnostic significance of the blink reflex in patients with infraorbital nerve dysfunction.MethodsThis study included 18 patients, all of whom complained of some degree of infraorbital nerve dysfunction preoperatively. A visual analog scale, the infraorbital blink reflex, static two-point discrimination, and the vibration threshold were assessed preoperatively, at 1 month postoperatively (T1), and at a final follow-up that took place at least 4 months postoperatively (T4). The results were analyzed using a multilevel generalized linear mixed model.ResultsScores on the visual analog scale significantly improved at T1 and T4. The infraorbital blink reflex significantly improved at T4. Visual analog scale scores improved more rapidly than the infraorbital blink reflex. Two-point discrimination significantly improved in all areas at T4, and the vibration perception threshold significantly improved in the eyelid at T4.ConclusionsRecovery of the infraorbital blink reflex reflected the recovery of infraorbital nerve dysfunction. We also determined that the lip tended to recover later than the other areas innervated by the infraorbital nerve.

Getting ahead while retaining ethnic salience: educational mobilities, class, and empowerment of a Tibetan student in China

ABSTRACT Adopting empowerment as a theoretical lens, this paper examines how a combination of structural (particularly class background) and individual factors (particularly empowering agents and a strong personal will to achieve) have contributed to school success and ethnic identity formation of minority students in China. Our longitudinal study on a Tibetan student (Dolma) from middle-class background who completed seven-year dislocated secondary schooling and four-year undergraduate studies in China’s interior (Neidi) suggests the complexity and lack of institutional empowerment in every-day schooling. Although the implementation of preferential policies has expanded educational opportunities for ethnic minorities, the systemic failure to acknowledge the ethnic capital of minority groups at large accounts for the struggles along Dolma’s educational mobilities. Thanks to two teachers who acted as empowering agents, Dolma’s school adaptation in neidi was made less bumpy. While parental involvement was largely missing during the dislocated secondary schooling, her middle-class background greatly facilitated Dolma’s social adaptation and educational success in undergraduate and postgraduate studies. With a strong will to represent Tibetan culture appropriately to the mainstream society, Dolma gradually learned to get ahead while retaining her ethnic salience. This study calls for more culturally reflexive policy changes to achieve institutional empowerment of ethnic minority students.

Fatal cerebral edema in patients with decompensated cirrhosis: A case series.

Unlike patients with acute liver failure, patients with cirrhosis are not traditionally thought to be at risk for developing cerebral edema. In the largest case series to date, we document clinical characteristics of cirrhotic patients who develop cerebral edema. In this retrospective case series, seventeen adult patients with acute-on-chronic liver failure (ACLF) were identified using Morbidity & Mortality data. Neurological decompensation was defined by focal neurological deficits or abnormal movements. Elevated ICP was diagnosed clinically by pupillary reflex change improving with hyperosmolar therapy, or by herniation on CT. Pulsatility indices >1.2 on transcranial Dopplers (TCDs) and/or optic nerve sheath diameter (ONSD) >0.5cm were acceptable alternatives. Median MELD-Na was 36 (IQR 31.5,43) compared with 20 (IQR 19,23) prior to admission. Neurological decompensation was associated with abnormal pupil reactivity in 76% and abnormal movements in 65%. Cerebral edema was diagnosed by CT (n=14). For those too ill to transport, elevated ICP was confirmed with TCDs for three patients and ONSD for two. Mortality was 100% a median of 3days (IQR 1.5,5) from neurologic decompensation. ACLF patients with neurological decompensation exhibit distinct clinical changes. Noninvasive bedside techniques may serve as surrogate measures for ICP.

Improvement of Asymmetric Vestibulo-Ocular Reflex Responses Following Onset of Vestibular Neuritis Is Similar Across Canal Planes.

Background: We examined whether, after onset of acute unilateral vestibular neuritis (aUVN), initial disease effects, subsequent peripheral recovery and central compensation cause similar changes in vestibular ocular reflex (VOR) gains in all 3 semi-circular canal planes.Methods: 20 patients, mean age 56.5 years, with pathological lateral canal video head impulse test (vHIT) VOR gains due to aUVN, were subsequently examined with vHIT in all 3 canal planes on average 4.3 and 36.7 days (“5 weeks”) after aUVN onset.Results: Lateral and anterior deficit side (DS) average gains equaled 0.41 at aUVN onset. Non-deficit, normal, side (NS) gains were 0.88 and 0.81, respectively. Mean posterior DS gain was similar at onset, 0.43, provided only gains lower than 0.6 (lower limit of healthy controls) were considered. NS posterior mean gain at onset (0.68) was less (p ≤ 0.0006) than lateral and anterior NS gains. After 5 weeks, DS lateral, anterior and posterior canal gains increased (p ≤ 0.05), on average, to 0.65, 0.59, and 0.58, respectively. NS gains increased to 0.91, 0.87, and 0.76 (p = 0.007), respectively. At 5 weeks deficit-lateral/normal-lateral canal plane gain asymmetries were significantly (p < 0.0008) reduced from 36.9 to 19.4%, deficit-anterior/normal-posterior asymmetry decreased from 28.6 to 18.1%, while deficit-posterior/normal-anterior asymmetry changed from 29.7 to 21.4%, all to circa 20%. Roll plane asymmetries decreased slightly over 5 weeks (28.6–18.1%) but pitch plane asymmetries remained significantly less (p = 0.001), not different from 0% regardless of initial DS posterior canal vHIT gain. Yaw plane asymmetry changes are identical to those of the lateral canals (36.7–19.4%).Conclusions: These results indicate that, at onset, aUVN of the superior vestibular nerve has a similar effect on lateral and anterior deficit DS VOR gains, and on posterior DS canal VOR gains if the inferior nerve was also affected at onset. The significant improvements to equal 5 week levels of DS gains and slightly greater posterior NS gain improvements, compared to lateral and anterior NS gains, yielding a common canal plane gain asymmetry of 20% at 5 weeks, suggest similar neural compensation mechanisms were active along VOR pathways. Unexpectantly, canal plane improvement was not replicated in pitch plane asymmetries.

Stretch reflex changes in ACL-deficient individuals and healthy controls during normal and surprise landings.

No studies in ACL-D individuals have examined neuromuscular adaptations during landing from a jump where an unexpected mechanical event changes the pre-programmed course of movement. The purpose of this study was to compare pre- and post-landing muscle activation in ACL-D individuals and uninjured controls during normal and surprise landings. Nineteen ACL-D and 17 uninjured volunteered. Participants performed repeated single leg landings from 30 and 15cm heights. During 15cm landings, a single surprise landing was performed where participants unexpectedly fell through a false surface at 15cm to the solid floor a further 15cm below. Electromyography (EMG) amplitude from vastus lateralis (VL), lateral hamstrings (LH), and soleus (Sol) was recorded. Pre-landing (-60 to 0ms), post-landing short latency (31-60ms), and post-landing medium latency (61-90ms) periods were examined. Comparisons in EMG amplitudes were made across limbs (ACL-D, ACL intact, and control) in 30cm landings. Additionally, the ratio of EMG amplitude in surprise:30cm normal landings was analyzed. Post-landing LH EMG was reduced in the ACL-D compared to control limbs at short latencies (P<0.05). Post-landing VL EMG was reduced in the ACL-D and ACL intact compared to the control limb at both latencies (P<0.05). Surprise landings notably increased post-landing EMG in all muscles, across all limbs (P<0.001). However, the gain in VL EMG was significantly greater in ACL-D and ACL intact limbs (P<0.05). These changes in neuromuscular control of ACL-D individuals during expected and surprise landings may have important implications for rehabilitation, instability, and the risk of secondary injury.

45. A prospective, in-depth analysis of perioperative anterior thigh symptoms associated with a direct lateral access approach for lumbar interbody fusion

BACKGROUND CONTEXT Anterior thigh symptoms post-transpsoas lateral approach for lumbar interbody arthrodesis are well documented. Symptoms may be transient ( PURPOSE The aim of this analysis was to prospectively characterize adverse perioperative neurological changes associated with a direct lateral transpsoas retroperitoneal closed tubular retractor system. Further, provider-reported changes were compared vs subject-reported changes. STUDY DESIGN/SETTING This investigation is a prospective, multicenter, single-arm, IRB approved post-market study. PATIENT SAMPLE One hundred fifteen subjects (115), 71 females (61.7%), with a mean age of 64.0 and mean BMI of 30.8 presenting with degenerative disc disease at one or two adjacent levels from L2 to L5 were included for analysis. OUTCOME MEASURES Subjects self-reported thigh pain, hip flexion weakness, and knee extension weakness on a 100mm Visual Analog Scale. Clinical assessments including muscle strength, Achilles reflexes, patellar reflexes, and sensory testing were performed at the same time points. Multiple questions specific to lateral access not typically collected in lumbar fusion studies were included in the analysis. METHODS All outcome measures were prospectively collected at the preoperative visit, prior to hospital discharge, and at the two-week, six-week, three-month, six-month, and twelve-month postoperative visits. Data were descriptively analyzed. RESULTS Objective neurological exam showed 17 (14.8%) subjects with access-sided adverse changes from baseline at hospital discharge. These 17 included 5 (4.4%) with changes in strength, 5 (4.4%) with sensation changes, and 11 (9.6%) with reflex changes. Of these, 2 subjects had changes in both strength and reflexes; 2 had changes in both sensation and reflexes. All strength and sensation changes were resolved by 6 weeks. All reflex changes resolved by 3 months. Twenty-two subjects (19.1%) reported increased thigh pain (>20mm) at discharge. All were resolved by 3 months. Forty-four (44) subjects (38.3%) reported increased hip flexion or extension weakness (>20mm) with 29 (65.9%) resolved by 6 weeks, 37 (84.1%) resolved by 3 months, 41/45 (93.2%) resolved by 6 months, and 3 have additional follow-up pending. Of the 17 subjects with objectively identified changes, 7 also reported subjective changes. Only 2 subjects’ (11.8%) reported symptoms (weakness) correlated with objectively reported results (strength). CONCLUSIONS This unique prospective study is the first to our knowledge that captures in-depth subjective and objective thigh symptom data specific to lateral access transpsoas surgery. The perioperative results provide a rare illustration of adverse changes and their almost complete resolution within 3 months. Further research to understand the differences in clinician reported vs subject reported changes is warranted. FDA DEVICE/DRUG STATUS Duo Interbody Fusion System (Approved for this indication)

Readaptation Treatment of Mal de Debarquement Syndrome With a Virtual Reality App: A Pilot Study.

Mal de Debarquement syndrome (MdDS) is composed of constant phantom sensations of motion, which are frequently accompanied by increased sensitivity to light, inability to walk on a patterned floor, the sensation of ear fullness, head pressure, anxiety, and depression. This disabling condition generally occurs in premenopausal women within 2 days after prolonged passive motion (e.g., travel on a cruise ship, plane, or in a car). It has been previously hypothesized that MdDS is the result of maladaptive changes in the polysynaptic vestibulo-ocular reflex (VOR) pathway called velocity storage. Past research indicates that full-field optokinetic stimulation is an optimal way to activate velocity storage. Unfortunately, such devices are typically bulky and not commonly available. We questioned whether virtual reality (VR) goggles with a restricted visual field could effectively simulate a laboratory environment for MdDS treatment. A stripes program for optokinetic stimulation was implemented using Google Daydream Viewer. Five female patients (42 ± 10 years; range 26–50), whose average MdDS symptom duration was 2 months, participated in this study. Four patients had symptoms triggered by prolonged passive motion, and in one, symptoms spontaneously occurred. Symptom severity was self-scored by patients on a scale of 0–10, where 0 is no symptoms at all and 10 is the strongest symptoms that the patient could imagine. Static posturography was obtained to determine objective changes in body motion. The treatment was considered effective if the patient's subjective score improved by at least 50%. All five patients reported immediate improvement. On 2-month follow-ups, symptoms returned only in one patient. These data provide proof of concept for the limited-visual-field goggles potentially having clinical utility as a substitute for full-field optokinetic stimulation in treating patients with MdDS in clinics or via telemedicine.

The potential role of the carotid body in COVID-19.

The carotid body (CB) plays a contributory role in the pathogenesis of various respiratory, cardiovascular, renal, and metabolic diseases through reflex changes in ventilation and sympathetic output. On the basis of available data about peripheral arterial chemoreception and severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), a potential involvement in the coronavirus disease 2019 (COVID-19) may be hypothesized through different mechanisms. The CB could be a site of SARS-CoV-2 invasion, due to local expression of its receptor [angiotensin-converting enzyme (ACE) 2] and an alternative route of nervous system invasion, through retrograde transport along the carotid sinus nerve. The CB function could be affected by COVID-19-induced inflammatory/immune reactions and/or ACE1/ACE2 imbalance, both at local or systemic level. Increased peripheral arterial chemosensitivity and reflex sympatho-activation may contribute to the increased morbidity and mortality in COVID-19 patients with respiratory, cardiovascular, renal, or metabolic comorbidities.

Changes in Vestibulo-Ocular Reflex Gain After Surgical Plugging of Superior Semicircular Canal Dehiscence.

Superior semicircular canal dehiscence (SCD), which is characterized by a “third mobile window” in the inner ear, causes various vestibular and auditory symptoms and signs. Surgical plugging of the superior semicircular canal (SC) can eliminate the symptoms associated with increased perilymph mobility due to the presence of the third window. However, the natural course of vestibular function after surgical plugging remains unknown. Therefore, we explored longitudinal vestibular function after surgery in 11 subjects with SCD who underwent SC plugging using the middle cranial fossa approach. Changes in vestibulo-ocular reflex (VOR) gain in all planes were measured over 1 year with the video head impulse test. We also evaluated surgical outcomes, including changes in symptoms, audiometric results, and electrophysiological tests, to assess whether plugging eliminated third mobile window effects. The mean VOR gain for the plugged SC decreased from 0.81 ± 0.05 before surgery to 0.65 ± 0.08 on examinations performed within 1 week after surgery but normalized thereafter. Four of seven subjects who were able to perform both VOR tests before surgery and immediately after surgery had pathologic values (SC VOR gain < 0.70). Conversely, the mean VOR gain in the other canals remained unchanged over 1 year. The majority of symptoms and signs were absent or markedly decreased at the last follow-up evaluation, and no complications associated with the surgery were reported. Surgical plugging significantly attenuated the air-bone gap, in particular at low frequencies, because of increased bone conduction thresholds and deceased air conduction thresholds. Moreover, surgical plugging significantly increased vestibular-evoked myogenic potential thresholds and decreased the ratio of summating potential to action potential in plugged ears. Postoperative heavily T2-weighted images were available for two subjects and showed complete obliteration of the T2-bright signal intensity in the patent SC lumen in preoperative imaging based on filling defect at the site of plugging. Our results suggest that successful plugging of dehiscent SCs is closely associated with a transient, rather than persistent, disturbance of labyrinthine activity exclusively involved in plugged SCs, which may have clinical implications for timely and individualized vestibular rehabilitation.

Characterization of Differences in the Time Course of Reflex and Voluntary Responses Following Botulinum Toxin Injections in Chronic Stroke Survivors.

Spasticity is a major impairment that can occur following a hemispheric stroke and is often treated with injections of botulinum toxin, a neurotoxin that impairs transmission at the neuromuscular junction. Hyperreflexia is a defining feature of spasticity. Our main objective here was to quantify the time course of changes in the deep tendon reflex (DTR) responses and voluntary activation capacity following BT injection as well as to track changes in a clinical assessment of spasticity. Four chronic stroke survivors, scheduled to receive BT in their Biceps Brachii(BB) as part of their clinical care plan, were recruited for repeated testing sessions over the course of 4 months post injection. Both surface BB EMG reflex response to bicipital tendon taps as well as signals of applied tendon tap forces were recorded before and up to 18 weeks post-BT. Voluntary force and biceps EMG signals were also recorded during maximum voluntary (isometric) contractions (MVC) at each testing session. Our results show major reductions (up to 75%) in voluntary sEMG and force arising between 11 to 35 days post-BT-injection. The stretch reflex gain declined two weeks after the maximal reductions in voluntary EMG and force. Paradoxically, there was a short-term increase in stretch reflex gain, in three out of four participants, approximately 11-35 days post BT. The time course of recovery of voluntary MVC and reflex responses varied considerably with a longer recovery time for the reflex responses.

Avaliação do desenvolvimento físico de lactentes no contexto da atenção primária à saúde

Objetivo: avaliar o desenvolvimento físico de lactentes no contexto do nível primário de atenção à saúde. Método: estudo transversal, descritivo e quantitativo, realizado em unidades de atenção primária à saúde de três cidades da região do Maciço de Baturité- CE: Acarape, Redenção e Itapiúna. A amostra foi constituída por lactentes acompanhados em unidades de saúde de acordo com a demanda apresentada. A coleta ocorreu entre março a abril de 2018 mediante dados sobre a caracterização geral e antropométrica do lactente, avaliação do desenvolvimento motor, com base no teste de desenvolvimento de Denver II e análise de reflexos primitivos. Os dados foram agrupados em planilhas Excel e compilados no software SPSS versão 20.0. Resultados: Participaram do estudo 75 crianças na fase de lactente. Um percentual de 60% dos lactentes era do sexo masculino, com média de 7,7 meses de idade. Na avaliação antropométrica dos escores z, a relação IMC/idade apresentou maior percentual de inadequação (66,7%), apresentando-se, na maioria, como acima do esperado. Na avaliação do desenvolvimento motor, houve risco de atraso em 13,3% dos lactentes (4% no motor fino e 9,3% no motor grosso). Na avaliação dos reflexos, em grande parte dos lactentes (85,3%) estavam presentes de acordo com o esperado para a idade Conclusões: nota-se um perfil de crianças com peso acima do adequado. Poucas alterações no desenvolvimento motor e nos reflexos foram constatadas, apontando para uma possível e adequada estimulação dos responsáveis e correta orientação dos profissionais de saúde.

Hypersensitivity of Airway Reflexes Induced by Hydrogen Sulfide: Role of TRPA1 Receptors.

The activation of capsaicin-sensitive lung vagal (CSLV) afferents can elicit airway reflexes. Hypersensitivity of these afferents is known to contribute to the airway hypersensitivity during airway inflammation. Hydrogen sulfide (H2S) has been suggested as a potential therapeutic agent for airway hypersensitivity diseases, such as asthma, because of its relaxing effect on airway smooth muscle and anti-inflammatory effect. However, it is still unknown whether H2S affects airway reflexes. Our previous study demonstrated that exogenous application of H2S sensitized CSLV afferents and enhanced Ca2+ transients in CSLV neurons. The present study aimed to determine whether the H2S-induced sensitization leads to functional changes in airway reflexes and elevates the electrical excitability of the CSLV neurons. Our results showed that, first and foremost, in anesthetized, spontaneously breathing rats, the inhalation of aerosolized sodium hydrosulfide (NaHS, a donor of H2S; 5 mg/mL, 3 min) caused an enhancement in apneic response evoked by several stimulants of the CSLV afferents. This enhancement effect was found 5 min after NaHS inhalation and returned to control 30 min later. However, NaHS no longer enhanced the apneic response after perineural capsaicin treatment on both cervical vagi that blocked the conduction of CSLV fibers. Furthermore, the enhancing effect of NaHS on apneic response was totally abolished by pretreatment with intravenous HC-030031 (a TRPA1 antagonist; 8 mg/kg), whereas the potentiating effect was not affected by the pretreatment with the vehicle of HC-030031. We also found that intracerebroventricular infusion pretreated with HC-030031 failed to alter the potentiating effect of NaHS on the apneic response. Besides, the cough reflex elicited by capsaicin aerosol was enhanced by inhalation of NaHS in conscious guinea pigs. Nevertheless, this effect was entirely eliminated by pretreatment with HC-030031, not by its vehicle. Last but not least, voltage-clamp electrophysiological analysis of isolated rat CSLV neurons showed a similar pattern of potentiating effects of NaHS on capsaicin-induced inward current, and the involvement of TRPA1 receptors was also distinctly shown. In conclusion, these results suggest that H2S non-specifically enhances the airway reflex responses, at least in part, through action on the TRPA1 receptors expressed on the CSLV afferents. Therefore, H2S should be used with caution when applying for therapeutic purposes in airway hypersensitivity diseases.

Understanding and extending the Starling principle.

The Starling Principle states that fluid movements between blood and tissues are determined by differences in hydrostatic and colloid osmotic (oncotic) pressures between plasma inside microvessels and fluid outside them. The Revised Starling Principle recognizes that, because microvessels are permeable to macromolecules, a balance of pressures cannot halt fluid exchange. In most tissues, steady oncotic pressure differences between plasma and interstitial fluid depend on low levels of steady filtration from plasma to tissues for which the Revised Principle provides the theory. Plasma volume is normally maintained by fluid losses from filtration being matched by fluid gains from lymph.Steady state fluid uptake into plasma only occurs in tissues such as intestinal mucosa and renal peri-tubular capillaries where a protein-free secretion of adjacent epithelia contributes significantly to interstitial fluid volume and keeps interstitial oncotic pressure low. Steady filtration rates in different tissues are disturbed locally by reflex changes in capillary pressure and perfusion. The rapid overall decline in capillary pressure after acute blood loss initiates rapid fluid uptake from tissue to plasma, that is, autotransfusion. Fluid uptake is transient, being rapid at first then attenuating but low levels may continue for more than an hour. The Revised Principle highlights the role of oncotic pressure of small volumes of interstitial fluid within a sub-compartment surrounding the microvessels rather than the tissue's mean interstitial fluid oncotic pressure. This maximizes oncotic pressure differences when capillary pressure are high and enhances initial absorption rates when pressures are low, accelerating short-term regulation of plasma volume.

Joint and Muscle Assessments of the Separate Effects of Botulinum NeuroToxin-A and Lower-Leg Casting in Children With Cerebral Palsy.

Botulinum NeuroToxin-A (BoNT-A) injections to the medial gastrocnemius (MG) and lower-leg casts are commonly combined to treat ankle equinus in children with spastic cerebral palsy (CP). However, the decomposed treatment effects on muscle or tendon structure, stretch reflexes, and joint are unknown. In this study, BoNT-A injections to the MG and casting of the lower legs were applied separately to gain insight into the working mechanisms of the isolated treatments on joint, muscle, and tendon levels. Thirty-one children with spastic CP (GMFCS I-III, age 7.4 ± 2.6 years) received either two weeks of lower-leg casts or MG BoNT-A injections. During full range of motion slow and fast passive ankle rotations, joint resistance and MG stretch reflexes were measured. MG muscle and tendon lengths were assessed at resting and at maximum dorsiflexion ankle angles using 3D-freehand ultrasound. Treatment effects were compared using non-parametric statistics. Associations between the effects on joint and muscle or tendon levels were performed using Spearman correlation coefficients (p < 0.05). Increased joint resistance, measured during slow ankle rotations, was not significantly reduced after either treatment. Additional joint resistance assessed during fast rotations only reduced in the BoNT-A group (−37.6%, p = 0.013, effect size = 0.47), accompanied by a reduction in MG stretch reflexes (−70.7%, p = 0.003, effect size = 0.56). BoNT-A increased the muscle length measured at the resting ankle angle (6.9%, p = 0.013, effect size = 0.53). Joint angles shifted toward greater dorsiflexion after casting (32.4%, p = 0.004, effect size = 0.56), accompanied by increases in tendon length (5.7%, p = 0.039, effect size = 0.57; r = 0.40). No associations between the changes in muscle or tendon lengths and the changes in the stretch reflexes were found. We conclude that intramuscular BoNT-A injections reduced stretch reflexes in the MG accompanied by an increase in resting muscle belly length, whereas casting resulted in increased dorsiflexion without any changes to the muscle length. This supports the need for further investigation on the effect of the combined treatments and the development of treatments that more effectively lengthen the muscle.

Learning New Feedforward Motor Commands Based on Feedback Responses.

Learning a new motor task modifies feedforward (i.e., voluntary) motor commands and such learning also changes the sensitivity of feedback responses (i.e., reflexes) to mechanical perturbations [1-9]. For example, after people learn to generate straight reaching movements in the presence of an external force field or learn to reduce shoulder muscle activity when generating pure elbow movements with shoulder fixation, evoked stretch reflex responses to mechanical perturbations reflect the learning expressed during self-initiated reaching. Such a transfer from feedforward motor commands to feedback responses is thought to take place because of shared neural circuits at the level of the spinal cord, brainstem, and cerebral cortex [10-13]. The presence of shared neural resources also predicts the transfer from feedback responses to feedforward motor commands. Little is known about such a transfer presumably because it is relatively hard to elicit learning in reflexes without engaging associated voluntary responses following mechanical perturbations. Here, we demonstrate such transfer by leveraging two approaches to elicit stretch reflexes while minimizing engagement of voluntary motor responses in the learning process: applying very short mechanical perturbations [14-19] and instructing participants to not respond to them [20-26]. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

Augmented Sympathetic Neural Activation in response to Static Handgrip during Early Pregnancy in Humans

Pregnancy is a dynamic process with systemic neuro‐vascular adaptations. Normal pregnancy is associated with sympathetic activation and attenuated vasoconstrictor responsiveness to alpha‐adrenergic stimulation, which starts as early as 4 weeks of gestation. However, little is known about changes in the exercise pressor reflex in pregnancy, a robust sympathetic stimulus originating from contracting skeletal muscle. We hypothesized that the muscle sympathetic nerve activity (MSNA) response to isometric muscle contraction would be greater in early pregnant women compared with non‐pregnant women.We measured heart rate (HR), blood pressure (BP), and MSNA in 21 early pregnant women (6–10 weeks of gestation) and 22 age‐matched healthy non‐pregnant women (controls; mid‐luteal phase) during static handgrip (SHG) exercise to fatigue at 40% of maximal voluntary contraction (MVC) force followed by 2 min of postexercise circulatory arrest (PECA). The total SHG time was divided evenly into five stages. We further utilized matched wavelet‐based methodology to extract sympathetic action potential (AP) discharge patterns.Baseline characteristics were comparable between groups. MVC was not different but the time to fatigue was shorter in pregnant women than non‐pregnant women (109±56 vs. 188±76 secs; P=0.003, mean±SD). Supine resting MSNA was greater in pregnant women (burst frequency (BF): 23±10 vs. 14±11 bursts/min; P=0.01) and sympathetic neural discharge was augmented (AP firing frequency: 235±108 vs. 142±87 spikes/min, P=0.04). Mean arterial pressure was not different between groups (80±9 vs. 83±7 mmHg; P=0.3). In response to SHG and PECA, pregnant women exhibited greater increases in MSNA than controls (time × group interaction P=0.03, group P=0.02). At peak exercise and last min of PECA, changes in MSNA BF were greater in pregnant women compared to controls (Δ MSNA at peak exercise: 34±7 vs.19±7 bursts/min; P=0.01, PECA: 25±6 vs.17±7 bursts/min; P=0.03). Similarly, the augmented sympathetic neural response was concomitant with exaggerated AP recruitment (AP firing frequency: group × time interaction P=0.004, group P=0.02 and Δ AP firing frequency at peak exercise: 365±129 vs.193±116 spikes/min; P=0.006, PECA: 241±88 vs.126±55 spikes/min; P=0.03). BP and HR responses to SHG and PECA were not different between groups.In conclusion, early pregnancy is associated with augmented sympathetic neural responses to isometric muscle contraction, which may be attributed to enhanced metabo‐reflex activation. Despite the heightened neural response, vasoconstriction is blunted in early pregnant women. Our findings provide unique mechanistic insight into blood pressure regulation during early pregnancy.Support or Funding InformationSupported by R01HL142605Changes in muscle sympathetic nerve activity (MSNA) burst frequency (BF) in response to static handgrip (SHG), postexercise circulatory arrest (PECA) and recovery.Figure 1Changes in action potential (AP) recruitment in response to static handgrip (SHG), postexercise circulatory arrest (PECA) and recovery.Figure 2

Sympathetic outflow to skin predicts central autonomic dysfunction in multiple system atrophy.

To find out the physiological method for evaluating the severity of central autonomic dysfunction, we performed detailed evaluation of cutaneous vasomotor neural function in a comparatively large sample of multiple system atrophy (MSA). We evaluated cutaneous vasomotor neural function in 24 MSA patients. Skin sympathetic nerve activity (SSNA) and sympathetic skin response (SSR) and skin blood flow (skin vasomotor reflex [SVR]) were recorded at rest, as well as reflex changes after electrical stimulation. The parameters investigated were SSNA frequency at rest, reflex latency and amplitude of SSNA reflex bursts, absolute decrease and percent reduction of SVR, recovery time, and spontaneous SVR and SSR frequency. There were negative correlations between resting SSNA and disease duration or the SCOPA-AUT score, but these were not significant. SSNA reflex latency displayed significant positive correlations with disease duration and SCOPA-AUT score (p < 0.001 and p < 0.01, respectively). In all five patients who underwent the same examination twice, SSNA reflex latency was significantly longer at the second examination than at the first examination (p < 0.005). A significant positive correlation was identified between recovery time of skin blood flow and SCOPA-AUT score or reflex latency (p < 0.05). Significant correlations were not observed between SCOPA-AUT score or disease duration and other parameters. These results suggest that some MSA patients with a comparatively short duration of disease potentially have impaired thermoregulatory function. Measurement of sympathetic outflow to the skin is potentially a useful tool for predicting the severity of central autonomic dysfunction in MSA.

The startle reflex in echolocating odontocetes: basic physiology and practical implications.

ABSTRACTThe acoustic startle reflex is an oligo-synaptic reflex arc elicited by rapid-onset sounds. Odontocetes evolved a range of specific auditory adaptations to aquatic hearing and echolocation, e.g. the ability to downregulate their auditory sensitivity when emitting clicks. However, it remains unclear whether these adaptations also led to changes of the startle reflex. We investigated reactions to startling sounds in two bottlenose dolphins (Tursiops truncatus) and one false killer whale (Pseudorca crassidens). Animals were exposed to 50 ms, 1/3 octave band noise pulses of varying levels at frequencies of 1, 10, 25 and 32 kHz while positioned in a hoop station. Startle responses were quantified by measuring rapid muscle contractions using a three-dimensional accelerometer attached to the dolphin. Startle magnitude increased exponentially with increasing received levels. Startle thresholds were frequency dependent and ranged from 131 dB at 32 kHz to 153 dB at 1 kHz (re. 1 µPa). Startle thresholds only exceeded masked auditory AEP thresholds of the animals by 47 dB but were ∼82 dB above published behavioural audiograms for these species. We also tested the effect of stimulus rise time on startle magnitude using a broadband noise pulse. Startle responses decreased with increasing rise times from 2 to 100 ms. Models suggested that rise times of 141–220 ms were necessary to completely mitigate startle responses. Our data showed that the startle reflex is conserved in odontocetes and follows similar principles as in terrestrial mammals. These principles should be considered when assessing and mitigating the effects of anthropogenic noise on marine mammals.

Sensemaking Corporate Social Responsibility, Reflexive Organisational Change and Moral Transpose, the Case of Volkswagen ‘Diesel Dupe’ Crisis

The world has witnessed corporate scandals of monstrosity magnitude. The Enron Scandal, the Nike Sweatshop scandal and the recent Johnson and Johnson baby talc in 2018 are some dishonors that reshaped the business world and reinvigorated the importance of business ethics. Indeed, supranational and national movements such as the Global Reporting Initiatives have responded to these scandals by imposing stricter corporate reporting to instill greater transparency and corporate responsibility. Ironically, despite unwavering efforts, corporations are still blatantly flouting regulations. The Volkswagen &amp;ldquo;diesel dupe&amp;rdquo; crisis is a stark reminder of the inherent weakness of current regulations. Despite Volkswagen&amp;rsquo;s staunch adherence to those stringent reporting guidelines, they breached ethics to the core, creating a tsunami of vehicle recalls, massive social, political and legal repercussions. Volkswagen&amp;rsquo;s cheat device is a &amp;lsquo;creative destruction&amp;rsquo; that challenged the fundamental usefulness of corporate reporting. Corporate social responsibility has evolved tremendously, now taking the form of positivistic reporting patterns. Corporations are measured by their ecological, social and economic performance where they flamboyantly table those data and information to garner stakeholders&amp;rsquo; support and legitimacy. However, a pragmatic approach towards corporate social responsibility is self-defeating. It erodes and dilutes a corporation&amp;rsquo;s ability to make sense, communicate and adapt to their externalities. Instead, corporations boast of their corporate prowess and triple bottom line. Using Volkswagen as a subject, this paper exposes the inherent weaknesses of a positivistic corporate reporting approach to social responsibility. A positivistic approach such as this cannot engender a truthful, honest and open posture in business corporations. Instead, this paper exemplifies that a meaningful sensemaking corporate social responsibility instills reflexive organisation change and moral transpose within corporations. This paper underlines this reflexive organisational change and moral transpose in Volkswagen as they encounter the diesel crisis. This study is novel and greatly enhances previous literatures in corporate social responsibility by instilling an appropriate model to underline these momentous reflexive organisational changes and moral transformations in Volkswagen.

KCa and KV channels modulate the venoarteriolar reflex in non-glabrous human skin with no roles of KATP channels, NOS, and COX

The venoarteriolar reflex is a local mechanism that induces vasoconstriction during venous congestion in various tissues, including skin. This response is thought to play a critical role in minimizing capillary damage or edema resulting from overperfusion, though factors that modulate this response remain largely unknown. Here, we hypothesized that nitric oxide synthase (NOS), cyclooxygenase (COX), and Ca2+-activated, ATP-sensitive, and voltage-gated K+ channels (KCa, KATP, and KV channels, respectively) modulate the venoarteriolar reflex in human skin. Cutaneous blood flow (laser-Doppler flowmetry) was monitored during a 3-min pre-occlusion baseline and following a 3-min venous occlusion of 45 mmHg, the latter maneuver was used to induce the venoarteriolar reflex. The venoarteriolar reflex was assessed at the following forearm skin sites: Experiment 1 (n = 11): 1) lactated Ringer solution (Control), 2) 10 mM Nω-nitro-L-arginine (NOS inhibitor), 3) 10 mM ketorolac (COX inhibitor), and 4) combined NOS + COX inhibition; Experiment 2 (n = 15): 1) lactated Ringer solution (Control), 2) 50 mM tetraethylammonium (KCa channel blocker), 3) 5 mM glybenclamide (KATP channel blocker), and 4) 10 mM 4-aminopyridine (KV channel blocker). Separate and combined NOS and COX inhibition as well as KATP channel blocker had no effect on venoarteriolar reflex. Conversely, venoarteriolar reflex was attenuated by KCa channel blockade (36–38%) and augmented by KV channel blockade (38–55%). We showed that KCa and KV channels modulate the venoarteriolar reflex with minimum roles of NOS, COX, and KATP channels in human non-glabrous forearm skin in vivo. Thus, cutaneous venoarteriolar reflex changes could reflect altered K+ channel function.