Cat hindlimb tactile dermatomes determined with single-unit recordings

1. Single-unit recording from dorsal root ganglia was used to determine the dermatomes of L4-S2 segments in the cat. Dermatomes for low-threshold myelinated mechanoreceptor afferents are smaller than those reported in earlier studies of whole-root dermatomes. There are also sufficient discrepancies among earlier studies and with the present data to merit reexamination of hindlimb whole-root dermatomes. 2. Receptive-field size varies directly with distance from toes. Length/width ratio is essentially constant for different parts of the hindlimb. 3. Estimates of innervation density verify the long-standing assumption that innervation density is greater for foot and toes than for proximal hindlimb, at least for low-threshold cutaneous myelinated afferents.

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Organization and receptive fields of primate spinothalamic tract neurons

Journal of Neurophysiology ◽

10.1152/jn.1975.38.3.572 ◽

1975 ◽

Vol 38 (3) ◽

pp. 572-586 ◽

Cited By ~ 94

Author(s):

A. E. Applebaum ◽

J. E. Beall ◽

R. D. Foreman ◽

W. D. Willis

Keyword(s):

Receptive Field ◽

Receptive Fields ◽

Ventral Surface ◽

Field Size ◽

Width Ratio ◽

High Threshold ◽

Spinothalamic Tract ◽

Dorsal Funiculus ◽

Length Width ◽

Low Threshold

A technique is described for recording from axons belonging to the spinothalamic tract of the monkey. The axons arose from cell bodies located within the spinal cord since the latency of orthodromic activation by afferents within the dorsal funiculus was short. The axons were antidromically activated from the ipsilateral diencephalon. The spectrum of conduction velocities indicates that the recordings favored large-diamter axons. However, all of the classes of spinothalamic tract units described from soma-dendritic recordings were represented in the sample. When the locations of the axons in the ventrolateral white matter were mapped, there was virtually complete overlap in the distributions of hair-activated, low-, and high-threshold spinothalamic tract axons, suggesting that the "lateral spinothalamic tract" conveys tactile, as well as pain and temperature, information. The only segregated population of axons were those belonging to units activated by receptors in deep tissues, including muscle. These were in a band along the ventral surface of the cord. The stimulus points for antidromically activating spinothalamic cells of axons were in the known diencephalic course of the spinothalamic tract, including the ventral posterior lateral nucleus. Stimulus point locations were similar for high-threshold and other categories of units. Receptive-field sizes were smaller for high-threshold spinothalamic cells or axons than for hair-activated or low-threshold units. Receptive-field size was correlated with position on the hindlimb. The smallest fields belonged to cells in lamina I, with progressively larger sizes for cells in laminae IV and V. Receptive-field shape was evaluated by the length/width ratio, which was smallest for high-threshold units and progressively larger for low-threshold and hair-activated units. The receptive-field positions of spinothalamic tract axons were related to the locations of the axons. There was a rough somatotopic representation in the tract, with the most caudal dermatomes represented dorsolaterally, and the most rostral ventromedially.

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Single Units and Sensation: 25 Years on

Perception ◽

10.1068/v970016 ◽

1997 ◽

Vol 26 (1_suppl) ◽

pp. 230-230

Author(s):

B Lee

Keyword(s):

Visual System ◽

Single Unit ◽

Single Units ◽

Single Unit Recording ◽

Unit Recording ◽

Visual Neuroscience ◽

Neurophysiological Data ◽

20Th Anniversary ◽

Single Unit Recordings ◽

Perceptual Psychology

In 1972 Horace Barlow (“Single units and sensation: a neuron doctrine for perceptual psychology?” Perception1 371 – 394) proposed a set of dogmas to guide vision scientists in interpreting neurophysiological data. The 20th anniversary of ECVP is an appropriate occasion to ask if single-unit recordings have really helped us understand the visual system. The answer may be affirmative, but interpreting single-unit data has proved to be much more of a challenge than was anticipated in that early and optimistic era of single-unit recording. I review data from retinal and cortical experiments to illustrate this thesis, and ask if Barlow's dogmas are still relevant to current visual neuroscience.

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Faculty Opinions recommendation of In vivo visualization of single-unit recording sites using MRI-detectable elgiloy deposit marking.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.9957958.10693054 ◽

2011 ◽

Author(s):

Wolf Singer ◽

Sean Lee

Keyword(s):

Single Unit ◽

Single Unit Recording ◽

Unit Recording

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Pressure-clamped single-fiber recording technique: A new recording method for studying sensory receptors

Molecular Pain ◽

10.1177/1744806920927852 ◽

2020 ◽

Vol 16 ◽

pp. 174480692092785 ◽

Cited By ~ 1

Author(s):

Mayumi Sonekatsu ◽

Hiroshi Yamada ◽

Jianguo G Gu

Keyword(s):

Nerve Fiber ◽

Single Unit ◽

Single Fiber ◽

Single Unit Recording ◽

Sensory Receptors ◽

Unit Recording ◽

Recording Technique ◽

C Fibers ◽

Recording Method ◽

Single Nerve

An electrophysiological technique that can record nerve impulses from a single nerve fiber is indispensable for studying modality-specific sensory receptors such as low threshold mechanoreceptors, thermal receptors, and nociceptors. The teased-fiber single-unit recording technique has long been used to resolve impulses that are likely to be from a single nerve fiber. The teased-fiber single-unit recording technique involves tedious nerve separation procedures, causes nerve fiber impairment, and is not a true single-fiber recording method. In the present study, we describe a new and true single-fiber recording technique, the pressure-clamped single-fiber recording method. We have applied this recording technique to mouse whisker hair follicle preparations with attached whisker afferents as well as to skin-nerve preparations made from mouse hindpaw skin and saphenous nerves. This new approach can record impulses from rapidly adapting mechanoreceptors (RA), slowly adapting type 1 mechanoreceptors (SA1), and slowly adapting type 2 mechanoreceptors (SA2) in these tissue preparations. We have also applied the pressure-clamped single-fiber recordings to record impulses on Aβ-fibers, Aδ-fibers, and C-fibers. The pressure-clamped single-fiber recording technique provides a new tool for sensory physiology and pain research.

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