Objective:To analyze the magnetic resonance imaging (MRI) features of epithelioid glioblastoma (eGBM), and to quantitatively analyze the characteristics of apparent diffusion coefficient (ADC) , perfusion-weighted imaging (PWI) and magnetic resonance spectrum (MRS) of eGBM patients.Methods:The MRI results of eight cases of eGBM confirmed by pathology in the Affiliated Hospital of Qingdao University from October 2016 to November 2018 were analyzed retrospectively. The location, edge, signal, peritumoral edema, adjacent meningeal invasion and enhancement of the patients were observed, and the changes of ADC value, relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and the ratio of choline (Cho)/N-acetyl-L-aspartic acid (NAA) were analyzed.Results:Among the eight patients, the main tumors were located in temporal lobe ( n=3), frontal lobe ( n=3) and parietal lobe ( n=2). The boundary of the lesion was clear in six cases and unclear in two cases. The lesions were superficial in five cases and in deep white matter in three cases. Bleeding could be seen in four cases. There were three cases with cystic change and four cases with necrosis, and there was no cystic necrosis only in one case. There was no edema around the lesion in one case, severe edema in five cases and moderate edema in two cases. The adjacent meninge was involved in four cases and the ependyma was involved in one case. Two patients had leptomeningeal metastasis within two months after operation. The average ADC value of tumor parenchyma in eight patients was 7.15×10 -4 mm 2/s, which was 17.6% lower than that of the contralateral side. MRS showed that the ratio of Cho/NAA in the lesions of two patients were 5.27, 0.81. PWI showed that the rCBV in the lesions of two patients was 3.51 ml/100 g and 3.32 ml/100 g, respectively, which was 36% and 29% higher than that of the contralateral side, respectively. And the rCBF of the lesions was 31.5 ml·100 g -1·min -1and 82.1 ml·100 g -1·min -1, respectively, which increased by 49% and 203% respectively compared with the contralateral side. Conclusions:eGBM has the characteristics of superficial location, easy to be cystic, but the wall of the cyst is not smooth and uneven, the boundary of the mass is clear, the adjacent meninges are easy to be involved and the meningeal tail sign appears, and it is easy to be spread by cerebrospinal fluid. ADC value, PWI and MRS can provide some help for preoperative tumor grading.

OBJECTIVE It's known that post-retrieval extinction but not extinction alone could erase fear memory.However,whether the coding pattern of original fear engrams is remod-eled or inhibited remains largely unclear.Here we try to investigate whether the coding pattern of memory engrams is altered during post-retrieval extinction induced memory updating.METHODS To answer the question,by using activity-depen-dent neuronal-tagging technology,neuronal trac-ing technique combined with optogenetic manipu-lation and in vivo calcium imaging,we identified the fear and extinction cells in PrL and BLA and investigated the dynamic encoding of memory engram ensembles in the PrL and BLA during CS versus US initiated memory updating.RESULTS We found increased reactivation of engram cells in the prelimbic cortex and basolat-eral amygdala during memory updating.More-over,conditioned stimulus and unconditioned stimulu sinitiated memory updating depend on the engram cells reactivation in the prelimbic cor-tex or basolateral amygdala respectively.Finally,we found memory updating causes increased overlapping between fear and extinction cells and the original fear engrams encoding was altered during memory updating.CONCLUSION Our data provide the first evidence to show the overlapping ensembles between fear and extinc-tion cells and functional reorganization of original engrams underlying conditioned stimulus and unconditioned stimulus initiated memory updating.