Library

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
    Springer
    Experimental brain research 40 (1980), S. 131-145 
    ISSN: 1432-1106
    Keywords: Interstitiospinal neurons ; Vestibular system ; Semicircular canal inputs ; Axon branching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Interstitiospinal neurons were activated by antidromic stimulation of the ventromedial funiculus of the spinal cord at C1 and C4 in cerebellectomized cats under chloralose anesthesia. 46% of these neurons responded only at C1 (N cells) and the remaining 54% responded at C4 also (D cells). There is no topographical difference in the location of N and D cells. Conduction velocities of N cells were significantly slower than those of D cells. 2. Stimulation of the contralateral whole vestibular nerve evoked firing of 31% of both N and D cells; some responded early enough to suggest disynaptic connections, many responded late. Stimulation of the ipsilateral whole vestibular nerve evoked firing of several cells, one spontaneously discharging D cell was inhibited. 3. Stimulation of the contralateral individual semicircular canal nerves evoked firing of 33% of N cells and 13% of D cells. Most of these responses were late. N cells responded not only to the vertical canals but also to the horizontal canal, whereas D cells responded to the horizontal canal, but seldom to the vertical ones. Most canal responding neurons received specific input, only two N cells received convergent input from both the anterior and horizontal canals. Stimulation of the ipsilateral canals did not evoke excitation of any cells tested; one D cell was inhibited by stimulation of the horizontal canal nerve. 4. Stimulation of the rostral medial vestibular nucleus evoked characteristic negative field potentials centered in the contralateral interstitial nucleus of Cajal (INC). Approximately 60% of both N and D cells received excitation from the contralateral vestibular nuclei. About 17% of these responding neurons received monosynaptic excitation, most frequently from the rostral medial nucleus. Stimulation of the ipsilateral vestibular nuclei evoked firing of 12% of both N and D cells. 5. Twenty-nine neurons were fired antidromically by weak stimuli applied to the ipsilateral vestibular nuclei. Twenty-seven of the 29 were activated only from C1 and were found in the INC (10 cells) and in the reticular formation dorsal to the INC (19 cells). Measurement of the spread of the effect of stimulus current and comparison of latencies to stimulation of the vestibular nuclei and C1 indicated that these neurons have axon collaterals going to the ipsilateral vestibular nuclei. Only one of them received excitation from the contralateral posterior canal, others did not respond to the labyrinth. Some were activated by stimulation of the vestibular nuclei.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1106
    Keywords: Midbrain reticular formation ; Interstitio-vestibular neurons ; Vestibular system ; Semicircular canal inputs ; Axon branching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experiments were performed on cats anesthetized with a chloralose to locate neurons in and around the interstitial nucleus of Cajal (INC) that project to the vestibular nuclei, and to study labyrinthine inputs to these neurons. Neurons that project to the vestibular nuclei were identified by microstimulation confined to the vestibular nuclei on both sides. All neurons thus identified were activated antidromically from the ipsilateral (but not contralateral) vestibular nuclei. Vestibular projecting neurons were found in the INC and the reticular formation rostral, dorsal and caudal to the INC. About 23% of these neurons were vestibular branching spinal projecting neurons. The median conduction velocity of vestibular projecting neurons was estimated to be in the neighborhood of 12–16 m/s. Stimulation of the contralateral vestibular nerve evoked firing in 29% of neurons projecting to the vestibular nuclei, but not to the spinal cord. Interstitial neurons responded more frequently than reticular neurons (45% vs 11%, χ2 test, p 〈 0.001). By stimulation of individual semicircular canal nerves, it was shown that vestibular projecting neurons receive excitation from the contralateral vertical canals, but do not receive substantial inputs from the horizontal canal. Stimulation of the ipsilateral vestibular nerve excited 10% of neurons; suppression of activity was observed for six cells and four of the six were excited by stimulation of the contralateral vestibular nerve. Stimulation of ipsilateral individual semicircular canal nerves did not excite any cells tested; the activity of a few cells was suppressed by stimulation of the vertical canal nerves. One neuron received excitation from the contralateral anterior canal and suppression from the ipsilateral posterior canal. Vestibular branching spinal projecting neurons rarely received labyrinthine inputs as already reported (Fukushima et al. 1980a). These results suggest that vestibular projecting neurons may be involved in vertical vestibular reflexes.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...