Sensory Mechanisms of the Spinal Cord

Willis, William D.; Coggeshall, Richard E.

doi:10.1007/978-1-4757-1688-7

Cited by 578 publications

(326 citation statements)

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“…However, the proportion of RA neurons increases significantly within VB. Although the changes as one enters the spinal cord might be attributable to a sorting process whereby information arising from different receptor types ascends the spinal cord via different pathways (Brown, 1968;Petit and Burgess, 1968), such an explanation cannot account for differences between the cuneate and ventrobasal nuclei, as the thalamus represents a focus of convergence from many different ascending pathways, including the spinocervicothalamic and spinothalamic systems, as well as the dorsal column-medial lemniscal system (see Willis and Coggeshall, 1978, for a review).…”

Section: Discussionmentioning

confidence: 99%

The somatosensory thalamus of the raccoon: properties of single neurons responsive to light mechanical stimulation of the forepaw

Warren¹,

Kelahan²,

Pubols³

1986

J. Neurosci.

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These studies were undertaken to characterize the discharge properties of single neurons of the raccoon thalamic ventrobasal complex (VB) that respond to light mechanical stimulation of the glabrous surfaces of the forepaw. Microelectrodes were used to record the extracellular activity of 146 cells in anesthetized raccoons, and all neurons were histologically verified as falling within or along the boundaries of VB. Sixty-one neurons were tested for activation by electrical stimulaton of primarily somatosensory cortex. Of these, 88% were antidromically activated, 5% were synaptically activated, and the remaining 7% were unresponsive.Out of the total sample of 146 neurons, 136 had peripheral receptive fields (RFs) that were restricted to glabrous skin and revealed properties of modality and place-specificity predictable through knowledge of properties of primary mechanoreceptive afferents. Rapidly adapting (RA) neurons accounted for 77% of this modality-place-specific sample, while 19% were slowly adapting (SA), and 4% revealed properties indicative of input from Pacinian afferents (PC). Absolute displacement thresholds were comparable for RA and SA neurons (range = 6-415 pm). Palmar RF areas (range = 3.3-328 mmZ) were significantly larger than digital RF areas (range = 0.5-98.2 mm*).As defined by exponents ( A small number of neurons (7% of total sample) revealed "complex" properties, not predictable from knowledge of properties of primary afferents. These included five neurons whose RFs encompassed both glabrous and hairy skin, and several linear orientation, or "tactile edge," detectors.The present results, in conjunction with those of earlier stud-

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Section: Discussionmentioning

confidence: 99%

The somatosensory thalamus of the raccoon: properties of single neurons responsive to light mechanical stimulation of the forepaw

Warren¹,

Kelahan²,

Pubols³

1986

J. Neurosci.

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“…This is because there is substantial anatomical and physiological evidence for segmentally distributed interaction among different cutaneous inputs onto dorsal horn neurons (Willis, 1985;Willis and Coggeshall, 1978;Cervero, 1986;Ruda, 1986). Furthermore, afferent interactions established at the spinal level are likely to be represented to some degree at rostra1 levels.…”

Section: Neural Mechanismsmentioning

confidence: 98%

“…The behavioral experiments of Kirk and Denny-Brown (1970) and of Denny-Brown et al (1973) show that neurons contributing to the tract of Lissauer control segmental and intersegmental sensory transmission in the monkey. There is now substantial evidence that the interneurons of the substantia gelatinosa, which contribute axons to this tract, form complex synaptic arrangements that could mediate these controls and the interactions among physiologically distinct cutaneous afferents (Willis and Coggeshall, 1978;Maxwell and Rethelyi, 1987;Hayes and Carlton, 1992).…”

Section: Neural Mechanismsmentioning

confidence: 99%

Afferent Modulation of Warmth Sensation and Heat Pain in the Human Hand

Casey

Zumberg

Heslep

et al. 1993

Somatosensory & Motor Research

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The hands of 14 normal humans were used to determine the somatotopic organization of the modulation of warmth sensation and heat pain by different forms of cutaneous stimuli. Test stimuli were 5-sec heat pulses ranging from 36 degrees to 51 degrees C, delivered to the fingerpads of digits 1, 2, 4, and 5 with a contact thermode. Conditioning stimuli (15 sec) bracketed the test stimuli and included vibration, noxious and innocuous heat, cold, and electrical pulses delivered to the fingerpads of digits that were adjacent or nonadjacent to the tested digits. Noxious (48 degrees +/- 1.3 degrees C), but not innocuous (43 degrees C), heat stimuli increased the perceived magnitude estimation of innocuous test stimuli (36-43 degrees C) by 20-37% when delivered to adjacent, but not to nonadjacent, digits. No other conditioning stimuli had any effect on the intensity of warmth perception. In contrast, both noxious and innocuous heat or electrical conditioning reduced the magnitude estimation of noxious (50-51 degrees C), but not innocuous, test pulses by 12-22% when delivered to adjacent digits. Conditioning of nonadjacent digits was significantly less effective. The analgesic effects of noxious and innocuous conditioning were approximately equal. Vibratory (120 Hz, 3.5 microns) and cold (15 degrees C) conditioning stimuli were ineffective. The results are consistent with a dermatomal somatotopic organization of tactile and heat modulatory influences on warmth sensation and heat pain. The results further suggest that the neural mechanism subserving warmth mediate a negative feedback influence on heat pain intensity.

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“…The isotropic fractionator technique allows us to quantify the number of cell bodies of neurons and nonneurons in our sample, and thus this study only examines cells in which the soma is contained within the spinal cord. Therefore, the neurons in our data set come from the dorsal, intermediate and ventral horns of the gray matter, which include cells related to interoception, preganglionic autonomic neurons, the motor system, intrinsic spinal systems such as reflex arc neurons and spinal pattern generators, and a portion of the proprioceptive inputs from the body [Willis and Coggeshall, 1978]. Thus, cord mass includes a number of fibers, such as those in the corticospinal and dorsal column tracts, whose neuronal cell nuclei are not included, as their soma are located in the cortex and dorsal root ganglia, respectively.…”

Section: Spinal Cord Nonneuronal Scaling Rulesmentioning

confidence: 99%

Cellular Scaling Rules for Primate Spinal Cords

Burish¹,

Peebles²,

Baldwin³

et al. 2010

Brain Behav Evol

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The spinal cord can be considered a major sensorimotor interface between the body and the brain. How does the spinal cord scale with body and brain mass, and how are its numbers of neurons related to the number of neurons in the brain across species of different body and brain sizes? Here we determine the cellular composition of the spinal cord in eight primate species and find that its number of neurons varies as a linear function of cord length, and accompanies body mass raised to an exponent close to 1/3. This relationship suggests that the extension, mass and number of neurons that compose the spinal cord are related to body length, rather than to body mass or surface. Moreover, we show that although brain mass increases linearly with cord mass, the number of neurons in the brain increases with the number of neurons in the spinal cord raised to the power of 1.7. This faster addition of neurons to the brain than to the spinal cord is consistent with current views on how larger brains add complexity to the processing of environmental and somatic information.

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Sensory Mechanisms of the Spinal Cord

Cited by 578 publications

References 0 publications

The somatosensory thalamus of the raccoon: properties of single neurons responsive to light mechanical stimulation of the forepaw

The somatosensory thalamus of the raccoon: properties of single neurons responsive to light mechanical stimulation of the forepaw

Afferent Modulation of Warmth Sensation and Heat Pain in the Human Hand

Cellular Scaling Rules for Primate Spinal Cords

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