Protective Reflexes Research Articles

Overzealous over-the-counter cough syrup ingestion leading to serious manifestation in a child – A case report

ABSTRACT Cough is a protective reflex that allows clearance of secretions from upper respiratory tract. It is not a disease by itself but a symptom of underlying disease. In a majority of cases, it is self-limiting and requires only supportive care. But over-the-counter cough syrups are inadvertently used to relieve cough in Indian settings. We hereby report a case of a 6-year-old girl child who presented to pediatrics emergency services with complaints of loss of consciousness and abnormal body movement after ingestion of dextromethorphan and chlorpheniramine containing cough syrup. All investigations including cerebrospinal fluid examination, neuroimaging, and electroencephalogram revealed no significant abnormality. The child was admitted for 5 days and discharged after that in stable conditions.

Prospects for dry cough therapy with Herbion®, Iceland moss syrup, during tripledemic: A review

Cough is a common reason for seeking medical care, regardless of the season, but especially during the increased prevalence of respiratory infections and other diseases often associated with prolonged cough. Cough is an essential physiological protective reflex that cleanses the airways of secretions and inhaled or aspirated substances; however, it significantly worsens the child's condition. A dry, unproductive, persistent cough especially affects the quality of life. The article addresses various aspects of using the medicinal product Herbion®, Iceland moss syrup, for treating dry, unproductive, persistent cough in various diseases, including post-infectious cough.

Effectiveness of NDT method in cases of Cerebral Palsy Ataxia

Background: As many as 2.5% of children out of 1000 live births in the world have a higher risk of developing CP, and as many as 70% of CP occurs if the baby's birth weight is low, infections during pregnancy and the child's growth and development, obstruction of the birth canal, and stress experienced by the mother. causes the baby to experience CP. Objective: The case study aims to determine the benefits of the NDT approach method for CP Ataxia in improving movement control, eliciting reflexes, increasing core stability and lower extremity muscle strength, and increasing functional activity. Method: In the case of CP Ataxia, the NDT method is used in the form of handling with falling reflex training, handling with training standing on a balance board, facilitation with training getting up and down a balance board, facilitation with walking and pushing a chair. Evaluation was carried out 4 times over 3 weeks with GMFM, and checking balance reflexes. Results: After physiotherapy, it was found that there was an increase in movement control, the emergence of reflexes in children where the appearance of the protective side ward reflex increased starting at T3, while the emergence of the paracute side ward reflex began at T4. There was an increase in muscle strength and functional activity measured by GMFM, resulting in T1 63.36%; T2 63.36%; T3 64.36%; T4 67.3%. Conclusion: The NDT approach as a method for managing CP Ataxia with 4x therapy for 3 weeks is effective in improving movement control, eliciting reflexes, increasing core stability and lower extremity muscle strength, and increasing functional activity.

Medications to Modify Aspiration Risk: Those That Add to Risk and Those That May Reduce Risk.

Aspiration pneumonia results from the abnormal entry of fluids into the respiratory tract. We present a review of drugs known to affect the risk of aspiration. Drugs that increase the risk of aspiration pneumonia can be broadly divided into those that affect protective reflexes (like cough and swallowing) due to direct or indirect mechanisms, and drugs that facilitate gastric dysbiosis or affect esophageal and intestinal motility. Chief among the first group are benzodiazepines and antipsychotics, while proton pump inhibitors are the most well-studied in the latter group. Pill esophagitis may also exacerbate swallowing dysfunction. On the other hand, some research has also focused on pharmaceutical modulation of the risk of aspiration pneumonia. Angiotensin-converting enzyme inhibitors have been demonstrated to be associated with a decrease in the hazard of aspiration pneumonia in high-risk patients of Chinese or Japanese origin. Drugs like amantadine, nicergoline, or folic acid have shown some promising results in stroke patients, although the available evidence is thus far not enough to allow for any meaningful conclusions. Importantly, antimicrobial prophylaxis has been proven to be ineffective. Focusing on modifiable risk factors for aspiration pneumonia is relevant since this may help to reduce the incidence of this often severe problem. Among these, several commonly used drug classes have been shown to increase the risk of aspiration pneumonia. These drugs should be withheld in the high-risk population whenever possible, alongside general measures, such as the semirecumbent position during sleep and feeding.

Molecular and cellular mechanisms of itch sensation and the anti-itch drug targets.

Itch is an uncomfortable feeling that evokes a desire to scratch. This protective reflex can effectively eliminate parasites that invade the skin. When itchy skin becomes severe or lasts for more than six weeks, it has deleterious effects on both quality of life and productivity. Despite decades of research, the complete molecular and cellular coding of chronic itch remains elusive. This persistent condition often defies treatment, including with antihistamines, and poses a significant societal challenge. Obtaining pathophysiological insights into the generation of chronic itch is essential for understanding its mechanisms and the development of innovative anti-itch medications. In this review we provide a systematic overview of the recent advancement in itch research, alongside the progress made in drug discovery within this field. We have examined the diversity and complexity of the classification and mechanisms underlying the complex sensation of itch. We have also delved into recent advancements in the field of itch mechanism research and how these findings hold potential for the development of new itch treatment medications. But the treatment of clinical itch symptoms still faces significant challenges. Future research needs to continue to delve deeper, not only to discover more itch-related pathways but also to explore how to improve treatment efficacy through multitarget or combination therapy.

Procedural Sedation and Analgesia in an Australian Emergency Department: Results of the First 3 Months of a Procedural Sedation Registry

Background: Procedural sedation and analgesia (PSA) is commonly performed in emergency departments (EDs) to reduce anxiety, discomfort, or pain during a procedure. The primary goal of PSA is to produce a state of relaxation and drowsiness without eliminating the patient’s protective reflexes. Despite the discovery of new techniques and medications to deliver PSA, there is a paucity of research evaluating PSA in EDs over the last decade. We aim to describe the current practice of PSA in an Australian tertiary mixed ED with 75,000 presentations per year. Methods: A retrospective study of the initial 3 months of a PSA registry, which was part of the Tasmanian Emergency Care Outcomes Registry, was analyzed; Results: All told, 80 consecutive cases were entered over a 3-month period, with pediatric patients (<14 years old) making up 35% of all cases. Joint reductions (17, 39%) and fracture reductions (13, 29%) were the most common indications for the adult population, whilst fracture reductions (9, 36%), laceration repairs (7, 28%), and other distressing procedures (7, 28%) were the most common indications in the pediatric cohort. Pharmacological approaches also differed between groups, with ketamine (25, 92%) preferred in the pediatric cohort whilst the combination of propofol and fentanyl (22, 42%) was preferred in the adult cohort. No adverse events were recorded in the pediatric cohort whilst 6 (8%) minor events occurred in the adult population, with no severe events occurring for either cohort. PSA also occurred more frequently at 0900–1000 and the incidence was reduced between 0000 and 0800. Conclusions: PSA is commonly performed in our tertiary mixed ED and is both safe and effective, with non-severe complication rates similar to those in the reported literature. Severe complications are rare and therefore a larger cohort will be required to assess this aspect. The approach to ED PSA is also different between pediatric and adult populations and therefore research needs to differentiate both populations.

Acute Onset of Impaired Consciousness.

Mortality in patients with acute onset of impaired consciousness is high: as many as 10% do not survive. The spectrum of differential diagnoses is wide, and more than one underlying condition is found in one-third of all cases. In this article, we describe a structured approach to patients with acute onset of impaired consciousness in the emergency department. This review is based on pertinent articles retrieved by a selective search of PubMed and on the AWMF guidelines on the most common causes of impairment of consciousness. Impairments of consciousness are classified as quantitative (reduced wakefulness) or qualitative (abnormal content of consciousness). Of all such cases, 45-50% have a primary neurological cause, and approximately 20% are of metabolic or infectious origin. Some cases are due to intoxications, cardiovas - cular disorders, or psychiatric disorders. Important warning signs ("red flags") in acute onset of impaired consciousness are a hyperacute onset, pupillomotor disturbances, focal neurologic deficits, meningismus, headache, tachycardia and tachypnea (with or without fever), muscle contractions, and skin abnormalities. Patients with severely impaired consciousness should be initially treated in the shock room according to the ABCDE scheme. Acute onset of impaired consciousness is a medical emergency. Red flags must be rapidly recognized and treatment initiated immediately. Patients with severely impaired consciousness of new onset and uncertain cause, status epilepticus, lack of protective reflexes, or a new, acute neuro - logic deficit should be admitted via the resuscitation room.

All‐Photonic Synapses for Biomimetic Ocular System

AbstractThe human visual system to process real‐time light signals and safeguard against excessive light exposure serves as a model for artificial vision systems. Despite the wide use of optoelectronic synaptic devices in such simulations, their complex circuitry and high energy consumption have impeded further development. Herein, a biomimetic ocular system utilizing organic all‐photonic synapses is constructed to realize sensation, memory, processing, and protective light reflex abilities. The synaptic performances are facially regulated by simple molecular engineering to afford a record PPF value of 430%. Impressively, a large area (400 cm2) synaptic device with a high uniformity (96%) exhibited four fundamental functions of an ocular system for the first time, which significantly simplified the circuit system and reduced energy consumption. This work provides a facial strategy to construct all‐photonic synapses, holding great potential in prosthetics and neurorobotics.

Evaluating the Quality of Systematic Reviews on Pediatric Sedation in Dentistry: An Umbrella Review.

Sedation is a depression of a patient's state of consciousness, induced by medications, that can reach different levels of intensity during a medical procedure. Conscious sedation produces a minimally depressed level of consciousness without impairment of the ability to maintain an open airway, of protective reflexes or of responses to verbal and physical stimulation. This umbrella review is aimed at critically assessing the available systematic reviews (SRs) and meta-analyses (MA) on sedation in children/adolescents. An electronic database search was conducted that included Pubmed-Medline, Web of Science, Cochrane, Scopus, Scielo, Embase, LILACS and TRIP and the scope of which extended until January 2023. The risk of bias (RoB) of SRs was analyzed using the Measurement Tool to Assess SRs criteria 2 (AMSTAR2). Of 998 entries, 37 SRs were included. In terms of methodological quality, eight studies were assessed as having critically low quality, four studies had low quality, nine studies had moderate quality, and sixteen were considered to be of high quality. Based on the current guidelines, the most employed drugs in pediatric dentistry for sedation are nitrous oxide and midazolam; however, the available evidence supporting their use is insufficient and of low/critically low quality. The combined technique is recommended (nitrous oxide (30-50%) + midazolam). The optimal dose of oral midazolam is 0.75 mg/kg. The level of methodological quality of SRs is expected to increase according to the results and future directions of this umbrella review.

Age-Specific Differences in Laryngotracheal Trauma Characteristics: A Retrospective Study of Clinical Profiles, Outcomes, and Mortality Risk.

Background: Laryngotracheal trauma is associated with a substantial risk of mortality. Age can be a critical factor in trauma management, as older adults often have diminished airway protective reflexes and preexisting respiratory conditions. Objective: This study aimed to characterize the clinical profiles and outcomes in different age groups of adult patients with laryngotracheal trauma using data from the National Trauma Data Bank (NTDB). Methods: We retrospectively analyzed the NTDB and included adult patients (aged ≥ 18 years) who had laryngotracheal fractures (closed or open) and were admitted directly after the injury. The patients were categorized into different age groups for analysis. A multivariate logistic regression analysis was performed to assess whether the elderly population (age ≥ 65 years) was predisposed to post-trauma death under care. Results: The study included 1171 patients, with the following age distributions: 13.7% aged 18-24 years, 21.6% aged 25-34 years, 55.2% aged 35-64 years, and 9.6% aged ≥ 65 years. Notable differences were observed in comorbidities, mechanisms, types of injuries, and associated injuries among age groups. There was no significant trend in airway surgical outcomes according to age. In-hospital mortality was highest among patients aged ≥ 65 years (22.3%), compared to 14.4% for those aged 18-24 years. Regression analysis indicated that age ≥ 65 was an independent mortality predictor. Conclusions: These findings underscore significant age-related differences in the presentation and outcomes of laryngotracheal trauma, emphasizing the need for age-specific treatment protocols, primarily to address the elevated risk among elderly patients.

Concurrent, dual perturbations of the 5-HT and NA systems reveal dynamic interplay in regulating the neonate autoresuscitation reflex

Sudden Infant Death Syndrome (SIDS) is a leading cause of infant mortality worldwide. Failure of the neonate auto-resuscitation reflex is hypothesized to be a common endpoint in many SIDS cases. Although SIDS is idiopathic, postmortem studies indicate abnormalities in the serotonergic (5-HT) and noradrenergic (NA) systems of the respiratory network. To better understand the contributions and interactions of these two systems in autoresuscitation, we combined a novel series of Cre- and FLPo- recombinase driver mouse lines and conditional inhibitory and excitatory DREADD lines for singular excitation or inhibition of either the whole 5-HT or whole NA systems. These models were then uniquely combined to further enable 1) concurrent excitation or inhibition of both systems in the same neonate or 2) inhibition of one system while exciting the other system in the same neonate. In total, we developed 8 distinct sets of conditional genetic mouse models for singular and combined 5-HT and NA system perturbation paradigms. The 8 experimental groups and 2 control groups were repeatedly assayed for the autoresuscitation reflex using a robotic neonate cardiorespiratory assessment platform, Looper. Neonates are repeatedly tested until they succumb. Resulting data were analyzed with our recently published waveform analysis software, Breathe Easy, to calculate operant outcomes. In 320 mice total, we found 4 groups with decreased autoresuscitation success: NA activation, NA activation + 5-HT activation, NA activation + 5-HT inhibition, and 5-HT activation. There was no change in survival in any of the other groups including 5-HT inhibition. Preliminary results suggest a potential cardiovascular mechanism of autoresuscitation failure independent of respiratory outcomes. At baseline, all 4 groups with decreased survival showed increased heart rate (HR) whereas the other groups either had the same HR or a decreased HR. During early recovery, defined as beginning at the 10th breath following the primary gasp until recovery, the 4 groups with decreased survival show higher HR than the other groups following the 1st bout of autoresuscitation. As recovery progressed in these groups, HR continued to increase as well until the next autoresuscitation test. Ventilatory frequency, tidal volume, and ventilation all increased in the 3 groups where NA was activated either in isolation or in combination, but there were decreases in all other groups, including 5-HT activation. As the underlying genetic and environmental mechanisms driving SIDS are likely to have pleiotropic effects across multiple neural systems, our first-of-its-kind dual 5-HT and NA system modulations set the stage to more comprehensively model key aspects of SIDS neuropathology that reveal a previously uncharacterized dynamic functional interplay between the NA and 5-HT systems in protective respiratory reflexes. NIH: 1F32HL160073-01A1, R01HL130249 44617-S4. BCM McNair Scholar Program, March of Dimes Basil O'Connor Research Award, Parker B. Francis Fellowship, CJ Foundation for SIDS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Role of OPRM1 in the Neonatal Autoresuscitation Reflex and Sudden Infant Death Syndrome

Opioid receptors are widely expressed throughout the brain and integral in nociception as well as homeostatic regulation of autonomic processes including respiration through modulation of respiratory rhythmogenesis and chemosensory responses. Perturbations to homeostatic mu opioid receptor (MOR) signaling via opiate overdose results in respiratory depression, aberrant breathing, and often death. With the rise of opioid use over the last two decades, many infants are being diagnosed with Neonatal Abstinence Syndrome (NAS), a congenital cardio-respiratory disorder resulting from prenatal exposure to opioids. Infants born with NAS have a fourfold increased risk for Sudden Infant Death Syndrome (SIDS). SIDS and related Sudden Unexpected Infant Death takes the lives of approximately 3,400 infants annually under the age of one and its etiology remains mostly unknown. Currently SIDS is explained via the triple risk model that proposes that SIDS occurs in a vulnerable infant during a critical developmental period when triggered by an external stressor, converging on the failure of the neonate autoresuscitation reflex in most cases. Recently a study identified an association between a mutation in the OPRM1 gene encoding MORs and SIDS cases. However, how this gene and perturbations in its native function modulates respiratory regulation are poorly understood. We hypothesize that native OPRM1 function is integral to protective neonate respiratory reflexes and that perturbation of native OPRM1 signaling negatively affects the neonatal autoresuscitation reflex. Male and female OPRM1 loss of function mice were assayed for their autoresuscitation reflex on our novel testbed, Looper. Mice were exposed to repeated bouts of anoxia and allowed to autoresuscitate until death occurred. Preliminary data suggest that loss of OPRM1 function results in a higher mortality rate on the autoresuscitation assay with OPRM1 KO mice surviving significantly less anoxic challenges compared to wild type controls. No sex differences were observed between male and female survival for all genotype groups. Results indicate that perturbation of the native function of OPRM1 produces a vulnerability to autoresuscitation dysfunction and mitigated survival. Our data demonstrate the first functional assessment of OPRM1 in neonatal cardiovascular function and autoresuscitation and reveal an important risk factor that may be implicated in perpetuating SIDS and NAS phenotypes. Additional analyses of distinct parameters from respiratory trace data for OPRM1 loss of function mice will aid in a deeper, mechanistic understanding of features implicated in autoresuscitation dysfunction. Future studies aim to characterize specific splice variants of OPRM1, known to produce neomorphic function and model the SIDS associated VUS, to further characterize the implication of OPRM1 and its variants in congenital respiratory diseases. Funding sources NIH/NHLBI R01HLN161142-01 and R01HL130249-07. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Butyrylcholinesterase Is Not Required for the Neonatal Autoresuscitation Reflex

Sudden Infant Death Syndrome (SIDS) is the leading cause of infant death under the age of one year of age, taking the lives of more than 1,400 infants annually, and comprising approximately 41% of all Sudden Unexpected Infant Death (SUID) cases. SIDS etiology remains vastly unknown but is best explained via a triple risk model that proposes SIDS occurs in a vulnerable infant during a critical developmental period when triggered by an external stressor. In SIDS it is hypothesized that there is first a failure in arousal followed by failure in the protective autoresuscitation reflex; a defense mechanism for an infant that is in a hypoxic coma, that promotes deep gasping to attempt to restart cardiovascular function. Many SIDS case studies reveal associations with genetic variants and abnormal biomarkers; however, it is unclear whether these variants are causal. Recently a case study identified a broad association between reduced blood BChE activity and SIDS cases, yet the functional relationship between BChE and respiratory regulation remains to be investigated. We aimed to functionally test the relationship between BChE and the neonatal autoresuscitation reflex utilizing a rapid pipeline for precision genetic modeling and high-throughput functional testing developed by the Ray Lab. BChE loss of function mice, generated through targeted genetic editing, were tested for neonatal autoresuscitation on our automated closed loop phenotyping platform, Looper. Postnatal day 7-8 mice were exposed to 3% CO2 and 97% N2 stimuli to induce a state of hypoxia resulting in detection of bradycardia, initial hyperventilation, hypoventilation, and apnea followed by restoration of room air conditions to facilitate the autoresuscitation reflex and cardio-respiratory recovery. Male and female mice were exposed to repeated anoxic gas challenges and allowed to autoresuscitate until death occurred. Data suggest that loss of BChE function does not affect neonatal autoresuscitation. BChE knockout mice and heterozygous mice survived similar amounts of anoxic challenges as wild type controls. No sex differences were observed between the number of anoxic challenges survived in males and females for all genotypes. Our data demonstrate the first functional assessment of BChE in neonatal cardio-respiratory regulation and the autoresuscitation response and highlight that BChE is not required for successful neonatal autoresuscitation. Additional analyses of respiratory parameters from respiratory trace data for BChE loss of function mice will aid in a further understanding if BChE loss of function is implicated in other aspects respiratory regulation. Funding: Precision Core funding U54 OD030165. NIH/NHLBI R01HLN161142-01 and R01HL130249-07. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Delayed Sequence Intubation in Children, Why Not?

Tracheal intubation in pediatric patients is a clinical scenario that can quickly become an emergency. Complication rates can potentially reach up to 60% in rapid sequence intubation. An alternate to this is delayed sequence intubation, which may reduce potential complications-mostly hypoxemia-and can be especially useful in non-cooperative children. This technique consists of the prior airway and oxygenation optimization. This is done through sedation using agents that preserve ventilatory function and protective reflexes and continuous oxygen therapy-prior and after the anesthetic induction-using nasal prongs. The objective of this narrative review is to provide a broader perspective on delayed sequence intubation by defining the concept and indications; reviewing its safety, effectiveness, and complications; and describing the anesthetic agents and oxygen therapy techniques used in this procedure.

The many faces of a cough in a child: Issues of differential diagnosis and treatment

Studying the causes of cough, which is one of the most common respiratory symptoms when seeking medical help, remains a pressing problem for doctors of various specialties. Due to the growing interest in herbal remedies, in the current study we aimed to analyze the effectiveness of marshmallow root in the treatment of cough. We conducted a systematic search in modern scientific literature in electronic databases PubMed, EMBASE, Cochrane Library, Wiley, PubFacts, Springer Link platform, scientific publishing house Elsevier, CyberLeninka. An analysis of 80 full-text reviews on the use of herbal medicine in the treatment of cough showed higher quality of life scores, lower rates of adverse events and less severe cough. The authors also provide evidence that herbal therapy successfully complements traditional treatment methods, providing longer periods of remission for chronic cough. Although coughing is a protective reflex responsible for clearing secretions and foreign bodies from the airways, it can be an unpleasant symptom that causes discomfort in patients. The use of preparations based on root extract of Althaea officinalis L leads to the formation of a protective film, which promotes faster regeneration of the damaged mucous membrane of the respiratory tract caused by a dry cough. The mucous membrane of the respiratory tract is a highly vascularized tissue. In this regard, anti-inflammatory phytochemicals that improve lesion repair, such as local neovascularization, are critical to promote healing. The herbal medicinal product containing the active component marshmallow root extract fully meets safety requirements and can be successfully used in patients with acute and chronic respiratory diseases.

Neural substrates of cough control during coughing

Cough is known as a protective reflex to keep the airway free from harmful substances. Although brain activity during cough was previously examined mainly by functional magnetic resonance imaging (fMRI) with model analysis, this method does not capture real brain activity during cough. To obtain accurate measurements of brain activity during cough, we conducted whole-brain scans during different coughing tasks while correcting for head motion using a restraint-free positron emission tomography (PET) system. Twenty-four healthy right-handed males underwent multiple PET scans with [15O]H2O. Four tasks were performed during scans: “resting”; “voluntary cough (VC)”, which simply repeated spontaneous coughing; “induced cough (IC)”, where participants coughed in response to an acid stimulus in the cough‐inducing method with tartaric acid (CiTA); and “suppressed cough (SC)”, where coughing was suppressed against CiTA. The whole brain analyses of motion-corrected data revealed that VC chiefly activated the cerebellum extending to pons. In contrast, CiTA-related tasks (IC and SC) activated the higher sensory regions of the cerebral cortex and associated brain regions. The present results suggest that brain activity during simple cough is controlled chiefly by infratentorial areas, whereas manipulating cough predominantly requires the higher sensory brain regions to allow top-down control of information from the periphery.

Примитивные рефлексы спинально-стволового уровня и их реабилитационное значение у постинсультных больных: краткое сообщение

INTRODUCTION. Primitive reflexes of the spinal-brainstem level (defensive reflexes, support reactions, cervical and vestibular tonic reflexes) can often be observed in the first days after a stroke. In clinical neurology, they are used for topical diagnosis and serve as an indicator of the severity of damage to the central nervous system. Their rehabilitation value has not been sufficiently studied. AIM. Based on literature data, to study the features of primitive spinal-brainstem automatisms in post-stroke patients, and to evaluate the possibility of their use to optimize rehabilitation methods (kinesitherapy). RESULTS. Simple protective reflexes are suitable for awakening elementary motor activity in one of the paralyzed limbs, and complex ones are suitable for stimulating static-locomotor reactions in the arm and leg on the side of hemiparesis. Support reactions are a reliable tool for awakening both flexion movements and for restoring the support ability of paretic limbs. They should be considered when treating with positioning using positioning, splints, and orthoses. Cervical and vestibular tonic reflexes are suitable for stimulating motor activity on the side of hemiparesis, as well as for suppressing pyramidal spasticity. CONCLUSION. Thus, all studied primitive reflexes of the spinal-brainstem level have significant rehabilitation potential. Their use is most justified to facilitate flexion-extension movements in paretic limbs. The better the rehabilitologist is familiar with the characteristics of the patient’s reflex activity, the more opportunities he has for conducting a “dialogue” with paretic muscles and the more effective the rehabilitation treatment will be. KEYWORDS: protective reflex, support reaction reflex, cervical tonic reflexes, vestibular tonic reflexes, ehabilitation

Conscious sensations and protective reflexes driven by eye surface nerves in health and disease

The trigeminal primary sensory neurons that innervate the ocular surface, especially the cornea, have been classified in three functional types: polymodal nociceptors, mechano‐nociceptors and cold thermoreceptors. These sensory nerves are responsible for the conscious sensations evoked in response to ocular surface stimulation as well as for the regulation of tearing and blinking, and they are also involved in the trophic maintenance of the ocular tissues.Depending on the transducing channels they express in their membrane, sensory nerves from the ocular surface respond to different types of stimulus and, after this information is processed by the CNS, different conscious sensations are evoked: corneal mechano‐nociceptors' activation led to pricking pain; polymodal nociceptors evoke burning irritation, and cold thermoreceptors' activation may evoke freshness/cold/dryness/pain depending on the subtype of cold thermoreceptor neuron activated by the stimulus. While reflex blinking and tearing are driven by the activation of polymodal nociceptors as the afferent arm of the reflex, basal blinking and tearing rate are under the control of cold thermoreceptors' activity.During inflammation and after injury (such as UV‐induced keratitis, allergic keratoconjunctivitis, corneal surgery, tear‐deficient dry eye) the activity of corneal sensory nerves is modified in both eyes, even when inflammation or damage affects only one eye. The abnormal corneal sensory nerve activity constitutes the basis for the discomfort, dryness and pain sensations experienced under these conditions. Also, protective mechanisms depending on ocular nerve activity such as blinking and tearing become altered.(Supported by PID2020‐115934RB‐I00 from DOI: MCIN/AEI/10.13039/50110001103, and CIPROM/2021/48 from the Generalitat Valenciana, Spain)

Tryptophan metabolism as a 'reflex' feature of neuroimmune communication: Sensor and effector functions for the indoleamine-2, 3-dioxygenase kynurenine pathway.

Although the central nervous system (CNS) and immune system were regarded as independent entities, it is now clear that immune system cells can influence the CNS, and neuroglial activity influences the immune system. Despite the many clinical implications for this 'neuroimmune interface', its detailed operation at the molecular level remains unclear. This narrative review focuses on the metabolism of tryptophan along the kynurenine pathway, since its products have critical actions in both the nervous and immune systems, placing it in a unique position to influence neuroimmune communication. In particular, since the kynurenine pathway is activated by pro-inflammatory mediators, it is proposed that physical and psychological stressors are the stimuli of an organismal protective reflex, with kynurenine metabolites as the effector arm co-ordinating protective neural and immune system responses. After a brief review of the neuroimmune interface, the general perception of tryptophan metabolism along the kynurenine pathway is expanded to emphasize this environmentally driven perspective. The initial enzymes in the kynurenine pathway include indoleamine-2,3-dioxygenase (IDO1), which is induced by tissue damage, inflammatory mediators or microbial products, and tryptophan-2,3-dioxygenase (TDO), which is induced by stress-induced glucocorticoids. In the immune system, kynurenic acid modulates leucocyte differentiation, inflammatory balance and immune tolerance by activating aryl hydrocarbon receptors and modulates pain via the GPR35 protein. In the CNS, quinolinic acid activates N-methyl-D-aspartate (NMDA)-sensitive glutamate receptors, whereas kynurenic acid is an antagonist: the balance between glutamate, quinolinic acid and kynurenic acid is a significant regulator of CNS function and plasticity. The concept of kynurenine and its metabolites as mediators of a reflex coordinated protection against stress helps to understand the variety and breadth of their activity. It should also help to understand the pathological origin of some psychiatric and neurodegenerative diseases involving the immune system and CNS, facilitating the development of new pharmacological strategies for treatment.

Comprehensive review of laryngeal nerve

The laryngeal nerve plays a crucial role in vital functions of the larynx, such as breathing, phonation, and airway protection. This review explores its intricate origination, extracranial pathways, anatomical variations, and functions. Emerging from the vagus nerve, it descends through the jugular foramen, exhibiting distinct pathways on each side of the body. Understanding these pathways is vital in surgery to prevent complications. Anatomical variations, including the non-recurrent laryngeal nerve and extralaryngeal branching, pose challenges during thyroid surgery. Surgeons must be vigilant, as failure to recognize these variations can lead to nerve injuries. Meticulous preoperative evaluation and surgical expertise are essential. The superior laryngeal nerve triggers protective reflexes like the cough reflex, safeguarding the respiratory tract. The recurrent laryngeal nerve controls crucial laryngeal muscles for phonation and respiration. Understanding these functions is paramount, especially for surgeons, ensuring optimal patient outcomes. In conclusion, this review underscores the laryngeal nerve's complexity and the need for in-depth knowledge, particularly in surgery. Ongoing research and medical advancements are crucial for refining techniques and enhancing patient care. Acknowledging these complexities empowers medical surgeons contributing to safer and more effective surgeries.