NEURONAL NETWORKS REGULATING DRINKING BEHAVIOR IN THE EEL(Department of Sciences for Biospheric Coexistence)

博士学位論文要

Brain Atlas of the Japanese Eel:Comparison to Other Fishes

The whole brain atlas of the eel was constructed in the first place by Klüver-Barréra's staining. Eighty onenuclei and thirty fiber tracts were identified in the present study. Basically, the brain topology of the eel wassimilar to that of the rainbow trout, the goldfish, the zebrafish, and the catfish. However, some details differedfrom those of other teleosts. The parvocellular preoptic nucleus (PP) was not subdivided, whereas the anteriorPP is distinguished from the posterior part in the zebrafish and the rainbow trout. The intermediate thalamicnucleus was not distinguished, whereas it is identified in the zebrafish, the goldfish, and the rainbow trout. Theparaventricular organ (PVO) was single, while paired PVOs are observed in the zebrafish. The torus semicircularis(TS) was smaller than that in the goldfish and rainbow trout. The cell size of the nucleus of medial longitudinalfascicle (NMLF) in the tegmentum was larger than that in the glass knifefish and the zebrafish. The protrusionof the nucleus lateralis valvulae (NLV) into the mesencephalic ventricle (VMes) was larger than that in thezebrafish and the rainbow trout. The valvula cerebelli was smaller than those in the goldfish and the zebrafish.The facial lobes (LVII) ran through the medulla oblongata (MO), whereas the two lobes fuse at the caudalcerebellum in the goldfish, the catfish, and the zebrafish. The expansion of the vagal lobe (LX) in the caudalMO was smaller than that in the goldfish and the zebrafish. The glossopharyngeal motor nucleus (MNIX) andthe vagal motor nucleus (MNX) were fused to make a columnar structure named glossopharyngeal-vagal motorcomplex (GVC). Such a columnar complex seems to be common in fishes, since similar columns are observedin the lamprey, the elasmobranch and other teleost fishes. The facial motor nucleus (MNVII) was separatedfrom the GVC, whereas it is fused with the GVC in the sturgeon, the reedfish and the tarpon

Impact of Hands-on Experience of a Cadaver Dissection on the Professional Identity Formation of Health Sciences Students

[Background] In Japan, some nursing and health science universities that train nurses and/or clinical laboratory technicians have a curriculum in which students observe medical students performing a cadaver dissection. Observing a cadaver dissection is believed to affect the formation of a student’s professional identity. This study aimed to investigate the effects of observing a cadaver dissection on the professional identity of nursing and clinical laboratory science students to find an effective educational support system for developing professional identity. [Methods] Sophomores majoring in nursing science or clinical laboratory science were asked to complete a questionnaire with a professional identity scale before and after hands-on experience of a cadaver dissection performed by medical students. After their hands-on session was complete, they responded to a free-answer question about acquiring a professional identity. [Results] The professional identity score of nursing students significantly decreased after the hands-on experience of the cadaver dissection. No significant change in professional identity score was observed in the clinical laboratory science students. However, the effect size (r) was moderate. [Conclusion] Although professional identity formation fluctuates immediately after the experience of the hands-on experience of a cadaver dissection, the findings do suggest that these hands-on sessions will be effective for developing their professional identity if educational support is provided to help them utilize what they learned through reflection

ウナギの飲水行動を調節している神経回路網の探索

広島大学(Hiroshima University)博士(学術)Sciencedoctora

Central regulation of the pharyngeal and upper esophageal reflexes during swallowing in the Japanese eel

We investigated the regulation of the pharyngeal and upper esophageal reflexes during swallowing in eel. By retrograde tracing from the muscles, the motoneurons of the upper esophageal sphincter (UES) were located caudally within the mid-region of the glossopharyngeal-vagal motor complex (mGVC). In contrast, the motoneurons innervating the pharyngeal wall were localized medially within mGVC. Sensory pharyngeal fibers in the vagal nerve terminated in the caudal region of the viscerosensory column (cVSC). Using the isolated brain, we recorded 51 spontaneously active neurons within mGVC. These neurons could be divided into rhythmically (n = 8) and continuously (n = 43) firing units. The rhythmically firing neurons seemed to be restricted medially, whereas the continuously firing neurons were found caudally within mGVC. The rhythmically firing neurons were activated by the stimulation of the cVSC. In contrast, the stimulation of the cVSC inhibited firing of most, but not all the continuously firing neurons. The inhibitory effect was blocked by prazosin in 17 out of 38 neurons. Yohimbine also blocked the cVSC-induced inhibition in five of prazosin-sensitive neurons. We suggest that the neurons in cVSC inhibit the continuously firing motoneurons to relax the UES and stimulate the rhythmically firing neurons to constrict the pharynx simultaneously

Middle Miocene ostracods from the Fujina Formation, Shimane Prefecture, Southwest Japan and their paleoenvironmental significance

金沢大学国際基幹教育院GS教育系Thirty-five ostracod species belonging to 18 genera are recognized from the Middle Miocene Fujina Formation (ca. 14-12 Ma), 3km southwest of Matsue City, Shimane Prefecture, Japan. Most of these species are part of the recent Japan Sea proper water fauna; they are also classified into 4 categories, circumpolar, cryophilic, endemic cool-temperate and temperate species. These ostracod assemblages indicate that the Fujina Formation was deposited under a cold-water environment. Ten new species, Ambtonia shimanensis, A. takayasui, Acanthocythereis fujinaensis, A. izumoensis, Cluthia tamayuensis, C. subjaponica, Kotoracythere tsukagoshii, Laperousecythere ikeyai, Palmoconcha irizukii, and Robertsonites yatsukanus are described