Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Cortical influences on the vestibular nuclei of the cat (1999)
    Springer
    Experimental brain research 125 (1999), S. 1-13 
    Details
    ISSN: 1432-1106
    Keywords: Key words Cerebral cortex ; Area 3a ; Area 2 ; Vestibular nuclei ; Vestibulospinal neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Our goal was to study potential substrates for cortical modulation of vestibular reflexes in the cat. In initial experiments, injections of wheat-germ-agglutinate-horseradish-peroxidase into Deiters’ nucleus and the rostral descending nucleus revealed bilateral colonies of retrogradely filled neurons in cortical areas 6, 2, and 3a (about 60 cells per colony). In cats anesthetized with chloralose-urethane, we stimulated areas 2 and 3a with trains of pulses while recording from ipsilateral vestibular-nucleus neurons, which were characterized by their responses to sinusoidal tilts and tested for the presence of antidromic responses to stimulation of the upper cervical cord. A majority of the neurons was affected by cortical stimulation, showing either facilitation, inhibition, or a mixture of the two. Stimulation in area 2 was more effective than stimulation in area 3a. Despite the anatomic presence of direct cortico-vestibular projections, properties of facilitation and inhibition suggest that both were evoked by polysynaptic pathways. Cortical effects were broadly distributed to vestibular neurons without regard to responses of these neurons to sinusoidal tilts. There was no significant difference between effects on lateral and medial vestibulospinal tract neurons, but, as a group, vestibulospinal neurons were much more likely to be affected by cortical stimulation than neurons not antidromically activated from the C2 segment. We conclude that, by their influence on vestibulospinal neurons, neurons in cortical areas 2 and 3a should be able to modulate, in behaving animals, vestibular reflexes acting on the neck and limbs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050651
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The neural substrate of the vestibulocollic reflex (1999)
    Springer
    Experimental brain research 129 (1999), S. 483-493 
    Details
    ISSN: 1432-1106
    Keywords: Key words Vestibulocollic reflex ; Short-latency pathways ; Vestibulospinal and reticulospinal pathways ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The purpose of this review is to assess the role of short-latency pathways in the vestibulocollic reflex (VCR). First the current knowledge about the disynaptic and trisynaptic pathways linking semicircular canal and otolith afferents with cat neck motoneurons is summarized. We then discuss whether these pathways are sufficient or necessary to produce the responses observed in neck muscles by natural vestibular stimulation and conclude that they are neither. Finally, alternate pathways are considered, most likely involving reticulospinal fibers, which are an important part of the neural substrate of the VCR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050918
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Influence of neck afferents on vestibulospinal neurons (1980)
    Springer
    Experimental brain research 38 (1980), S. 285-292 
    Details
    ISSN: 1432-1106
    Keywords: Neck afferents ; Neck-labyrinth interaction ; Vestibulospinal neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of neck afferent stimulation on vestibulospinal neurons in Deiters' nucleus and in the descending nucleus, and the interaction of cervical and vestibular input, were examined extracellularly in decerebrate, decerebellate cats. Many of the vestibulospinal neurons were identified as having axons in the lateral or medial vestibulospinal tract (LVST or MVST) and as being driven antidromically from C3 or C6. Half of the spontaneously active neurons were excited with a latency of 2.5–5.5 ms (early excitation) by stimulation of the contralateral C2 ganglion. In some neurons early excitation was followed by late excitation (latency 〉 6 ms), which was in other neurons the only effect seen. Early excitation was due to stimulation of proximal afferents because stimulation of the C2 dorsal or ventral rami usually produced late excitation only. Early excitation was seen in LVST and MVST neurons terminating between C3 and C6 and in those projecting beyond C6. Neurons with early excitation were scattered throughout Deiters' nucleus and the rostral part of the descending nucleus. In some neurons, mainly in the descending nucleus, the initial effect of contralateral C2 ganglion stimulation was inhibition. Inhibition could be evoked by stimulation of the ganglion or dorsal rami bilaterally. The axons of all tested inhibited neurons were in the MVST. Thirty-five percent of the population studied received convergence of early excitation and short-latency input from the labyrinth, sometimes from the semicircular canals. There was also convergence between late excitation or inhibition and vestibular input. The influence of neck afferent input on vestibulospinal neurons provides one pathway for this input to the neck and limb segments of the spinal cord. This pathway may be part of the substrate of the tonic neck reflex. In addition, vestibulospinal neurons are one site of interaction between neck and vestibular reflexes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236647
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Responses of different compartments of cat's splenius muscle to optokinetic stimulation (1983)
    Springer
    Experimental brain research 50 (1983), S. 153-156 
    Details
    ISSN: 1432-1106
    Keywords: Neck muscle ; Head-Eye movements ; Optokinetic stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The EMG in different compartments of the splenius muscle was recorded simultaneously with the horizontal electrooculogram in the alert, head restrained and head freed cat during optokinetic and vestibular stimulation. All compartments of the splenius muscle behaved qualitatively similarly. Tonic and phasic muscle activity was closely related to eye position.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238243
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Modulation by eye position of neck muscle contraction evoked by electrical labyrinthine stimulation in the alert cat (1987)
    Springer
    Experimental brain research 67 (1987), S. 411-419 
    Details
    ISSN: 1432-1106
    Keywords: Vestibular system ; Eye movements ; Vestibulo-collic reflexes ; Neck muscles ; Motor-strategies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Modulation of vestibulo-spinal reflexes by gaze is a model system for studying interactions between voluntary and reflex motor activity. In the alert cat, the EMG of Splenius and Obliquus capitis muscles increases with ipsilateral gaze eccentricity during spontaneous eye movements. Labyrinth stimulation by current pulses evokes EMGs with latencies consistent with a three neuron vestibulocollic pathway. The amplitude of evoked activity increases with eye position. The directions in which eye movements increase EMG was usually the same for both spontaneous and induced EMG activity, namely, horizontal and ipsilateral. However, sometimes the increase in spontaneous EMG occurred with horizontal eye position, whereas the induced EMG changed with vertical eye position. Spontaneous and evoked EMG are then modulated by different eye position signals. Command signals reflecting eye position probably reach two different types of neurons in the vestibulo-collic pathway, most likely secondary vestibular neurons and neck muscle motoneurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248561
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Supraspinal monosynaptic excitation and inhibition of thoracic back motoneurons (1970)
    Springer
    Experimental brain research 11 (1970), S. 282-295 
    Details
    ISSN: 1432-1106
    Keywords: Thoracic motoneurons ; Supraspinal ; Monosynaptic IPSP, EPSP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of brain stem stimulation on thoracic back motoneurons were studied in cats anesthetized with pentobarbital. The population sampled consisted of the extensors interspinales (IS), longissimus dorsi (LD) and spinalis dorsi (SD), and of unidentified (UIC) motoneurons. The location of the motoneurons, between Th 1 and Th 10, at widely varying distances from the stimulating electrode permitted linear regression analysis of the descending neural influences. EPSPs evoked by MLF stimulation in all types of motoneurons were produced by a pathway with an average conduction velocity in the thoracic cord of 127 m/sec, and were monosynaptic. IPSPs were also produced by MLF stimulation. The IPSPs in IS and UIC motoneurons were monosynaptic and were produced by a pathway with an average conduction velocity of 69 m/sec. Stimulation of Deiters' nucleus evoked short latency EPSPs in many motoneurons. EPSPs in LD and UIC motoneurons were shown to be monosynaptic, although latency scatter and sample size made accurate determination of vestibulospinal conduction velocity impossible. Stimulation of the labyrinth evoked disynaptic EPSPs and IPSPs in many cells, as previously observed in neck motoneurons. IPSPs were frequently produced by stimulation of the contralateral labyrinth, probably by a pathway with a relay in the contralateral medial vestibular nucleus. Ipsilateral stimulation usually produced EPSPs. The excitatory pathway relays in Deiters' nucleus and, we suggest, in the descending vestibular nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01474387
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Excitatory connections between neurons of the central cervical nucleus and vestibular neurons in the cat (1997)
    Springer
    Experimental brain research 115 (1997), S. 381-386 
    Details
    ISSN: 1432-1106
    Keywords: Key words Central cervical nucleus ; Vestibular projection ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The central cervical nucleus (CCN) of the cat receives input from upper cervical muscle afferents, particularly primary spindle afferents. Its axons cross in the spinal cord, and while in the contralateral restiform body give off collaterals to the vestibular nuclei. In order to study the connections between CCN axons and vestibular neurons, we stimulated the area of the CCN in decerebrate cats while recording intra- or extracellularly from neurons in the contralateral vestibular nuclei. CCN stimulation evoked excitatory postsynaptic potentials (EPSPs) or extracellularly recorded firing in the lateral, medial and descending vestibular nuclei. The latency of EPSPs (mean 1.6 ms) was on average 0.4 ms longer than the latency of antidromic spikes evoked in the CCN by stimulation of the contralateral vestibular nuclei (mean 1.2 ms), demonstrating that the excitation was typically monosynaptic. The results provide further evidence that the CCN is an important excitatory relay between upper cervical muscle afferents and neurons in the contralateral vestibular nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005708
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Compartmentalization of the cervicocollic reflex in cat splenius muscle (1983)
    Springer
    Experimental brain research 51 (1983), S. 397-404 
    Details
    ISSN: 1432-1106
    Keywords: Cervicocollic reflex ; Muscle Compartmentalization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have examined the cervicocollic reflex (CCR), evoked by horizontal rotation of the head of decerebrate cats, in the dorsal neck extensor muscle splenius. This muscle is divided into compartments which are innervated by three or four spinal segments; an analogous Compartmentalization may be observed in the CCR. When the CCR is evoked by rotation of the head about a vertical axis centered over C1–C2, the modulation of EMG activity is higher in the rostral than in the caudal compartments; in some cases, the rostral compartments can be modulated selectively. The rostrocaudal gradient of modulation is absent if the axis of rotation is shifted caudally to C4–C5. In muscles which had been completely detached from their origin and insertion, the pattern of activation of the CCR was similar to that observed in intact muscle, although the gain of the reflex fell by two thirds. This suggests that significant inputs to this reflex arise both from within splenius itself and from receptors outside this muscle. The typical CCR disappears if the C1–C4 dorsal roots ipsilateral to splenius are cut; furthermore, the reflex appears normal in animals with spinal transections above C1. A significant component of the CCR in splenius appears to be a segmental stretch reflex, originating partly in splenius and partly from receptors outside the muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237876
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Interaction of tonic neck and vestibular reflexes in the forelimb of the decerebrate cat (1984)
    Springer
    Experimental brain research 54 (1984), S. 289-292 
    Details
    ISSN: 1432-1106
    Keywords: Tonic neck reflex ; Vestibulo-forelimb reflex ; Neck-vestibular interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tonic neck reflexes, studied with EMG recording, have similar dynamics in forelimb extensor muscles of acutely labyrinthectomized cats, and in cats with intact labyrinths. The reflex occurs more frequently in the latter and its gain is higher. In intact preparations we evoked vestibular and tonic neck reflexes separately or in combination, at frequencies of 0.05–0.5 Hz. As expected from earlier work, the two reflexes oppose each other and frequently cancel; the two reflexes add linearly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236229
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Labyrinthine influence on cat forelimb motoneurons (1975)
    Springer
    Experimental brain research 22 (1975), S. 69-86 
    Details
    ISSN: 1432-1106
    Keywords: Labyrinth ; Forelimb motoneurons ; Lateral vestibulospinal tract
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Intracellular responses in forelimb motoneurons to electrical stimulation of the whole labyrinth and of individual semicircular canal nerves were studied in decerebrated, unanesthetized cats. 2. Stimulation of the whole labyrinth typically produced EPSPs, usually bilaterally, in forelimb extensor (LON, LAT, MED) and shoulder (SI) motoneurons and bilateral IPSPs in forelimb flexor (BIC) motoneurons. 3. Latencies of PSPs indicated that most of those in extensor motoneurons were trisynaptic and many seen in flexor motoneurons may involve four synapses. 4. In the cells sampled, stimulation of the anterior, horizontal or posterior canal nerves often evoked EPSPs in extensor and IPSPs in flexor motoneurons, both ipsi-and contralaterally. Responses to canal stimulation were weaker and more variable than those to stimulation of the whole nerve. 5. Transection of the MLF in the lower medulla had no effect on PSPs evoked in forelimb motoneurons. Lesions in the medulla in the area of the LVST greatly reduced the occurrence of contralateral EPSPs in extensor and IPSPs in flexor motoneurons. The pathway linking labyrinths to forelimb motoneurons therefore appears to include the LVST. Hemisection shows that the pathway to contralateral motoneurons descends in the cord on the side of the stimulated labyrinth before crossing to influence these cells. 6. Labyrinthine control of forelimb motoneurons is less direct than control of neck and back motoneurons. It is suggested that the interneuron in the pathway to forelimb motoneurons is the site of integration of labyrinthine with other reflexes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235412
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...