Parametric studies of dorsal horn neurons responding to tactile stimulation

1975 ◽  
Vol 38 (1) ◽  
pp. 19-25 ◽  
Author(s):  
P. B. Brown ◽  
J. L. Fuchs ◽  
D. N. Tapper
Keyword(s):  
Dorsal Horn ◽  
Discharge Rate ◽  
Spontaneous Discharge ◽  
Width Ratio ◽  
Size And Shape ◽  
Dorsal Horn Neurons ◽  
Tactile Input ◽  
Somatotopic Map ◽  
Length Width ◽  
Central Delay

Dorsal horn neurons responding to tactile input were recorded in segments L3-S2 of unanesthetized, low-spinal cats. Single units were characterized with regard to receptive field (RF) location, RF size and shape, spontaneous discharge rate, central delay, and convergence of four tactile afferent types. 1. RF size increased from the toes to the calf region. 2. Length-width ratio increased from the toes to the calf and declined from the calf to the hip. 3. The relation between RF size and position on the limb was independent of segmental and laminar location of the neurons. 4. RF size was positively correlated with spontaneous discharge rate. 5. The relation between RF size and shape and RF position can be interpreted in terms of regional variations in the magnitude of the gradient of representation in the dorsal horn somatotopic map. 6. Central delay was negatively correlated with both RF size and rate of ongoing discharge. 7. There were no statistically significant differences among the laminae with respect to central delay, RF size or shape, ongoing discharge, or convergence combinations of the four tactile afferent systems. 8. Data presented were at variance with Wall's laminar cascading model for laminae IV-VI. Our results suggest that the model should be modified, at least to emphasize monosynaptic tactile input to all three of these laminae.

Dorsal Horn Spatial Representation of Simple Cutaneous Stimuli

1998 ◽  
Vol 79 (2) ◽  
pp. 983-998 ◽  
Author(s):  
Paul B. Brown ◽  
Ronald Millecchia ◽  
Jeffrey J. Lawson ◽  
Stephanie Stephens ◽  
Paul Harton ◽  
...  
Keyword(s):  
Dorsal Horn ◽  
Spatial Representation ◽  
Single Point ◽  
Receptive Fields ◽  
Width Ratio ◽  
Contour Plots ◽  
Somatotopic Map ◽  
Length Width ◽  
Stimulus Features ◽  
Segmental Representations

Brown, Paul B., Ronald Millecchia, Jeffrey J. Lawson, Stephanie Stephens, Paul Harton, and James C. Culberson. Dorsal horn spatial representation of simple cutaneous stimuli. J. Neurophysiol. 79: 983–998, 1998. A model of lamina III–IV dorsal horn cell receptive fields (RFs) has been developed to visualize the spatial patterns of cells activated by light touch stimuli. Low-threshold mechanoreceptive fields (RFs) of 551 dorsal horn neurons recorded in anesthetized cats were characterized by location of RF center in cylindrical coordinates, area, length/width ratio, and orientation of long axis. Best-fitting ellipses overlapped actual RFs by 90%. Exponentially smoothed mean and variance surfaces were estimated for these five variables, on a grid of 40 points mediolaterally by 20/segment rostrocaudally in dorsal horn segments L4–S1. The variations of model RF location, area, and length/width ratio with map location were all similar to previous observations. When elliptical RFs were simulated at the locations of the original cells, the RFs of real and simulated cells overlapped by 64%. The densities of cell representations of skin points on the hindlimb were represented as pseudocolor contour plots on dorsal view maps, and segmental representations were plotted on the standard views of the leg. Overlap of modeled and real segmental representations was at the 84% level. Simulated and observed RFs had similar relations between area and length/width ratio and location on the hindlimb: r( A) = 0.52; r( L/ W) = 0.56. Although the representation of simple stimuli was orderly, and there was clearly only one somatotopic map of the skin, the representation of a single point often was not a single cluster of active neurons. When two-point stimuli were simulated, there usually was no fractionation of response zones or addition of new zones. Variation of stimulus size (area of skin contacted) produced less variation of representation size (number of cells responding) than movement of stimuli from one location to another. We conclude that stimulus features are preserved poorly in their dorsal horn spatial representation and that discrimination mechanisms that depend on detection of such features in the spatial representation would be unreliable.

Quantitative analysis of dorsal horn cell receptive fields following limited deafferentation

1995 ◽  
Vol 74 (5) ◽  
pp. 2065-2076 ◽  
Author(s):  
H. R. Koerber ◽  
P. B. Brown
Keyword(s):  
Dorsal Horn ◽  
Receptive Fields ◽  
Afferent Input ◽  
Width Ratio ◽  
Survival Times ◽  
Long Survival ◽  
Dorsal Horns ◽  
Length Width ◽  
Low Threshold ◽  
And Control

1. To test the hypothesis that subtotal deafferentation of dorsal horn cells can stimulate plastic changes in their receptive fields (RFs), diffuse deafferentation of the cat hindlimb dorsal horn was produced by transection of L7 or L6 and L7 dorsal roots. The following single-unit cutaneous low-threshold mechanoreceptor RF properties were compared between operated and control dorsal horns: 1) distance of RF center from tips of toes, 2) RF length-width ratio; and 3) RF area. 2. In both L7 and L6-L7 rhizotomized animals there was an increased incidence of silent electrode tracks in the most deafferented portion of the hindlimb map (the foot and toe representation). In the rhizotomized L6-L7 animals, there was also an increased incidence of symmetrically placed tracks in deafferented and control dorsal horns, in which cell RFs had no mirror-symmetrical components. In addition, cells in the lateral half of the L6 and L7 dorsal horns exhibited a proximal shift in the location of their RFs. In the rhizotomized L7 animals there was a distal shift of RFs in the L5 segment at long survival times. RFs had lower length-width ratios in L5 and L6 at short survival times and in L6 at long survival times. 3. In intact preparations, dorsal horn cells normally respond to inputs via single or small numbers of low-threshold cutaneous mechanoreceptors. Because these rhizotomies do not remove all inputs from any given area of skin, the deafferentations would produce only patchy loss of input from individual receptors. Therefore observed changes cannot be accounted for entirely by loss of afferent input, suggesting that some reorganization of dorsal horn cell RFs occurred. We conclude that the threshold stimulus for plastic change is less than total deafferentation of dorsal horn cells. At least some of the mechanisms underlying these changes may be active in normal animals in the maintenance of the somatotopic map or in conditioning.

The detailed somatotopic organization of the dorsal horn in the lumbosacral enlargement of the cat spinal cord

1986 ◽  
Vol 55 (3) ◽  
pp. 604-617 ◽  
Author(s):  
P. Wilson ◽  
D. E. Meyers ◽  
P. J. Snow
Keyword(s):  
Dorsal Horn ◽  
Receptive Fields ◽  
Glabrous Skin ◽  
Lateral Part ◽  
Depth Range ◽  
Dorsal Horn Neurons ◽  
Somatotopic Organization ◽  
Line Of Discontinuity ◽  
Somatotopic Map ◽  
Alpha Chloralose

The somatotopic organization of spinocervical tract cells and unidentified dorsal horn neurons that lie in the same depth range as the spinocervical tract cells has been examined in detail in the lumbosacral enlargement of cats anesthetized with alpha-chloralose. Only gentle hair movement or light touch of glabrous skin were used as stimuli. Within the region of the dorsal horn containing these neurons there is a precise somatotopic organization. However, there is considerable variation between animals in the relationship between the somatotopic map and the lumbosacral segmental boundaries. The somatotopic map described here is considered to be restricted to a 300- to 500-micron thick lamina. In the medial half to two-thirds of this lamina in the L6 and L7 segments the toes are represented in a rostrocaudal sequence from toe 2 to toe 5. Over the most medial 200-500 micron of this part of the dorsal horn are found cells that respond to stimulation of the glabrous skin of the toe pads and the central pad. The toe representation is surrounded by a strip of foot representation, which is in turn surrounded by a strip of leg representation. The most lateral part of the lamina curves ventrally in the L6 and L7 segments and contains a continuous rostrocaudal representation of the skin of the thigh. In this region are found both spinocervical tract cells and unidentified dorsal horn neurons with receptive fields on the thigh. The skin of the hindlimb is represented such that a line of discontinuity runs down the posteromedial thigh, leg, and foot. Skin lateral to this line is represented caudally, while skin medial to it is represented rostrally.

scholarly journals Determining the length-width ratio of the quarry exploited under sea level to recover maximally extraction reserves

2019 ◽  
Vol 61 (1) ◽  
pp. 110-115
Author(s):  
Nguyen Tuan Thanh ◽  
Keyword(s):  
Sea Level ◽  
Surface Area ◽  
Significant Influence ◽  
Width Ratio ◽  
Size And Shape ◽  
Length Width ◽  
Mining Design

The boundary of the quarry exploited under sea level has a significant influence on mining design, especially the determination of extraction reserves. For a quarry project, with the same given exploiting depth, the size and shape on the surface of the quarry will yield different mining alternatives and extraction reserves. This paper proposed an approach for determining the length-width ratio of the quarry (with the surface area is rectangular) to achieve maximum reserves corresponding to the quarry boundary.

scholarly journals Image-based phenotyping for identification of QTL determining fruit shape and size in American cranberry (Vaccinium macrocarponL.)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5461 ◽  
Author(s):  
Luis Diaz-Garcia ◽  
Giovanny Covarrubias-Pazaran ◽  
Brandon Schlautman ◽  
Edward Grygleski ◽  
Juan Zalapa
Keyword(s):  
Persistent Homology ◽  
Fruit Size ◽  
Fruit Shape ◽  
Quality Parameters ◽  
Width Ratio ◽  
Size And Shape ◽  
American Cranberry ◽  
Length Width ◽  
Fruit Size And Shape ◽  
End Use

Image-based phenotyping methodologies are powerful tools to determine quality parameters for fruit breeders and processors. The fruit size and shape of American cranberry (Vaccinium macrocarponL.) are particularly important characteristics that determine the harvests’ processing value and potential end-use products (e.g., juice vs. sweetened dried cranberries). However, cranberry fruit size and shape attributes can be difficult and time consuming for breeders and processors to measure, especially when relying on manual measurements and visual ratings. Therefore, in this study, we implemented image-based phenotyping techniques for gathering data regarding basic cranberry fruit parameters such as length, width, length-to-width ratio, and eccentricity. Additionally, we applied a persistent homology algorithm to better characterize complex shape parameters. Using this high-throughput artificial vision approach, we characterized fruit from 351 progeny from a full-sib cranberry population over three field seasons. Using a covariate analysis to maximize the identification of well-supported quantitative trait loci (QTL), we found 252 single QTL in a 3-year period for cranberry fruit size and shape descriptors from which 20% were consistently found in all years. The present study highlights the potential for the identified QTL and the image-based methods to serve as a basis for future explorations of the genetic architecture of fruit size and shape in cranberry and other fruit crops.

scholarly journals Diversity of Pod Shape in Pisum

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 203
Author(s):  
Thomas Henry Noel Ellis ◽  
Julie M. I. Hofer ◽  
Eleni Vikeli ◽  
Michael J. Ambrose ◽  
Paola Higuera-Poveda ◽  
...  
Keyword(s):  
Allelic Variation ◽  
Size Variation ◽  
Width Ratio ◽  
Negative Regulators ◽  
Wide Range ◽  
Yield Determination ◽  
Organ Specific ◽  
Length Width ◽  
End Use ◽  
Pod Length

The seed-containing pod is the defining structure of plants in the legume family, yet pods exhibit a wide range of morphological variation. Within a species pod characters are likely to be correlated with reproductive strategy, and within cultivated forms will correspond to aspects of yield determination and/or end use. Here variation in pod size, described as pod length: pod width ratio, has been analyzed in pea germplasm represented by 597 accessions. This pod size variation is discussed with respect to population structure and to known classical pod morphology mutants. Variability of the pod length: width ratio can be explained by allelic variation at two genetic loci that may correspond to organ-specific negative regulators of growth.

scholarly journals Neuron-specific spinal cord translatomes reveal a neuropeptide code for mouse dorsal horn excitatory neurons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rebecca Rani Das Gupta ◽  
Louis Scheurer ◽  
Pawel Pelczar ◽  
Hendrik Wildner ◽  
Hanns Ulrich Zeilhofer
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Functional Organization ◽  
Affinity Purification ◽  
Expression Patterns ◽  
Inhibitory Neurons ◽  
Dorsal Horn Neurons ◽  
Expression Of Genes ◽  
Excitatory Neurons ◽  
Genes Encoding

AbstractThe spinal dorsal horn harbors a sophisticated and heterogeneous network of excitatory and inhibitory neurons that process peripheral signals encoding different sensory modalities. Although it has long been recognized that this network is crucial both for the separation and the integration of sensory signals of different modalities, a systematic unbiased approach to the use of specific neuromodulatory systems is still missing. Here, we have used the translating ribosome affinity purification (TRAP) technique to map the translatomes of excitatory glutamatergic (vGluT2+) and inhibitory GABA and/or glycinergic (vGAT+ or Gad67+) neurons of the mouse spinal cord. Our analyses demonstrate that inhibitory and excitatory neurons are not only set apart, as expected, by the expression of genes related to the production, release or re-uptake of their principal neurotransmitters and by genes encoding for transcription factors, but also by a differential engagement of neuromodulator, especially neuropeptide, signaling pathways. Subsequent multiplex in situ hybridization revealed eleven neuropeptide genes that are strongly enriched in excitatory dorsal horn neurons and display largely non-overlapping expression patterns closely adhering to the laminar and presumably also functional organization of the spinal cord grey matter.

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