Youssef Hanna El-Hayek

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The tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a lipid and protein phosphatase. We report here that PTEN physically associates with the NR1 and NR2B subunits of NMDA receptors (NMDARs) in rat hippocampus. Downregulating the protein expression of PTEN inhibits the function of extrasynaptic NMDARs and decreases NMDAR(More)
Regulated AMPA receptor (AMPAR) trafficking at excitatory synapses is a mechanism critical to activity-dependent alterations in synaptic efficacy. The role of regulated AMPAR trafficking in insult-induced synaptic remodeling and/or cell death is, however, as yet unclear. Here we show that brief oxygen-glucose deprivation (OGD), an in vitro model of brain(More)
Postischemic seizures are associated with worsened outcome following stroke, but the underlying pathophysiology is poorly understood. Here we examined acute seizures in adult mice following hypoxia-ischemia (HI) via combined behavioral, electrophysiological, and histological assessments. C57BL/6 mice aged 4-9 months received a permanent occlusion of the(More)
Rett syndrome is a pediatric neurological condition caused by mutations of the gene encoding the transcriptional regulator MECP2. In this study, we examined cortical and hippocampal electroencephalographic (EEG) activity in male and female MeCP2-deficient mice at symptomatic stages during different behavioral states. During acute sleep, MeCP2-deficient mice(More)
The phosphatase and tensin homologue PTEN was originally identified as a tumor suppressor. In the CNS, mutation or inactivation of PTEN is best known for playing a tumorigenic role in the molecular pathogenesis of glioblastoma. However, recent studies show that PTEN is associated with several brain diseases other than cancer, suggesting a broader role of(More)
The type A GABA receptors are thought to mediate synchronization of clock cell activity within the suprachiasmatic nuclei (SCN). Here we report that casein kinases I epsilon and delta (CKI epsilon and CKI delta), the crucial clock regulators, form a complex with GABA(A) receptors and inhibit the receptors' function within the SCN according to a circadian(More)
Intracortical microelectrodes play a prominent role in the operation of neural interfacing systems. They provide an interface for recording neural activities and modulating their behavior through electric stimulation. The performance of such systems is thus directly meliorated by advances in electrode technology. We present a new architecture for(More)
Aging is known to be associated with a high risk of developing seizure disorders. Currently, the mechanisms underlying this increased seizure susceptibility are not fully understood. Several previous studies have shown a loss of subgroups of GABAergic inhibitory interneurons in the hippocampus of aged rodents, yet the network excitability intrinsic to the(More)
The objective of this study is to determine whether early alterations in intracranial EEG activity predict overall outcome in non-anesthetized adult mice following hypoxia-ischemia (HI). Adult C57BL/6 mice received surgical implantation of bilateral intracranial EEG electrodes in the hippocampus and cerebral cortex. Animals were subjected to a(More)
We introduce a new 3-D flexible microelectrode array for high performance electrographic neural signal recording and stimulation. The microelectrode architecture maximizes the number of channels on each shank and minimizes its footprint. The electrode was implemented on flexible polyimide substrate using microfabrication and thin-film processing. The(More)