Effects of nerve injury on sympathetic excitation of A delta mechanical nociceptors

1995 ◽  
Vol 73 (4) ◽  
pp. 1721-1723 ◽  
Author(s):  
D. F. Bossut ◽  
E. R. Perl
Keyword(s):  
Receptive Field ◽  
Nerve Injury ◽  
High Threshold ◽  
Myelinated Fiber ◽  
Mechanical Stimuli ◽  
Sympathetic Stimulation ◽  
Great Auricular Nerve ◽  
C Fiber ◽  
Field Organization ◽  
Receptive Field Organization

1. The effects of sympathetic stimulation and close arterial injection of norepinephrine were tested on cutaneous myelinated-fiber (A delta) mechanical nociceptors [high-threshold mechanoreceptors-(MyHTMs)] from normal and from partially transsected nerves. 2. Neither sympathetic stimulation nor close arterial injection of norepinephrine (200 ng) excited MyHTMs (18) recorded from the uninjured great auricular nerve of adult rabbits. 3. MyHTMs (58) conducting across the site of partial cut lesions, made 2 to 28 days previously, had threshold and responsiveness to mechanical stimuli, receptive field organization, and absence of background discharge typical of such elements in normal nerve. 4. Four MyHTMs recorded from the injured nerves were excited by sympathetic stimulation and/or norepinephrine injection but only one gave more than two impulses within 60 s to either form of stimulation. 5. The meagerness of the sympathetic and adrenergic excitation of MyHTMs after nerve injury contrasts with that observed under similar conditions for C-fiber polymodal nociceptors. Therefore, induction of adrenergic responsiveness in nociceptors after partial denervation in cutaneous MyHTMs appears to be less important for mechanisms related to pathogenic pain than alterations in certain C-fiber nociceptors.

scholarly journals Nerve injury induces a new profile of tactile and mechanical nociceptor input from undamaged peripheral afferents

2015 ◽  
Vol 113 (1) ◽  
pp. 100-109 ◽  
Author(s):  
M. Danilo Boada ◽  
Silvia Gutierrez ◽  
Carol A. Aschenbrenner ◽  
Timothy T. Houle ◽  
Ken-ichiro Hayashida ◽  
...  
Keyword(s):  
Receptive Field ◽  
Nerve Injury ◽  
Dorsal Root ◽  
Fold Increase ◽  
Spinal Nerve ◽  
Spinal Nerve Ligation ◽  
High Threshold ◽  
Mechanical Stimuli ◽  
Mechanical Threshold ◽  
Field Area

Chronic pain after nerve injury is often accompanied by hypersensitivity to mechanical stimuli, yet whether this reflects altered input, altered processing, or both remains unclear. Spinal nerve ligation or transection results in hypersensitivity to mechanical stimuli in skin innervated by adjacent dorsal root ganglia, but no previous study has quantified the changes in receptive field properties of these neurons in vivo. To address this, we recorded intracellularly from L4 dorsal root ganglion neurons of anesthetized young adult rats, 1 wk after L5 partial spinal nerve ligation (pSNL) or sham surgery. One week after pSNL, hindpaw mechanical withdrawal threshold in awake, freely behaving animals was decreased in the L4 distribution on the nerve-injured side compared with sham controls. Electrophysiology revealed that high-threshold mechanoreceptive cells of A-fiber conduction velocity in L4 were sensitized, with a seven-fold reduction in mechanical threshold, a seven-fold increase in receptive field area, and doubling of maximum instantaneous frequency in response to peripheral stimuli, accompanied by reductions in after-hyperpolarization amplitude and duration. Only a reduction in mechanical threshold (minimum von Frey hair producing neuronal activity) was observed in C-fiber conduction velocity high-threshold mechanoreceptive cells. In contrast, low-threshold mechanoreceptive cells were desensitized, with a 13-fold increase in mechanical threshold, a 60% reduction in receptive field area, and a 40% reduction in instantaneous frequency to stimulation. No spontaneous activity was observed in L4 ganglia, and the likelihood of recording from neurons without a mechanical receptive field was increased after pSNL. These data suggest massively altered input from undamaged sensory afferents innervating areas of hypersensitivity after nerve injury, with reduced tactile and increased nociceptive afferent response. These findings differ importantly from previous preclinical studies, but are consistent with clinical findings in most patients with chronic neuropathic pain.

Sensory enrichment after peripheral nerve injury restores cortical, not thalamic, receptive field organization

2001 ◽  
Vol 13 (9) ◽  
pp. 1755-1766 ◽  
Author(s):  
S. L. Florence ◽  
L. A. Boydston ◽  
T. A. Hackett ◽  
H. Taub Lachoff ◽  
F. Strata ◽  
...  
Keyword(s):  
Receptive Field ◽  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Field Organization ◽  
Receptive Field Organization

Comparison of the responses of AII amacrine cells in the dark- and light-adapted rabbit retina

1999 ◽  
Vol 16 (4) ◽  
pp. 653-665 ◽  
Author(s):  
DAIYAN XIN ◽  
STEWART A. BLOOMFIELD
Keyword(s):  
Receptive Field ◽  
Light Adaptation ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Rabbit Retina ◽  
Response Component ◽  
Synaptic Inputs ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Aii Amacrine Cells

We studied the light-evoked responses of AII amacrine cells in the rabbit retina under dark- and light-adapted conditions. In contrast to the results of previous studies, we found that AII cells display robust responses to light over a 6–7 log unit intensity range, well beyond the operating range of rod photoreceptors. Under dark adaptation, AII cells showed an ON-center/OFF-surround receptive-field organization. The intensity–response profile of the center-mediated response component followed a dual-limbed sigmoidal function indicating a transition from rod to cone mediation as stimulus intensities were increased. Following light adaptation, the receptive-field organization of AII cells changed dramatically. Light-adapted AII cells showed both ON- and OFF-responses to stimulation of the center receptive field, but we found no evidence for an antagonistic surround. Interestingly, the OFF-center response appeared first following rapid light adaptation and was then replaced gradually over a 1–4 min period by the emerging ON-center response component. Application of the metabotropic glutamate receptor agonist APB, the ionotropic glutamate blocker CNQX, 8-bromo-cGMP, and the nitric oxide donor SNAP all showed differential effects on the various center-mediated responses displayed by dark- and light-adapted AII cells. Taken together, these pharmacological results indicated that different synaptic circuits are responsible for the generation of the different AII cell responses. Specifically, the rod-driven ON-center responses are apparently derived from rod bipolar cell synaptic inputs, whereas the cone-driven ON-center responses arise from signals crossing the gap junctions between AII cells and ON-center cone bipolar cells. Additionally, the OFF-center response of light-adapted AII cells reflects direct synaptic inputs from OFF-center cone bipolar cells to AII dendritic processes in the distal inner plexiform layer.

Two-dimensional receptive-field organization in striate cortical neurons of the cat

1994 ◽  
Vol 11 (4) ◽  
pp. 703-720 ◽  
Author(s):  
Ming Sun ◽  
A. B. Bonds
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Field Size ◽  
Two Dimensional ◽  
Cortical Layers ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Cortical Receptive Fields

AbstractThe two-dimensional organization of receptive fields (RFs) of 44 cells in the cat visual cortex and four cells from the cat LGN was measured by stimulation with either dots or bars of light. The light bars were presented in different positions and orientations centered on the RFs. The RFs found were arbitrarily divided into four general types: Punctate, resembling DOG filters (11%); those resembling Gabor filters (9%); elongate (36%); and multipeaked-type (44%). Elongate RFs, usually found in simple cells, could show more than one excitatory band or bifurcation of excitatory regions. Although regions inhibitory to a given stimulus transition (e.g. ON) often coincided with regions excitatory to the opposite transition (e.g. OFF), this was by no means the rule. Measurements were highly repeatable and stable over periods of at least 1 h. A comparison between measurements made with dots and with bars showed reasonable matches in about 40% of the cases. In general, bar-based measurements revealed larger RFs with more structure, especially with respect to inhibitory regions. Inactivation of lower cortical layers (V-VI) by local GABA injection was found to reduce sharpness of detail and to increase both receptive-field size and noise in upper layer cells, suggesting vertically organized RF mechanisms. Across the population, some cells bore close resemblance to theoretically proposed filters, while others had a complexity that was clearly not generalizable, to the extent that they seemed more suited to detection of specific structures. We would speculate that the broadly varying forms of cat cortical receptive fields result from developmental processes akin to those that form ocular-dominance columns, but on a smaller scale.

Dynamic aspects of receptive field organization in area VI of the macaque monkey

1992 ◽  
pp. 177-188
Author(s):  
James M. Fox ◽  
David C. Van Essen ◽  
Tobias Delbrück ◽  
Jack Gallant ◽  
Charles H. Anderson
Keyword(s):  
Receptive Field ◽  
Macaque Monkey ◽  
Field Organization ◽  
Receptive Field Organization

scholarly journals Electrophysiological Changes in Adult Rat Dorsal Horn Neurons After Neonatal Peripheral Inflammation

2003 ◽  
Vol 90 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Yuan Bo Peng ◽  
Qing Dong Ling ◽  
M. A. Ruda ◽  
Daniel R. Kenshalo
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Dorsal Horn ◽  
Dynamic Range ◽  
High Threshold ◽  
Peripheral Inflammation ◽  
Mechanical Stimuli ◽  
Neonatal Rats ◽  
Adult Rats ◽  
Dorsal Horn Neurons

Neonatal peripheral inflammation has been shown to produce profound anatomical changes in the dorsal horn of adult rats. In this study, we explored whether parallel physiological changes exist. Neonatal rats were injected with complete Freund's adjuvant (CFA) into the left hind paw. At 8–10 wk of age, single dorsal horn neurons were recorded in response to graded intensities of mechanical stimuli delivered to the receptive field. In addition, cord dorsum potentials, produced by electrical stimuli delivered to the left sciatic nerve at 2.5× threshold, were recorded bilaterally from L2 to S3. There were significant increases in background activity and responses to brush and pinch in neonatal rats that were treated with CFA, as compared with control rats. Further analysis showed similar significant changes when dorsal horn neurons were categorized into wide dynamic range (WDR), high-threshold (HT), and low-threshold (LT) groups. The receptive field was significantly larger in neonatally treated rats as compared with control rats. Additionally, there was a significant increase in the response to a 49°C heat stimulus in neonatally treated rats as compared with control rats. There was also a trend for the amplitudes of N1, N2, and P waves of the cord dorsum potential to increase and latencies to decrease in neonatally treated rats, but no significant differences were detected between different levels of the spinal cord (L2 to S3). These data further support the notion that anatomical and physiological plasticity changes occurred in the spinal cord following early neonatal CFA treatment.

scholarly journals Spatiotemporal Receptive Field Properties of a Looming-Sensitive Neuron in Solitarious and Gregarious Phases of the Desert Locust

2010 ◽  
Vol 103 (2) ◽  
pp. 779-792 ◽  
Author(s):  
Stephen M. Rogers ◽  
George W. J. Harston ◽  
Fleur Kilburn-Toppin ◽  
Thomas Matheson ◽  
Malcolm Burrows ◽  
...  
Keyword(s):  
Receptive Field ◽  
Schistocerca Gregaria ◽  
Visual Space ◽  
Lifestyle Changes ◽  
Movement Detector ◽  
Local Motion ◽  
Gregarious Locusts ◽  
Spatiotemporal Receptive Field ◽  
Field Organization ◽  
Receptive Field Organization

Desert locusts ( Schistocerca gregaria ) can transform reversibly between the swarming gregarious phase and a solitarious phase, which avoids other locusts. This transformation entails dramatic changes in morphology, physiology, and behavior. We have used the lobula giant movement detector (LGMD) and its postsynaptic target, the descending contralateral movement detector (DCMD), which are visual interneurons that detect looming objects, to analyze how differences in the visual ecology of the two phases are served by altered neuronal function. Solitarious locusts had larger eyes and a greater degree of binocular overlap than those of gregarious locusts. The receptive field to looming stimuli had a large central region of nearly equal response spanning 120° × 60° in both phases. The DCMDs of gregarious locusts responded more strongly than solitarious locusts and had a small caudolateral focus of even further sensitivity. More peripherally, the response was reduced in both phases, particularly ventrally, with gregarious locusts showing greater proportional decrease. Gregarious locusts showed less habituation to repeated looming stimuli along the eye equator than did solitarious locusts. By contrast, in other parts of the receptive field the degree of habituation was similar in both phases. The receptive field organization to looming stimuli contrasts strongly with the receptive field organization of the same neurons to nonlooming local-motion stimuli, which show much more pronounced regional variation. The DCMDs of both gregarious and solitarious locusts are able to detect approaching objects from across a wide expanse of visual space, but phase-specific changes in the spatiotemporal receptive field are linked to lifestyle changes.

scholarly journals Center/surround organization of retinal bipolar cells: High correlation of fundamental responses of center and surround to sinusoidal contrasts

2011 ◽  
Vol 28 (3) ◽  
pp. 183-192 ◽  
Author(s):  
DWIGHT A. BURKHARDT ◽  
THEODORE M. BARTOLETTI ◽  
WALLACE B. THORESON
Keyword(s):  
Receptive Field ◽  
Maximum Amplitude ◽  
High Gain ◽  
Bipolar Cells ◽  
Ambystoma Tigrinum ◽  
Response Curves ◽  
On And Off Cells ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Contrast Response

AbstractReceptive field organization of cone-driven bipolar cells was investigated by intracellular recording in the intact light-adapted retina of the tiger salamander (Ambystoma tigrinum). Centered spots and concentric annuli of optimum dimensions were used to selectively stimulate the receptive field center and surround with sinusoidal modulations of contrast at 3 Hz. At low contrasts, responses of both the center and surround of both ON and OFF bipolar cells were linear, showing high gain and thus contrast enhancement relative to cones. The contrast/response curves for the fundamental response, measured by a Fast Fourier Transform, reached half maximum amplitude quickly at 13% contrast followed by saturation at high contrasts. The variation of the normalized amplitude of the center and surround responses was remarkably similar, showing linear regression over the entire response range with very high correlations, r2 = 0.97 for both ON and OFF cells. The contrast/response curves of both center and surround for both ON and OFF cells were well fit (r2 = 0.98) by an equation for single-site binding. In about half the cells studied, the nonlinear waveforms of center and surround could be brought into coincidence by scaling and shifting the surround response in time. This implies that a nonlinearity, common to both center and surround, occurs after polarity inversion at the cone feedback synapse. Evidence from paired whole-cell recordings between single cones and OFF bipolar cells suggests that substantial nonlinearity is not due to transmission at the cone synapse but instead arises from intrinsic bipolar cell and network mechanisms. When sinusoidal contrast modulations were applied to the center and surround simultaneously, clear additivity was observed for small responses in both ON and OFF cells, whereas the interaction was strikingly nonadditive for large responses. The contribution of the surround was then greatly reduced, suggesting attenuation at the cone feedback synapse.

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