PubMed Health⌕ Search

Biomedical subjects

Hidetoshi Ishibashi

Publications and source records attributed to Hidetoshi Ishibashi.

10 recordsLinked to original sources
PubMed2006

Tactile stimulation-induced rapid elevation of the synaptophysin mRNA expression level in rat somatosensory cortex.

Synaptophysin is an integral membrane protein abundant in the synaptic vesicle and is found in nerve terminals throughout the brain. It was recently suggested that synaptophysin is also involved in the modulation of activity-dependent synapse formation. In this study, we examined at the individual level whether tactile stimulation selectively influenced the synaptophysin mRNA expression level in the somatosensory cortex of rats. Anesthetized rats were caressed on the back by an experimenter's palms for 20 min and the mRNA expression levels in the somatosensory and the visual cortices 5 min afterwards were determined using quantitative PCR methodology. The synaptophysin mRNA expression level was selectively higher in the experimental group than in the control group in the somatosensory cortex but not in the visual cortex. This suggests that the mRNA expression level of synaptophysin induced by neuronal activity is related to the regulation of synapse formation or remodeling or both.

Animals↗
PubMed2005

Posterior corneal surface changes after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate posterior corneal surface topographic changes after hyperopic laser in situ keratomileusis (H-LASIK) using Orbscan I (Orbtek, Inc.). SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: In 25 eyes of 15 patients who had H-LASIK, the posterior corneal surface was measured with slit-scanning corneal topography (Orbscan I) preoperatively and 1 year postoperatively. The center as a fit zone and calculated posterior corneal surface changes were taken at 4 points: nasal, temporal, superior, and inferior sides in the 5.0 mm diameter. The posterior corneal topographic changes were analyzed using an analysis of variance. The postoperative:preoperative magnification ratio of the posterior corneal surface was calculated in a theoretical eye model. RESULTS: When a "+" reading was defined as the forward displacement and "-" was defined as the backward displacement, the mean posterior corneal topographic changes were -2.8 microm +/- 27.9 (SD) at the nasal side, -4.5 +/- 27.8 microm at the temporal side, -3.9 +/- 20.1 microm at the superior side, and -2.3 +/- 20.1 microm at the inferior side. The posterior corneal surface between any 2 examined points showed no significant difference after H-LASIK. In addition, the hypothetical change in the posterior cornea was -8.3 microm after +3.0 diopter H-LASIK, which was approximately closer to the study results. In each side, the amount of the attempted correction was significantly correlated with the posterior corneal topographic change. CONCLUSIONS: Clinical measurement of the posterior corneal displacement after H-LASIK with Orbscan revealed a backward shift. This change corresponded to the hypothetical artifactual changes with Orbscan; that is, changes in the magnification ratio.

Adult↗
PubMed2004

Association of food location with biological cues in the macaque monkey.

Many animal species including humans are endowed with the ability to use biological cues and can extract information by observing other individuals. This study explored whether the macaque monkey could use biological cue to find a hidden target. When the experimenter hid food in one hand and crossed and uncrossed hands quickly, the monkey had no difficulty in finding the food and correctly reached for the baited hand. However, when the food was hidden in one of two cups and the cups were shuffled, the monkey could correctly select the baited cup only at an equal level of luck. These results indicate that the macaque monkey could associate the location of food with a biological cue better than a non-biological cue and keep it in memory when the target was unseen.

Animals↗
PubMed2003

Natural imitation induced by joint attention in Japanese monkeys.

To examine whether joint attention enables Japanese monkeys to imitate human actions, we presented an oral action and manual actions directed towards targets to three monkeys who had joint attention through communicative eye-gaze and pointing gestures and to one monkey who had incomplete joint attention and who had acquired imperative pointing but not the use of eye-gaze gestures. Two of the monkeys who were already capable of joint attention were also able to imitate naturally, while the monkey who did not previously show joint attention was not able to imitate until acquiring joint attention capacity. We suggest that joint attention induces natural imitation during interaction between different species--in this case, between monkeys and humans--while individuals not showing joint attention but only attention to a target or movement are only able to follow motion. The monkey may be endowed by nature with motion-following capacity. We speculate that motion-following capacity is developed and controlled through joint attention, and is connected with natural imitation.

Animals↗
PubMed2003

Evaluation of the corneal endothelium after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate corneal endothelial changes after hyperopic laser in situ keratomileusis (LASIK) considering overestimation and underestimation of the cell count measurement. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: The data were from the clinical trial of the Nidek EC-5000 excimer laser for hyperopic LASIK. The mean correction was 3.59 diopters (D) +/- 1.54 (SD) (range 2.0 to 6.0 D). Using noncontact specular microscopy, the corneal endothelial changes in 25 eyes of 15 patients who had hyperopic LASIK were measured. Follow-up ranged from 6 months (n = 25) to 1 year (n = 21). The overestimation and underestimation of the corneal endothelial cell count that would occur after +5.0 D hyperopic LASIK was hypothetically calculated. RESULTS: The measured endothelial cell count per 1.0 mm(2) did not significantly decrease up to 1 year after hyperopic LASIK (preoperatively, 2508 +/- 395; at 1 year, 2814 +/- 349). The hypothetical calculation revealed that a +5.0 D hyperopic correction corresponded to a 0.1% underestimation of the corneal endothelial cell count. CONCLUSIONS: Underestimation of the corneal endothelial cell count after hyperopic LASIK was negligible. Hyperopic LASIK with the Nidek EC-5000 excimer laser did not significantly decrease corneal endothelial cells up to 1 year after surgery.

Adult↗
PubMed2002

Tool-use learning induces BDNF expression in a selective portion of monkey anterior parietal cortex.

Learning but not execution of tool-use induced expression of brain-derived neurotrophic factor (BDNF). The expression was highest in the anterior bank of the intraparietal sulcus, especially in the region posteriorly adjacent to the somatosensory shoulder and forearm region in area 3b, suggesting that BDNF plays a role in altering the body image of the hand to include the repeatedly used tool as its extension.

Animals↗
PubMed2002

Tool-use learning selectively induces expression of brain-derived neurotrophic factor, its receptor trkB, and neurotrophin 3 in the intraparietal multisensorycortex of monkeys.

When humans repeatedly use a tool, our body image alters until the tool finally becomes a part or an extension of the body. This alteration of body image perhaps results from re-integration of somatosensory and visual signals. We trained Japanese monkeys to use a rake-shaped tool to retrieve a distant food pellet, then used a novel tissue-sampling method to suction brain tissue from the anterior bank of their intraparietal sulcus, where somatosensory and visual signals converge. Examination of the messenger RNA expression levels of neurotrophins and their receptors using real-time quantitative polymerase chain reaction revealed learning-selective induction in the expression of brain-derived neurotrophic factor, its receptor trkB, and NT-3 during, but not after, the learning. These results suggest that these factors are involved in the reorganization of the somatosensory and visual signals in the anterior bank of the intraparietal sulcus when monkeys are learning the use of the tool.

Animals↗
PubMed2002

Increased synaptophysin expression through whisker stimulation in rat.

1. Synaptophysin is responsible for the cycling of the synaptic vesicles containing the neurotransmitter, and it can be phosphorylated. 2. This study examined whether repeated whisker stimulation alters the expression of synaptophysin mRNA in the rat barrel cortex, and found induced expression of synaptophysin mRNA in the contralateral barrel cortex compared to that in the ipsilateral hemi sphere. 3. This result suggests that synaptophysin is involved in the modulation of the synaptic plasticity.

Afferent Pathways↗
PubMedDate not supplied

Relationship between corneal aberrations and contrast sensitivity after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate the relationship between corneal aberrations and contrast sensitivity (CS) after hyperopic laser in situ keratomileusis (H-LASIK). METHODS: In 13 patients (13 eyes) who underwent H-LASIK, we measured CS and corneal topography preoperatively and at 1 year postoperatively. Photopic and scotopic CS values were measured at 3, 6, and 12 cycles/degree (cpd) using an MCT-8000 contrast tester. Corneal aberrations were determined from the data on corneal topography using CTView. The corneal high-order aberrations were defined as the sum of the third- and fourth-order aberrations in the 4-mm zone and the sum of the third- to sixth-order aberrations in the 6-mm-zone. RESULTS: Under scotopic conditions at 12 cpd, the changes in CS significantly correlated with changes in the corneal aberrations. Scotopic CS was significantly deteriorated by glare, but photopic CS was not significantly changed. H-LASIK induced a significant increase in corneal aberrations that positively correlated with the amount of correction, regardless of the improvement in logMAR corrected visual acuity. LogMAR corrected visual acuity did not significantly correlate with corneal aberrations. Furthermore, decentration significantly correlated with the changes in the 6-mm zone corneal aberrations. CONCLUSIONS: In eyes after H-LASIK, the changes in scotopic CS significantly correlated with those in the corneal aberrations, which might have resulted from decentration or ablation profiles in H-LASIK and a relatively small optical zone. Further studies will be needed to validate this relationship.

Adult↗