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Y Shinoda

Publications and source records attributed to Y Shinoda.

118 records · Page 7Linked to original sources
PubMedDate not supplied

Morphology of single neurones in the cerebello-rubrospinal system.

Axonal branching patterns of physiologically identified cerebellar nucleus neurones and rubrospinal neurones were investigated in the cat with intra-axonal injection of horseradish peroxidase and 3-dimensional reconstruction on serial sections. Axons of dentate and interpositus neurones projected to the VL nucleus of the thalamus and on their way, several axon collaterals were given off from the stem axons to the red nucleus. Axon terminals of interpositus neurones terminated as a sagittal sheet of arborizations in the red nucleus. Their terminal boutons made apparent contact with cell bodies and proximal dendrites of rubrospinal neurones. In rubrospinal axons, multiple axon collaterals were identified at different segments of the cervical spinal cord.

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PubMedDate not supplied

Thalamocortical organization in the cerebello-thalamo-cortical system.

In the cat, the cerebellum projects via the ventroanterior-ventrolateral (VA-VL) complex of the thalamus to the motor and premotor cortices and also to the parietal association cortex. Cerebellar inputs to each of these regions have been characterized electrophysiologically by depth profiles of cortical potentials following stimulation of the brachium conjunctivum and of the VA-VL complex, and morphologically by the laminar distribution of thalamocortical (TC) terminations, in aggregate and at the single-axon level. One population of TC neurons terminated mainly in layer I and was associated with late surface negative potentials. A second population, with terminations in layers III and IV, was associated with early deep negative potentials. Terminations in layer III of the motor cortex formed multiple patches about 1-1.5 mm wide (mediolateral), which aligned to form 2-5 mm stripes extended rostrocaudally. This pattern correlates with the configuration of individual TC axons, which have two to six separate terminal patches distributed over 6 mm (rostrocaudal). The wide morphological divergence of single TC axons in the cortex may imply functionally multiple innervation of different efferent columns. Alternately, along with other inputs, it may permit a highly dynamic output selection from multiple representations, for example, of a variety of muscle groups in different combinations.

Animals↗
PubMedDate not supplied

The origin of amyloid in gelatinous drop-like corneal dystrophy.

The origin of amyloid in gelatinous drop-like corneal dystrophy, one of the primary corneal amyloidoses, was studied by light and electron microscopy. Milky-white granules over the corneal surface are the first clinical findings. In the initial stage, the amyloid substance exists between the basal cell of the corneal epithelium and the basal lamina of the cell. The basal lamina, Bowman's membrane and the stroma remained intact. Numerous filaments, about 7nm in width, were seen in the normal basal cells. In addition, many fibrils, about 10nm in width, were observed in the damaged basal cells. With progressing of the disease, the amyloid increased in amount and Bowman's membrane disappeared. Our results suggest that the basal cell of the corneal epithelium may produce and secreted the amyloid substance and gelatinous drop-like corneal dystrophy occurred.

Adult↗
PubMedDate not supplied

The vestibulocollic reflex.

Stabilization of the head is required not only for adequate motor performance, such as maintaining balance while standing or walking, but also for the adequate reception of sensory inputs such as visual and auditory information. The vestibular organs, which consist of three approximately orthogonal semicircular canals (anterior, horizontal, posterior) and two otolith organs (utriculus, sacculus), provide the most important input for the detection of head movement. Activation of afferents from these receptors evokes the vestibulocollic reflex (VCR), which stabilizes head position in space. In this review, which is the outgrowth of a session of the vestibular symposium held in Hawaii in April, 1994, we discuss the neural substrate of this reflex and some aspects of the central processing involved in its production. Some topics are not considered, in particular the important interaction between the VCR and the cervicocollic reflex evoked by activation of neck afferents (70,119), and attempts to model the reflex (69).

Afferent Pathways↗
PubMedDate not supplied

How to construct and move a cat's neck.

Extensive information has been accumulated over the past several years about the head-neck sensory-motor system, in particular that relating to cats. Using still x-ray and cineradiographic analysis, the skeletal geometry of head-neck posture in three dimensions--when an animal is resting, actively orienting, or locomoting--is described. From these descriptions, cervical, vertebral, and craniocervical joint biomechanics for all three rotational dimensions are quantified. These behavioral data on muscle and skeletal movements have been incorporated in a biomechanical, functional anatomical model of the head-neck movement system. Individual as well as groups of neck muscles have been measured in detail and their kinematics determined. The role of a number of these muscles will be described for several reflex and voluntary behavioral contexts, including muscle co-contractions. Having established how each movement is accomplished, the neuronal sensory-motor reflex basis of head-neck system stabilization in space is addressed. The vestibular system is largely responsible for acquisition and maintenance of upright posture. The bilateral semicircular canals (horizontal, anterior, posterior) and otoliths (sacculus, utriculus) feed information differentially to specific neck muscles: these connections are reviewed with regard to the origin of the reflex are from each receptor to its destination of specific muscles. Behavioral data from normal animals, and from animals whose vestibular receptor systems are selectively lesioned, will be reviewed to complement the functional interpretation of the sensory-motor transformations. Finally, the requirements for space-time coordinated cat head-neck movements will be synthesized, based on biomechanics, muscle kinematics, canal/otolith connectivity, and selective lesion experiments.

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