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H Jijiwa

Publications and source records attributed to H Jijiwa.

16 recordsLinked to original sources
PubMed2001

Passage of dextran magnetite nanoparticles through the subcupular space of the pigeon.

We examined the permeability of the subcupular space for endolymph flow in the pigeon. A new technique was developed in which nanoparticles consisting of dextran magnetite were attracted by use of a magnet, instead of injecting a dye solution. The method was revealed to prevent an excess pressure application by the injection of dye solution. The Berlin blue color resulting from the dextran magnetite nanoparticles was found mainly within the subcupular space contacting with the sensory hairs. Further formation of the Berlin blue was found within the sensory cells. The result supports the idea that the fluid passes through the subcupular space.

Animals↗
PubMed2001

Cupular response and functional anatomy to pressure application in the pigeon.

In this study, horizontal semicircular canal of the pigeon was inserted with a microfill, 164 micrometers in outer diameter, to gauge the pressure change in the canal and to clarify two things. One is whether the endolymph passes through the crista ampullaris or not. The other is as to the space where the endolymph passes through in the crista ampullaris if the endolymph goes through the crista. The pressure applications were performed by using Evans blue solution and as a result three pressure groups, i.e., 1) high, 2) moderate and 3) low were discriminated. Our results suggest that the endolymphatic fluid passes through the subcupular space or the top of the crista ampullaris when the pressure is enough small like the head rotates in daily life. Accordingly we present a new hypothesis as to the functional anatomy of the cupula in contrast to current hypotheses e.g. drum membrane or revolving door.

Animals↗
PubMed1993

The dynamics of phase relationships of alpha waves during photic driving.

Inter- and intrahemispheric phase relationships of alpha waves during photic driving with intermittent flash stimuli were successively calculated by our newly developed method and compared with the results obtained during the resting condition. Of 12 healthy subjects, 6 showed obvious photic driving responses in the occipital regions (driven group) but the remaining 6 did not (non-driven group). In the driven group, the interhemispheric phase differences decreased, especially when EEG frequencies coincided with stimulating frequencies. However, this was not maintained throughout the stimulation period but was accompanied by some fluctuation. The interhemispheric phase difference decreased in the posterior temporal and, in particular, in the occipital areas. The intrahemispheric phase difference for the occipito-frontal and the occipito-central pairs in each hemisphere tended to increase and remained at approximately pi radians, especially for the former pair. These findings suggest the presence of a specific response in the occipital area. Time ratios of the phase lead in longitudinal and transverse directions and the high similarity of the time courses of intrahemispheric phase differences between bilaterally homologous pairs at rest suggest that there exist phasing mechanisms which act in parallel between the left and right hemispheres with dominant antero-posterior time delay.

Adult↗
PubMed1975

Responses of cortical vestibular center produced by stimulation of vestibular nuclei and visual association area in the cat.

(1) The cortical projection of the vestibular nuclei (LVN, MVN and IVN) was investigated by the evoked potential and unit discharge analyses in the cat anesthetized with alpha-chloralose and/or immobilized with gallamine triethiodide. (2) This projection field coincided well with that of the vestibular nerves, being principally contralateral by LVN stimulation but nearly symmetrical by either MVN or IVN stimulation. (3) Of 11 units responsive to vestibular nuclei stimulation, 6 reacted to stimulation of the visual association cortex (anterior part of the Clare-Bishop area). The response pattern of the cortical vestibular units by C-B stimulation was a sequence of excitation, inhibition and rebound. (4) Interaction of visual information with the cortical vestibular neurons was discussed.

Animals↗
PubMedDate not supplied

Does the endolymph pass through the base of the cupula?

Whether the endolymph of the semicircular canal passes the cupular partition or not was examined using the lateral semicircular canal system of adult pigeons (Columba livia). By applying various pressures by means of injection of a dye solution through the membranous canal, it was found that the dye solution, was seen to pass the cupula even under very low pressures when the pressure was increased gradually. When pulled by a magnet, the ultrafine particles of the dextran magnetite contained in the injected fluid were found to pass through the subcupular space without evident increase of the ampullary pressure.

Animals↗