Anatomy of the eighth nerve: III.—General plan of structure of the primary cochlear nuclei

Nó, R. Lorente de

doi:10.1288/00005537-193304000-00014

Cited by 307 publications

(64 citation statements)

References 6 publications

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“…In mice about 200 octopus cells (23) sample the array of about 12,000 auditory nerve fibers (24). As all auditory nerve fibers have been observed to terminate in the octopus cell area, octopus cells receive on average at least 60 inputs (25,26). However, the number of auditory nerve inputs onto octopus cells may be several times 60 because many auditory nerve fibers probably innervate multiple octopus cells.…”

Section: Projection Of the Auditory Nerve On Octopus Cellsmentioning

confidence: 99%

Detection of synchrony in the activity of auditory nerve fibers by octopus cells of the mammalian cochlear nucleus

Oertel

Bal

Gardner

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

205

251

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The anatomical and biophysical specializations of octopus cells allow them to detect the coincident firing of groups of auditory nerve fibers and to convey the precise timing of that coincidence to their targets. Octopus cells occupy a sharply defined region of the most caudal and dorsal part of the mammalian ventral cochlear nucleus. The dendrites of octopus cells cross the bundle of auditory nerve fibers just proximal to where the fibers leave the ventral and enter the dorsal cochlear nucleus, each octopus cell spanning about one-third of the tonotopic array. Octopus cells are excited by auditory nerve fibers through the activation of rapid, calciumpermeable, ␣-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptors. Synaptic responses are shaped by the unusual biophysical characteristics of octopus cells. Octopus cells have very low input resistances (about 7 M⍀), and short time constants (about 200 sec) as a consequence of the activation at rest of a hyperpolarization-activated mixed-cation conductance and a lowthreshold, depolarization-activated potassium conductance. The low input resistance causes rapid synaptic currents to generate rapid and small synaptic potentials. Summation of small synaptic potentials from many fibers is required to bring an octopus cell to threshold. Not only does the low input resistance make individual excitatory postsynaptic potentials brief so that they must be generated within 1 msec to sum but also the voltage-sensitive conductances of octopus cells prevent firing if the activation of auditory nerve inputs is not sufficiently synchronous and depolarization is not sufficiently rapid. In vivo in cats, octopus cells can fire rapidly and respond with exceptionally well-timed action potentials to periodic, broadband sounds such as clicks. Thus both the anatomical specializations and the biophysical specializations make octopus cells detectors of the coincident firing of their auditory nerve fiber inputs.

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Section: Projection Of the Auditory Nerve On Octopus Cellsmentioning

confidence: 99%

Detection of synchrony in the activity of auditory nerve fibers by octopus cells of the mammalian cochlear nucleus

Oertel

Bal

Gardner

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

205

251

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“…Single fibres of the nerve make synapses in both the dorsal and ventral divisions of the cochlear nuclear complex (Lorente de No, 1933No, , 1981Fekete, Roullier, Liberman & Ryugo, 1984). In vivo, many cells in the ventral cochlear nucleus (VCN) respond to sound with firing patterns that reproduce those recorded from primary afferents (Godfrey, Kiang & Norris, 1975b;Shofner & Young, 1985;Rhode & Smith, 1986b).…”

Section: Introductionmentioning

confidence: 99%

Intrinsic properties of neurones in the dorsal cochlear nucleus of mice, in vitro.

Hirsch

Oertel

1988

The Journal of Physiology

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SUMMARY1. Intracellular recordings were made from the dorsal cochlear nucleus (DCN) in slices of the cochlear nuclear complex. Probably the larger and most frequent cells were impaled.2. The steady-state current-voltage (I-V) properties of all cells impaled were nonlinear. The I-V curve was steepest in the voltage range depolarized from the resting potential and most shallow when the cell was hyperpolarized from rest by more than about 10 mV. Thus, the inwardly rectifying I-V characteristics of cells in the DCN distinguish them from those of ventral cochlear nuclear neurones (Oertel, 1983).3. When depolarized with current, most cells fired trains of large, all-or-none action potentials. The undershoot after single spikes comprised an initial, fast component followed by a second, slower wave. A few cells (15 %) generated bursts of smaller, graded spikes in addition to the large ones.4. Repetitive firing evoked by depolarizing pulses of current was followed by an after-hyperpolarization whose magnitude depended on the strength and duration of the preceding current pulse.5. Blocking the large action potentials with tetrodotoxin (TTX) revealed Ca21-dependent spikes in all cells examined.6. The steady-state I-V relationship became linear in the presence of TTX, suggesting that a persistent Na+ conductance probably mediates the inward rectification seen above the resting potential.7. Muscarine at micromolar concentrations excited cells and increased their input resistance.

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“…The cochlear nucleus is the first central station of the auditory pathway where all of the axons of nerve VIII terminate (Lorente de N6 1933). It is a complex structure consisting of 3 separate nuclei: anteroventral (AVCN), posteroventral (PVCN) and dorsal (DCN).…”

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confidence: 99%

“…The anteroventral nucleus can be subdivided into 3 divisions; anterior (AVCNa), anterior posterior (AVCNap), and posterodorsal (AVCNpd) (Osen 1969). Other investigators have subdivided the cochlear nucleus into even more regions (Lorente de N6 1933;Brawer et al 1974). The outputs of the cochlear nucleus traverse the brain-stem to terminate widely in the auditory brain-stem nuclei (Warr 1982) including the superior olivary complex, the lateral lemniscus, the inferior colliculus, and the contralateral cochlear nucleus (Cant and Gaston 1982).…”

mentioning

confidence: 99%

Auditory brain-stem evoked potentials in cat after kainic acid induced neuronal loss. II. Cochlear nucleus

Zaaroor

Starr

1991

Electroencephalography and Clinical Neurophysiology/Evoked Pote

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Summary Auditory brain-stem potentials (ABRs) were studied in cats for up to 6 weeks after kainic acid had been injected unilaterally into the cochlear nucleus (CN) producing extensive neuronal destruction. The ABR components were labeled by the polarity at the vertex (P, for positive) and their order of appearance (the arabic numerals 1, 2, etc.). Component P1 can be further subdivided into 2 subcomponents, Pla and Plb. The assumed correspondence between the ABR components in cat and man is indicated by providing human Roman numeral designations in parentheses following the feline notation, e.g., P2 (III). To stimulation of the ear ipsilateral to the injection, the ABR changes consisted of a loss of components P2 (III) and P3 (IV), and an attenuation and prolongation of latency of components P4 (V) and P5 (VI). The sustained potential shift from which the components arose was not affected. Wave Pla (I) was also slightly but significantly attenuated compatible with changes of excitability of nerve VIII in the cochlea secondary to cochlear nucleus destruction. Unexpectedly, to stimulation of the ear contralateral to the injection side, waves P2 (III), P3 (IV), and P4 (V) were also attenuated and delayed in latency but to a lesser degree than to stimulation of the ear ipsilateral to the injection. Changes in binaural interaction of the ABR following cochlear nucleus lesions were similar to those produced in normal animals by introducing a temporal delay of the input to one ear. The results of the present set of studies using kainic acid to induce neuronal loss in auditory pathway when combined with prior lesion and recording experiments suggest that each of the components of the ABR requires the integrity of an anatomically diffuse system comprising a set of neurons, their axons, and the neurons on which they terminate. Disruption of any portion of the system will alter the amplitude and/or the latency of that component.

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Anatomy of the eighth nerve: III.—General plan of structure of the primary cochlear nuclei

Cited by 307 publications

References 6 publications

Detection of synchrony in the activity of auditory nerve fibers by octopus cells of the mammalian cochlear nucleus

Detection of synchrony in the activity of auditory nerve fibers by octopus cells of the mammalian cochlear nucleus

Intrinsic properties of neurones in the dorsal cochlear nucleus of mice, in vitro.

Auditory brain-stem evoked potentials in cat after kainic acid induced neuronal loss. II. Cochlear nucleus

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