It has been found that in biological studies, the simple linear superposition mathematical model cannot be used to express the feature mapping relationship from multiple activated grid cells' grid fields to a single place cell's place field output in the hippocampus of the cerebral cortex of rodents. To solve this problem, people introduced the Gauss distribution activation function into the area. We in this paper use the localization properties of the function to deal with the linear superposition output of grid cells' input and the connection weights between grid cells and place cells, which filters out the low activation rate place fields. We then obtained a single place cell field which is consistent with biological studies. Compared to the existing competitive learning algorithm place cell model, independent component analysis method place cell model, Bayesian positon reconstruction method place cell model, our experimental results showed that the model on the neurophysiological basis can not only express the feature mapping relationship between multiple activated grid cells grid fields and a single place cell's place field output in the hippocampus of the cerebral cortex of rodents, but also make the algorithm simpler, the required grid cells input less and the accuracy rate of the output of a single place field higher.
Elderly patients account for 80% of cardiac arrest patients. The incidence of poor neurological prognosis after return of spontaneous circulation of these patients is as high as 90%, much higher than that of young. This is related to the fact that the mechanism of hippocampal brain tissue injury after ischemia-reperfusion in elderly cardiac arrest patients is aggravated. Therefore, this study reviews the possible mechanisms of poor neurological prognosis after return of spontaneous circulation in elderly cardiac arrest animals, and the results indicate that the decrease of hippocampal perfusion and the number of neurons after resuscitation are the main causes of the increased hippocampal injury, among which oxidative stress, mitochondrial dysfunction and protein homeostasis disorder are the important factors of cell death. This review hopes to provide new ideas for the treatment of elderly patients with cardiac arrest and the improvement of neurological function prognosis through the comparative analysis of elderly and young animals.
ObjectiveTo study the cytokine changes in the cerebrospinal fluid (CSF) of mesial temporal lobe epilepsy (MTLE) patients, and the mechanism of the development of hippocampal sclerosis. MethodsFifty MTLE patients who sought treatment from January 2013 to March 2014 were included in the study. Clinical features were investigated. All CSF samples of the 59 patients along with 19 samples of the control group were tested for 12 common cytokines using a chemokine magnetic bead panel. Data were statistically analyzed. ResultsClinical features showed no significant difference between hippocampal sclerosis and non-hippocampal sclerosis patients. Interleukin (IL)-1 receptor antagonist (RA), IL-4 and IL-9 expression decreased, and tumor necrosis factor (TNF)-α, IL-3 and IL-5 expression increased. Up-regulation of TNF-α was significantly different between hippocampal sclerosis and non-hippocampal sclerosis patients. ConclusionIL-1RA, IL-3, IL-4, IL-5 and IL-9 changes may be non-specific seizure-related cytokine regulation. TNF-α is associated with hippocampal sclerosis pathology. TNF-α is a possible pathological element in hippocampal sclerosis development.
This study aims to explore the diagnosis in patients with Alzheimer's disease (AD) based on magnetic resonance (MR) images, and to compare the differences of bilateral hippocampus in classification and recognition. MR images were obtained from 25 AD patients and 25 normal controls (NC) respectively. Three-dimensional texture features were extracted from bilateral hippocampus of each subject. The texture features that existed significant differences between AD and NC were used as the features in a classification procedure. Back propagation (BP) neural network model was built to classify AD patients from healthy controls. The classification accuracy of three methods, which were principal components analysis, linear discriminant analysis and non-linear discriminant analysis, was obtained and compared. The correlations between bilateral hippocampal texture parameters and Mini-Mental State Examination (MMSE) scores were calculated. The classification accuracy of nonlinear discriminant analysis with a neural network model was the highest, and the classification accuracy of right hippocampus was higher than that of the left. The bilateral hippocampal texture features were correlated to MMSE scores, and the relative of right hippocampus was higher than that of the left. The neural network model with three-dimensional texture features could recognize AD patients and NC, and right hippocampus might be more helpful to AD diagnosis.
ObjectiveTo observe the dynamic changes of neuroglobin (NGB) expression in hippocampus after status epilepticus(SE) in rats, and to explore the role of NGB in epileptic seizures.Methods40 healthy male Sprague Dawley rats were randomly divided into two group according to random number table method:control group (n=5) and epilepsy model group(n=35).Epilepsy model group according to observation time was divided into:0h, 1h, 3h, 12h, 24h, 10d and 30d.Intraperitoneal injection Lithium-pilocarpine (20 mg/kg~127 mg/kg, Li-PC) to establish the rat model of SE.Observe the behavioral changes in rats with epilepsy.Nissl staining was used to detect the neuronal damage in hippocampus. Streptavidin-biotin-peroxidase complex immunohistochemical method was used to detect the expression level of NGB in hippocampus;ResultsAfter SE, the neurons in hippocampus were severely damaged with the progress of epileptic seizures, the number of surviving neurons in CA1, CA3 regions showed a near linear decline.Among them, the number of surviving neurons in (12h, 24h, 10d, 30d)CA1, (0h, 12h, 24h, 10d, 30d)CA3 and(12h, 24h, 10d, 30d) DG area were significantly lower than that of the control group (P < 0.05).The expression level of NGB in CA1, CA3 and DG region of hippocampus were increased after SE, and both of CA1 and DG were reached peak in 24h after SE, but was still higher than the control group.And the CA3 area showed a continue rising trend.Among them, CA1(24h, 10d, 30d), CA3(24h, 10d, 30d) and DG(12h, 24h, 10d, 30d) were higher than that of control group significantly (P < 0.05).In addition, it was found that there was a positive correlation between the number of surviving neurons in CA3 area and the expression level of NGB (R=0.306, P=0.011).ConclusionUp-regulation of NGB expression in hippocampus after status epilepticus, and was positively correlated with the number of neurons in the CA3 area, suggesting that up regulation of NGB expression may be a compensatory protective mechanism of ischemic injury induced by seizures, and participate in the protection of epilepsy related neuronal damage.
ObjectiveTo explore the dynamic expression changes of neuronal growth and differentiation-associated miR-124a and miR-9 in the process of epileptogenesis. MethodsEstablish the lithium-pilocarpine induced status epilepticus (SE) rat model. Animal behavior change induced by SE as well as in the period of chronic epilepsy was observed by naked-eye or video-recording. Major time points for the study were chosen at 1d, 7d, 14d and 28d post-SE, on which the post-SE rats were decapitated and their hippocampal specimens were obtained. Total RNA from each specimen was extracted and qPCR was exploited to detect miR-124a and miR-9 expression in the specimens. Statistical analysis was used to show the dynamic expressional changes of miR-124a and miR-9 in rat hippocampus at 1d, 7d, 14d and 28d post-SE during the process of epileptogenesis. ResultsCompared with normal rats, the expression level of miR-124a in rat hippocampus did not show a significant difference at 1d post-SE, but it had shown markedly differences at 7d, 14d and 28d post-SE(P < 0.05), with a declining trend. Compared with normal rats, the expression level of miR-9 had demonstrated significant differences at 1d, 7d, 14d and 28d post-SE(P < 0.05)with a generally increasing trend, although there was slight fluctuation of expressional up-regulation at 7d post-SE. ConclusionNeuronal growth and differentiation-associated miR-124a and miR-9 had shown dynamic changes of down-regulation or up-regulation in the process of epileptogenesis. It can be suspected that miR-124a and miR-9 take part in hippocampal neurogenesis post-SE and be involved in epileptogenesis process.