The Rôle Played by the Sizes of the Constituent Fibers of a Nerve Trunk in Determining the Form of Its Action Potential Wave

Gasser, Herbert S.; Erlanger, Joseph

doi:10.1152/ajplegacy.1927.80.3.522

Cited by 314 publications

(78 citation statements)

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“…The storage of the preparation in a refrigerator has in itself no detrimental effect, if optimum temperature Fig. 1 A can be easily identified as that occurring in alpha fibres (Gasser & Erlanger, 1927 Fig. 1 Fig.…”

Section: Resultsmentioning

confidence: 99%

The delay and blockage of sensory impulses in the dorsal root ganglion*

Dun¹

1955

The Journal of Physiology

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The aim of the present series of experiments is to try to clarify these controversial issues and to determine whether the dorsal root ganglion modified in any way the passage of sensory impulses. Besides suffering a delay under normal conditions, the sensory impulses are found to be blocked in their passage through the dorsal root ganglion during the early relatively refractory period of the afferent fibres. METHODIn most of the experiments the 9th or 10th dorsal root ganglion of the frog (Hyla aurea, Rana cate8biana and R. pipiens) was used. These ganglia were dissected intact and in continuity with the roots and the trunk. The roots were severed adjacent to the spinal cord. The trunk was either cut prior to its entry into the sciatic plexus, or followed into one or several of the branches of the plexus, e.g. (1) posterior femoral cutaneous nerve, (2) lateral crural cutaneous nerve, (3) tibial nerve, and (4) peroneal nerve (see Ecker, 1881). The fibres of the posterior femoral cutaneous nerve have been found to go mainly to the 10th dorsal root, while those of the lateral crural cutaneous nerve go mainly to the 9th. The preparations were always scrupulously cleaned to remove connective tissue and blood clots. Every effort was made to avoid injury ofthe preparation.In some experiments requiring a small number of nerve fibres the 11th dorsal root ganglion was used. This ganglion is very small, lying on the lateral surface of the columella. As a considerable segment of its nerve trunk is buried in the coccygeal muscle and as its roots are thin and penetrate * Part of the work was carried out in the Department of Physiology, University of Otago Medical School, Dunedin, New Zealand, and has been reported as short communications (J. cell. comp. Physiol. 38, 131-135, 1951).

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Section: Resultsmentioning

confidence: 99%

The delay and blockage of sensory impulses in the dorsal root ganglion*

Dun¹

1955

The Journal of Physiology

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“…Ritchie (1967) suggested that the per-fiber cost of firing was similar for unmyelinated and myelinated axons. He arrived at this conclusion by comparing peraxon oxygen consumption for C fibers, which are unmyelinated, with an estimated value for myelinated axons obtained by dividing the oxygen consumption of whole sciatic nerve (Brink et al, 1952) by the total number of axons (Dunn, 1909;Gasser and Erlanger, 1927). However, anatomical work since that time has established that two-thirds of the axons in adult sciatic nerve are unmyelinated (Jenq et al 1986).…”

Section: Discussionmentioning

confidence: 99%

Functional Trade-Offs in White Matter Axonal Scaling

et al. 2008

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The brains of large mammals have lower rates of metabolism than those of small mammals, but the functional consequences of this scaling are not well understood. An attractive target for analysis is axons, whose size, speed and energy consumption are straightforwardly related. Here we show that from shrews to whales, the composition of white matter shifts from compact, slow-conducting, and energetically expensive unmyelinated axons to large, fast-conducting, and energetically inexpensive myelinated axons. The fastest axons have conduction times of 1-5 ms across the neocortex and Ͻ1 ms from the eye to the brain, suggesting that in select sets of communicating fibers, large brains reduce transmission delays and metabolic firing costs at the expense of increased volume. Delays and potential imprecision in cross-brain conduction times are especially great in unmyelinated axons, which may transmit information via firing rate rather than precise spike timing. In neocortex, axon size distributions can account for the scaling of per-volume metabolic rate and suggest a maximum supportable firing rate, averaged across all axons, of 7 Ϯ 2 Hz. Axon size distributions also account for the scaling of white matter volume with respect to brain size. The heterogeneous white matter composition found in large brains thus reflects a metabolically constrained trade-off that reduces both volume and conduction time.

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“…Classical work from motor neurons and peripheral axons informs our current understanding of action potential initiation and propagation, including effects of myelination and fiber size on conduction properties (Gasser and Erlanger, 1927;Huxley and Stampfli, 1949). On the topic of action potential initiation, intracellular recordings from motor neuron somas and initial segments showed that the action potential waveform, whether driven synaptically or antidromically, contains multiple components.…”

Section: Introductionmentioning

confidence: 99%

Action potential initiation and propagation: Upstream influences on neurotransmission

2009

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Axonal action potentials initiate the cycle of inter-neuronal, synaptic communication that is key to our understanding of nervous system functioning. The field has accumulated vast knowledge of the signature action potential waveform, firing patterns, and underlying channel properties of many cell types, but in most cases this information comes from somatic intracellular/whole-cell recordings, which necessarily measure a mixture of the currents compartmentalized in the soma, dendrites, and axon. Because the axon in many neuron types appears to be the site of lowest threshold for action potential initiation, the channel constellation in the axon is of particular interest. However, the axon is more experimentally inaccessible than the soma or dendrites. Recent studies have developed and applied single-fiber extracellular recording, direct intracellular recording, and optical recording techniques from axons toward understanding the behavior of the axonal action potential. We are starting to understand better how specific channels and other cellular properties shape action potential threshold, waveform, and timing: key elements contributing to downstream transmitter release. From this increased scrutiny emerges a theme of axons with more computational power than in traditional conceptualizations.

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The Rôle Played by the Sizes of the Constituent Fibers of a Nerve Trunk in Determining the Form of Its Action Potential Wave

Cited by 314 publications

References 0 publications

The delay and blockage of sensory impulses in the dorsal root ganglion*

The delay and blockage of sensory impulses in the dorsal root ganglion*

Functional Trade-Offs in White Matter Axonal Scaling

Action potential initiation and propagation: Upstream influences on neurotransmission

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