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Showing 2 results for Fallah
Hajar Estiri, Ali Fallah, Mansoure Movahedin,
Volume 1, Issue 4 (Autumn - 2013)
Abstract
Introduction: Unique features of embryonic stem cells (ESCs) such as unlimited proliferation and differentiation into other types of cells make them a favorable tool for biomedical researches as well as a potential source for therapeutic application for neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases. In recent years, in vitro methods have been developed which permit the growth of neurons from pluripotent cells in culture. These cells can be maintained as stable, proliferative and undifferentiated cell lines if cultured on feeder layer or in presence of leukemia inhibitory factor. Since ESCs can be proliferated and differentiated, it is possible to generate large numbers of donor cells for neural transplantation. Retinoic acid (RA) is one of the most important morphogenesis, and its embryonic distribution correlates with neural differentiation and positional specification in the developing central nervous system. Materials and Methods: After proliferation on the mouse embryonic fibroblast feeder cells in the presence of LIF, for the study of CCE cell line differentiation these cells were cultured to producing cell aggregates (embryoid bodies). The embryoid bodies were under the protocol 4- / 4+ (four days in the presence or absence of retinoic acid) at concentration of 10-6 µM retinoic acid for differentiation. Then morphological, molecular and immunocytochemistry examination were used to assess neurological factors. Results: In this induction protocol, highly proportion (%80) of ESCs could be induced to differentiation into neuron-like cells. The cells expressed neuroepitelial cell marker nestin. In addition, the results indicated that RA could induce nerve growth factor gene expression in the ESCs. Conclusion: These findings suggest that RA strictly regulates the neuralization and specification during differentiation of mouse ESCs, especially for the differentiation into nerve cells.
Fatemeh Fallah, Reza Ebrahimpour,
Volume 6, Issue 2 (Spring - 2018)
Abstract
Introduction: Human visual system is able to recognize the objects relevant information in natural images rapidly and efficiently. In the recognition process, an object can belong to different levels of abs traction (superordinate, basic, and subordinate) in a hierarchical s tructure. However, it remains unclear whether different ques tions at levels of object categorization for identical s timulus create different activation responses in the brain or not. Materials and Methods: In order to inves tigate the relation between brain function and human behavior, three behavioral experimental s tudies have been designed with help of psychophysics’ toolbox in MATLAB R2015a. During these experiments, the participants asked to record animate, face, and animal face images as target images respect to the superordinate, basic, and subordinate levels, respectively. The experiments include seven blocks of 96 trials in superordinate (four blocks), basic (two blocks), and subordinate (one block) levels. Totally each subject has done 672 trials. Results: We observed that subjects’ reaction time were task dependent for the same images in contras t to previous s tudies. That is, images in the superordinate level were observed in the early component of reaction time whereas basic and subordinate levels emerged relatively late. In all levels, only a set of 48 target images (animal face) was analyzed. These target images were randomly mixed with other ones. Conclusion: The results showed that superordinate level is well separated from the other two levels. In other words, this level needs more general information for object recognition process than other levels. These findings sugges t that categorization of objects at different levels has done by three dis tinct neuronal circuits. Moreover, these results indicate that there are some top-down signals which change the information processing path respect to the ques tions.
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