OBJECTIVE: A radial arm maze (RAM) is an essential tool for assessing spatial learning and memory. Although this tool is widely used to study deficits in spatial memory in animal models, it has several restrictions that prevent its adaptation to human research and training. Therefore, we developed a head-mounted-display RAM (HMD-RAM) program for humans and verified its validity by comparing it to the results obtained by previous RAM studies. We also compared the HMD and a flat monitor as experimental devices. METHODS: Forty participants were recruited for the current study (Study 1: 20 participants with the HMD device; Study 2: 20 participants with the flat monitor). They navigated a virtual room as a first-person viewer and used environmental landmarks to remember their spatial position and orientation. The main dependent measures were working memory error, reference memory error, detection time, travel distance, and participant’s head movements. To validate the program, participants also conducted neuropsychological assessments and self-reported measures. RESULTS: The results for HMD-RAM tasks were consistent with the results of previous research conducted on animals, and the HMD elicited a higher sense of presence, immersion, and simulator sickness than the flat monitor. According to post-experiment questions on navigation strategy, creating landmarks was important when people were discovering locations in their environment, and an HMD was beneficial for better navigation strategy. CONCLUSION: These results suggest that the HMD-RAM is valuable for estimating spatial learning and memory in humans and may be a useful tool for early diagnosis of deficits in spatial learning and memory, including amnestic mild cognitive impairment and Alzheimer’s disease.
Animals ; Arm* ; Early Diagnosis ; Head Movements ; Humans ; Immersion ; Memory* ; Memory, Short-Term ; Mild Cognitive Impairment ; Models, Animal ; Spatial Learning* ; Spatial Memory

OBJECTIVE: Previous studies have suggested that a virtual classroom is immersive and ecologically valid neuropsychological assessment, but those studies have limited components for social attentions. Therefore, the objective in the current study is the development of a joint attention virtual reality (JA-VR) classroom to incorporate social attentions between a participant and a virtual avatar teacher. METHODS: Fifty-eight participants were recruited for current study (25 for pilot and 33 for main studies; 32.8% female, n=19; age: M=24.5, SD=4.0). We suggested a JA-VR classroom, and compared it with previous methods including a VR classroom without JA components. We conducted attention experiments with AX-version of continuous performance tasks. RESULTS: Our results suggest that the new JA-VR classroom had convergent validity with previous methods, and that the JA-VR classroom promoted attentional processing among participants better than both old VR and non-VR measures. CONCLUSION: We add an important social attention concept to the virtual classroom, and believe that this work is an methodological foundation for the study of social attention in school life. We hope it ultimately help people with mental handicaps in social attention.
Attention ; Female ; Hope ; Humans ; Joints

Comparison of pancreaticoduodenal transplants (PDT) and duct-ligated pancreas transplant (DLPT) were performed using syngeneic and allogeneic studies in rats. Both DLPT and PDT allogeneic grafts showed mild rejection. DLPT groups showed disorganized pathology and acini replaced by fat. Eventually, massive fibrosis was seen in the Islets of Langerhans, as well as rejection cellular infiltrates. In both PDT groups, normal histology was observed in the same period. Thus the effect of duct occlusion is highly detrimental for the grafts.
Animals ; Graft Rejection/pathology ; Ligation/adverse effects ; Pancreas/*pathology ; Pancreas Transplantation/*adverse effects ; Pancreatic Ducts/surgery ; Postoperative Period ; Rats ; Rats, Inbred Lew ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Transplantation, Homologous ; Transplantation, Isogeneic

This study was conducted by consecutively transplanting spleens, which had gonads implanted previously. A total of 84 cases for infantile testicles and 106 cases for ovarian follicles were performed. In the case of ovarian implants, the results were determined by the total number of follicle implants. A modified spleen transplantation technique called double implantation of ovarian follicles was applied to increase the amount of the implants. In this technique, an extra spleen is implanted into the potential donor so that the ovarian follicles can be implanted to two different spleens, doubling the amount of implants. Through consecutive spleen transplantation, we observed the results beyond a typical rat's life span. In many of these cases, we found more aggressive forms of malignant tumor, seminoma and dysgerminoma. We present the results and discuss possible pathogenic mechanisms of tumor formation.
Animals ; Animals, Newborn ; Female ; Male ; Ovarian Neoplasms/*etiology ; Ovary/*transplantation ; Rats ; Rats, Inbred Lew ; Research Support, Non-U.S. Gov't ; Spleen/*surgery/*transplantation ; Testicular Neoplasms/*etiology/pathology ; Testis/*transplantation ; *Transplantation, Heterotopic