Publications by authors named "S Okoyama"

Anatomical plasticity of projections from brainstem auditory structures to the inferior colliculus (IC) was examined in albino rats to determine the effects of unilateral destruction of the IC during early development. The IC in the right hemisphere was destroyed by aspiration on postnatal day 3. Upon reaching adulthood, the rats were examined by retrograde tract tracing methods with fluoro-gold (FG) and [3H]-glycine to determine patterns of brainstem projections to the undamaged left IC.

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Objective: We investigated free radical scavenging activity and the possible neuroprotective effect of Tokishakuyakusan (TJ-23) on facial motor nucleus (FMN) motoneurons after peripheral axotomy.

Study Design: In 40 adult rats, the right facial nerve was transected at the level of the stylomastoid foramen. Following axotomy, the effects of TJ-23 on nitric oxide synthase were investigated using NADPH-d histochemistry.

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The central nucleus of the inferior colliculus (CNIC) contains different types of neurons and is a source of ascending projection to the medial geniculate body (MGB), commissural projection to the contralateral IC, direct descending projection to the cochlea nucleus (CN) and indirect projection to the CN via the superior olivary complex (SOC). Using a retrograde tracing technique, we examined what kind of neurons and what percentage of neurons of each type recognized in the CNIC participated in the above-mentioned four projection pathways. We also examined whether the individual CNIC neurons send the collateral to the MGB, the contralateral IC, the CN and the SOC.

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Cerebellar Purkinje cells are key elements in motor learning and motor coordination, and therefore, it is important to clarify the mechanisms by which Purkinje cells integrate information and control cerebellar function. Gene transfer into neurons, followed by the assessment of the effects on neural function, is an effective approach for examining gene function. However, this method has not been used fully in the study of the cerebellum because adenovirus vectors, the vectors most commonly used for in vivo gene transfer, have very low affinity for Purkinje cells.

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The onset and distribution of calbindin (CB) and parvalbumin (PV) immunoreactivity were investigated in the lateral geniculate nuclear complex and the olivary pretectal nucleus (OPT) in developing rats. CB expression occurred early (before eye-opening) in the relay neurons of the intergeniculate leaflet, parvocellular portion of the ventral lateral geniculate nucleus and OPT relating to ambient vision mediated by W-like retinal ganglion cells. On the contrary, PV expression occurred late (after eye-opening) in the relay neurons of the magnocellular portion of the ventral lateral geniculate nucleus (VLGMC) and OPT relating to focal vision mediated by Y-like retinal ganglion cells.

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