The Experts below are selected from a list of 510 Experts worldwide ranked by ideXlab platform

Carey D. Balaban - One of the best experts on this subject based on the ideXlab platform.

  • identification of neural networks that contribute to motion sickness through principal components analysis of fos labeling induced by galvanic Vestibular stimulation
    PLOS ONE, 2014
    Co-Authors: Carey D. Balaban, Sw Ogburn, Sg Warshafsky, Abdul Ahmed, Bill J Yates
    Abstract:

    Motion sickness is a complex condition that includes both overt signs (e.g., vomiting) and more covert symptoms (e.g., anxiety and foreboding). The neural pathways that mediate these signs and symptoms are yet to identified. This study mapped the distribution of c-fos protein (Fos)-like immunoreactivity elicited during a galvanic Vestibular stimulation paradigm that is known to induce motion sickness in felines. A principal components analysis was used to identify networks of neurons activated during this stimulus paradigm from functional correlations between Fos labeling in different nuclei. This analysis identified five principal components (neural networks) that accounted for greater than 95% of the variance in Fos labeling. Two of the components were correlated with the severity of motion sickness symptoms, and likely participated in generating the overt signs of the condition. One of these networks included neurons in locus coeruleus, medial, inferior and lateral Vestibular nuclei, lateral Nucleus tractus solitarius, medial parabrachial Nucleus and periaqueductal gray. The second included neurons in the Superior Vestibular Nucleus, precerebellar nuclei, periaqueductal gray, and parabrachial nuclei, with weaker associations of raphe nuclei. Three additional components (networks) were also identified that were not correlated with the severity of motion sickness symptoms. These networks likely mediated the covert aspects of motion sickness, such as affective components. The identification of five statistically independent component networks associated with the development of motion sickness provides an opportunity to consider, in network activation dimensions, the complex progression of signs and symptoms that are precipitated in provocative environments. Similar methodology can be used to parse the neural networks that mediate other complex responses to environmental stimuli.

  • Locations of Fos-labeled neurons in the two unstimulated control animals (C83 and C84).
    2014
    Co-Authors: Carey D. Balaban, Sg Warshafsky, Abdul Ahmed, Sarah W. Ogburn, Bill J Yates
    Abstract:

    Neuronal locations were plotted on photomontages of sections taken using a 4X objective. Sections (A, B, E) are from animal C83, whereas (C, D) are from animal C84. The sections were located at the following approximate distances posterior to stereotaxic zero, in accordance with Berman’s atlas: A, 13.5 mm; B, 12 mm; C, 8 mm; D, 6 mm; E, 4 mm. Abbreviations are the same as in Fig. 1, with the following additions: 5M, motor trigeminal Nucleus; 5P, principal trigeminal Nucleus; LC, locus coeruleus; S, solitary Nucleus; SO, Superior olivary Nucleus; SVN, Superior Vestibular Nucleus.

  • anterograde tracing of projections from the dorsal raphe Nucleus to the Vestibular nuclei
    Neuroscience, 2006
    Co-Authors: Adam L Halberstadt, Carey D. Balaban
    Abstract:

    Abstract This study used the anterograde transport of biotinylated dextran amine (BDA) to identify the course and terminal distribution of projections from the dorsal raphe Nucleus (DRN) to the Vestibular nuclei in rats. After iontophoretic injection of BDA into the medial and lateral regions of DRN, anterogradely labeled fibers descend within the medial longitudinal fasciculus and the ventricular fiber plexus to terminate within two discrete regions of the Vestibular nuclear complex. One terminal field was located primarily ipsilateral to the injection site and involved rostrodorsal aspects of the Vestibular nuclei, including Superior Vestibular Nucleus and rostral portions of the medial Vestibular Nucleus (MVN) and lateral Vestibular Nucleus (LVN). The other terminal field involved caudoventral aspects of both ipsilateral and contralateral MVN and LVN and was less heavily innervated. These findings confirm that the Vestibular nuclei are targeted by a regionally-selective projection from the DRN. The segregation of DRN terminals into anatomically distinct fields indicates that the DRN-Vestibular Nucleus projections are organized to selectively modulate processing within specific functional domains of the Vestibular nuclear complex. In particular, these terminal fields may be organized to modulate Vestibular regions involved in eye movement–related velocity storage, coordination of Vestibular and affective responses, and the bilateral coordination of horizontal eye movement reflexes.

  • projections from the parabrachial Nucleus to the Vestibular nuclei potential substrates for autonomic and limbic influences on Vestibular responses
    Brain Research, 2004
    Co-Authors: Carey D. Balaban
    Abstract:

    Previous anatomical studies in rabbits and rats have shown that the Superior Vestibular Nucleus (SVN), medial Vestibular Nucleus (MVN) and inferior Vestibular Nucleus (IVN) project to the parabrachial Nucleus (PBN) and Kolliker-Fuse (KF) Nucleus. Adult male albino rabbits and Long-Evans rats received iontophoretic injections of biotinylated dextran amine, Phaseolus vulgaris leucoagglutinin, Fluoro-Gold or tetramethylrhodamine dextran amine into either the Vestibular nuclei or the PBN and KF nuclei. The results were similar in both rats and rabbits. Injections of retrograde tracers into the Vestibular nuclei produced retrogradely labeled neurons bilaterally in caudal third of the medial, external medial, and external lateral PBN in both species, with more variable labeling in KF. Rats also had consistent bilateral (predominantly contralateral) labeling in the ventrolateral PBN. The most prominent labeling was produced from injections that included the SVN, with fewer labeled neurons observed from injections in the caudal MVN and the IVN. Anterograde transport of BDA from injections into the PBN and KF nuclei of rabbits revealed prominent projections to the SVN, dorsal aspect of the rostral MVN, caudal MVN, pars beta of the LVN and IVN. These connections appear to contain a component that is reciprocal to the vestibulo-parabrachial pathway and a non-reciprocal component to regions connected with the vestibulocerebellum and vestibulo-motor reflex pathways. These connections support the concept that a synthesis of autonomic, Vestibular and limbic information is an integral property of pathways related to balance control in both the brain stem and forebrain. It is suggested that these projections may contribute broadly to both performance tradeoffs in Vestibular-related pathways during variations in the behavioral context and affective state and the close association between anxiety and balance function.

  • organization of projections from the raphe nuclei to the Vestibular nuclei in rats
    Neuroscience, 2003
    Co-Authors: Adam L Halberstadt, Carey D. Balaban
    Abstract:

    Abstract Previous anatomic and electrophysiological evidence suggests that serotonin modulates processing in the Vestibular nuclei. This study examined the organization of projections from serotonergic raphe nuclei to the Vestibular nuclei in rats. The distribution of serotonergic axons in the Vestibular nuclei was visualized immunohistochemically in rat brain slices using antisera directed against the serotonin transporter. The density of serotonin transporter-immunopositive fibers is greatest in the Superior Vestibular Nucleus and the medial Vestibular Nucleus, especially along the border of the fourth ventricle; it declines in more lateral and caudal regions of the Vestibular nuclear complex. After unilateral iontophoretic injections of Fluoro-Gold into the Vestibular nuclei, retrogradely labeled neurons were found in the dorsal raphe Nucleus (including the dorsomedial, ventromedial and lateral subdivisions) and Nucleus raphe obscurus, and to a minor extent in Nucleus raphe pallidus and Nucleus raphe magnus. The combination of retrograde tracing with serotonin immunohistofluorescence in additional experiments revealed that the Vestibular nuclei receive both serotonergic and non-serotonergic projections from raphe nuclei. Tracer injections in densely innervated regions (especially the medial and Superior Vestibular nuclei) were associated with the largest numbers of Fluoro-Gold-labeled cells. Differences were observed in the termination patterns of projections from the individual raphe nuclei. Thus, the dorsal raphe Nucleus sends projections that terminate predominantly in the rostral and medial aspects of the Vestibular nuclear complex, while Nucleus raphe obscurus projects relatively uniformly throughout the Vestibular nuclei. Based on the topographical organization of raphe input to the Vestibular nuclei, it appears that dense projections from raphe nuclei are colocalized with terminal fields of flocculo-nodular lobe and uvula Purkinje cells. It is hypothesized that raphe–Vestibular connections are organized to selectively modulate processing in regions of the Vestibular nuclear complex that receive input from specific cerebellar zones. This represents a potential mechanism whereby motor activity and behavioral arousal could influence the activity of cerebelloVestibular circuits.

Bernard Cohen - One of the best experts on this subject based on the ideXlab platform.

  • nystagmus induced by electrical stimulation of the Vestibular and prepositus hypoglossi nuclei in the monkey evidence for site of induction of velocity storage
    Experimental Brain Research, 1992
    Co-Authors: Junichi Yokota, Harvey Reisine, Bernard Cohen
    Abstract:

    Electrical stimulation of the Vestibular nuclei (VN) and prepositus hypoglossi nuclei (PPH) of alert cynomolgus monkeys evoked nystagmus and eye deviation while they were in darkness. At some sites in VN, nystagmus and after-nystagmus were induced with characteristics suggesting that velocity storage had been excited. We analyzed these responses and compared them to the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN). We then recorded unit activity in VN and determined which types of nystagmus would be evoked from the sites of recording. Nystagmus and eye deviations were also elicited by electrical stimulation of PPH, and we characterized the responses where unit activity was recorded in PPH. Horizontal slow phase velocity of the VN “storage” responses was contralateral to the side of stimulation. The rising time constants and peak steady-state velocities were similar to those of OKN, and the falling time constants of the after-nystagmus and of OKAN were approximately equal. Both the induced after-nystagmus and OKAN were habituated by stimulation of the VN. When horizontal after-nystagmus was evoked with animals on their sides, it developed yaw and pitch components that tended to shift the vector of the slow phase velocity toward the spatial vertical. Similar “cross-coupling” occurs for horizontal OKAN or for Vestibular post-rotatory nystagmus elicited in tilted positions. Thus, the storage component of nystagmus induced by VN stimulation had the same characteristics as the slow component of OKN and the VOR. Positive stimulus sites for inducing nystagmus with typical storage components were located in rostral portions of VN. They lay in caudal ventral Superior Vestibular Nucleus (SVN), dorsal portions of central medial Vestibular Nucleus (MVN) caudal to the abducens nuclei and in adjacent lateral Vestibular Nucleus (LVN). More complex stimulus responses, but with contralateral after-nystagmus, were induced from surrounding regions of ventral MVN and LVN, rostral descending Vestibular Nucleus and the marginal zone between MVN and PPH. Vestibular-only (VO), Vestibular plus saccade (VPS) and tonic Vestibular pause (TVP) units were identified by extracellular recording. Stimulation near type I lateral and vertical canalrelated VO units elicited typical “storage” responses with after-nystagmus in 23 of 29 tracks (79%). Stimulus responses were more complex from the region of neurons with oculomotor-related signals, i.e., TVP or VPS cells, although after-nystagmus was also elicited from these sites. Effects of Vestibular nerve and Nucleus stimulation were compared. Nerve stimulation evoked nystagmus with both a rapid and slow component and after-nystagmus. There was a more prominent rapid rise in slow phase velocity, higher peak velocities, shorter latencies and a shorter falling time constant from nerve than from Nucleus stimulation. This indicates more prominent activation of rapid pathways from nerve stimulation. From a comparison of nerve- and Nucleus-induced nystagmus, we infer that there was predominant activation of the network responsible for velocity storage by electrical stimulation at many sites in the VN. Microstimulation at sites in PPH elicited nystagmus with ipsilateral slow phases or ipsilateral eye deviations. Slow phase eye velocity changed rapidly at the onset of nystagmus, and peak eye velocities were about 10–15°/s lower than from VN stimulation. The nystagmus had no slow component, and it was not followed by after-nystagmus. Only burst or burst-tonic neurons were recorded in PPH. Stimulation at sites of recording of these units induced either nystagmus with a rapid component or ipsilateral eye deviation. We conclude that the slow component of optokinetic and Vestibular nystagmus, attributable to velocity storage is produced in the VN, not in the PPH. We postulate that VO neurons lying in caudal ventral portions of SVN, dorsal portions of MVN and adjacent LVN are part of the network that generates velocity storage.

  • nystagmus induced by electrical stimulation of the Vestibular and prepositus hypoglossi nuclei in the monkey evidence for site of induction of velocity storage
    Experimental Brain Research, 1992
    Co-Authors: Junichi Yokota, Harvey Reisine, Bernard Cohen
    Abstract:

    Electrical stimulation of the Vestibular nuclei (VN) and prepositus hypoglossi nuclei (PPH) of alert cynomolgus monkeys evoked nystagmus and eye deviation while they were in darkness. At some sites in VN, nystagmus and after-nystagmus were induced with characteristics suggesting that velocity storage had been excited. We analyzed these responses and compared them to the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN). We then recorded unit activity in VN and determined which types of nystagmus would be evoked from the sites of recording. Nystagmus and eye deviations were also elicited by electrical stimulation of PPH, and we characterized the responses where unit activity was recorded in PPH. Horizontal slow phase velocity of the VN "storage" responses was contralateral to the side of stimulation. The rising time constants and peak steady-state velocities were similar to those of OKN, and the falling time constants of the after-nystagmus and of OKAN were approximately equal. Both the induced after-nystagmus and OKAN were habituated by stimulation of the VN. When horizontal after-nystagmus was evoked with animals on their sides, it developed yaw and pitch components that tended to shift the vector of the slow phase velocity toward the spatial vertical. Similar "cross-coupling" occurs for horizontal OKAN or for Vestibular post-rotatory nystagmus elicited in tilted positions. Thus, the storage component of nystagmus induced by VN stimulation had the same characteristics as the slow component of OKN and the VOR. Positive stimulus sites for inducing nystagmus with typical storage components were located in rostral portions of VN. They lay in caudal ventral Superior Vestibular Nucleus (SVN), dorsal portions of central medial Vestibular Nucleus (MVN) caudal to the abducens nuclei and in adjacent lateral Vestibular Nucleus (LVN). More complex stimulus responses, but with contralateral after-nystagmus, were induced from surrounding regions of ventral MVN and LVN, rostral descending Vestibular Nucleus and the marginal zone between MVN and PPH. Vestibular-only (VO), Vestibular plus saccade (VPS) and tonic Vestibular pause (TVP) units were identified by extracellular recording. Stimulation near type I lateral and vertical canal-related VO units elicited typical "storage" responses with after-nystagmus in 23 of 29 tracks (79%). Stimulus responses were more complex from the region of neurons with oculomotor-related signals, i.e., TVP or VPS cells, although after-nystagmus was also elicited from these sites. Effects of Vestibular nerve and Nucleus stimulation were compared.(ABSTRACT TRUNCATED AT 400 WORDS)

S. M. Highstein - One of the best experts on this subject based on the ideXlab platform.

  • properties of Superior Vestibular Nucleus flocculus target neurons in the squirrel monkey i general properties in comparison with flocculus projecting neurons
    Journal of Neurophysiology, 1995
    Co-Authors: Yihong Zhang, A. M. Partsalis, S. M. Highstein
    Abstract:

    1. Using single-unit recording and microstimulation methods, a group of flocculus target neurons (FTNs) were identified in the Superior Vestibular Nucleus (SVN) and were studied using visual-Vestibular interaction paradigms in alert squirrel monkeys. The response properties of these FTNs were characterized and compared with those of flocculus projecting neurons (FPNs). 2. FTNs were monosynaptically inhibited by single-pulse flocculus stimulation. The mean inhibition latency was 1.0 +/- 0.57 (SD) ms (n = 40) and the mean inhibition period was 6.7 +/- 2.69 ms. FTNs were also monosynaptically activated by VIIIth nerve stimulation. The mean response latency was 1.10 +/- 0.25 ms (n = 12). This is about the same as that of the FPNs (1.14 +/- 0.16 ms, n = 17). 3. The most characteristic response property of the FTNs is their firing rate modulation during visual following eye movements induced by sinusoidal rotation of an optokinetic drum at 0.5 Hz. This modulation was mainly related to eye velocity and was therefore termed a visual following eye velocity signal. The average eye velocity gain for all FTNs is 0.79 spikes.s-1.deg-1.s-1. In contrast, the responses of FPNs were not modulated under the same conditions. 4. Even though FTNs are inhibited by the flocculus, they have a relatively higher mean firing rate (124 +/- 23 spikes/s, n = 45) than FPNs (66 +/- 28 spikes/s, n = 42). The underlying mechanism may be related to commissural facilitation of FTNs and commissural inhibition of FPNs. 5. Thirty FTNs were identified as upward eye velocity FTNs because their firing rate increased for upward eye velocity during a visual following eye movement. The mean eye velocity sensitivity was 1.09 spikes.s-1.deg-1.s-1. Most of these cells also modulated during vestibuloocular reflex (VOR) in the dark, with firing rate increasing for downward head velocity. During VOR suppression the firing rate either did not modulate or modulated in phase with head or drum velocity with a smaller amplitude in comparison with the response during visual following. For all cells (with 1 exception) the response during a visual following eye movement can be approximately predicted by a linear vectorial subtraction of the response during VOR suppression and the response during VOR in the dark [modulation response vector of FTNs during visual following of the optokinetic stimulus (OKR) approximately modulation response vector of FTNs during VOR suppression-modulation response vector of FTNs during VOR in the dark].(ABSTRACT TRUNCATED AT 400 WORDS)

  • properties of Superior Vestibular Nucleus flocculus target neurons in the squirrel monkey ii signal components revealed by reversible flocculus inactivation
    Journal of Neurophysiology, 1995
    Co-Authors: Yihong Zhang, A. M. Partsalis, S. M. Highstein
    Abstract:

    1. Seven upward eye velocity flocculus target neurons (FTNs) and two flocculus projecting neurons (FPNs) were studied before and after ipsilateral flocculus inactivation by injection of muscimol in the alert squirrel monkey. An additional seven FTNs and seven FPNs recorded from the corresponding FTN and FPN areas were recorded after injection. Response properties of FTNs and FPNs were characterized by visual-Vestibular interaction paradigms and were compared before and after flocculus inactivation. 2. In FTNs the mean firing rate increased within 2-5 min after muscimol injection in the flocculus and reached a plateau level in approximately 10-20 min. The average mean firing rate for seven FTNs increased from 117 to 174 spikes/s, a net increase of 57 spikes/s (49%). Accompanying the large increase of the mean firing rate, a spontaneous nystagmus in the darkness developed with the slow phase directed upward and contralateral. 3. The firing rate modulation during visual following of a sinusoidal optokinetic drum (0.5 Hz) decreased within 2-5 min after muscimol injection in the flocculus and reached a level of 0 in approximately 10-20 min for all FTNs. After that, some cells remained unmodulated for the period of recording; other cells gradually reversed their phase and developed a modulation out of phase with drum velocity. The depletion of the visual following eye velocity signal on Superior Vestibular Nucleus (SVN) FTNs accompanied a small but consistent decrease of visual following eye velocity amplitude. The average maximum decrease of eye velocity was 26 +/- 9% (mean +/- SD). 4. After flocculus inactivation, even though the modulation response at 0.5 Hz during visual following was abolished, a slow-component eye velocity signal with the same on direction was revealed by a constant-velocity optokinetic stimulus. It is concluded that there are at least two kinds of eye velocity signals during the optokinetic response. These signals are combined at the FTNs and are subsequently relayed to the oculomotor neurons. The source of the fast component is the flocculus, and the source of the slow component is another, as yet unidentified brain structure. 5. The effect of flocculus inactivation on the modulation amplitude during the vestibuloocular reflex (VOR) in darkness was variable: two cells did not change, two cells decreased, and three cells increased their amplitude. The response phase tended to move toward a phase lead, but the change was small. The effect on VOR suppression was more prominent.(ABSTRACT TRUNCATED AT 400 WORDS)

  • dorsal y group in the squirrel monkey ii contribution of the cerebellar flocculus to neuronal responses in normal and adapted animals
    Journal of Neurophysiology, 1995
    Co-Authors: A. M. Partsalis, Yihong Zhang, S. M. Highstein
    Abstract:

    1. The effects of electrical pulse stimulation and temporary pharmacological inactivation of the ipsilateral cerebellar flocculus on the activity of single Y group cells were studied in three alert squirrel monkeys. The extent of the flocculus was mapped by multiunit recording and by electrical pulse train stimulation, which elicited slow eye movement. 2. Single electrical pulse stimulation of the flocculus (0.1-ms constant current, 25-400 microA) resulted in inhibition of all 24 Y cells examined. The inhibition was evidenced as a cessation of cell firing for varying periods [8.8 +/- 2.4 (SD) ms] after the stimulus. The latency of inhibition (0.71 +/- 0.34 ms) suggests that the effect was due to direct activation of Purkinje cells monosynaptically projecting to the Y group. 3. The gamma-aminobutyric acid (GABA) agonist muscimol was used to temporarily inactivate the flocculus while recording from single Y neurons. After control responses of cells under various behavioral paradigms were collected, muscimol (total volume of 3-4 microliters of 2.0% muscimol in saline) was injected in the flocculus through a pair of fine syringes. With this technique, the contribution of the flocculus to the signal content of Y group cells was examined, both in the animals with normal vestibuloocular reflex (VOR) gain (5 cells in 3 animals) and after adaptation of the VOR to either high (5 cells in 1 animal) or low gain (7 cells in 2 animals). 4. In the normal animal, pharmacological floccular inactivation resulted in increased dc firing and in the loss of normal modulation with eye velocity. Modulation during visual-Vestibular interactions was also lost, so cell responses did not differ from those during the VOR in darkness. Only minor changes (usually gain increases) in the latter response were noted after flocculus inactivation. The results suggests an extrafloccular input source to the Y group, conveying head velocity information. We believe that this input originates in the brain stem, probably in the Superior Vestibular Nucleus. 5. To examine whether the adapted responses of Y cells during the VOR in darkness are due to their floccular input, single cells were studied before and after pharmacological floccular inactivation, in animals whose VOR had been adapted.(ABSTRACT TRUNCATED AT 400 WORDS)

  • Properties of Superior Vestibular Nucleus neurons projecting to the cerebellar flocculus in the squirrel monkey
    Journal of neurophysiology, 1993
    Co-Authors: Yihong Zhang, A. M. Partsalis, S. M. Highstein
    Abstract:

    1. Properties of Superior Vestibular Nucleus (SVN) neurons and their projection to the cerebellar flocculus were studied in alert squirrel monkeys by using chronic unit and eye movement recording and microstimulation techniques. Twenty-three cells were antidromically activated from the ipsilateral flocculus, and seventeen of these were also orthodromically activated from the ipsilateral VIIth nerve at monosynaptic latencies. Only 1 of these 23 units was also inhibited by flocculus stimulation. According to their response properties, 9 of the cells were pure Vestibular, 2 were Vestibular-pause, and 12 were position-Vestibular cells. The mean eye position sensitivity of these position-Vestibular cells was significantly lower than that of cells projecting to the oculomotor Nucleus (OMN). No eye movement-only neurons were antidromically activated from the flocculus. No cells could be antidromically activated from both the oculomotor Nucleus and the flocculus.

Douglas R Wylie - One of the best experts on this subject based on the ideXlab platform.

  • distribution of zebrin immunoreactive purkinje cell terminals in the cerebellar and Vestibular nuclei of birds
    The Journal of Comparative Neurology, 2012
    Co-Authors: Douglas R Wylie, Janelle M P Pakan, David J Graham, Hang Huynh, Andrew N Iwaniuk
    Abstract:

    Zebrin II (aldolase C) is expressed in a subset of Purkinje cells in the mammalian and avian cerebella such that there is a characteristic parasagittal organization of zebrin-immunopositive stripes alternating with zebrin-immunonegative stripes. Zebrin is expressed not only in the soma and dendrites of Purkinje cells but also in their axonal terminals. Here we describe the distribution of zebrin immunoreactivity in both the Vestibular and the cerebellar nuclei of pigeons (Columba livia) and hummingbirds (Calypte anna, Selasphorus rufus). In the medial cerebellar Nucleus, zebrin-positive labeling was particularly heavy in the “shell,” whereas the “core” was zebrin negative. In the lateral cerebellar Nucleus, labeling was not as heavy, but a positive shell and negative core were also observed. In the Vestibular nuclear complex, zebrin-positive terminal labeling was heavy in the dorsolateral Vestibular Nucleus and the lateral margin of the Superior Vestibular Nucleus. The central and medial regions of the Superior Nucleus were generally zebrin negative. Labeling was moderate to heavy in the medial Vestibular Nucleus, particulary the rostral half of the parvocellular subNucleus. A moderate amount of zebrin-positive labeling was present in the descending Vestibular Nucleus: this was heaviest laterally, and the central region was generally zebrin negative. Zebrin-positive terminals were also observed in the the cerebelloVestibular process, prepositus hypoglossi, and lateral tangential Nucleus. We discuss our findings in light of similar studies in rats and with respect to the corticonuclear projections to the cerebellar nuclei and the functional connections of the vestibulocerebellum with the Vestibular nuclei.

  • differential projections from the Vestibular nuclei to the flocculus and uvula nodulus in pigeons columba livia
    The Journal of Comparative Neurology, 2008
    Co-Authors: Janelle M P Pakan, David J Graham, Andrew N Iwaniuk, Douglas R Wylie
    Abstract:

    The pigeon vestibulocerebellum is divided into two regions based on the responses of Purkinje cells to optic flow stimuli: the uvula-nodulus responds best to self-translation, and the flocculus responds best to self-rotation. We used retrograde tracing to determine whether the flocculus and uvula-nodulus receive differential mossy fiber input from the Vestibular and cerebellar nuclei. From retrograde injections into the both the flocculus and uvula-nodulus, numerous cells were found in the Superior Vestibular Nucleus (VeS), the cerebelloVestibular process (pcv), the descending Vestibular Nucleus (VeD), and the medial Vestibular Nucleus (VeM). Less labeling was found in the prepositus hypoglossi, the cerebellar nuclei, the dorsolateral Vestibular Nucleus, and the lateral Vestibular Nucleus, pars ventralis. In the VeS, the differential input to the flocculus and uvula-nodulus was distinct: cells were localized to the medial and lateral regions, respectively. The same pattern was observed in the VeD, although there was considerable overlap. In the VeM, the majority of cells labeled from the flocculus were in rostral margins on the ipsilateral side, whereas labeling from uvula-nodulus injections was distributed bilaterally throughout the VeM. Finally, from injections in the flocculus but not the uvulanodulus, moderate labeling was observed in a paramedian area, adjacent to the medial longitudinal fasciculus. In summary, there were clear differences with respect to the projections from the Vestibular nuclei to functionally distinct parts of the vestibulocerebellum. Generally speaking, the mossy fibers to the flocculus and uvula-nodulus arise from regions of the Vestibular nuclei that receive input from the semicircular canals and otolith organs, respectively. J. Comp. Neurol.

  • zonal organization of the vestibulocerebellum in pigeons columba livia iii projections of the translation zones of the ventral uvula and nodulus
    The Journal of Comparative Neurology, 2003
    Co-Authors: Douglas R Wylie, Matthew R G Brown, Ian R Winship, Nathan A Crowder, Katherine G Todd
    Abstract:

    Previous electrophysiological studies in pigeons have shown that the complex spike activity of Purkinje cells in the medial vestibulocerebellum (nodulus and ventral uvula) is modulated by patterns of optic flow that result from self-translation along a particular axis in three-dimensional space. There are four response types based on the axis of preferred translational optic flow. By using a three axis system, where +X, +Y, and +Z represent rightward, upward, and forward self-motion, respectively, the four cell types are t(+Y), t(-Y), t(-X-Z), and t(-X+Z), with the assumption of recording from the left side of the head. These response types are organized into parasagittal zones. In this study, we injected the anterograde tracer biotinylated dextran amine into physiologically identified zones. The t(-X-Z) zone projected dorsally within the vestibulocerebellar process (pcv) on the border with the medial cerebellar Nucleus (CbM), and labeling was found in the CbM itself. The t(-X+Z) zone also projected to the pcv and CbM, but to areas ventral to the projection sites of the t(-X-Z) zone. The t(-Y) zone also projected to the pcv, but more ventrally on the border with the Superior Vestibular Nucleus (VeS). Some labeling was also found in the dorsal VeS and the dorsolateral margin of the caudal descending Vestibular Nucleus, and a small amount of labeling was found laterally in the caudal margin of the medial Vestibular Nucleus. The data set was insufficient to draw conclusions about the projection of the t(+Y) zone. These results are contrasted with the projections of the flocculus, compared with the primary Vestibular projection, and implications for collimotor function are discussed.

  • projections of individual purkinje cells of identified zones in the flocculus to the Vestibular and cerebellar nuclei in the rabbit
    The Journal of Comparative Neurology, 1994
    Co-Authors: Douglas R Wylie, C I De Zeeuw, P L Digiorgi, John Simpson
    Abstract:

    The rabbit flocculus can be divided into five zones (zones 1, 2, 3, 4, and C2) with the use of acetylcholinesterase histochemistry. The projections of individual Purkinje cells in these zones to the Vestibular and cerebellar nuclei were studied by using biocytin as an anterograde tracer. The zones were physiologically identified in terms of the Purkinje cell complex spike modulation occurring in response to optokinetic stimulation. In zones 1 and 3 neurons respond best to rotation about a horizontal axis that is close to perpendicular to the ipsilateral anterior semicircular canal, whereas in zones 2 and 4 neurons respond best to rotation about the vertical axis. Complex spike activity in zone C2 is unresponsive to optokinetic stimulation. Collectively, Purkinje cells of zone 1 projected to the ventral dentate Nucleus, dorsal group y, and Superior Vestibular Nucleus; Purkinje cells of zones 2 and 4 projected to the magnocellular and parvicellular parts of the medial Vestibular Nucleus; Purkinje cells of zone 3 projected to dorsal group y, ventral group y, and the Superior Vestibular Nucleus; and Purkinje cells of zone C2 projected to the interposed posterior Nucleus and dorsal group y. Some of the labeled Purkinje cell axons branched and innervated two nuclei. Branching axons from zone 1 either innervated both the ventral dentate Nucleus and the Superior Vestibular Nucleus or both dorsal group y and the Superior Vestibular Nucleus. Branching axons from zones 2 and 4 innervated both the magnocellular and the parvicellular parts of the medial Vestibular Nucleus. Branching axons from zone 3 innervated both dorsal group y and the Superior Vestibular Nucleus, or both ventral group y and the Superior Vestibular Nucleus. Branching axons from zone C2 innervated both the interposed posterior Nucleus and dorsal group y. Some of the target nuclei of the floccular Purkinje cell axons (e.g., dorsal group y and interposed posterior Nucleus) project to the part of the inferior olive that, in turn, projects to the corresponding floccular zone, thus completing a closed pathway consisting of the inferior olive, the cerebellar cortex, and the cerebellar and Vestibular nuclei. Other target nuclei (e.g., Superior Vestibular Nucleus and medial Vestibular Nucleus) do not project back to the olivary subnuclei that innervate the flocculus and are part of an open olivofloccular pathway. An individual Purkinje cell thus can innervate a Nucleus in the closed pathway as well as a Nucleus in the open pathway.(ABSTRACT TRUNCATED AT 400 WORDS)

Harvey Reisine - One of the best experts on this subject based on the ideXlab platform.

  • nystagmus induced by electrical stimulation of the Vestibular and prepositus hypoglossi nuclei in the monkey evidence for site of induction of velocity storage
    Experimental Brain Research, 1992
    Co-Authors: Junichi Yokota, Harvey Reisine, Bernard Cohen
    Abstract:

    Electrical stimulation of the Vestibular nuclei (VN) and prepositus hypoglossi nuclei (PPH) of alert cynomolgus monkeys evoked nystagmus and eye deviation while they were in darkness. At some sites in VN, nystagmus and after-nystagmus were induced with characteristics suggesting that velocity storage had been excited. We analyzed these responses and compared them to the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN). We then recorded unit activity in VN and determined which types of nystagmus would be evoked from the sites of recording. Nystagmus and eye deviations were also elicited by electrical stimulation of PPH, and we characterized the responses where unit activity was recorded in PPH. Horizontal slow phase velocity of the VN “storage” responses was contralateral to the side of stimulation. The rising time constants and peak steady-state velocities were similar to those of OKN, and the falling time constants of the after-nystagmus and of OKAN were approximately equal. Both the induced after-nystagmus and OKAN were habituated by stimulation of the VN. When horizontal after-nystagmus was evoked with animals on their sides, it developed yaw and pitch components that tended to shift the vector of the slow phase velocity toward the spatial vertical. Similar “cross-coupling” occurs for horizontal OKAN or for Vestibular post-rotatory nystagmus elicited in tilted positions. Thus, the storage component of nystagmus induced by VN stimulation had the same characteristics as the slow component of OKN and the VOR. Positive stimulus sites for inducing nystagmus with typical storage components were located in rostral portions of VN. They lay in caudal ventral Superior Vestibular Nucleus (SVN), dorsal portions of central medial Vestibular Nucleus (MVN) caudal to the abducens nuclei and in adjacent lateral Vestibular Nucleus (LVN). More complex stimulus responses, but with contralateral after-nystagmus, were induced from surrounding regions of ventral MVN and LVN, rostral descending Vestibular Nucleus and the marginal zone between MVN and PPH. Vestibular-only (VO), Vestibular plus saccade (VPS) and tonic Vestibular pause (TVP) units were identified by extracellular recording. Stimulation near type I lateral and vertical canalrelated VO units elicited typical “storage” responses with after-nystagmus in 23 of 29 tracks (79%). Stimulus responses were more complex from the region of neurons with oculomotor-related signals, i.e., TVP or VPS cells, although after-nystagmus was also elicited from these sites. Effects of Vestibular nerve and Nucleus stimulation were compared. Nerve stimulation evoked nystagmus with both a rapid and slow component and after-nystagmus. There was a more prominent rapid rise in slow phase velocity, higher peak velocities, shorter latencies and a shorter falling time constant from nerve than from Nucleus stimulation. This indicates more prominent activation of rapid pathways from nerve stimulation. From a comparison of nerve- and Nucleus-induced nystagmus, we infer that there was predominant activation of the network responsible for velocity storage by electrical stimulation at many sites in the VN. Microstimulation at sites in PPH elicited nystagmus with ipsilateral slow phases or ipsilateral eye deviations. Slow phase eye velocity changed rapidly at the onset of nystagmus, and peak eye velocities were about 10–15°/s lower than from VN stimulation. The nystagmus had no slow component, and it was not followed by after-nystagmus. Only burst or burst-tonic neurons were recorded in PPH. Stimulation at sites of recording of these units induced either nystagmus with a rapid component or ipsilateral eye deviation. We conclude that the slow component of optokinetic and Vestibular nystagmus, attributable to velocity storage is produced in the VN, not in the PPH. We postulate that VO neurons lying in caudal ventral portions of SVN, dorsal portions of MVN and adjacent LVN are part of the network that generates velocity storage.

  • nystagmus induced by electrical stimulation of the Vestibular and prepositus hypoglossi nuclei in the monkey evidence for site of induction of velocity storage
    Experimental Brain Research, 1992
    Co-Authors: Junichi Yokota, Harvey Reisine, Bernard Cohen
    Abstract:

    Electrical stimulation of the Vestibular nuclei (VN) and prepositus hypoglossi nuclei (PPH) of alert cynomolgus monkeys evoked nystagmus and eye deviation while they were in darkness. At some sites in VN, nystagmus and after-nystagmus were induced with characteristics suggesting that velocity storage had been excited. We analyzed these responses and compared them to the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN). We then recorded unit activity in VN and determined which types of nystagmus would be evoked from the sites of recording. Nystagmus and eye deviations were also elicited by electrical stimulation of PPH, and we characterized the responses where unit activity was recorded in PPH. Horizontal slow phase velocity of the VN "storage" responses was contralateral to the side of stimulation. The rising time constants and peak steady-state velocities were similar to those of OKN, and the falling time constants of the after-nystagmus and of OKAN were approximately equal. Both the induced after-nystagmus and OKAN were habituated by stimulation of the VN. When horizontal after-nystagmus was evoked with animals on their sides, it developed yaw and pitch components that tended to shift the vector of the slow phase velocity toward the spatial vertical. Similar "cross-coupling" occurs for horizontal OKAN or for Vestibular post-rotatory nystagmus elicited in tilted positions. Thus, the storage component of nystagmus induced by VN stimulation had the same characteristics as the slow component of OKN and the VOR. Positive stimulus sites for inducing nystagmus with typical storage components were located in rostral portions of VN. They lay in caudal ventral Superior Vestibular Nucleus (SVN), dorsal portions of central medial Vestibular Nucleus (MVN) caudal to the abducens nuclei and in adjacent lateral Vestibular Nucleus (LVN). More complex stimulus responses, but with contralateral after-nystagmus, were induced from surrounding regions of ventral MVN and LVN, rostral descending Vestibular Nucleus and the marginal zone between MVN and PPH. Vestibular-only (VO), Vestibular plus saccade (VPS) and tonic Vestibular pause (TVP) units were identified by extracellular recording. Stimulation near type I lateral and vertical canal-related VO units elicited typical "storage" responses with after-nystagmus in 23 of 29 tracks (79%). Stimulus responses were more complex from the region of neurons with oculomotor-related signals, i.e., TVP or VPS cells, although after-nystagmus was also elicited from these sites. Effects of Vestibular nerve and Nucleus stimulation were compared.(ABSTRACT TRUNCATED AT 400 WORDS)

  • neural basis for eye velocity generation in the Vestibular nuclei of alert monkeys during off vertical axis rotation
    Experimental Brain Research, 1992
    Co-Authors: Harvey Reisine, Theodore Raphan
    Abstract:

    Activity of “Vestibular only” (VO) and “Vestibular plus saccade” (VPS) units was recorded in the rostral part of the medial Vestibular Nucleus and caudal part of the Superior Vestibular Nucleus of alert rhesus monkeys. By estimating the “null axes” of recorded units (n = 79), the optimal plane of activation was approximately the mean plane of reciprocal semicircular canals, i.e., lateral canals, left anterior-right posterior (LARP) canals or right anterior-left posterior (RALP) canals. All units were excited by rotation in a direction that excited a corresponding ipsilateral semicircular canal. Thus, they all displayed a “type I” response. With the animal upright, there were rapid changes in firing rates of both VO and VPS units in response to steps of angular velocity about a vertical axis. The units were bidirectionally activated during Vestibular nystagmus (VN), horizontal optokinetic nystagmus (OKN), optokinetic afternystagmus (OKAN) and off-vertical axis rotation (OVAR). The rising and falling time constants of the responses to rotation indicated that they were closely linked to velocity storage. There were differences between VPS and VO neurons in that activity of VO units followed the expected time course in response to a stimulus even during periods of drowsiness, when eye volocity was reduced. Firing rates of VPS units, on the other hand, were significantly reduced in the drowsy state. Lateral canal-related units had average firing rates that were linearly related to the bias or steady state level of horizontal eye velocity during OVAR over a range of ±60 deg/s. These units could be further divided into two classes according to whether they were modulated during OVAR. Non-modulated units (n = 5) were VO types and all modulated units (n = 5) were VPS types. There was no significant difference between the bias level sensitivities relative to eye velocity of the units with and without modulation (P>0.05). The modulated units had no sustained change in firing rate in response to static head tilts and their phases relative to head position varied from unit to unit. The phase did not appear to be linked to the modulation of horizontal eye velocity during OVAR. The sensitivities of unit activity to eye velocity were similar during all stimulus modalities despite the different gains of eye velocity vs stimulus velocity during VN, OKN and OVAR. Therefore, VO and VPS units are likely to carry an eye velocity signal related to velocity storage. For example, when unit sensitivities were related to head or surround velocity, sensitivity relative to OVAR was less than for VN or OKN. Firing rates of both vertical canal-related VO and VPS units (n= 19) were strongly modulated during OVAR, although they did not show changes in discharge rate during static head tilts relative to the spatial vertical up to a maximal 25 deg. In some cases the amplitude of the modulation increased with increases in head velocity and eye velocity. Average activity of vertical canal-related units was linearly related to steady state horizontal eye velocity in the ipsilateral direction during OVAR. The mean sensitivities of RALP units were not significantly different from those of LARP neurons (P>0.05). Together, their mean sensitivity during OVAR about a subject yaw axis was 0.34 (imp/s)/(deg/s) relative to horizontal eye velocity. This could be explained as a contribution of the vertical canals to horizontal eye velocity due to their orientation in the head. During OVAR to the ipsilateral side, the bias level of neuronal activity decreased and saturated. For steps of rotation about a vertical axis with the animal upright, the firing rates of RALP and LARP units were linearly related to stimulus velocity and eye velocity. Contralateral rotation excited the units reflecting the orientation of the semicircular canals relative to the yaw axis of rotation. RALP and LARP units also responded during horizontal optokinetic stimulation producing both OKN and OKAN. All the “vertical canal” units had dynamic characteristics closely related to velocity storage. Their response characteristics were consistent with the model that they contribute to horizontal slow phase velocity as part of a three-dimensional system based on a semicircular canal frame of reference. Otolith-related units (n= 5) in the Vestibular nuclei showed no evidence of velocity storage and were modulated in accordance with head position during OVAR. Mean amplitude of the modulation of activity during OVAR at a 20 deg tilt and 60 deg/s rotational velocity was 24 imp/s. The data indicate that the Vestibular nuclei contain the requisite signals to generate horizontal eye velocity during OVAR. VO and VPS units probably contribute to the “bias” or velocity storage component while otolith units mainly contribute to the oscillations in eye velocity by generating gravity dependent eye position changes during OVAR. In addition to the velocity storage component of horizontal eye velocity, the vertical VO neurons also have oscillations in their discharge patterns probably related to the vertical component of eye movements generated by the velocity storage integrator.