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Edwin W. Rubel - One of the best experts on this subject based on the ideXlab platform.
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Tonotopic organization of the superior Olivary Nucleus in the chicken auditory brainstem
The Journal of comparative neurology, 2012Co-Authors: Kathryn M. Tabor, Edwin W. Rubel, William L. Coleman, R. Michael BurgerAbstract:Topographic maps are salient features of neuronal organization in sensory systems. Inhibitory components of neuronal circuitry are often embedded within this organization, making them difficult to isolate experimentally. The auditory system provides opportunities to study the topographic organization of inhibitory long-range projection nuclei, such as the superior Olivary Nucleus (SON). We analyzed the topographic organization of response features of neurons in the SON of chickens. Quantitative methods were developed to assess and communicate this organization. These analyses led to three main conclusions: 1) sound frequency is linearly arranged from dorsal (low frequencies) to ventral (high frequencies) in SON; 2) this tonotopic organization is less precise than the organization of the excitatory nuclei in the chicken auditory brainstem; and 3) neurons with different response patterns to pure tone stimuli are interspersed throughout the SON and show similar tonotopic organizations. This work provides a predictive model to determine the optimal stimulus frequency for a neuron from its spatial location in the SON.
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Topography and morphology of the inhibitory projection from superior Olivary Nucleus to Nucleus laminaris in chickens (Gallus gallus).
The Journal of comparative neurology, 2010Co-Authors: Kathryn M. Tabor, Rachel O.l. Wong, Edwin W. RubelAbstract:The avian Nucleus laminaris (NL) is involved in computation of interaural time differences (ITDs) that encode the azimuthal position of a sound source. Neurons in NL are bipolar, with dorsal and ventral dendritic arbors receiving input from separate ears. NL neurons act as coincidence detectors that respond maximally when input from each ear arrives at the two dendritic arbors simultaneously. Computational and physiological studies demonstrated that the sensitivity of NL neurons to coincident inputs is modulated by an inhibitory feedback circuit via the superior Olivary Nucleus (SON). To understand the mechanism of this modulation, the topography of the projection from SON to NL was mapped, and the morphology of the axon terminals of SON neurons in NL was examined in chickens (Gallus gallus). In vivo injection of AlexaFluor 568 dextran amine into SON demonstrated a coarse topographic projection from SON to NL. Retrogradely labeled neurons in NL were located within the zone of anterogradely labeled terminals, suggesting a reciprocal projection from SON to NL. In vivo extracellular physiological recording further demonstrated that this topography is consistent with tonotopic maps in SON and NL. In addition, three-dimensional reconstruction of single SON axon branches within NL revealed that individual SON neurons innervate a large area of NL and terminate on both dorsal and ventral dendritic arbors of NL neurons. The organization of the projection from SON to NL supports its proposed functions of controlling the overall activity level of NL and enhancing the specificity of frequency mapping and ITD detection.
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Avian superior Olivary Nucleus provides divergent inhibitory input to parallel auditory pathways.
The Journal of comparative neurology, 2005Co-Authors: R. Michael Burger, Karina S. Cramer, Joshua D. Pfeiffer, Edwin W. RubelAbstract:The avian auditory brainstem displays parallel processing, a fundamental feature of vertebrate sensory systems. Nuclei specialized for temporal processing are largely separate from those processing other aspects of sound. One possible exception to this parallel organi- zation is the inhibitory input provided by the superior Olivary Nucleus (SON) to Nucleus angularis (NA), Nucleus magnocellularis (NM), and Nucleus laminaris (NL) and contralateral SON (SONc). We sought to determine whether single SON neurons project to multiple targets or separate neuronal populations project independently to individual target nuclei. We introduced two different fluorescent tracer molecules into pairs of target nuclei and quanti- fied the extent to which retrogradely labeled SON neurons were double labeled. A large proportion of double-labeled SON somata were observed in all cases in which injections were made into any pair of ipsilateral targets (NA and NM, NA and NL, or NM and NL), suggesting that many individual SON neurons project to multiple targets. In contrast, when injections involved the SONc and any or all of the ipsilateral targets, double labeling was rare, suggesting that contralateral and ipsilateral targets are innervated by distinct popu- lations of SON neurons arising largely from regionally segregated areas of SON. Therefore, at the earliest stages of auditory processing, there is interaction between pathways special- ized to process temporal cues and those that process other acoustic features. We present a conceptual model that incorporates these results and suggest that SON circuitry, in part, functions to offset interaural intensity differences in interaural time difference processing.
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The Superior Olivary Nucleus and Its Influence on Nucleus Laminaris: A Source of Inhibitory Feedback for Coincidence Detection in the Avian Auditory Brainstem
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1999Co-Authors: Lichuan Yang, Pablo Monsivais, Edwin W. RubelAbstract:Located in the ventrolateral region of the avian brainstem, the superior Olivary Nucleus (SON) receives inputs from Nucleus angularis (NA) and Nucleus laminaris (NL) and projects back to NA, NL, and Nucleus magnocellularis (NM). The reciprocal connections between the SON and NL are of particular interest because they constitute a feedback circuit for coincidence detection. In the present study, the chick SON was investigated. In vivo tracing studies show that the SON projects predominantly to the ipsilateral NM, NL, and NA. In vitro whole-cell recording reveals single-cell morphology, firing properties, and postsynaptic responses. SON neurons are morphologically and physiologically suited for temporal integration; their firing patterns do not reflect the temporal structure of their excitatory inputs. Of most interest, direct stimulation of the SON evokes long-lasting inhibition in NL neurons. The inhibition blocks both intrinsic spike generation and orthodromically evoked activity in NL neurons and can be eliminated by bicuculline methiodide, a potent antagonist for GABA A receptor-mediated neurotransmission. These results strongly suggest that the SON provides GABAergic inhibitory feedback to laminaris neurons. We discuss a mechanism whereby SON-evoked GABAergic inhibition can influence the coding of interaural time differences for sound localization in the avian auditory brainstem.
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The superior Olivary Nucleus and its influence on Nucleus laminaris: a source of inhibitory feedback for coincidence detection in the avian auditory brainstem
1999Co-Authors: Lichuan Yang, Pablo Monsivais, Edwin W. RubelAbstract:Located in the ventrolateral region of the avian brainstem, the superior Olivary Nucleus (SON) receives inputs from Nucleus angularis (NA) and Nucleus laminaris (NL) and projects back to NA, NL, and Nucleus magnocellularis (NM). The reciprocal connections between the SON and NL are of particular interest because they constitute a feedback circuit for coincidence detection. In the present study, the chick SON was investigated. In vivo tracing studies show that the SON projects predominantly to the ipsilateral NM, NL, and NA. In vitro wholecell recording reveals single-cell morphology, firing properties, and postsynaptic responses. SON neurons are morphologically and physiologically suited for temporal integration; their firing patterns do not reflect the temporal structure of their excitatory inputs. Of most interest, direct stimulation of the SON evokes long-lasting inhibition in NL neurons. The inhibition blocks both intrinsic spike generation and orthodromically evoked activity in NL neurons and can be eliminated by bicuculline methiodide, a potent antagonist for GABA A receptor-mediated neurotransmission. These results strongly suggest that the SON provides GABAergic inhibitory feedback to laminaris neurons. We discuss a mechanism whereby SON-evoked GABAergic inhibition can influence the coding of interaural time differences for sound localization in the avian auditory brainstem. Key words: avian superior Olivary Nucleus; GABAergic inhibition; coincidence detection; Nucleus laminaris; membrane conductance; shunting effect In the avian auditory brainstem there are four primary nuclei for acoustic processing. Nucleus magnocellularis (NM) and Nucleus angularis (NA) receive direct excitatory inputs from the auditor
Anna Maria Lavezzi - One of the best experts on this subject based on the ideXlab platform.
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Neuroanatomical dysmorphology of the medial superior Olivary Nucleus in sudden fetal and infant death
2020Co-Authors: Bradford C Dickerson, Luigi Matturri, Anna Maria LavezziAbstract:This study expands our understanding of the organization of the human caudal pons, providing a morphologic characterization of the medial superior Olivary Nucleus (MSO), component of the superior Olivary complex (SOC) that plays an important role in the processing of acoustic information. We examined victims of sudden unexplained fetal and infant death and controls (n = 75), from 25 gestational weeks to 8 months of postnatal age, by complete autopsy and in-depth autonomic nervous system histological examination, particularly of the MSO Nucleus, the focus of this study. Peculiar cytoarchitectural features of the MSO Nucleus were found in sudden death cases, such as hypoplasia/agenesis and immature hypercellularity, frequently related to dysgenesis of contiguous structures involved in respiratory rhythm-generating circuit, in particular to hypoplasia of the retrotrapezoid and the facial nuclei. We propose the involvement of this Nucleus in more important functions than those related to hearing, as breathing and, more extensively, all the vital activities. Besides, we highlight the fundamental role of the maternal smoking in pregnancy as etiological factor in the dysmorphic neuroanatomical development of the MSO Nucleus. Keywords: sudden infant death syndrome, sudden intrauterine unexplained death syndrome, medial superior Olivary Nucleus, superior Olivary complex, neuropatholog
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Neuroanatomical dysmorphology of the medial superior Olivary Nucleus in sudden fetal and infant death
Frontiers in human neuroscience, 2012Co-Authors: Anna Maria Lavezzi, Luigi MatturriAbstract:This study expands our understanding of the organization of the human caudal pons, providing a morphologic characterization of the medial superior Olivary Nucleus (MSO), component of the superior Olivary complex (SOC) that plays an important role in the processing of acoustic information. We examined victims of sudden unexplained fetal and infant death and controls (n = 75), from 25 gestational weeks to 8 months of postnatal age, by complete autopsy and in-depth autonomic nervous system histological examination, particularly of the MSO Nucleus, the focus of this study. Peculiar cytoarchitectural features of the MSO Nucleus were found in sudden death cases, such as hypoplasia/agenesis and immature hypercellularity, frequently related to dysgenesis of contiguous structures involved in respiratory rhythm-generating circuit, in particular to hypoplasia of the retrotrapezoid and the facial nuclei. We propose the involvement of this Nucleus in more important functions than those related to hearing, as breathing and, more extensively, all the vital activities. Besides, we highlight the fundamental role of the maternal smoking in pregnancy as etiological factor in the dysmorphic neuroanatomical development of the MSO Nucleus.
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study of the brainstem particularly the arcuate Nucleus in sudden infant death syndrome sids and sudden intrauterine unexplained death siud
American Journal of Forensic Medicine and Pathology, 2004Co-Authors: Luigi Matturri, Giulia Ottaviani, Graziella Alfonsi, Marina Crippa, Lino Rossi, Anna Maria LavezziAbstract:Complete examination of the brainstem involves trans- verse serial 5-m sections made throughout the entire brainstem. The number of serial sections varies from 360 in sudden intrauterine unexplained death (SIUD) to 600 in term fetuses to over 1400 sections in sudden infant death syndrome (SIDS) victims. The procedure is not applicable in all histopathological laboratories, owing to the need for additional technical personnel. The simplified procedure allows a remarkable reduction of the number of sections. The brainstem is divided into 3 blocks. The first, cranial block, extends from the border between the medulla oblongata and pons up to the upper pole of the Olivary Nucleus. The second, intermediate block, corresponding to the submedian area of the inferior Olivary Nucleus, has as reference point the obex and extends 2 to 3 mm above and below the obex itself. The third, caudal block, includes the lower pole of the inferior Olivary Nucleus and the lower adjacent area of the medulla oblongata. Examinations of the brainstems from 106 SIDS victims, 30 controls, and 51 stillborns underlined a remarkable variability, particularly of the arcuate Nucleus. The simplified examination of the brainstem makes it possible to eval- uate the structures, examining 3 specific levels, defined by morpho- logic reference points.
Craig K Henkel - One of the best experts on this subject based on the ideXlab platform.
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Organization of the disynaptic pathway from the anteroventral cochlear Nucleus to the lateral superior Olivary Nucleus in the ferret.
Anatomy and embryology, 1999Co-Authors: Craig K Henkel, Mark L. GabrieleAbstract:The medial Nucleus of the trapezoid body (MNTB) is one of three major nuclei of the superior Olivary complex and provides an important inhibitory input from the contralateral ear to the lateral superior Olivary Nucleus (LSO) in the initial binaural pathway for coding interaural intensity differences. The major input to the MNTB from the contralateral anteroventral cochlear Nucleus (AVCN) involves giant, calyx-like endings that have a one-to-one relationship with cells in the MNTB as confirmed in the ferret in this study. The main objective of the present study was to define the subsequent organization of projections from cells receiving these calyx-like endings. Several anatomical tracers (Phaseolus vulgaris leucoagglutinin, dextran-biotin, and biocytin) were used that are transported both anterogradely and retrogradely within neuronal projections in order to define the organization of MNTB connections with the LSO in the adult ferret. Analysis focused on determining the topography in both the transverse and longitudinal planes of the projections. Focal tracer injections in the LSO resulted in retrograde labeling of a long, narrow column of cells in the MNTB. The orientation and location of labeled cells was dependent on the medial-lateral position of the injection site. In the rostral-caudal dimension of MNTB, there was no such topographic relation between the injection site and the position of labeled cells. Labeled cells in the MNTB were distributed more or less evenly in a longitudinal column regardless of whether the injection site was restricted to the rostral, middle or caudal part of the LSO. In keeping with this pattern, tracer injections in the MNTB resulted in bands of labeled axons that distributed endings throughout the rostral-caudal axis of the LSO. These bands or sheets varied in medial-lateral position relative to the location of the injection site, but lacked any such rostral-caudal gradient. Thus, overall the MNTB-LSO projections have a convergent-divergent pattern of organization. While MNTB cells receive singular calyx-like endings from the AVCN, LSO cells receive projections from a long column of cells in the MNTB. Implications for processing interaural intensity differences are discussed.
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calcium binding proteins and gaba reveal spatial segregation of cell types within the developing lateral superior Olivary Nucleus of the ferret
Microscopy Research and Technique, 1998Co-Authors: Craig K Henkel, Judy K BrunsobechtoldAbstract:Chemical characteristics of developing neurons in the superior Olivary complex of the ferret were analyzed using immunohistochemical methods. The present report of calcium-binding proteins in the developing and adult superior Olivary complex shows distinct distribution patterns for parvalbumin, calbindin, and calretinin in the lateral superior Olivary Nucleus (LSO) of the developing ferret that correspond to distribution patterns for different projection cell types and neurotransmitters. In the neonate, there was an initial complementary distribution of calcium-binding proteins between the shell and core of the body of the developing LSO. Parvalbumin and calbindin-immunoreactive cells were present in the shell, whereas calretinin-immunoreactive cells were restricted to the core of the LSO. Gamma amino butyric acid (GABA), but not glycine, immunoreactive cells were distributed similarly in the shell of the LSO in the neonate. There were, in addition, reciprocal medial-to-lateral gradients of parvalbumin and calbindin-immunoreactive cells in the LSO shell of the neonate. These complementary patterns in the LSO were transient, however, and by the end of the second postnatal week, each calcium-binding protein differed markedly in its cellular distribution in the superior olive, including the LSO. GABA-immunoreactive cells also were restricted transiently to the shell of the LSO in neonates. The radial segregation of transient calcium-binding expression in LSO cells was orthogonal to the medial-to-lateral axis in the LSO and, therefore, parallels fibrodendritic layers and presumed isofrequency planes of the LSO. The early postnatal segregation of calcium-binding proteins in the isofrequency axis was congruent with the gradients of contralateral and ipsilateral projection cell types in adult LSO. It seems likely that developmental mechanisms regulate expression of calcium-binding protein and neurotransmitter phenotypes and that these mechanisms operate in development within the isofrequency axis as well as along the tonotopic axis of this auditory Nucleus.
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Axonal morphology in fibrodendritic laminae of the dorsal Nucleus of the lateral lemniscus: afferent projections from the medial superior Olivary Nucleus.
The Journal of comparative neurology, 1997Co-Authors: Craig K HenkelAbstract:The distribution and morphology of axons projecting from the medial superior Olivary Nucleus to the dorsal Nucleus of the lateral lemniscus were studied in the adult cat. Injections of Phaseolus vulgaris-leucoagglutinin, biocytin, or dextran-rhodamine in the medial superior Olivary Nucleus labeled axons that ascended in the lateral lemniscus. Before entering the inferior colliculus, collateral branches of these labeled axons ended in the dorsal Nucleus of the lateral lemniscus in thin, horizontal bands forming laminae that extended throughout the rostral-caudal length of the dorsal Nucleus of the lateral lemniscus. A dorsal-ventral topography was apparent in the position of the lamina with respect to the injection site, but no relation between the rostral-caudal location of labeled endings and the injection site was observed. There was a divergent pattern of connections within the horizontal laminae rather than a point-to-point organization. The terminal branches of the collateral axons exhibited round or oval boutons en passant and terminaux. Individual arbors reconstructed from serial sections distributed varicosities in circumscribed domains that were only a subcomponent of the area of the afferent laminae in which they were distributed. The spatial relationships of axonal domains of several axons labeled from a single injection in the medial superior Olivary Nucleus suggest a mosaic pattern in the laminar connections with the dorsal Nucleus of the lateral lemniscus.
Paul D Gamlin - One of the best experts on this subject based on the ideXlab platform.
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Behavior of luminance neurons in the pretectal Olivary Nucleus during the pupillary near response
Experimental Brain Research, 1996Co-Authors: Hongyu Zhang, Robert J Clarke, Paul D GamlinAbstract:In cats and monkeys, extrastriate visual areas that have been reported to be involved in the near triad of pupilloconstriction, convergence, and accommodation have well-defined projections to the pretectal Olivary Nucleus (PON), the retinorecipient pretectal Nucleus mediating the pupillary light reflex in mammals. We have therefore used alert, behaving primates to investigate the possibility that PON neurons are involved in the pupillary near response in addition to the pupillary light reflex. Single-unit recording revealed that PON luminance neurons significantly increased their firing rate with increases in retinal illumination and the resultant pupilloconstriction. In contrast, their activity did not significantly increase during pupilloconstriction elicited by near viewing. Thus the behavior of PON luminance neurons is appropriate for their participation in the pupillary light reflex, but is inappropriate for any proposed role in the pupillary near response. This result strongly suggests that neurons in the primate PON are solely related to the pupillary light reflex and that the cortical projections to this pretectal Nucleus are related to this reflex and do not play a role in the pupillary near response.
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luminance neurons in the pretectal Olivary Nucleus mediate the pupillary light reflex in the rhesus monkey
Experimental Brain Research, 1995Co-Authors: Paul D Gamlin, Hongyu Zhang, Robert J ClarkeAbstract:In humans and other primates, an increase in luminance in either eye elicits bilateral pupilloconstriction that is essentially equal in both eyes. Current models of the neural substrate for this clinically important light reflex propose that a retinorecipient pretectal Nucleus projects bilaterally to the Edinger-Westphal Nucleus (EW), which contains the parasympathetic, preganglionic neurons controlling pupilloconstriction. Based on single-unit recording studies in anesthetized cats and rats, it has been further suggested that luminance neurons in only one pretectal Nucleus, the pretectal Olivary Nucleus, mediate this reflex. However, to our knowledge, there have been no comparable electrophysiological studies in primates of the pupillary light reflex or the pretectal luminance neurons that mediate this reflex. To address this issue, single-unit recording and electrical microstimulation studies were carried out in the pretectum of alert, trained, rhesus monkeys. These studies demonstrated that the primate pretectum contains luminance neurons with the characteristics appropriate for mediating the pupillary light reflex and that these neurons are located in one retinorecipient pretectal Nucleus, the pretectal Olivary Nucleus. Electrical microstimulation at the site of these neurons often elicited pupilloconstriction. Our results provide clear evidence for the involvement of the pretectum, and more specifically the pretectal Olivary Nucleus, in mediating the pupillary light reflex in primates.
Matthis Synofzik - One of the best experts on this subject based on the ideXlab platform.
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abnormal paraplegin expression in swollen neurites tau and alpha synuclein pathology in a case of hereditary spastic paraplegia spg7 with an ala510val mutation
International Journal of Molecular Sciences, 2015Co-Authors: Dietmar R Thal, Stephan Zuchner, Stephan Gierer, Claudia Schulte, Ludger Schols, Rebecca Schule, Matthis SynofzikAbstract:Mutations in the SPG7 gene are the most frequent cause of autosomal recessive hereditary spastic paraplegias and spastic ataxias. Ala510Val is the most common SPG7 mutation, with a frequency of up to 1% in the general population. Here we report the clinical, genetic, and neuropathological findings in a homozygous Ala510Val SPG7 case with spastic ataxia. Neuron loss with associated gliosis was found in the inferior Olivary Nucleus, the dentate Nucleus of the cerebellum, the substantia nigra and the basal Nucleus of Meynert. Neurofilament and/or paraplegin accumulation was observed in swollen neurites in the cerebellar and cerebral cortex. This case also showed subcortical τ-pathology in an unique distribution pattern largely restricted to the brainstem. α-synuclein containing Lewy bodies (LBs) were observed in the brainstem and the cortex, compatible with a limbic pattern of Braak LB-Disease stage 4. Taken together, this case shows that the spectrum of pathologies in SPG7 can include neuron loss of the dentate Nucleus and the inferior Olivary Nucleus as well as neuritic pathology. The progressive supranuclear palsy-like brainstem predominant pattern of τ pathology and α-synuclein containing Lewy bodies in our SPG7 cases may be either coincidental or related to SPG7 in addition to neuron loss and neuritic pathology.
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abnormal paraplegin expression in swollen neurites τ and α synuclein pathology in a case of hereditary spastic paraplegia spg7 with an ala510val mutation
International Journal of Molecular Sciences, 2015Co-Authors: Dietmar R Thal, Stephan Zuchner, Stephan Gierer, Claudia Schulte, Ludger Schols, Rebecca Schule, Matthis SynofzikAbstract:Mutations in the SPG7 gene are the most frequent cause of autosomal recessive hereditary spastic paraplegias and spastic ataxias. Ala510Val is the most common SPG7 mutation, with a frequency of up to 1% in the general population. Here we report the clinical, genetic, and neuropathological findings in a homozygous Ala510Val SPG7 case with spastic ataxia. Neuron loss with associated gliosis was found in the inferior Olivary Nucleus, the dentate Nucleus of the cerebellum, the substantia nigra and the basal Nucleus of Meynert. Neurofilament and/or paraplegin accumulation was observed in swollen neurites in the cerebellar and cerebral cortex. This case also showed subcortical τ-pathology in an unique distribution pattern largely restricted to the brainstem. α-synuclein containing Lewy bodies (LBs) were observed in the brainstem and the cortex, compatible with a limbic pattern of Braak LB-Disease stage 4. Taken together, this case shows that the spectrum of pathologies in SPG7 can include neuron loss of the dentate Nucleus and the inferior Olivary Nucleus as well as neuritic pathology. The progressive supranuclear palsy-like brainstem predominant pattern of τ pathology and α-synuclein containing Lewy bodies in our SPG7 cases may be either coincidental or related to SPG7 in addition to neuron loss and neuritic pathology.
