Regularity and latency of units in ventral cochlear nucleus: implications for unit classification and generation of response properties

1988 ◽  
Vol 60 (1) ◽  
pp. 1-29 ◽  
Author(s):  
E. D. Young ◽  
J. M. Robert ◽  
W. P. Shofner
Keyword(s):  
Standard Deviation ◽  
Cochlear Nucleus ◽  
Interspike Interval ◽  
Rate Adaptation ◽  
Stellate Cells ◽  
Instantaneous Rate ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cell ◽  
Low Pass ◽  
The Mean

1. The responses of neurons in the ventral cochlear nucleus (VCN) of decerebrate cats are described with regard to their regularity of discharge and latency. Regularity is measured by estimating the mean and standard deviation of interspike intervals as a function of time during responses to short tone bursts (25 ms). This method extends the usual interspike-interval analysis based on interval histograms by allowing the study of temporal changes in regularity during transient responses. The coefficient of variation (CV), equal to the ratio of standard deviation to mean interspike interval, is used as a measure of irregularity. Latency is measured as the mean and standard deviation of the latency of the first spike in response to short tone bursts, with 1.6-ms rise times. 2. The regularity and latency properties of the usual PST histogram response types are shown. Five major PST response type classes are used: chopper, primary-like, onset, onset-C, and unusual. The presence of a prepotential in a unit's action potentials is also noted; a prepotential implies that the unit is recorded from a bushy cell. 3. Units with chopper PST histograms give the most regular discharge. Three varieties of choppers are found. Chop-S units (regular choppers) have CVs less than 0.35 that are approximately constant during the response; chop-S units show no adaptation of instantaneous rate, as measured by the inverse of the mean interspike interval. Chop-T units have CVs greater than 0.35, show an increase in irregularity during the response and show substantial rate adaptation. Chop-U units have CVs greater than 0.35, show a decrease in irregularity during the response, and show a variety of rate adaptation behaviors, including negative adaptation (an increase in rate during a short-tone response). Irregular choppers (chop-T and chop-U units) rarely have CVs greater than 0.5. Choppers have the longest latencies of VCN units; all three groups have mean latencies at least 1 ms longer than the shortest auditory nerve (AN) fiber mean latencies. 4. Chopper units are recorded from stellate cells in VCN (35, 42). Our results for chopper units suggest a model for stellate cells in which a regularly firing action potential generator is driven by the summation of the AN inputs to the cell, where the summation is low-pass filtered by the membrane capacitance of the cell.(ABSTRACT TRUNCATED AT 400 WORDS)

Classification of unit types in the anteroventral cochlear nucleus: PST histograms and regularity analysis

1989 ◽  
Vol 62 (6) ◽  
pp. 1303-1329 ◽  
Author(s):  
C. C. Blackburn ◽  
M. B. Sachs
Keyword(s):  
Cochlear Nucleus ◽  
Interspike Interval ◽  
Discharge Rate ◽  
Low Frequency ◽  
Initial Response ◽  
Instantaneous Rate ◽  
Anteroventral Cochlear Nucleus ◽  
The Mean ◽  
Spike Latency

1. The responses of neurons in the anteroventral cochlear nucleus (AVCN) of barbiturate-anesthetized cats are characterized with regard to features of their responses to short tone bursts (STBs; 25 ms). A "decision tree" is presented to partition AVCN units on the basis of post-stimulus time histogram (PSTH) shape, first spike latency, and discharge rate and regularity calculated as functions of time during responses to STBs. The major classes of AVCN units (primary-like, primary-like-with-notch, chopper, and onset) have been described previously; in this paper, special attention is given to clarifying and systematizing boundaries between classes. Certain types of "unusual" units that may be confused with units in one of the major classes are also examined. 2. When STBs are presented synchronously (constant phase at onset), PSTHs of responses to very-low-frequency (less than 1.0 kHz) tones are difficult if not impossible to resolve into the classes listed above because all unit types phase-lock to low-frequency tones. However, when STBs are presented asynchronously, the responses of units with low best frequencies can be categorized on the basis of PSTH shape and first spike latency. 3. Primary-like, primary-like-with-notch, and onset units are distinguished primarily on the basis of PSTH shape. These three unit types have comparable minimum first spke latencies and synchronization to tones. One type of "unusual" response poses a particular hazard with respect to the generation of uncontaminated primary-like populations. Such "unusual" units have PSTHs that appear primary-like; these units are, however, distinguished by their unusually long first spike latencies. Unlike primary-like units, these "unusual" units show extremely poor synchronization to tones. 4. Chopper units are defined as having an initial response that is highly regular, resulting in the characteristic multimodal PSTH. "Unusual" units with multimodal PSTHs but whose initial responses are not highly regular (measured by the reproducibility of the initial firing pattern in response to multiple repetitions of a STB) are eliminated from the chopper populations. 5. In barbiturate-anesthetized cats, at least three patterns of chopper response can be distinguished on the basis of temporal patterns of rate and regularity adaptation. "Sustained" choppers show no adaptation of instantaneous rate (measured by the inverse of the mean interspike interval), and their discharge remains highly regular throughout the response. "Transiently adapting" choppers undergo a very rapid (less than 10 ms) decrease in instantaneous rate accompanied by a sharp increase in discharge irregularity.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals A bushy cell network in the rat ventral cochlear nucleus

2009 ◽  
Vol 516 (4) ◽  
pp. 241-263 ◽  
Author(s):  
Ricardo Gómez-Nieto ◽  
María E. Rubio
Keyword(s):  
Cochlear Nucleus ◽  
Cell Network ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cell

Response of forelimb guard hair afferent units to air-jet stimulation of entire receptive field

1980 ◽  
Vol 44 (5) ◽  
pp. 961-978 ◽  
Author(s):  
M. D. Goldfinger ◽  
V. E. Amassian
Keyword(s):  
Standard Deviation ◽  
Receptive Field ◽  
Density Function ◽  
Interspike Interval ◽  
Dead Time ◽  
Single Mode ◽  
Air Jet ◽  
The Mean ◽  
Plateau Level ◽  
Stimulation Of

1. In anesthetized, immobilized cats, individual axonal responses to movement of forelimb G hairs were recorded in the ipsilateral cuneate fasciculus at C1-C2 with a glass-insulated tungsten microelectrode. Several test criteria were used to identify primary afferent axons among the recorded neurons. 2. The output discharge in the parent sensory axon during continuous air-jet stimulation of the entire receptive field was irregular and was usually maintained. Criteria for statistical stability were introduced, permitting an analysis of the response as a stable point process. 3. The main interspike interval during the response to maximal air-jet stimulation ranged in different units from 4 to 100 ms, with a transition zone near 20 ms (50/s) between short and long mean interval units. Long and short mean interval units tended to be related to G2- and G1-type hair receptors, respectively. 4. In both short and long mean interval units, the interspike-interval distribution (IID) had a dead time (usually 2-4 ms), a sigmoidal rising limb, a single mode, and a monotonic falling limb, a single mode, and a monotonic falling limb. In short mean interval units, the decrement of the falling limb was described by a single exponential. 5. The value of the standard deviation of the IID was a little less than that of the mean interval minus dead time, the inequality probably resulting from the finite duration of the rising limb and, in long mean interval units, the nonexponential falling limb. 6. Joint interval analysis revealed that successive intervals were independent except in short mean interval units, where the shortest intervals tended to be followed by intervals shorter than the mean. 7. The expectation density function did not reveal any periods in the output discharge. In short mean interval units, a constant mean (planteau) level was attained after a finite rise time and usually one or more overshooting-undershooting sequences. In long mean interval units, the expectation density function monotonically rose to the plateau level. 8. Reducing the air-jet intensity caused an increase in mean interval of discharge and in standard deviation of the IID and slowed the rise time of the expectation density function to the plateau level. 9. Similarities and differences between the whole-field response to air-jet stimulation and the Poisson process are discussed.

Morphology of physiologically characterised ventral cochlear nucleus stellate cells

2003 ◽  
Vol 153 (4) ◽  
pp. 418-426 ◽  
Author(s):  
A. R. Palmer ◽  
M. N. Wallace ◽  
R. H. Arnott ◽  
T. M. Shackleton
Keyword(s):  
Cochlear Nucleus ◽  
Stellate Cells ◽  
Ventral Cochlear Nucleus

Synaptic Inputs to Stellate Cells in the Ventral Cochlear Nucleus

1998 ◽  
Vol 79 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Michael J. Ferragamo ◽  
Nace L. Golding ◽  
Donata Oertel
Keyword(s):  
Receptor Antagonist ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Stellate Cells ◽  
Nerve Fibers ◽  
Synaptic Inputs ◽  
Ventral Cochlear Nucleus ◽  
Cochlear Nuclei ◽  
Potential Source ◽  
Synaptic Responses

Ferragamo, Michael J., Nace L Golding, and Donata Oertel. Synaptic inputs to stellate cells in the ventral cochlear nucleus. J. Neurophysiol. 79: 51–63, 1998. Auditory information is carried from the cochlear nuclei to the inferior colliculi through six parallel ascending pathways, one of which is through stellate cells of the ventral cochlear nuclei (VCN) through the trapezoid body. To characterize and identify the synaptic influences on T stellate cells, intracellular recordings were made from anatomically identified stellate cells in parasagittal slices of murine cochlear nuclei. Shocks to the auditory nerve consistently evoked five types of synaptic responses in T stellate cells, which reflect sources intrinsic to the cochlear nuclear complex. 1) Monosynaptic excitatory postsynaptic potentials (EPSPs) that were blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX), an antagonist of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, probably reflected activation by auditory nerve fibers. Electrophysiological estimates indicate that about five auditory nerve fibers converge on one T stellate cell. 2) Disynaptic, glycinergic inhibitory postsynaptic potentials (IPSPs) arise through inhibitory interneurons in the VCN or in the dorsal cochlear nucleus (DCN). 3) Slow depolarizations, the source of which has not been identified, that lasted between 0.2 and 1 s and were blocked by dl-2-amino-5-phosphonovaleric acid (APV), the N-methyl-d-aspartate (NMDA) receptor antagonist. 4) Rapid, late glutamatergic EPSPs are polysynaptic and may arise from other T stellate cells. 5) Trains of late glycinergic IPSPs after single or repetitive shocks match the responses of D stellate cells, showing that D stellate cells are one source of glycinergic inhibition to T stellate cells. The source of late, polysynaptic EPSPs and IPSPs was assessed electrophysiologically and pharmacologically. Late synaptic responses in T stellate cells were enhanced by repetitive stimulation, indicating that the interneurons from which they arose should fire trains of action potentials in responses to trains of shocks. Late EPSPs and late IPSPs were blocked by APV and enhanced by the removal of Mg2+, indicating that the interneurons were driven at least in part through NMDA receptors. Bicuculline, a γ-aminobutyric acid-A (GABAA) receptor antagonist, enhanced the late PSPs, indicating that GABAergic inhibition suppresses both the glycinergic interneurons responsible for the trains of IPSPs in T-stellate cells and the interneuron responsible for late EPSPs in T stellate cells. The glycinergic interneurons that mediate the series of IPSPs are intrinsic to the ventral cochlear nucleus because long series of IPSPs were recorded from T stellate cells in slices in which the DCN was removed. These experiments indicate that T stellate cells are a potential source of late EPSPs and that D stellate cells are a potential source for trains of late IPSPs.

Analysis of temporal discharge characteristics of dorsal cochlear nucleus neurons of unanesthetized decerebrate cats

1992 ◽  
Vol 67 (5) ◽  
pp. 1247-1263 ◽  
Author(s):  
K. Parham ◽  
D. O. Kim
Keyword(s):  
Standard Deviation ◽  
Cochlear Nucleus ◽  
Time Window ◽  
Tone Burst ◽  
Dorsal Cochlear Nucleus ◽  
Interspike Intervals ◽  
Discharge Characteristics ◽  
Present Sample ◽  
The Mean ◽  
Decerebrate Cats

1. We examined the mean and standard deviation (SD) of interspike intervals (ISI) and the coefficient of variation (CV, the ratio of SD of ISI to mean ISI) of ISIs versus time to study discharge regularity of units in the dorsal cochlear nucleus (DCN) of decerebrate unanesthetized cats. The units were characterized by the use of both poststimulus time histograms (PSTH) and excitatory-inhibitory area (EI-area) schemes. We present results of a systematic examination of all of 87 DCN pause-build units recorded in this study. In addition, we present examples of chopper subtypes of the DCN. 2. A major finding of this study is that a majority of the pause-build units in the present sample exhibited regular discharges in response to short (50 ms) tone bursts at characteristic frequency (CF), as revealed by CVs less than 0.5. A predominant portion of pause-build units (80% of 44 units with sufficient number of spikes for CV analysis) exhibited mean CVs less than 0.5 in the 20- to 39.9-ms time window in response to 50-ms tone burst at CF at 60 dB SPL re 20 microPa; 39% of the 44 units exhibited highly regular discharges (mean CV less than 0.35). During the onset (2-14.9 ms) time window, 77% (of 53 units with sufficient number of spikes for CV analysis) of the units had mean CVs less than 0.5, and 55% were less than 0.35. 3. In our sample of 87 DCN pause-build units, 59% had spontaneous rates (SR) greater than 15 spikes/s. The pause-build units of the present sample were distributed across four different EI-area types: III (51%), I/III (25%), II (15%), or IV (9%). In the 20- to 39.9-ms time window, the pause-build units with mean CVs less than 0.35 were exclusively of types III and I/III. All of the above EI-area types were represented in the lowest CV group for the 2- to 14.9-ms window. 4. The mean ISIs of DCN pause-build units typically showed a decrease during the first 20-25 ms of the response to 50-ms CF tone bursts, and stable mean ISIs in the latter half, when off-discharges were absent. In the presence of off-discharges, the mean ISIs decreased further in the last 5-10 ms of the response.(ABSTRACT TRUNCATED AT 400 WORDS)

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