Central Reflex Research Articles

Evaluation of eyelid features' changes before and after COVID-19 pandemic amongst healthcare and home office workers.

To evaluate the eyelid features' changes after N95 face mask (FM) usage in healthcare workers through the new type of Coronavirus Disease 2019 (COVID-19) pandemic and make a comparison with home-office workers as a control group with a computer vision algorithm. Sixty healthcare workers and forty control participants with similar demographic features included. Standardized biometric photographs which were taken before and after the COVİD-19 pandemic, analyzed by the ImageJ program (NIH, Bethesda, Md.) software. The distances between the central light reflex on the cornea and the upper (UE) and lower eyelid (LE) were recorded as the marginal reflex distances. (MRD1, MRD2 respectively) Parameters of pretarsal show (PTS) of UE and brow pupil diameter (BPD) were analyzed for both of the eyes. There were no significant differences among the groups' measurements before the COVID-19 pandemic. In healthcare workers' group after the pandemic, values of MRD1, PTS, BPD showed a significant decrease in their right eye (p = 0.001, p = 0.002, p = 0.001 respectively) and same values reduced in the left eyes as well when compared with pre-pandemic measurements. (p = 0.048, p = 0.001, p = 0.001 respectively) PTS and BPD values were decreased for both right and left eyes of the controls. (p = 0.044, p = 0.001 and p = 0.001, p = 0.001 respectively) MRD1 measurements after the pandemic showed no difference either in the right or left eyes of the control group after the pandemic. (p = 0.071 and p = 0.065 respectively). Results showed that both BPD and PTS values decreased independently from the previous FM usage in both of the groups. Even though MRD1 values remained within the normal values, a significant decrease was detected in the healthcare workers group which suggested the cause was newly developed upper eyelid (UE) dermatochalasis after long hours of FM usage. Although it is hard to make a truly objective evaluation both usage of standardized biometric photographs and a computer-based measurement system makes the results reliable.

Analysis of the photographers' quality control in the diabetic retinopathy screening at the IOBA's Reading Center

Aims/Purpose: Diabetic retinopathy (DR) is the most frequent ocular complication of diabetes and one of the leading causes of avoidable blindness. Teleophthalmology screening by taken retinal images is an effective tool in its early detection and delivering prompt treatment. IOBA's Reading Center (RC) of the University of Valladolid is in charge for the Regional Health System (SACYL) DR screening program. Retinographies are taken at Primary Care Centers, under mydriasis, following the three‐field Joslin Vision Network protocol by certified photographers. Quality control (QC) is an indispensable process in a RC to ensure an accurate retinography reading. An upper limit of 5% of photographs taken with low quality has been set as acceptable. This study aimed to analyse the quality of the retinographies taken in the DR screening at the IOBA's RC during 2021 and 2022.Methods: A retrospective study was designed analysing the quality outcomes of DR screening. Certified in image reading Optometrists determined if images received at the RC had enough quality according to seven factors (halo >1/3, inadequate vessels/parenchyma sharpness, inadequate central, nasal, temporal or fundus reflex image and inadequate disk sharpness). Statistical analysis was performed using SPSS 26 (Chicago, USA). Chi‐square test was used to compare frequencies between 2021 and 2022 outcomes.Results: 4474 retinographies were taken during 2021 and 6345 during 2022. 14 photographers took part in the program (8 in both years, 2 left in 2021, and 4 joined in 2022). All analysed factors showed less than 3% of incorrect images. 6.1% of images showed at least one error in 2021 and 4.4% in 2022 (p < 0.01). Every analysed factor showed a significant improvement (p < 0.02) between 2021 and 2022 except for disk sharpness in both eyes (p > 0.05).Conclusions: The quality of the images of the IOBA RC is adequate for the SACYL DR screening program showing values below the fixed upper limit in all the analysed factors with a significant decrease in almost all values that can be attributed to increased experience of capture personnel.

Unusual refractive anomaly in Alport syndrome with lenticonus: A challenging case

Herein, we report a 15-year-old male with Alport syndrome, exhibiting hemorrhagic nephritis, hearing loss, and a 1-year history of poor distance visual acuity. Slit-lamp examination revealed bilateral anterior lenticonus, with unremarkable findings in other ocular structures. Unusual reflex movements were observed during retinoscopy, characterized by distinct central and annular reflexes yielding objectively an intraeye discrepancy of 12 D. Similar to the objective findings, a pair of subjective findings for each eye was obtained and each pair resulted almost equal visual acuity. However, small pupil size veiled plus error and final prescription was myopic.

Width measurement of retinal vessels using cubic spline fitting and extended edge‐searching mode

AbstractAbnormal changes in the retinal vessel width usually indicate the presence of certain diseases. This paper presents a novel model to measure the width of retinal vessels. This method firstly employs cubic spline fitting to determine the vessel cross‐sectional direction at the center point of a vessel profile, then uses the extended edge‐searching mode to detect vessel edge points along the vessel cross‐sectional direction, and finally obtains the width value by calculating the distance between the edge point and the center point. The method can accurately locate vessel edge points and successfully solve the problem of central light reflex in blood vessels. Experimental analyses on a publicly available database show that the proposed approach has excellent performance in accuracy with other existing measurement techniques. It provides an effective idea for analyzing morphological changes in blood vessels and can be extended to obtain the shape features of other objects.

Potential measurement error from vessel reflex and multiple light paths in dual-wavelength retinal oximetry.

This study aims to characterize the dependence of measured retinal arterial and venous saturation on vessel diameter and central reflex in retinal oximetry, with an ultimate goal of identifying potential causes and suggesting approaches to improve measurement accuracy. In 10 subjects, oxygen saturation, vessel diameter and optical density are obtained using Oxymap Analyzer software without diameter correction. Diameter dependence of saturation is characterized using linear regression between measured values of saturation and diameter. Occurrences of negative values of vessel optical densities (ODs) associated with central vessel reflex are acquired from Oxymap Analyzer. A conceptual model is used to calculate the ratio of optical densities (ODRs) according to retinal reflectance properties and single and double-pass light transmission across fixed path lengths. Model-predicted values are compared with measured oximetry values at different vessel diameters. Venous saturation shows an inverse relationship with vessel diameter (D) across subjects, with a mean slope of -0.180 (SE = 0.022) %/μm (20 < D < 180 μm) and a more rapid saturation increase at small vessel diameters reaching to over 80%. Arterial saturation yields smaller positive and negative slopes in individual subjects, with an average of -0.007 (SE = 0.021) %/μm (20 < D < 200 μm) across all subjects. Measurements where vessel brightness exceeds that of the retinal background result in negative values of optical density, causing an artifactual increase in saturation. Optimization of model reflectance values produces a good fit of the conceptual model to measured ODRs. Measurement artefacts in retinal oximetry are caused by strong central vessel reflections, and apparent diameter sensitivity may result from single and double-pass transmission in vessels. Improvement in correction for vessel diameter is indicated for arteries however further study is necessary for venous corrections.

Retinal Vessel Caliber Measurement Bias in Fundus Images in the Presence of the Central Light Reflex.

To investigate the agreement between a fundus camera and a scanning laser ophthalmoscope in retinal vessel caliber measurements and to identify whether the presence of the central light reflex (CLR) explains potential discrepancies. For this cross-sectional study, we obtained fundus camera and scanning laser ophthalmoscope images from 85 eyes of 85 healthy individuals (aged 50-65 years) with different blood pressure status. We measured the central retinal artery equivalent (CRAE) and central retinal artery vein equivalent (CRVE) with the Knudtson-Parr-Hubbard algorithm and assessed the CLR using a semiautomatic grading method. We used Bland-Altman plots, 95% limits of agreement, and the two-way mixed effects intraclass correlation coefficient for consistency [ICC(3,1)] to describe interdevice agreement. We used multivariable regression to identify factors associated with differences in between-device measurements. The between-device difference in CRAE (9.5 µm; 95% confidence interval, 8.0-11.1 µm) was larger than the between-device difference in CRVE (2.9 µm; 95% confidence interval, 1.3-4.5 µm), with the fundus camera yielding higher measurements (both P < 0.001). The 95% fundus camera-scanning laser ophthalmoscope limits of agreement were -4.8 to 23.9 µm for CRAE and -12.0 to 17.8 µm for CRVE. The corresponding ICCs(3,1) were 0.89 (95% confidence interval, 0.83-0.92) and 0.91 (95% confidence interval, 0.86-0.94). The between-device CRAE difference was positively associated with the presence of a CLR (P = 0.002). Fundus cameras and scanning laser ophthalmoscopes yield correlated but not interchangeable caliber measurements. The CLR induces bias in arteriolar caliber in fundus camera images, compared with scanning laser ophthalmoscope images. Refined measurements could yield better estimates of the association between retinal vessel caliber and ophthalmic or systemic disease.

Hypotensive Effect of Electric Stimulation of Caudal Ventrolateral Medulla in Freely Moving Rats.

Background and Objectives: An altered sympathetic function is established in primary arterial hypertension (PAH) development. Therefore, PAH could be targeted by applying an electric current to the medulla where reflex centers for blood pressure control reside. This study aims to evaluate the electric caudal ventrolateral medulla (CVLM) stimulation effect on blood pressure and animal survivability in a freely moving rat model. Materials and Methods: A total of 20 Wistar rats aged 12-16 weeks were randomly assigned to either: the experimental group (n = 10; electrode tip implanted in CVLM region) or the control group (n = 10; tip implanted 4 mm above the CVLM in the cerebellum). After a period of recovery (4 days), an experimental phase ensued, divided into an "OFF stimulation" period (5-7 days post-surgery) and an "ON stimulation" period (8-14 days post-surgery). Results: Three animals (15%, one in the control, two in the experimental group) dropped out due to postoperative complications. Arterial pressure in the experimental group rats during the "OFF stimulation" period decreased by 8.23 mm Hg (p = 0.001) and heart rate by 26.93 beats/min (p = 0.008). Conclusions: From a physiological perspective, CVLM could be an effective deep brain stimulation (DBS) target for drug-resistant hypertension: able to influence the baroreflex arc directly, having no known direct integrative or neuroendocrine function. Targeting the baroreflex regulatory center, but not its sensory or effector parts, could lead to a more predictable effect and stability of the control system. Although targeting neural centers in the medullary region is considered dangerous and prone to complications, it could open a new vista for deep brain stimulation therapy. A possible change in electrode design would be required to apply CVLM DBS in clinical trials in the future.

Neuroimmunology of allergic rhinitis : Part1: Cellular and humoral basic principles

Allergic rhinitis (AR) is avery common disease with ahigh prevalence worldwide. It is an IgE-mediated type2 inflammatory disease following exposure to inhalant allergens. Amultitude of different neuropeptides including substanceP, vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), nerve growth factor (NGF), and neuromedinU (NMU) can be released via peripheral axon or central reflexes, interact with immune cells, and thus contribute to neurogenic inflammation which causes the nasal hyperreactivity (NHR) characteristic of AR. Independent production of neuroendocrine hormones and neuropeptides by immune cells has also been demonstrated. Neuro-immune cell units arise when immune and neuronal cells colocalize, for which typical anatomic regions are, e.g., the mast cell-nerve functional unit. The focus of this review is the elucidation of neuroimmune communication mechanisms in AR.

Closed-loop modeling of central and intrinsic cardiac nervous system circuits underlying cardiovascular control.

The baroreflex is a multi-input, multi-output control physiological system that regulates blood pressure by modulating nerve activity between the brainstem and the heart. Existing computational models of the baroreflex do not explictly incorporate the intrinsic cardiac nervous system (ICN), which mediates central control of the heart function. We developed a computational model of closed-loop cardiovascular control by integrating a network representation of the ICN within central control reflex circuits. We examined central and local contributions to the control of heart rate, ventricular functions, and respiratory sinus arrhythmia (RSA). Our simulations match the experimentally observed relationship between RSA and lung tidal volume. Our simulations predicted the relative contributions of the sensory and the motor neuron pathways to the experimentally observed changes in the heart rate. Our closed-loop cardiovascular control model is primed for evaluating bioelectronic interventions to treat heart failure and renormalize cardiovascular physiology.

Excess Dietary Vitamin B-6 Alters Startle Behavior of Rats

Excessive intakes of vitamin B-6 can produce peripheral nervous system abnormalities, but few reports of central nervous system effects exist. We measured startle response, a central nervous system reflex, in rats fed excess pyridoxine to determine if subtle effects on central nervous system function could be detected. Female Long-Evans rats (218 g; n = 12) were fed either 1, 10, 100, 200 or 300 times the requirement of pyridoxine HCl (7 mg/kg) for 7 wk. Startle behavior was assessed weekly in chambers that allowed quantification of movement in response to stimuli. Food intake and body weights did not differ among groups (P > 0.1), and urinary vitamin B-6 excretion reflected intake (P < 0.001). Overt toxicity was not observed. There was a marginally significant effect of pyridoxine intake over time (P = 0.053) on the amplitude of response to a startling acoustic stimulus (117 dB, 40 ms) administered alone; the response appeared attenuated at the three highest pyridoxine concentrations. When the same stimulus was preceded by either a 70- or 75-dB prepulse (40 ms), responses of groups fed the two highest pyridoxine concentrations were significantly reduced relative to those fed the two lowest concentrations (P < 0.05). No effect of diet was seen with a startling tactile stimulus. Changes in central nervous system function were detected in rats fed excess vitamin B-6 using techniques of startle behavior measurement.

Targeting the ATP-Axis in Lungs as a New Therapheutic Modality for COPD

Adenosine 5’-triphosphate (ATP) is found in every cell of the body where it plays a critical role in cellular metabolism and energetics. ATP is released from cells under physiologic and pathophysiologic conditions; extracellular ATP acts as an autocrine and paracrine agent. Its effects on targeted cells are mediated by subtypes of purinergic receptors (P2R). In the lungs, relatively large amounts of ATP are released under inflammatory conditions. Extracellular ATP triggers a central vagal reflex by activating purinergic receptor P2XR localized on pulmonary vagal sensory nerve terminals. This results in cough, bronchoconstriction and the release of pro-inflammatory neuropeptides via axon reflex. COPD patients manifest higher sensetivity to aerosolized ATP than healthy subjects, and the levels of ATP in COPD patients’ lungs are 3x that found in healthy subjects. This review succinctly details (i) the sources amd mechanisms of ATP’s release into the extracellular space, (ii) the ways extracellular ATP is eliminated, (iii) the deleterious effects of ATP in the lungs in general and in COPD in particular, and (iv) the rationale for the blockade of these actions of ATP in the lungs as a novel therapeutic approach in the management of COPD patients.

The Longitudinal Assessment of Vascular Parameters of the Retina and Their Correlations with Systemic Characteristics in Type 2 Diabetes-A Pilot Study.

The aim of the study was to assess various retinal vessel parameters of diabetes mellitus (DM) patients and their correlations with systemic factors in type 2 DM. A retrospective exploratory study in which 21 pairs of baseline and follow-up images of patients affected by DM were randomly chosen from the Sankara Nethralaya–Diabetic Retinopathy Study (SN DREAMS) I and II datasets. Patients’ fundus was photographed, and the diagnosis was made based on Klein classification. Vessel thickness parameters were generated using a web-based retinal vascular analysis platform called VASP. The thickness changes between the baseline and follow-up images were computed and normalized with the actual thicknesses of baseline images. The majority of parameters showed 10~20% changes over time. Vessel width in zone C for the second vein was significantly reduced from baseline to follow-up, which showed positive correlations with systolic blood pressure and serum high-density lipoproteins. Fractal dimension for all vessels in zones B and C and fractal dimension for vein in zones A, B and C showed a minimal increase from baseline to follow-up, which had a linear relationship with diastolic pressure, mean arterial pressure, serum triglycerides (p < 0.05). Lacunarity for all vessels and veins in zones A, B and C showed a minimal decrease from baseline to follow-up which had a negative correlation with pulse pressure and positive correlation with serum triglycerides (p < 0.05). The vessel widths for the first and second arteries significantly increased from baseline to follow-up and had an association with high-density lipoproteins, glycated haemoglobin A1C, serum low-density lipoproteins and total serum cholesterol. The central reflex intensity ratio for the second artery was significantly decreased from baseline to follow-up, and positive correlations were noted with serum triglyceride, serum low-density lipoproteins and total serum cholesterol. The coefficients for branches in zones B and C artery and the junctional exponent deviation for the artery in zone A decreased from baseline to follow-up showed positive correlations with serum triglycerides, serum low-density lipoproteins and total serum cholesterol. Identifying early microvascular changes in diabetic patients will allow for earlier intervention, improve visual outcomes and prevent vision loss.

Respiratory Sinus Arrhythmia is Mainly Driven by Central Feedforward Mechanisms in Healthy Humans.

Heart rate variability (HRV) has prognostic and diagnostic potential, however, the mechanisms behind respiratory sinus arrhythmia (RSA), a main short-term HRV, are still not well understood. We investigated if the central feedforward mechanism or pulmonary stretch reflex contributed most to RSA in healthy humans. Ventilatory support reduces the centrally mediated respiratory effort but remains the inspiratory stretch of the pulmonary receptors. We aimed to quantify the difference in RSA between spontaneous breathing and ventilatory support. Nineteen healthy, young subjects underwent spontaneous breathing and non-invasive intermittent positive pressure ventilation (NIV) while we recorded heart rate (HR, from ECG), mean arterial pressure (MAP) and stroke volume (SV) estimated from the non-invasive finger arterial pressure curve, end-tidal CO2 (capnograph), and respiratory frequency (RF) with a stretch band. Variability was quantified by an integral between 0.15–0.4 Hz calculated from the power spectra. Median and 95% confidence intervals (95%CI) were calculated as Hodges–Lehmann’s one-sample estimator. Statistical difference was calculated by the Wilcoxon matched-pairs signed-rank test. RF and end-tidal CO2 were unchanged by NIV. NIV reduced HR by 2 bpm, while MAP and SV were unchanged in comparison to spontaneous breathing. Variability in both HR and SV was reduced by 60% and 75%, respectively, during NIV as compared to spontaneous breathing, but their interrelationship with respiration was maintained. NIV reduced RSA through a less central respiratory drive, and pulmonary stretch reflex contributed little to RSA. RSA is mainly driven by a central feedforward mechanism in healthy humans. Peripheral reflexes may contribute as modifiers of RSA.

Retinal Vessel Segmentation Based on the Anam-Net Model

Accurate segmentation of retinal blood vessels can help ophthalmologists diagnose eye-related diseases such as diabetes and hypertension. The task of segmentation of the vessels comes with a number of challenges. Some of the challenges are due to haemorrhages and microaneurysms in fundus imaging, while others are due to the central vessel reflex and low contrast. Encoder-decoder networks have recently achieved excellent performance in retinal vascular segmentation at the trade-off of increased computational complexity. In this work, we use the Anam-Net model to accurately segment retinal vessels at a low computational cost. The Anam-Net model consists of a lightweight convolutional neural network (CNN) along with bottleneck layers in the encoder and decoder stages. Compared to the standard U-Net model and the R2U-Net model, the Anam-Net model has 6.9 times and 10.9 times fewer parameters. We evaluated the Anam-Net model on three open-access datasets: DRIVE, STARE, and CHASE_DB. The results show that the Anam-Net model achieves better segmentation accuracy compared to several state-of-the-art methods. For the DRIVE, STARE, and CHASE DB datasets, the model achieved {sensitivity and accuracy} of {0.8601, 0.9660}, {0.8697, 0.9728}, and {0.8553, 0.9746}, respectively. On the DRIVE, STARE, and CHASE_DB datasets, we also conduct cross-training experiments. The outcome of this experiment demonstrates the generalizability and robustness of the Anam-Net model.

Pharmacological Anti-Remodelling Effects of Disease-Modifying Drugs in Heart Failure with Reduced Ejection Fraction.

Cardiac remodelling is an adverse phenomenon linked to heart failure progression and an important contributor to heart failure severity. Cardiac remodelling could represent the real therapeutic goal in the treatment of patients with heart failure with reduced ejection fraction, being potentially reversed through different pharmacotherapies. Currently, there are well-established drugs such as angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers and β-blockers with anti-remodelling effects; recently, angiotensin receptor neprilysin inhibitor effects on inhibiting cardiac remodelling (improving N-terminal pro-B-type natriuretic peptide levels, echocardiographic parameters of reverse cardiac remodelling and right ventricular function in patients with heart failure with reduced ejection fraction) were demonstrated. More recently, hemodynamic consequences of gliflozins, reduced cardiac hydrostatic pressure as a possible cause of ventricular remodelling and hypertrophy were proposed to explain potential anti-remodelling effects of gliflozins. Gliflozins exert their cardioprotective effects by attenuating myofibroblast activity and collagen-mediated remodelling. Another postulated mechanism is represented by the reduction in sympathetic activity, through the reduction in renal afferent nervous activity and the suppression of central reflex mechanisms. Benefits of gliflozins on left ventricular hypertrophy, dilation, and systolic and diastolic function were also described. In this review, we aimed to provide a wide overview on cardiac remodelling with a particular focus on possible anti-remodelling effects of angiotensin receptor neprilysin inhibitors and gliflozins.

Impact of Single Eyelid on Superior Visual Field.

A puffy eyelid without a crease, also known as single eyelid, is a common characteristic in East Asians. Existence of a lid crease is generally considered an aesthetic concern for both patients and surgeons, and postoperative evaluations have mainly focused on the appearance of the eye. The aim of this study was to clarify the functionality of the superior visual field (SVF) with single eyelid.This prospective cohort study compared edge of the upper eyelid to central corneal light reflex distance (edge reflex distance [ERD]) preoperatively and postoperatively and examined the SVF, as measured by Goldmann perimetry, in single-eyelid patients who underwent blepharoplasty.Twenty patients (40 eyelids) with a median age of 21 years were examined. The median preoperative and postoperative ERDs were 1.45 and 3.4 mm, respectively. The median areas of the SVF preoperatively and postoperatively were 34,443 and 50,796 degrees2, respectively. Although a positive correlation existed between preoperative ERD and SVF, no correlation was observed between postoperative ERD and SVF.The SVF of the single eyelid is narrower than that of the double eyelid, even under circumstances of equivalent palpebral fissure height. The single eyelid commonly found in East Asian populations is associated with both cosmetic and functional issues.

Intravenous Thrombolysis in a Rare Case of Bilateral Medial Medullary Infarction

Based on our PuBMed and Cochrane search, this is the first case report that describes the clinical outcome of thrombolysis in a rare case of bilateral medial medullary infarction. OBJECTIVE: To describe the outcome of thrombolysis in a frequently devastating bilateral medial medullary infarction. CLINICAL PRESENTATION: A 37-year-old Chinese male was seen at the emergency department four hours from symptom onset of sudden and rapidly progressing bilateral motor weakness with associated dizziness. The patient was seen awake, not in cardiorespiratory distress. Pupils were 3 millimeters isocoric and briskly reactive to light. Extraocular muscle movements were full and equal and there was torsional nystagmus on all gazes. There was right central facial palsy and weak gag reflex bilaterally. Tongue was midline on protrusion. Motor strength test revealed right sided hemiplegia and left sided hemiparesis (2-/5 on MMT). Bilateral Babinski sign was elicited. There was no sensory deficit to light touch. Magnetic resonance imaging of the brain showed acute infarction of the bilateral anteromedial medulla. TREATMENT AND OUTCOME: Alteplase was given at a dose of 0.7 mg/kg was given at exactly 4.5 hours post-ictus. There was no complication after thrombolysis. He was discharged on the 12th day post-ictus, still with dizziness but with improved muscle strength on all extremities to 3/5 MMT except for the right arm which remained paralyzed. He was able to tolerate oral feeding and had a Modified Rankin Scale score of 4.

On the influence of an unconditioned reflex on a conditioned negative reflex

The formation of a temporary connection is based on one of the main conditions: the coincidence in time of the action of an indifferent agent with the action of an unconditioned stimulus. In this case, the coincidence should take place in such a way that the onset of the action of the indifferent agent, at least slightly, but precedes in time the action of the unconditioned stimulus. If the coincidence occurs from the precedence of the action of the unconditioned to the indifferent agent, it is not possible to develop a conditioned stimulus from the latter (Krestovnikov, Podkopaev). This fact must be understood in such a way that during the action of the unconditioned stimulus, the center of the unconditioned reflex, due to the mechanism of negative induction, causes inhibition that spreads to the cerebral hemispheres, and the indifferent stimulus falls on the cell in a state of inhibition.

Investigating the control of exercise hyperpnoea: A synergy of contributions.

Investigating the control of exercise hyperpnoea: A synergy of contributions.

Inhibition and Facilitation of the Spinal Locomotor Central Pattern Generator and Reflex Circuits by Somatosensory Feedback From the Lumbar and Perineal Regions After Spinal Cord Injury.

Somatosensory feedback from peripheral receptors dynamically interacts with networks located in the spinal cord and brain to control mammalian locomotion. Although somatosensory feedback from the limbs plays a major role in regulating locomotor output, those from other regions, such as lumbar and perineal areas also shape locomotor activity. In mammals with a complete spinal cord injury, inputs from the lumbar region powerfully inhibit hindlimb locomotion, while those from the perineal region facilitate it. Our recent work in cats with a complete spinal cord injury shows that they also have opposite effects on cutaneous reflexes from the foot. Lumbar inputs increase the gain of reflexes while those from the perineal region decrease it. The purpose of this review is to discuss how somatosensory feedback from the lumbar and perineal regions modulate the spinal locomotor central pattern generator and reflex circuits after spinal cord injury and the possible mechanisms involved. We also discuss how spinal cord injury can lead to a loss of functional specificity through the abnormal activation of functions by somatosensory feedback, such as the concurrent activation of locomotion and micturition. Lastly, we discuss the potential functions of somatosensory feedback from the lumbar and perineal regions and their potential for promoting motor recovery after spinal cord injury.