Changes of functional connectivity between the right anterior insula and the frontal operculum in mild cognitive impairment / 中华老年心脑血管病杂志

Objective To investigate changes of functional connectivity between the right anterior insula and the frontal operculum in mild cognitive impairment(MCI).Methods Twenty-one MCI patients served as MCI group and twenty age-and gender-matched subjects with normal cognitive function served as a control group in this study.Resting-state fMRI was performed and functional connectivity to right anterior insula and the frontal operculum was obtained with a voxel-wise manner.The difference in functional connectivity between the two groups was obtained with two -sample t-test.Results The mini-mental state examination score was significantly lower in MCI group than in control group(25.8±0.6 vs 29.2±0.3,P＜0.01).In healthy elderly,a distributed set of regions,including bilateral inferior parietal lobule,right middle and posterior cingulated cortex,right middle frontal gyrus,right mediodorsal nucleus of thalamus,right supplementary motor area,left anterior insula and the frontal operculum,left superior temporal gyrus,left inferior frontal gyrus,left precentral gyrus and left olfactory cortex(orbital and vertical gyrus),showed functional connectivity to right anterior insula and the frontal operculum.While bilateral inferior parietal lobule,right inferior frontal gyrus(opercularis,orbitalis,triangularis),right middle frontal gyrus,right middle cingulated cortex,right thalamus,left anterior insula and the frontal operculum and ACC,showed functional connectivity to right anterior insula and the frontal operculum in MCI.Compared to healthy elderly,decreased functional connectivity to right anterior insula and the frontal operculum was identified in left olfactory cortex and left superior parietal lobule,while increased in right medial prefrontal lobe.At the same time,a tendency of decreased functional connectivity to left anterior insula and the frontal operculum was also observed in left olfactory cortex.Conclusion The changes of functional connectivity to right anterior insula and the frontal operculum can be a significant biomarker in the differential diagnosis of MCI.

Cortical Magnetic Resonance Imaging Findings in Patients With Posttraumatic Olfactory Dysfunction: Comparison According to the Interval Between Trauma and Evaluation

OBJECTIVES: Patients with smell loss after craniocerebral trauma are known to have some brain abnormalities, but there was no study to analyze the findings according to the time interval between injury and evaluation. We aimed to identify whether the time interval may influence on the findings in the brain. METHODS: Medical records of 19 patients with posttraumatic olfactory dysfunction were reviewed. All of them underwent a magnetic resonance imaging and olfactory function tests. The patients were divided into early (n=10) and delayed (n=9) groups according to the time interval. RESULTS: Magnetic resonance imaging was taken at a mean time of 2.2 and 59.6 months after trauma in the early and delayed groups, respectively. Abnormal findings in the brain were found in 6 and 8 patients in the early and delayed groups, respectively. The olfactory bulb and orbitofrontal cortex were commonly affected olfactory pathways in both groups. In the early group, the abnormalities were brain tissue defect, hemorrhage, and focal edema whereas tissue defect was the only finding in the delayed group. In the early group, 5 of 6 patients with severe olfactory dysfunction showed brain abnormality while 1 of 4 patients with mild dysfunction had abnormality. In the delayed group, all the patients had severe dysfunction and 8 of 9 patients showed brain abnormality. CONCLUSION: Most patients with traumatic olfactory dysfunction had abnormality in the brain, and brain abnormality might be different according to the timing of evaluation. Furthermore, there might be an association between the severity of olfactory dysfunction and radiological abnormalities.

Understanding the Human Sensory Conduction of Smell / 한양의대학술지

The olfactory epithelium is the main end organ for the sense of smell in humans and vertebrates. Specially differenciated neuronal cells called olfactory receptor neurons (ORNs) play a key role in the olfactory epithelium by expressing the olfactory receptors (ORs) on their apical surface membrane. The ORs are G-protein coupled receptors that transmit signals from odorants to ORNs by molecular cascades using cyclic adenosine monophosphate, calcium ions and other molecules, which result in the depolarization of ORN. Unlike other mammalian animals, only about 30% of OR genes in the human genome are expressed. The Nobel Prize was awarded to the scientists who cloned these ORs for the first time. Each ORN expresses only a single type of OR, and ORNs which express the same type of OR converge together into the same glomeruli in the olfactory bulb. A single OR recognizes multiple odorants, and a single odorant is recognized by multiple ORs with varying affinities. At the higher neurons beyond the bulb, neuronal connections are divergent. The combinatorial model of odor identification and discrimination is well established at the convergence level, but little is known about the action mechanisms of neuronal divergence for odor identification and discrimination and further study is required.

Advances in improving the efficiency of nasal delivery / 国际脑血管病杂志

At present,intranasal delivery has entered clinical trial stage.In recent years,how to imroving the efficiency of intranasal delivery has been extensively investigated.This article briefly reviews some factors that impact the targeting of intranasal delivery and the drug concentration in the central nervous system.

Functional Activity of the Central Olfactory Pathways

Olfactory processing involves a large number of central olfactory structures, interconnected with each other in complex fashion, and incorporating both feed forward and feed back interaction. Thus understanding how these structures in odor acquisition, perception, and memory perform functional roles is a central question in olfactory disorders that can only be addressed using a combination of approaches, including neuroimaging, neurophysiology and behavioral analyses. Recent whole-brain imaging studies have shown that multiple diverse neural structures become activated during tasks involving olfactory stimulation. This article reviews the current understanding of anatomy, sensory physiology of central olfactory structures. Especially the sensory physiology of main olfactory bulb, pyriform cortex, and orbitofrontal cortex will be emphasized here.

Immunohistological Study of the Effects of Intranasal ZnSO4 Instillation on the Mouse Olfactory Epithelium and Olfactory Bulb / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to evaluate the time course of functional and anatomical recovery of the olfactory epithelium (OE) and olfactory bulb (OB) following intranasal instillation of 1% ZnSO4 in mice. MATERIALS AND METHOD: Two groups of mice, normal control group (intranasal instillation of normal saline, n=6) and experimental group (intranasal instillation of ZnSO4, n=18), were studied. Tissues of olfactory pathways were obtained at 1, 3 and 5 weeks after bilateral intranasal instillation of 1%, 100 microliter ZnSO4 solution, and processed for immunohistochemistry using antisera, olfactory marker protein (OMP), proliferating cell nuclear antigen (PCNA) and tyrosine hydroxylase (TH) to evaluate the olfactory regeneration. For histological study, OE thickness stained with hematoxylin-eosin was analyzed. RESULTS: At 1 week after ZnSO4 intranasal instillation, the lowest peak of OMP expression in OE appeared. Then the number of OMP-positive cells increased progressively at weeks. However, PCNA expression in OE showed quite the opposite. In the corresponding OB at 1 week, there was decrease of TH-positive cells and at 3 weeks, there was few TH-positive cells. At 5 weeks, there was increase in the number of TH-positive cells again. OE thickness was reduced to 20% of control OE at 1 week, and was significantly recovered to 80% of control OE at 5 weeks. CONCLUSION: Our results demonstrated that intranasal instillation of 1% ZnSO4 to mice produces a brief, reversible but essentially complete destruction of functional connection from the olfactory epithelium to the main olfactory bulb.

Changes of Sema3A and Np1 in the entorhinal cortex and dentate gyrus of temporal lobe epilepsy rat / 中华神经科杂志

Objective To explore the changes of Sema3A and it′s receptor Npl in temporal lobe epilepsy(TLE)rat brain and the roles in epileptogenesis mechanism.Methods TLE model was established with male healthy SD rats,in which mossy fiber sprouting(MFS)was verified using Neo-Timm staining method.Sema3A mRNA,Npl mRNA and protein was respectively analyzed by immunohistochemistry and in situ hybridization in the entorhinal cortex(EC)or dentate gyrus(DG)at different time after LiCL-PILO induced TLE.Results There were Mossy fiber sprouting(7d:0.70?0.42,15d:1.50?0.52,30 d:2.20 ?0.41,60 d:2.50?0.51)in DG inner molecular layer(IML)of TLE rat compared with those of controls (P