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Duck O. Kim - One of the best experts on this subject based on the ideXlab platform.
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Projection of the marginal shell of the Anteroventral Cochlear Nucleus to olivoCochlear neurons in the cat.
The Journal of comparative neurology, 2000Co-Authors: D.g. Machado, Duck O. KimAbstract:The marginal shell of the Anteroventral Cochlear Nucleus is anatomically and physiologically different from its central core. Previous studies suggest that neurons in the marginal shell are well suited to encode the intensity of acoustic stimuli. To investigate the projections of the marginal shell, a focal injection (
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Marginal shell of the Anteroventral Cochlear Nucleus: single-unit response properties in the unanesthetized decerebrate cat.
Journal of neurophysiology, 1997Co-Authors: S. Ghoshal, Duck O. KimAbstract:Ghoshal, S. and D. O. Kim. Marginal shell of the Anteroventral Cochlear Nucleus: single-unit response properties in the unanesthetized decerebrate cat. J. Neurophysiol. 77: 2083–2097, 1997. The mar...
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Marginal shell of the Anteroventral Cochlear Nucleus: intensity coding in single units of the unanesthetized, decerebrate cat
Neuroscience letters, 1996Co-Authors: S. Ghoshal, Duck O. KimAbstract:Single units were recorded in the marginal shell (38 units in 10 cats) and central core (62 units in 15 cats) of the Anteroventral Cochlear Nucleus (AVCN) in unanesthetized decerebrate cats. The recording sites of the shell units were verified in reconstructed electrode tracks, and those of the core units were verified for 18 units and based on the recording depth for 44 units. There was a substantial presence of strongly driven units in the AVCN shell exhibiting non-saturating rate-level functions to pure tone, noise or both with dynamic ranges as wide as 89 dB. This finding supports a hypothesis that the AVCN shell may play a role in encoding acoustic stimulus intensity. The AVCN shell and core populations were different as follows. The shell population had more units which had wide dynamic ranges, low spontaneous rates (SRs) or were acoustically weakly or not driven than the core population. These differences were statistically significant (P < 0.001, Fisher's exact test).
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Marginal Shell of the Anteroventral Cochlear Nucleus: Acoustically Weakly-Driven and Not-Driven Units in the Unanesthetized Decerebrate Cat
Acta oto-laryngologica, 1996Co-Authors: S. Ghoshal, Duck O. KimAbstract:The ventral Cochlear Nucleus (VCN) of the cat is encapsulated by a marginal shell which is anatomically distinct from the central core of the VCN. Physiologically, little is known about the marginal shell. We report here a new finding that the marginal shell of the Anteroventral Cochlear Nucleus (AVCN) in the unanesthetized decerebrate cat contains neural units which were weakly driven or not driven acoustically. The locations of the single units were histologically determined. Our observations also included other neural units of the marginal shell which were strongly driven acoustically; the latter results will be reported separately. The present physiological findings, together with previous anatomical findings of vestibular and somatosensory inputs to the AVCN marginal shell, suggest that some neurons of the AVCN marginal shell receive non-auditory sensory inputs besides weak auditory inputs and that these may play a role in multi-sensory processing.
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Small neurons in the vestibular nerve root project to the marginal shell of the Anteroventral Cochlear Nucleus in the cat
Brain Research, 1995Co-Authors: H B Zhao, S. Ghoshal, K Parham, Duck O. KimAbstract:Abstract We injected biotinylated dextran amine (BDA) into marginal shell regions of the Anteroventral Cochlear Nucleus (AVCN) of the cat. These injections led to retrograde labeling of cells including small cells (median soma area = 111 μm 2 , equivalent diameter = 11.9 μm) in the vestibular nerve root (VNR), just ventral to an anterior part of the AVCN. This is an unexpected new finding. The cells were scattered among BDA-labeled fibers and were oriented parallel to the course of the VNR fibers. We suggest that the small neurons of the VNR might serve as second-order vestibular neurons conveying information from vestibular end organs to the Cochlear Nucleus (CN) and/or act as interneurons between the olivoCochlear fibers in the VNR and the CN.
S. Ghoshal - One of the best experts on this subject based on the ideXlab platform.
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Marginal shell of the Anteroventral Cochlear Nucleus: single-unit response properties in the unanesthetized decerebrate cat.
Journal of neurophysiology, 1997Co-Authors: S. Ghoshal, Duck O. KimAbstract:Ghoshal, S. and D. O. Kim. Marginal shell of the Anteroventral Cochlear Nucleus: single-unit response properties in the unanesthetized decerebrate cat. J. Neurophysiol. 77: 2083–2097, 1997. The mar...
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marginal shell of the Anteroventral Cochlear Nucleus single unit response properties in the unanesthetized decerebrate cat
Journal of Neurophysiology, 1997Co-Authors: S. Ghoshal, D O KimAbstract:The marginal shell of the Anteroventral Cochlear Nucleus (AVCN) is anatomically different from its central core. We investigated 38 single units in the shells of 10 cats and contrasted them with 62 single units in the cores of 15 cats. The sites of all shell units were localized with the use of reconstructed electrode tracks. The shell units were divided into acoustically well-driven (68%) and weakly/not-driven (32%) subgroups. The shell units mostly exhibited low spontaneous rates (SRs). Among the well-driven shell units, a large majority (68%) exhibited wide dynamic ranges (> or = 50 dB) to tones, noise, or both, with some ranges as wide as 89 dB. In contrast, a large majority (80%) of the core units exhibited narrow dynamic ranges (< 50 dB) to tones and noise. The poststimulus time histograms (PSTHs) of the well-driven shell units included pause-build (29%), onset (24%), and unusual (33%) types, whereas those of the core units included mainly primary-like (47%) and chopper (29%) types. The excitatory-inhibitory areas (EIAs) of the well-driven shell units included types I/III (47%), III (22%), IV (13%), and II (9%), whereas those of the core units included mainly types III (52%) and I/III (32%). On the basis of Fisher's exact tests, we conclude that the shell and core neural groups of the AVCN are significantly different regarding all of the following physiological characteristics: SR, maximum driven rate, threshold and dynamic range to tones and noise, frequency response area, PSTH type, latency, and EIA type. Wide dynamic ranges of the well-driven shell units suggest that they may play a role in encoding absolute intensity of acoustic stimulus.
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Marginal shell of the Anteroventral Cochlear Nucleus: intensity coding in single units of the unanesthetized, decerebrate cat
Neuroscience letters, 1996Co-Authors: S. Ghoshal, Duck O. KimAbstract:Single units were recorded in the marginal shell (38 units in 10 cats) and central core (62 units in 15 cats) of the Anteroventral Cochlear Nucleus (AVCN) in unanesthetized decerebrate cats. The recording sites of the shell units were verified in reconstructed electrode tracks, and those of the core units were verified for 18 units and based on the recording depth for 44 units. There was a substantial presence of strongly driven units in the AVCN shell exhibiting non-saturating rate-level functions to pure tone, noise or both with dynamic ranges as wide as 89 dB. This finding supports a hypothesis that the AVCN shell may play a role in encoding acoustic stimulus intensity. The AVCN shell and core populations were different as follows. The shell population had more units which had wide dynamic ranges, low spontaneous rates (SRs) or were acoustically weakly or not driven than the core population. These differences were statistically significant (P < 0.001, Fisher's exact test).
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Marginal Shell of the Anteroventral Cochlear Nucleus: Acoustically Weakly-Driven and Not-Driven Units in the Unanesthetized Decerebrate Cat
Acta oto-laryngologica, 1996Co-Authors: S. Ghoshal, Duck O. KimAbstract:The ventral Cochlear Nucleus (VCN) of the cat is encapsulated by a marginal shell which is anatomically distinct from the central core of the VCN. Physiologically, little is known about the marginal shell. We report here a new finding that the marginal shell of the Anteroventral Cochlear Nucleus (AVCN) in the unanesthetized decerebrate cat contains neural units which were weakly driven or not driven acoustically. The locations of the single units were histologically determined. Our observations also included other neural units of the marginal shell which were strongly driven acoustically; the latter results will be reported separately. The present physiological findings, together with previous anatomical findings of vestibular and somatosensory inputs to the AVCN marginal shell, suggest that some neurons of the AVCN marginal shell receive non-auditory sensory inputs besides weak auditory inputs and that these may play a role in multi-sensory processing.
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Small neurons in the vestibular nerve root project to the marginal shell of the Anteroventral Cochlear Nucleus in the cat.
Brain research, 1995Co-Authors: H B Zhao, S. Ghoshal, K Parham, D O KimAbstract:We injected biotinylated dextran amine (BDA) into marginal shell regions of the Anteroventral Cochlear Nucleus (AVCN) of the cat. These injections led to retrograde labeling of cells including small cells (median some area = 111 micron2, equivalent diameter = 11.9 microns) in the vestibular nerve root (VNR), just ventral to an anterior part of the AVCN. This is an unexpected new finding. The cells were scattered among BDA-labeled fibers and were oriented parallel to the course of the VNR fibers. We suggest that the small neurons of the VNR might serve as second-order vestibular neurons conveying information from vestibular end organs to the Cochlear Nucleus (CN) and/or act as interneurons between the olivoCochlear fibers in the VNR and the CN.
D O Kim - One of the best experts on this subject based on the ideXlab platform.
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projection of the marginal shell of the Anteroventral Cochlear Nucleus to olivoCochlear neurons in the cat
The Journal of Comparative Neurology, 2000Co-Authors: D.g. Machado, D O KimAbstract:The marginal shell of the Anteroventral Cochlear Nucleus is anatomically and physiologically different from its central core. Previous studies suggest that neurons in the marginal shell are well suited to encode the intensity of acoustic stimuli. To investigate the projections of the marginal shell, a focal injection (<100 nl) of a mixture of biotinylated dextran amine (BDA) and (3)H-leucine was made into the marginal shell of the cat combined with injection of cholera toxin subunit-B (CTB) into the cochleas. Following a 7-day survival, the cats were perfused. Axons and swellings labeled with BDA and olivoCochlear neurons labeled with CTB were immunocytochemically stained black and brown, respectively. (3)H-leucine labels were visualized by autoradiography. Labeled neural structures were examined via light microscopy. We found that swellings labeled with BDA, sometimes doubly labeled with BDA and (3)H-leucine, were in close apposition with dendrites and/or somata of olivoCochlear neurons identified with CTB labeling. Double labeling with BDA and (3)H-leucine signifies that the label was anterogradely transported. The results support the conclusion that the Anteroventral Cochlear Nucleus projects to medial olivoCochlear neurons bilaterally and to lateral olivoCochlear neurons ipsilaterally. Furthermore, the results are consistent with the interpretation that the marginal shell provides a source of the above-mentioned projections. Together with information in the literature, the present anatomical results support a hypothesis that the marginal shell provides information about stimulus intensity as a part of a reflex (or feedback gain control) system comprising the cochlea, Cochlear neurons, Cochlear Nucleus, medial olivoCochlear neurons, and Cochlear outer hair cells.
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marginal shell of the Anteroventral Cochlear Nucleus single unit response properties in the unanesthetized decerebrate cat
Journal of Neurophysiology, 1997Co-Authors: S. Ghoshal, D O KimAbstract:The marginal shell of the Anteroventral Cochlear Nucleus (AVCN) is anatomically different from its central core. We investigated 38 single units in the shells of 10 cats and contrasted them with 62 single units in the cores of 15 cats. The sites of all shell units were localized with the use of reconstructed electrode tracks. The shell units were divided into acoustically well-driven (68%) and weakly/not-driven (32%) subgroups. The shell units mostly exhibited low spontaneous rates (SRs). Among the well-driven shell units, a large majority (68%) exhibited wide dynamic ranges (> or = 50 dB) to tones, noise, or both, with some ranges as wide as 89 dB. In contrast, a large majority (80%) of the core units exhibited narrow dynamic ranges (< 50 dB) to tones and noise. The poststimulus time histograms (PSTHs) of the well-driven shell units included pause-build (29%), onset (24%), and unusual (33%) types, whereas those of the core units included mainly primary-like (47%) and chopper (29%) types. The excitatory-inhibitory areas (EIAs) of the well-driven shell units included types I/III (47%), III (22%), IV (13%), and II (9%), whereas those of the core units included mainly types III (52%) and I/III (32%). On the basis of Fisher's exact tests, we conclude that the shell and core neural groups of the AVCN are significantly different regarding all of the following physiological characteristics: SR, maximum driven rate, threshold and dynamic range to tones and noise, frequency response area, PSTH type, latency, and EIA type. Wide dynamic ranges of the well-driven shell units suggest that they may play a role in encoding absolute intensity of acoustic stimulus.
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Small neurons in the vestibular nerve root project to the marginal shell of the Anteroventral Cochlear Nucleus in the cat.
Brain research, 1995Co-Authors: H B Zhao, S. Ghoshal, K Parham, D O KimAbstract:We injected biotinylated dextran amine (BDA) into marginal shell regions of the Anteroventral Cochlear Nucleus (AVCN) of the cat. These injections led to retrograde labeling of cells including small cells (median some area = 111 micron2, equivalent diameter = 11.9 microns) in the vestibular nerve root (VNR), just ventral to an anterior part of the AVCN. This is an unexpected new finding. The cells were scattered among BDA-labeled fibers and were oriented parallel to the course of the VNR fibers. We suggest that the small neurons of the VNR might serve as second-order vestibular neurons conveying information from vestibular end organs to the Cochlear Nucleus (CN) and/or act as interneurons between the olivoCochlear fibers in the VNR and the CN.
M B Sachs - One of the best experts on this subject based on the ideXlab platform.
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The functional role of excitatory and inhibitory interactions in chopper cells of the Anteroventral Cochlear Nucleus
Neural Computation, 1994Co-Authors: Ying-cheng Lai, Raimond L. Winslow, M B SachsAbstract:Chopper cells in the Anteroventral Cochlear Nucleus of the cat maintain a robust rate-place representation of vowel spectra over a broad range of stimulus levels. This representation resembles that of low threshold, high spontaneous rate primary auditory nerve fibers at low stimulus levels, and that of high threshold, low spontaneous rate auditory-nerve fibers at high stimulus levels. This has led to the hypothesis that chopper cells in the Anteroventral Cochlear Nucleus selectively process inputs from different spontaneous rate populations of primary auditory-nerve fibers at different stimulus levels. We present a computational model, making use of shunting inhibition, for how this level dependent processing may be performed within the chopper cell dendritic tree. We show that this model (1) implements level-dependent selective processing, (2) reproduces detailed features of real chopper cell post-stimulus-time histograms, and (3) reproduces nonmonotonic rate versus level functions in response to single tones measured.
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Neural encoding of single-formant stimuli in the cat. II. Responses of Anteroventral Cochlear Nucleus units
Journal of neurophysiology, 1994Co-Authors: Xiaoqin Wang, M B SachsAbstract:1. We have studied responses of Anteroventral Cochlear Nucleus (AVCN) units to single-formant stimuli (SFS), in an effort to make quantitative comparisons with responses observed in auditory-nerve ...
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Coding of envelope modulation in the auditory nerve and Anteroventral Cochlear Nucleus.
Philosophical transactions of the Royal Society of London. Series B Biological sciences, 1992Co-Authors: Xiaoqin Wang, M B SachsAbstract:We have investigated responses of the auditory nerve fibres (ANFS) and Anteroventral Cochlear Nucleus (AVCN) units to narrowband `single-formant' stimuli (SFSS). We found that low and medium spontaneous rate (SR) ANFS maintain greater amplitude modulation (AM) in their responses at high sound levels than do high SR units when sound level is considered in dB SPL. However, this partitioning of high and low SR units disappears if sound level is considered in dB relative to unit threshold. Stimuli with carrier frequencies away from unit best frequency (BF) were found to generate higher AM in responses at high sound levels than that observed even in most low and medium SR units for stimuli with carrier frequencies near BF. AVCN units were shown to have increased modulation depth in their responses when compared with high SR ANFS with similar BFS and to have increased or comparable modulation depth when compared with low SR ANFS. At sound levels where AM almost completely disappears in high SR ANFS, most AVCN units we studied still show significant AM in their responses. Using a dendritic model, we investigated possible mechanisms of enhanced AM in AVCN units, including the convergence of inputs from different SR groups of ANFS and a postsynaptic threshold mechanism in the soma.
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regularity analysis in a compartmental model of chopper units in the Anteroventral Cochlear Nucleus
Journal of Neurophysiology, 1991Co-Authors: Matthew I Banks, M B SachsAbstract:1. We investigate the discharge patterns of chopper units in the Anteroventral Cochlear Nucleus (AVCN) by developing an equivalent cylinder compartmental model of AVCN stellate cells, which are the...
H B Zhao - One of the best experts on this subject based on the ideXlab platform.
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Small neurons in the vestibular nerve root project to the marginal shell of the Anteroventral Cochlear Nucleus in the cat.
Brain research, 1995Co-Authors: H B Zhao, S. Ghoshal, K Parham, D O KimAbstract:We injected biotinylated dextran amine (BDA) into marginal shell regions of the Anteroventral Cochlear Nucleus (AVCN) of the cat. These injections led to retrograde labeling of cells including small cells (median some area = 111 micron2, equivalent diameter = 11.9 microns) in the vestibular nerve root (VNR), just ventral to an anterior part of the AVCN. This is an unexpected new finding. The cells were scattered among BDA-labeled fibers and were oriented parallel to the course of the VNR fibers. We suggest that the small neurons of the VNR might serve as second-order vestibular neurons conveying information from vestibular end organs to the Cochlear Nucleus (CN) and/or act as interneurons between the olivoCochlear fibers in the VNR and the CN.
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Small neurons in the vestibular nerve root project to the marginal shell of the Anteroventral Cochlear Nucleus in the cat
Brain Research, 1995Co-Authors: H B Zhao, S. Ghoshal, K Parham, Duck O. KimAbstract:Abstract We injected biotinylated dextran amine (BDA) into marginal shell regions of the Anteroventral Cochlear Nucleus (AVCN) of the cat. These injections led to retrograde labeling of cells including small cells (median soma area = 111 μm 2 , equivalent diameter = 11.9 μm) in the vestibular nerve root (VNR), just ventral to an anterior part of the AVCN. This is an unexpected new finding. The cells were scattered among BDA-labeled fibers and were oriented parallel to the course of the VNR fibers. We suggest that the small neurons of the VNR might serve as second-order vestibular neurons conveying information from vestibular end organs to the Cochlear Nucleus (CN) and/or act as interneurons between the olivoCochlear fibers in the VNR and the CN.