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VESTIBULAR AND SOMATIC INPUTS TO CELLS OF THE LATERAL AND MEDIAL VESTIBULAR NUCLEI OF THE CAT
Pages 145-160

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From page 145... ... Electric stimulation of the labyrinth activates many projecting cells as well as many cells without long axons. There is also a somatic input to cells in the medial nucleus, and it is of particular interest that vestibular and somatic inputs, as well as commissural inputs and inputs from fibers descending from higher levels of the central nervous system, converge on many cells lacking long axons projecting rostrally or to the spinal cord. Read the entire page →
From page 146... ... Antidromic invasion of Deiters' cells resulted from stimulation of the vestibulospinal tract at various levels of the spinal cord; cells in the medial nucleus were activated antidromically either by DEITERS' EXPERIMENTS RECORDING ELECTRODE MEDIAL NUCLEUS EXPERIMENTS CONTRALATERAL LABYRINTH IPSILATERAL LABYRINTH FIGURE I -- Diagram of experimental arrangement. Read the entire page →
From page 147... ... This relatively small number of cells fired polysynaptically is in contrast to the much greater number of medial nucleus cells so fired (ref. 4, and below) Read the entire page →
From page 148... ... . Somatic Input to Cells in the Lateral Vestibular Nucleus It has been known for some time that fibers in the restiform body may give off collaterals to the vestibular nuclei (cf. Read the entire page →
From page 149... ... Nevertheless, it would be expected that stimulation of peripheral nerves in animals with the cerebellum intact should produce more inhibition of Deiters' cells than has so far been described, and systematic investigation of this matter seems to be required. What kind of afferent fibers, when stimulated, produce facilitation of cells in the lateral vestibular nucleus? Read the entire page →
From page 150... ... Most interesting is the fact, indicated by the ineffectiveness of electrical stimulation of group I fibers, that activation of the primary endings of muscle spindles, or of tendon organs, has little or no influence on cells of the lateral vestibular nucleus. Apparently the vestibulospinal system, closely involved in the regulation of posture and muscle tone, is little affected by information originating in the most important muscle receptors. Read the entire page →
From page 151... ... . I will refer to medial nucleus cells without long ascending or descending axons as interneurons, and will include among them commissural cells projecting to the contralateral vestibular nuclei (ref. Read the entire page →
From page 152... ... Many cells in the medial nucleus receive inputs from the horizontal canals. Those cells excited by ipsilateral and inhibited by contralateral acceleration have been called type I cells; those inhibited by ipsilateral and excited by contralateral acceleration have been called type II cells (cf. Read the entire page →
From page 153... ... . Somatic Input to Cells in the Medial Nucleus and Its Convergence With the Vestibular Input There is much less information about the somatic input to medial nucleus cells than there is about this input to Deiters' cells. Read the entire page →
From page 154... ... that was used for antidromic activation of medial nucleus cells; in some cases stimulation of peripheral nerves was also attempted. A number of cells were excited transsynaptically by the cord electrode and by strong shocks (above group III threshold) Read the entire page →
From page 155... ... 16. WALBERG, F.; BOWSHER, D.; AND BRODAL, A.: The Termination of Primary Vestibular Fibers in the Vestibular Nuclei in the Cat. Read the entire page →
From page 156... ... 50. MANO, M.; OSHIMA, T.; AND SHIMAZU, H.: Inhibitory Commissural Fibers Interconnecting the Bilateral Vestibular Nuclei. Read the entire page →
From page 157... ... It seems likely, at least in the preparation with the cerebellum intact, that some competition of facilitatory and inhibitory effects occurs at the level of the vestibular neurons from converging afferent volleys of different spatial and temporal dispersions. With respect to the second problem, I should like to mention that stimulation of the vestibular nerve performed in decerebrate cats evokes dorsal-root potentials in the lumbar cord at the time that descending vestibular volleys elicit motoneuronal discharges (Cook, W Read the entire page →
From page 158... ... Unfortunately, so far he has not had good tilting effects and good .minimum driving in the same cat, but we are pursuing this also. Precht: A short comment to the problem of monosynaptic and polysynaptic activation of the vestibular neurons in response to vestibular nerve stimulation. Read the entire page →
From page 159... ... SESSION VI Chairman: CESAR FERNANDEZ University of Chicago Read the entire page →

From page 145...

... Electric stimulation of the labyrinth activates many projecting cells as well as many cells without long axons. There is also a somatic input to cells in the medial nucleus, and it is of particular interest that vestibular and somatic inputs, as well as commissural inputs and inputs from fibers descending from higher levels of the central nervous system, converge on many cells lacking long axons projecting rostrally or to the spinal cord.

VESTIBULAR AND SOMATIC INPUTS TO CELLS OF THE LATERAL AND MEDIAL VESTIBULAR NUCLEI OF THE CAT Pages 145-160

VESTIBULAR AND SOMATIC INPUTS TO CELLS OF THE LATERAL AND MEDIAL VESTIBULAR NUCLEI OF THE CAT
Pages 145-160