ObjectiveThe research goal: to study the diagnostic value of T2-flair sequence of magnetic resonance imaging (MRI) in hippocampal sclerosis. MethodsThe clinical data of 135 patients with epilepsy caused by hippocampal sclerosis in the Epilepsy Center of Tianshui Third People's Hospital from March 2019 to December 2020 were analyzed retrospectively, studying the correlation between the changes of hippocampal sclerosis signal and the frequency of epileptic seizures in MRI T2-flair sequence multi axial scanning. ResultsThere were 109 cases of simple hippocampal sclerosis and 26 cases of hippocampal sclerosis with other lesions, including 8 cases of cavernous hemangioma, 9 cases of traumatic or infectious malacia, 2 cases of focal cortical dysplasia, 1 case of cerebral fissure malformation, 1 case of giant gyrus and 5 cases of perinatal brain injury. MRI features of hippocampal sclerosis were as follows: ① hippocampal volume increased slightly, structure blurred, and T2-flair showed slightly increased hippocampal signal in 15 cases, accounting for 11.11%; ② The hippocampal formation was fuzzy, T2-flair was punctate hyperintense, and the volume did not change in 17 cases (12.59%); ③ Hippocampal pyknosis into small lumps, T2-flair sequence showed high signal in 103 cases, accounting for 76.30%. Statistics showed that there was a correlation between hippocampal sclerosis signal and seizure frequency (χ2=94.94, P<0.05). The higher the hippocampal sclerosis signal, the more the seizure frequency. ConclusionMRI T2-flair sequence multi axial scanning can improve the diagnostic accuracy of hippocampal sclerosis. As the change of hippocampal sclerosis signal becomes more obvious, the trend of seizure frequency increases.
Physiological studies have revealed that rats perform spatial localization relying on grid cells and place cells in the entorhinal-hippocampal CA3 structure. The dynamic connection between the entorhinal-hippocampal structure and the prefrontal cortex is crucial for navigation. Based on these findings, this paper proposes a spatial navigation method based on the entorhinal-hippocampal-prefrontal information transmission circuit of the rat’s brain, with the aim of endowing the mobile robot with strong spatial navigation capability. Using the hippocampal CA3-prefrontal spatial navigation model as a foundation, this paper constructed a dynamic self-organizing model with the hippocampal CA1 place cells as the basic unit to optimize the navigation path. The path information was then fed back to the impulse neural network via hippocampal CA3 place cells and prefrontal cortex action neurons, improving the convergence speed of the model and helping to establish long-term memory of navigation habits. To verify the validity of the method, two-dimensional simulation experiments and three-dimensional simulation robot experiments were designed in this paper. The experimental results showed that the method presented in this paper not only surpassed other algorithms in terms of navigation efficiency and convergence speed, but also exhibited good adaptability to dynamic navigation tasks. Furthermore, our method can be effectively applied to mobile robots.
Currently, commercial devices for electrical neural stimulations can only provide fixed stimulation paradigms with preset constant parameters, while the development of new stimulation paradigms with time-varying parameters has emerged as one of the important research directions for expanding clinical applications. To facilitate the performance of electrical stimulation paradigms with time-varying parameters in animal experiments, the present study developed a well-integrated stimulation system to output various pulse sequences by designing a LabVIEW software to control a general data acquisition card and an electrical stimulus isolator. The system was able to generate pulse sequences with inter-pulse-intervals (IPI) randomly varying in real time with specific distributions such as uniform distribution, normal distribution, gamma distribution and Poisson distribution. It was also able to generate pulse sequences with arbitrary time-varying IPIs. In addition, the pulse parameters, including pulse amplitude, pulse width, interphase delay of biphasic pulse and duration of pulse sequence, were adjustable. The results of performance tests of the stimulation system showed that the errors of the parameters of pulse sequences output by the system were all less than 1%. By utilizing the stimulation system, pulse sequences with IPI randomly varying in the range of 5~10 ms were generated and applied in rat hippocampal regions for animal experiments. The experimental results showed that, even with a same mean pulse frequency of ~130 Hz, for neuronal populations, the excitatory effect of stimulations with randomly varying IPIs was significantly greater than the effect of stimulations with fixed IPIs. In conclusion, the stimulation system designed here may provide a useful tool for the researches and the development of new paradigms of neural electrical stimulations.
Alzheimer’s disease (AD) is a neurodegenerative disease characterized by cognitive impairment, with the predominant clinical diagnosis of spatial working memory (SWM) deficiency, which seriously affects the physical and mental health of patients. However, the current pharmacological therapies have unsatisfactory cure rates and other problems, so non-pharmacological physical therapies have gradually received widespread attention. Recently, a novel treatment using 40 Hz light flicker stimulation (40 Hz-LFS) to rescue the cognitive function of model animals with AD has made initial progress, but the neurophysiological mechanism remains unclear. Therefore, this paper will explore the potential neural mechanisms underlying the modulation of SWM by 40 Hz-LFS based on cross-frequency coupling (CFC). Ten adult Wistar rats were first subjected to acute LFS at frequencies of 20, 40, and 60 Hz. The entrainment effect of LFS with different frequency on neural oscillations in the hippocampus (HPC) and medial prefrontal cortex (mPFC) was analyzed. The results showed that acute 40 Hz-LFS was able to develop strong entrainment and significantly modulate the oscillation power of the low-frequency gamma (lγ) rhythms. The rats were then randomly divided into experimental and control groups of 5 rats each for a long-term 40 Hz-LFS (7 d). Their SWM function was assessed by a T-maze task, and the CFC changes in the HPC-mPFC circuit were analyzed by phase-amplitude coupling (PAC). The results showed that the behavioral performance of the experimental group was improved and the PAC of θ-lγ rhythm was enhanced, and the difference was statistically significant. The results of this paper suggested that the long-term 40 Hz-LFS effectively improved SWM function in rats, which may be attributed to its enhanced communication of different rhythmic oscillations in the relevant neural circuits. It is expected that the study in this paper will build a foundation for further research on the mechanism of 40 Hz-LFS to improve cognitive function and promote its clinical application in the future.
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.
Febrile seizures (FS) are one of the most common neurological disorders in pediatrics, commonly seen in children from three months to five years of age. Most children with FS have a good prognosis, but some febrile convulsions progress to refractory epilepsy (RE). Epilepsy is a common chronic neurological disorder , and refractory epilepsy accounts for approximately one-third of epilepsies. The etiology of refractory epilepsy is currently complex and diverse, and its mechanisms are not fully understood. There are many pathophysiological changes that occur after febrile convulsions, such as inflammatory responses, changes in the blood-brain barrier, and oxidative stress, which can subsequently potentially lead to refractory epilepsy, and inflammation is always in tandem with all physiological changes as the main response. This article focuses on the pathogenesis of refractory epilepsy resulting from post-febrile convulsions.
ObjectiveTo investigate the effect of electroacupuncture on the apoptosis of hippocampal neurons in C57BL/6J mice with status epilepticus by observing the changes of hippocampal subtle neuron pathology and apoptosis.MethodsMale C57BL/6J mice were used to prepare epileptic status models of lithium-pilocarpine mice, and then 7-day electroacupuncture stimulation (Baihui, Fengfu) were given to the mice model. Open field experiment and new object recognition experiment were performed to observe the changes of cognitive abilities. The pathological changes of hippocampal neurons were detected by HE staining. Hippocampal apoptosis protein (Caspase-3) and microtubule-associated protein (MAP-2) were detected by immunohistochemistry. Effect of electroacupuncture on apoptosis of hippocampal neurons in C57BL/6J mice with status epilepticus were recorded.Results① Compared with the control group, the vertical movement, modification times, and number of crossings of the model group all decreased significantly (P<0.000 1,P<0.000 1,P<0.000 1), and their cognitive ability decreased significantly (P<0.01). Compared with the model group, vertical movements, modification times, and number of crossings were increased in the electroacupuncture (EA) group (P<0.01,P<0.05,P<0.05), and the cognitive ability of new objects was increased (P<0.01). ② HE staining showed that the model group had significant damage to the hippocampal neurons of mice, and the cells swelled, nuclear collapsed and vacuoles appeared. In the EA group, the injury of hippocampal neurons was alleviated, and cell edema and vacuolization were alleviated. ③ Immunohistochemistry showed that compared with the control group, the IOD of the Caspase-3 positive cells in the hippocampus of the model group increased significantly (P<0.000 1), and the IOD of the MAP-2 positive cells decreased significantly (P<0.01); Compared with the electroacupuncture, the IOD of the Caspase-3 positive cells in the hippocampus of the mice decreased (P<0.05), and the IOD of the MAP-2 positive cells increased (P<0.05).ConclusionsElectroacupuncture can improve the pathological changes of hippocampal neurons in C57BL/6J mice with status epilepticus, promote cytoskeletal repair, reduce neuronal apoptosis in hippocampus, and antagonize the damage of hippocampal neurons induced by status epilepticus.