Re-innervation of axolotl limbs - II. Sensory nerves

1975 ◽  
Vol 190 (1098) ◽  
pp. 59-75 ◽  
Keyword(s):  
Tactile Stimulation ◽  
Receptive Fields ◽  
Sensory Information ◽  
Extracellular Recording ◽  
Sensory Nerves ◽  
Sensory Innervation ◽  
Contralateral Limb ◽  
Innervation Patterns ◽  
Control Limb ◽  
Left And Right

Segmental sensory receptive fields in axolotl hindlimb skin were mapped during extracellular recording of nerve responses to light tactile stimulation. Normally, cutaneous sensory innervation patterns for a given pair of left and right hindlimbs were similar, but there was variability among animals. Individual cutaneous fibres innervated a solitary receptive field whose borders were sharply defined. When spinal nerves were crushed or cut and allowed to regrow the receptive fields re-established were similar to those on the normal contralateral limb. However, many single cutaneous fibres innervated multiple receptive fields. After cutting and interchanging the two major limb nerve branches, regenerating cutaneous nerves tended to innervate skin toward which they were directed, and receptive fields did not resemble the patterns on the control limb skin. This contrasts with the results following the same operations on the motor innervation where patterns of re-innervation do resemble the control. Regenerating cutaneous fibres apparently cannot relocate their respective original cutaneous addresses, but readily re-innervate foreign skin areas. Nerves regenerating after a crush or cut appear to follow mechanical and/or biochemical orienting clues within the nerve trunks for restoration of typical innervation patterns. It is not known how the axolotl central nervous system copes with cutaneous sensory information from mislocated nerve terminals.

Summation for Stationary and Moving Visual Stimuli in Receptive Fields of Cat Pretectal Neurons

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 123-123
Author(s):  
K Dec ◽  
W J Waleszczyk ◽  
B A Harutiunian-Kozak
Keyword(s):  
Single Unit ◽  
Cellular Response ◽  
Visual Stimuli ◽  
Receptive Fields ◽  
Sensory Information ◽  
Extracellular Recording ◽  
Great Majority ◽  
Stimulus Size ◽  
Visually Guided ◽  
Negative Effects

Numerous investigations have shown that the cat's pretectal region is involved in various visual habits and in visually guided behaviour. Thus visually driven pretectal neurons should possess summation abilities for integration of incoming sensory information. We investigated responses of 102 neurons in the pretectal region of cats with pretrigeminal brain stem transection using single-unit extracellular recording. Cells were examined with moving and stationary visual stimuli of different sizes. Our purpose was to compare summation characteristics for stationary and moving visual stimuli in the same neuron. Only a small proportion (5%) of pretectal neurons revealed similar summation characteristics for stationary and moving stimuli. The great majority of neurons showed different patterns of summation, depending on the type of the visual stimulus. For example, positive and negative effects of an increase of the stimulus size on the intensity of cellular response were observed. The results suggest that there are several discrete mechanisms subserving integration of sensory information concerning stationary and moving visual stimuli.

scholarly journals Talar and Subtalar T1ρ Relaxation Times in Limbs with and without Chronic Ankle Instability

Cartilage ◽  
2021 ◽  
pp. 194760352199462
Author(s):  
Kyeongtak Song ◽  
Brian Pietrosimone ◽  
Joshua N. Tennant ◽  
Daniel B. Nissman ◽  
Katherine M. Dederer ◽  
...  
Keyword(s):  
Ankle Instability ◽  
Relaxation Times ◽  
Chronic Ankle Instability ◽  
Talar Dome ◽  
Contralateral Limb ◽  
Secondary Purpose ◽  
Healthy Control ◽  
Control Limb ◽  
Proteoglycan Content ◽  
Magnetic Resonance Imaging Mri

Objective The primary aim was to determine differences in talocrural and subtalar joint (STJ) articular cartilage composition, using T1ρ magnetic resonance imaging (MRI) relaxation times, between limbs in individuals with unilateral chronic ankle instability (CAI) and compare with an uninjured control. Our secondary purpose was to determine the association between talocrural and STJ composition in limbs with and without CAI. Design T1ρ MRI relaxation times were collected on 15 CAI (11 females, 21.13 ± 1.81 years, body mass index [BMI] = 23.96 ± 2.74 kg/m2) and 15 uninjured control individuals (11 females, 21.07 ± 2.55 years, BMI = 24.59 ± 3.44 kg/m2). Talocrural cartilage was segmented manually to identify the overall talar dome. The SJT cartilage was segmented manually to identify the anterior, medial, and posterior regions of interest consistent with STJ anatomical articulations. For each segmented area, a T1ρ relaxation time mean and variability value was calculated. Greater T1ρ relaxation times were interpreted as decreased proteoglycan content. Results Individuals with CAI demonstrated a higher involved limb talocrural T1ρ mean and variability relative to their contralateral limb ( P < 0.05) and the healthy control limb ( P < 0.05). The CAI-involved limb also had a higher posterior STJ T1ρ mean relative to the healthy control limb ( P < 0.05). In healthy controls ( P < 0.05), but not the CAI-involved or contralateral limbs (p>0.05), talocrural and posterior STJ composition measures were positively associated. Conclusions Individuals with CAI have lower proteoglycan content in both the talocrural and posterior STJ in their involved limbs relative to the contralateral and a healthy control limb. Cartilage composition findings may be consistent with the early development of posttraumatic osteoarthritis.

scholarly journals Renal sensory and sympathetic nerves reinnervate the kidney in a similar time-dependent fashion after renal denervation in rats

2013 ◽  
Vol 304 (8) ◽  
pp. R675-R682 ◽  
Author(s):  
Jan Mulder ◽  
Tomas Hökfelt ◽  
Mark M. Knuepfer ◽  
Ulla C. Kopp
Keyword(s):  
Substance P ◽  
Optical Density ◽  
Renal Denervation ◽  
Time Course ◽  
Sympathetic Nerves ◽  
Sensory Nerves ◽  
Sensory Innervation ◽  
Multiple Time ◽  
Sensory Reinnervation ◽  
Renal Sympathetic

Efferent renal sympathetic nerves reinnervate the kidney after renal denervation in animals and humans. Therefore, the long-term reduction in arterial pressure following renal denervation in drug-resistant hypertensive patients has been attributed to lack of afferent renal sensory reinnervation. However, afferent sensory reinnervation of any organ, including the kidney, is an understudied question. Therefore, we analyzed the time course of sympathetic and sensory reinnervation at multiple time points (1, 4, and 5 days and 1, 2, 3, 4, 6, 9, and 12 wk) after renal denervation in normal Sprague-Dawley rats. Sympathetic and sensory innervation in the innervated and contralateral denervated kidney was determined as optical density (ImageJ) of the sympathetic and sensory nerves identified by immunohistochemistry using antibodies against markers for sympathetic nerves [neuropeptide Y (NPY) and tyrosine hydroxylase (TH)] and sensory nerves [substance P and calcitonin gene-related peptide (CGRP)]. In denervated kidneys, the optical density of NPY-immunoreactive (ir) fibers in the renal cortex and substance P-ir fibers in the pelvic wall was 6, 39, and 100% and 8, 47, and 100%, respectively, of that in the contralateral innervated kidney at 4 days, 4 wk, and 12 wk after denervation. Linear regression analysis of the optical density of the ratio of the denervated/innervated kidney versus time yielded similar intercept and slope values for NPY-ir, TH-ir, substance P-ir, and CGRP-ir fibers (all R2 > 0.76). In conclusion, in normotensive rats, reinnervation of the renal sensory nerves occurs over the same time course as reinnervation of the renal sympathetic nerves, both being complete at 9 to 12 wk following renal denervation.

scholarly journals Endocannabinoids in Bladder Sensory Mechanisms in Health and Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Stewart Christie ◽  
Simon Brookes ◽  
Vladimir Zagorodnyuk
Keyword(s):  
Overactive Bladder ◽  
Sensory Neurons ◽  
Cannabinoid Receptors ◽  
Cannabinoid Receptor ◽  
Endocannabinoid System ◽  
Sensory Nerves ◽  
Sensory Innervation ◽  
Bladder Function ◽  
Painful Bladder ◽  
Bladder Diseases

The recent surge in research on cannabinoids may have been fueled by changes in legislation in several jurisdictions, and by approval for the use of cannabinoids for treatment of some chronic diseases. Endocannabinoids act largely, but not exclusively on cannabinoid receptors 1 and 2 (CBR1 and CBR2) which are expressed in the bladder mainly by the urothelium and the axons and endings of motor and sensory neurons. A growing body of evidence suggests that endocannabinoid system constitutively downregulates sensory bladder function during urine storage and micturition, under normal physiological conditions. Similarly, exogenous cannabinoid agonists have potent modulatory effects, as do inhibitors of endocannabinoid inactivation. Results suggest a high potential of cannabinoids to therapeutically ameliorate lower urinary tract symptoms in overactive bladder and painful bladder syndromes. At least part of this may be mediated via effects on sensory nerves, although actions on efferent nerves complicate interpretation. The sensory innervation of bladder is complex with at least eight classes identified. There is a large gap in our knowledge of the effects of endocannabinoids and synthetic agonists on different classes of bladder sensory neurons. Future studies are needed to reveal the action of selective cannabinoid receptor 2 agonists and/or peripherally restricted synthetic cannabinoid receptor 1 agonists on bladder sensory neurons in animal models of bladder diseases. There is significant potential for these novel therapeutics which are devoid of central nervous system psychotropic actions, and which may avoid many of the side effects of current treatments for overactive bladder and painful bladder syndromes.

Whole-body Vibration Attenuates Pyroptosis-Mediated Inflammation but Accelerates Progression of Intervertebral Disc Degeneration

2020 ◽  
Author(s):  
Fang-da Fu ◽  
Sai Yao ◽  
Zhi-tao Sun ◽  
Cheng-cong Zhou ◽  
Huan Yu ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Whole Body Vibration ◽  
Sensory Nerves ◽  
Sensory Innervation ◽  
Whole Body ◽  
Body Vibration ◽  
Pharmaceutical Therapy ◽  
The Matrix ◽  
Matrix Metabolism ◽  
Ivd Degeneration

Abstract Background Whole body vibration (WBV) is a non-pharmaceutical therapy that has been widely incorporated into clinical practice for musculoskeletal disorders, including low back pain (LBP). Intervertebral disc (IVD) degeneration (IVDD) is clinically associated with LBP and is known as the main cause for LBP. However, cumulative evidence also suggested WBV might have an adverse impact on IVDs. Moreover, previous studies have been focusing on the effects of WBV on healthy mice, rather than those suffering from IVDD. Thus, uncertainties still exist concerning the effects of WBV on IVDs undergoing IVDD. This study was aiming to evaluate the effects of WBV intervention on the development and progression of IVDD mouse model induced by lumbar spine instability (LSI) surgery. Methods LSI surgery, by resecting the lumbar 3 rd -5 th spinous processes along with the supraspinous and interspinous ligaments, was conducted in 10-week-old male mice which then received WBV treatment (1 h per day, 5 days per week, at 3 Hz with peak acceleration at 0.4 g) or sham treatment. The progression of IVDD was evaluated by MRI, μCT and histological analyses after WBV treatment. The matrix metabolism, distribution of sensory nerves, pyroptosis in IVDs tissues were determined by immunohistological analysis or real-time PCR. The apoptosis of IVD cells was detected by TUNEL assay. Results LSI surgery was successful in producing IVDD modeling. WBV caused decreases in IVD height and annulus fibrosus (AF) score, as well as increased numbers of apoptotic cells in IVD tissues. WBV contributed to sensory innervation into AF and upregulation of Adamts5 and MMP3 expression in IVDD mice received LSI surgery. In addition, WBV treatment triggered earlier activation of Wnt/β-catenin signaling in IVDD mice with WBV treatment compared with those without WBV treatment. Unexpectedly, WBV significantly attenuated Caspase-1 and IL-1β expression in AF. Conclusions Collectively, our findings demonstrate that WBV treatment may worsen the development of ongoing IVDD. Decrease of IL-1β expression after WBV intervention may partially account for patient self-reported pain relief after WBV treatment in some previous trials. This study may help us better understand the effects of WBV intervention on patients experiencing LBP resulting from the degeneration of lumbar IVDs.

scholarly journals A130 RETROGRADE TRACING ANALYSIS OF THE SENSORY INNERVATION OF THE MOUSE COLON

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. 150-151
Author(s):  
S Osman ◽  
A E Lomax
Keyword(s):  
Visceral Pain ◽  
Receptive Fields ◽  
Fluorescence Emission ◽  
Distal Colon ◽  
Proximal Colon ◽  
Sensory Innervation ◽  
Afferent Neurons ◽  
Drg Neurons ◽  
Fluorescence Emission Spectra ◽  
Fast Blue

Abstract Background Visceral pain is a primary symptom of many gastrointestinal diseases. One feature of visceral pain is its vague localization. We hypothesized that overlap in the receptive fields of spinal primary afferent neurons that innervate the gut may contribute to this vague localization. Many studies have confirmed that the proximal and distal colon are mainly innervated by spinal afferent neurons with cell bodies in thoraco-lumbar and lumbo-sacral dorsal root ganglia (DRG), respectively. However, no murine studies have examined whether individual DRG neurons simultaneously innervate both proximal and distal colon. Aims To determine the extent of overlap in receptive fields of colon-projecting DRG neurons. Methods C57BL/6 mice (n=8) were anesthetized, and two retrograde neuronal tracers with distinct fluorescence emission spectra (Fast blue and DiI) were injected separately into the smooth muscle layers of proximal and distal colon. Mice were left for 10–13 days for dye transport, before being euthanized. Thoraco, lumbar and lumbo-sacral DRGs (T8-13, L1-4, L5-S2) were dissected and fixed in 4% paraformaldehyde overnight. 12μm cryostat sections were obtained and analyzed using a fluorescent microscope equipped with filter cubes that detect Fast blue and DiI. Results When DiI was injected into the proximal colon, we observed labelling to be highest in T8-13 DRG with 12.6 +/- 4.5% of cell bodies labelled, followed by L1-4 was (8.2 +/- 1.4%) and in L5-S2 (6.5 +/- 0.8%). DiI injections into the distal colon resulted in labelling of similar numbers of neurons labelled in T8-13 and L1-4 ganglia, whereas half as many neurons were labelled in L5-S2 ganglia. This data shows that the majority of spinal afferent innervation of the colon originates in thoracolumbar DRG. Most importantly, 26.4% and 17.6% of thoracolumbar and lumbo-sacral DRG neurons labelled by Fast blue injection into the proximal colon were also double-labelled by DiI injected into the distal colon. Similarly, 16.6% and 13.8% of neurons in thoracolumbar and lumbosacral DRG labelled by Fast blue injection into the distal colon were double-labelled by DiI injected into the proximal colon. Conclusions These data reveal a surprisingly large number of DRG neurons that innervate the colon have receptive fields that cover both the proximal and distal colon, which may contribute to the poor spatial localization of pain emanating from the colon. Funding Agencies CCC, CIHR

Spatial determinants of multisensory integration in cat superior colliculus neurons

1996 ◽  
Vol 75 (5) ◽  
pp. 1843-1857 ◽  
Author(s):  
M. A. Meredith ◽  
B. E. Stein
Keyword(s):  
Receptive Field ◽  
Superior Colliculus ◽  
Neuronal Response ◽  
Receptive Fields ◽  
Spatial Relationship ◽  
Physiological Role ◽  
Extracellular Recording ◽  
Average Proportion ◽  
Relationship Of ◽  
High Degree

1. Although a representation of multisensory space is contained in the superior colliculus, little is known about the spatial requirements of multisensory stimuli that influence the activity of neurons here. Critical to this problem is an assessment of the registry of the different receptive fields within individual multisensory neurons. The present study was initiated to determine how closely the receptive fields of individual multisensory neurons are aligned, the physiological role of that alignment, and the possible functional consequences of inducing receptive-field misalignment. 2. Individual multisensory neurons in the superior colliculus of anesthetized, paralyzed cats were studied with the use of standard extracellular recording techniques. The receptive fields of multisensory neurons were large, as reported previously, but exhibited a surprisingly high degree of spatial coincidence. The average proportion of receptive-field overlap was 86% for the population of visual-auditory neurons sampled. 3. Because of this high degree of intersensory receptive-field correspondence, combined-modality stimuli that were coincident in space tended to fall within the excitatory regions of the receptive fields involved. The result was a significantly enhanced neuronal response in 88% of the multisensory neurons studied. If stimuli were spatially disparate, so that one fell outside its receptive field, either a decreased response occurred (56%), or no intersensory effect was apparent (44%). 4. The normal alignment of the different receptive fields of a multisensory neuron could be disrupted by passively displacing the eyes, pinnae, or limbs/body. In no case was a shift in location or size observed in a neuron's other receptive field(s) to compensate for this displacement. The physiological result of receptive-field misalignment was predictable and based on the location of the stimuli relative to the new positions of their respective receptive fields. Now, for example, one component of a spatially coincident pair of stimuli might fall outside its receptive field and inhibit the other's effects. 5. These data underscore the dependence of multisensory integrative responses on the relationship of the different stimuli to their corresponding receptive fields rather than to the spatial relationship of the stimuli to one another. Apparently, the alignment of different receptive fields for individual multisensory neurons ensures that responses to combinations of stimuli derived from the same event are integrated to increase the salience of that event. Therefore the maintenance of receptive-field alignment is critical for the appropriate integration of converging sensory signals and, ultimately, elicitation of adaptive behaviors.

scholarly journals Non-informative vision improves spatial tactile discrimination on the shoulder but does not influence detection sensitivity

2020 ◽  
Vol 238 (12) ◽  
pp. 2865-2875
Author(s):  
Fabrizio Leo ◽  
Sara Nataletti ◽  
Luca Brayda
Keyword(s):  
Tactile Stimulation ◽  
Detection Threshold ◽  
Receptive Fields ◽  
Judgment Task ◽  
The Body ◽  
Detection Sensitivity ◽  
Body Parts ◽  
Tactile Acuity ◽  
Tactile Stimuli ◽  
Numerosity Judgment

Abstract Vision of the body has been reported to improve tactile acuity even when vision is not informative about the actual tactile stimulation. However, it is currently unclear whether this effect is limited to body parts such as hand, forearm or foot that can be normally viewed, or it also generalizes to body locations, such as the shoulder, that are rarely before our own eyes. In this study, subjects consecutively performed a detection threshold task and a numerosity judgment task of tactile stimuli on the shoulder. Meanwhile, they watched either a real-time video showing their shoulder or simply a fixation cross as control condition. We show that non-informative vision improves tactile numerosity judgment which might involve tactile acuity, but not tactile sensitivity. Furthermore, the improvement in tactile accuracy modulated by vision seems to be due to an enhanced ability in discriminating the number of adjacent active electrodes. These results are consistent with the view that bimodal visuotactile neurons sharp tactile receptive fields in an early somatosensory map, probably via top-down modulation of lateral inhibition.

A Novel Technical Protocol for Improved Capture of the Genicular Nerves by Radiofrequency Ablation

Pain Medicine ◽  
2019 ◽  
Vol 20 (11) ◽  
pp. 2208-2212 ◽  
Author(s):  
Aaron Conger ◽  
Daniel M Cushman ◽  
Kortnie Walker ◽  
Russell Petersen ◽  
David R Walega ◽  
...  
Keyword(s):  
Radiofrequency Ablation ◽  
Anatomic Variation ◽  
Vastus Lateralis ◽  
Tendon Injury ◽  
Sensory Nerves ◽  
Sensory Innervation ◽  
Vastus Intermedius ◽  
Technical Report ◽  
Sensory Denervation ◽  
Anterior Knee

Abstract Background Fluoroscopically guided cooled genicular nerve radiofrequency ablation (RFA) is an increasingly performed procedure for chronic, refractory knee pain due to osteoarthritis. Traditionally, partial sensory denervation has been accomplished through ablation of the superomedial, superolateral, and inferomedial genicular nerves. However, recent cadaveric studies have demonstrated additional sensory nerves and significant anatomic variation that impact current protocols. Objective We describe an updated cooled genicular nerve radiofrequency ablation protocol that accounts for varied nerve location of the superomedial, superolateral, and inferomedial genicular nerves, as well as capture of the terminal articular branches of the nerves to the vastus intermedius, vastus lateralis, and vastus medialis. Furthermore, we describe an adjusted technique for inferomedial genicular nerve capture that mitigates the risk of pes anserine tendon injury. Design Technical report and brief literature review. Methods Cadaveric studies relating to the sensory innervation of the anterior knee joint were reviewed, and a more accurate and comprehensive cooled genicular nerve radiofrequency ablation (CRFA) protocol is proposed. Conclusions Based on recent, rigorous anatomic dissections of the knee, the proposed genicular nerve CRFA protocol will provide more complete sensory denervation and potentially improve clinical outcomes. Prospective studies will be needed to confirm the hypothesis that this protocol will result in improved effectiveness and safety of genicular nerve RFA.

Binocular Combination of Contrast Signals by Striate Cortical Neurons in the Monkey

1997 ◽  
Vol 78 (1) ◽  
pp. 366-382 ◽  
Author(s):  
Earl L. Smith ◽  
Yuzo Chino ◽  
Jinren Ni ◽  
Han Cheng
Keyword(s):  
Cortical Neurons ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Simple Cells ◽  
Complex Cells ◽  
Threshold Response ◽  
Binocular Interactions ◽  
Specific Complex ◽  
Left And Right

Smith, Earl L., III, Yuzo Chino, Jinren Ni, and Han Cheng. Binocular combination of contrast signals by striate cortical neurons in the monkey. J. Neurophysiol. 78: 366–382, 1997. With the use of microelectrode recording techniques, we investigated how the contrast signals from the two eyes are combined in individual cortical neurons in the striate cortex of anesthetized and paralyzed macaque monkeys. For a given neuron, the optimal spatial frequency, orientation, and direction of drift for sine wave grating stimuli were determined for each eye. The cell's disparity tuning characteristics were determined by measuring responses as a function of the relative interocular spatial phase of dichoptic stimuli that consisted of the optimal monocular gratings. Binocular contrast summation was then investigated by measuring contrast response functions for optimal dichoptic grating pairs that had left- to right-eye interocular contrast ratios that varied from 0.1 to 10. The goal was to determine the left- and right-eye contrast components required to produce a criterion threshold response. For all functional classes of cortical neurons and for both cooperative and antagonistic binocular interactions, there was a linear relationship between the left- and right-eye contrast components required to produce a threshold response. Thus, for example for cooperative binocular interactions, a reduction in contrast to one eye was counterbalanced by an equivalent increase in contrast to the other eye. These results showed that in simple cells and phase-specific complex cells, the contrast signals from the two eyes were linearly combined at the subunit level before nonlinear rectification. In non-phase-specific complex cells, the linear binocular convergence of contrast signals could have taken place either before or after the rectification process, but before spike generation. In addition, for simple cells, vector analysis of spatial summation showed that the inputs from the two eyes were also combined in a linear manner before nonlinear spike-generating mechanisms. Thus simple cells showed linear spatial summation not only within and between subregions in a given receptive field, but also between the left- and right-eye receptive fields. Overall, the results show that the effectiveness of a stimulus in producing a response reflects interocular differences in the relative balance of inputs to a given cell, however, the eye of origin of a light-evoked signal has no specific consequence.

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