Pre-stimulus thalamic theta power predicts human memory formation
NEUROIMAGE
Authors: Sweeney-Reed, Catherine M.; Zaehle, Tino; Voges, Juergen; Schmitt, Friedhelm C.; Buentjen, Lars; Kopitzki, Klaus; Richardson-Klavehn, Alan; Hinrichs, Hermann; Heinze, Hans-Jochen; Knight, Robert T.; Rugg, Michael D.
Abstract
Pre-stimulus theta (4-8 Hz) power in the hippocampus and neocortex predicts whether a memory for a subsequent event will be formed. Anatomical studies reveal thalamus-hippocampal connectivity, and lesion, neuroimaging, and electrophysiological studies show that memory processing involves the dorsomedial (DMTN) and anterior thalamic nuclei (ATN). The small size and deep location of these nuclei have limited real-time study of their activity, however, and it is unknown whether pre-stimulus theta power predictive of successful memory formation is also found in these subcortical structures. We recorded human electrophysiological data from the DMTN and ATN of 7 patients receiving deep brain stimulation for refractory epilepsy. We found that greater pre-stimulus theta power in the right DMTN was associated with successful memory encoding, predicting both behavioral outcome and post-stimulus correlates of successful memory formation. In particular, significant correlations were observed between right DMTN theta power and both frontal theta and right ATN gamma (32-50 Hz) phase alignment, and frontal-ATN theta-gamma cross-frequency coupling. We draw the following primary conclusions. Our results provide direct electrophysiological evidence in humans of a role for the DMTN as well as the ATN in memory formation. Furthermore, prediction of subsequent memory performance by pre-stimulus thalamic oscillations provides evidence that post-stimulus differences in thalamic activity that index successful and unsuccessful encoding reflect brain processes specifically underpinning memory formation. Finally, the findings broaden the understanding of brain states that facilitate memory encoding to include subcortical as well as cortical structures. (C) 2016 Elsevier Inc. All rights reserved.
MicroRNA-195 Functions as a Tumor Suppressor by Directly Targeting Fatty Acid Synthase in Malignant Meningioma
WORLD NEUROSURGERY
Authors: Song, Lai-Rong; Li, Da; Weng, Jian-Cong; Li, Cheng-Bei; Wang, Liang; Wu, Zhen; Zhang, Jun-Ting
Abstract
OBJECTIVE: Meningiomas are among the most common primary intracranial tumors. Up to 20% of cases will show increased malignancy at histological examination (World Health Organization grade II or III). Effective pharmacotherapy, except for radiotherapy, is lacking. Therefore, it is necessary to study the pathogenesis of malignant meningioma to provide more treatment strategies. METHODS: RNA sequencing and micro-RNA (miRNA) microarray detection were applied to identify differentially expressed messenger RNAs (mRNAs) and miRNAs in benign and malignant meningioma. The miRDB and TargetScan databases were used to predict the potential interaction between miRNAs and mRNAs. A proliferation assay was used to evaluate the cell growth. A wound healing assay and Transwell assay were performed to assess the cell migration and invasion abilities, respectively. The interaction between miRNA and mRNA was identified using a luciferase reporter assay. RESULTS: We found fatty acid synthase (FASN) was significantly upregulated in malignant meningioma compared with benign meningioma. Knockdown of FASN significantly inhibited proliferation, migration, and invasion of IOMM-Lee cells. Moreover, miR-195 was verified to directly target FASN using a luciferase reporter assay. Upregulation of mill-195 also significantly inhibited proliferation, migration, and invasion of IOMM-Lee cells. Furthermore, we performed bioinformatics analysis to predict the competing endogenous RNAs (ceRNAs) and found that NUP210, SPIRE2, SLC7A1, and DMTN might function as ceRNAs of FASN by sponging miR-195 in meningioma. CONCLUSIONS: Our results have suggested a tumor suppressive role for miR-195 in the tumorigenesis and progression of malignant meningioma by targeting FASN. In addition, NUP210, SPIRE2, SLC7A1, and DMTN might act as ceRNAs to regulate FASN expression by sponging miR-195.