32 research outputs found

    Postnatal BDNF Expression Profiles in Prefrontal Cortex and Hippocampus of a Rat Schizophrenia Model Induced by MK-801 Administration

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    Neonatal blockade of N-methyl-D-aspartic acid (NMDA) receptors represents one of experimental animal models for schizophrenia. This study is to investigate the long-term brain-derived neurotrophic factor (BDNF) expression profiles in different regions and correlation with “schizophrenia-like” behaviors in the adolescence and adult of this rat model. The NMDA receptor antagonist MK801 was administered to female Sprague-Dawley rats on postnatal days (PND) 5 through 14. Open-field test was performed on PND 42, and PND 77 to examine the validity of the current model. BDNF protein levels in hippocampus and prefrontal cortex (PFC) were analyzed on PND 15, PND 42, and PND 77. Results showed that neonatal challenge with MK-801 persistently elevated locomotor activity as well as BDNF expression; the alterations in BDNF expression varied at different developing stages and among brain regions. However, these findings provide neurochemical evidence that the blockade of NMDA receptors during brain development results in long-lasting alterations in BDNF expression and might contribute to neurobehavioral pathology of the present animal model for schizophrenia. Further study in the mechanisms and roles of the BDNF may lead to better understanding of the pathophysiology of schizophrenia

    Differential effects of antidepressant treatment on long-range and short-range functional connectivity strength in patients with major depressive disorder

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    Abstarct Although we have some basic understanding of the neurochemical mechanisms of the antidepressants, the network-level effect of antidepressant treatment is still not fully understood. This study was conducted to investigate the effects of antidepressant on functional brain networks of patients with major depressive disorder (MDD). We performed resting-state fMRI scans on 20 first-episode drug-naive MDD patients at baseline and after escitalopram medication for 8 weeks. Twenty healthy controls also received MRI scans with an 8-week interval. The graph theory indices, long- and short-range functional connectivity strength (FCS), were computed to characterize the brain connectivity. The analysis of covariance was conducted on FCS maps of patients and controls to obtain the interaction effect of group and time, which indicate treatment-related effect. Following treatment, increased long-range FCS in the bilateral posterior cingulate cortex/precuneus and right thalamus in MDD patients at baseline were reduced. Meanwhile, increased short-range FCS in the bilateral ventromedial prefrontal cortex and left amygdala in patients were reduced, while reduced short-range FCS in the right parahippocampal gyrus was increased. Results suggest that the brain regions associated with negative emotional processing and regulation, and self-referential function could be modulated by escitalopram treatment; long- and short-range FCS are differentially affected by antidepressant
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