A Research Platform for Artificial Neural Networks with Applications in Pediatric Epilepsy

This dissertation established a state-of-the-art programming tool for designing and training artificial neural networks (ANNs) and showed its applicability to brain research. The developed tool, called NeuralStudio, allows users without programming skills to conduct studies based on ANNs in a powerful and very user friendly interface. A series of unique features has been implemented in NeuralStudio, such as ROC analysis, cross-validation, network averaging, topology optimization, and optimization of the activation function’s slopes. It also included a Support Vector Machines module for comparison purposes. Once the tool was fully developed, it was applied to two studies in brain research. In the first study, the goal was to create and train an ANN to detect epileptic seizures from subdural EEG. This analysis involved extracting features from the spectral power in the gamma frequencies. In the second application, a unique method was devised to link EEG recordings to epileptic and non-epileptic subjects. The contribution of this method consisted of developing a descriptor matrix that can be used to represent any EEG file regarding its duration and the number of electrodes. The first study showed that the inter-electrode mean of the spectral power in the gamma frequencies and its duration above a specific threshold performs better than the other frequencies in seizure detection, exhibiting an accuracy of 95.90%, a sensitivity of 92.59%, and a specificity of 96.84%. The second study yielded that Hjorth’s parameter activity is sufficient to accurately relate EEG to epileptic and non-epileptic subjects. After testing, accuracy, sensitivity and specificity of the classifier were all above 0.9667. Statistical tests measured the superiority of activity at over 99.99 % certainty. It was demonstrated that 1) the spectral power in the gamma frequencies is highly effective in locating seizures from EEG and 2) activity can be used to link EEG recordings to epileptic and non-epileptic subjects. These two studies required high computational load and could be addressed thanks to NeuralStudio. From a medical perspective, both methods proved the merits of NeuralStudio in brain research applications. For its outstanding features, NeuralStudio has been recently awarded a patent (US patent No. 7502763)

Enhancing neuronal inhibition by cell and gene therapy as a novel treatment for Epilepsy

Epilepsy is a family of heterogeneous and multifactorial neurological disorders, unified by the occurrence of spontaneous recurrent seizures. Overall, it affects 50 million people worldwide of all ages and genders. Available treatments are only symptomatic and have severe side effects, while they also fail to provide adequate seizure control in a third of the patients. Therefore, a cure is yet to be found. In this warrant for novel strategies to treat those refractory patients, this thesis evolved. The two approaches presented here based their goal on increasing inhibitory drive in the epileptic focus to reduce the pathological hyperexcitable neuronal network that characterizes epilepsy, and thus counteract seizures.First, based on evidence of loss and/or alteration of gamma-aminobutyric acid (GABA)-ergic interneurons in the epileptic neuronal network, cell-based therapy has been developed and tested in three different scenarios for restoration of the excitatory/inhibitory balance. GABAergic interneurons (hdINs) were generated in vitro from human embryonic stem cells and proved to survive and integrate into both human and rodent epileptic environments. Host neuronal activity could be modulated by light-activation of hdINs using optogenetics. Finally, grafted hdINs were able to reduce the seizure frequency and total time spent in seizures in a rat model of temporal lobe epilepsy (TLE), the most common form of refractory epilepsy in adults. However, grafted hdINs failed to improve the pathology in a genetic mouse model of cortical dysplasia-focal epilepsy syndrome associated with autism spectrum disorder, which highlights the diversity of epilepsies and the need for gaining a better understanding of the mechanisms underpinning the disease.Finally, direct inhibition of principal cells, similar to the one exerted by endogenous inhibitory interneurons, in the chronic epileptic hippocampus by using a chemogenetic approach delivered as gene therapy was also tested. Positive results were observed by decreasing ability to generate action potentials, although further investigation is required to evaluate the efficacy of this approach on seizures.Collectively, the work presented here has moved the field forward in testing two different therapeutic strategies in a TLE model, and also one of them in a genetic epilepsy model

Modeling genetic epilepsies in a dish

Human pluripotent stem cells (hPSCs), including embryonic and induced pluripotent stem cells, provide a powerful platform for mechanistic studies of disorders of neurodevelopment and neural networks. hPSC models of autism, epilepsy, and other neurological disorders are also advancing the path toward designing and testing precision therapies. The field is evolving rapidly with the addition of genome‐editing approaches, expanding protocols for the two‐dimensional (2D) differentiation of different neuronal subtypes, and three‐dimensional (3D) human brain organoid cultures. However, the application of these techniques to study complex neurological disorders, including the epilepsies, remains a challenge. Here, we review previous work using both 2D and 3D hPSC models of genetic epilepsies, as well as recent advances in the field. We also describe new strategies for applying these technologies to disease modeling of genetic epilepsies, and discuss current challenges and future directions.Key FindingsZebrafish post‐embryonic intestinal development is slow during the first two weeks due to proliferation pattern.Transformation to the juvenile intestine is preceded by increased proliferation and changes in mitotic pattern.cells integrate between proliferating fold base epithelial cells and may regulate proliferation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153080/1/dvdy79.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153080/2/dvdy79_am.pd

Technology 2002: the Third National Technology Transfer Conference and Exposition, Volume 1

The proceedings from the conference are presented. The topics covered include the following: computer technology, advanced manufacturing, materials science, biotechnology, and electronics

Development and preclinical assessment of novel therapies for Epilepsy. Exploring the potential of human-derived cell lines and glial cell line-derived neurotrophic factor for network inhibition.

Epilepsy is one of the leading neurological disorders affecting not only patients who suffer from seizures but also people around them and society in general. The striking one third of patients not responding to pharmacological treatments implies the necessity of developing alternative options for controlling seizures in these individuals. Moreover, the possibility to stop the progression of the disease before seizures occur would pose a viable option in the future. A rising treatment approach targeting focal epilepsies, such as temporal lobe epilepsy (TLE), commonly diagnosed as pharmacoresistant, is cell therapy. The results presented in this thesis, reflect the efforts to suppress seizures in the chronic phase of epilepsy by transplanting inhibitory GABAergic interneurons, and to ameliorate the outcomes of epileptogenesis after a brain-damaging insult by transplanting mesenchymal stem cells (MSCs) alone or modified to release glial cell line-derived neurotrophic factor (GDNF). These studies were performed in the post-status epilepticus (SE) rat model of TLE induced by systemic kainic acid injections.Using electrophysiology and optogenetics, the maturation and synaptic integration of human embryonic stem cell-derived GABAergic interneurons (hdInts) was confirmed in vitro in human neuronal networks and in vivo in the hippocampi of the rat TLE model. In both cases the cells differentiated mostly into calretinin and calbindin interneuron subtypes confirmed by immunohistochemistry. In hippocampal slices from the epileptic animals the optogenetic activation of these cells reduced epileptiform activity and with video monitoring, fewer seizures were detected in animals treated with hdInts.GDNF has reported anti-seizure effects in animal epilepsy models. The mechanism of this inhibitory potential was investigated, specifically how GDNF acts on principal neurons in the mouse and human hippocampus. An increase in frequency and amplitude of inhibitory postsynaptic currents was observed electrophysiologically. Additionally, this effect was attributed to the GDNF family receptor alpha-1 and the transmembrane receptor tyrosine kinase signalling pathway using electrophysiology and western blot.Next, the use of GDNF was combined with the use of MSCs as carriers. This approach was implemented to modify epileptogenesis by transplanting either naïve MSCs or GDNF-releasing MSCs into the hippocampi of rats one day after SE. Both cell types altered the progress of epileptogenesis as seen by analysing 35 days of continuous video-EEG recordings, the MSCs alone reducing seizure occurrence and the GDNF-MSCs prolonging the intervals between seizures. Some behavioural alterations of the epileptic animals were partially corrected after 5 weeks of monitoring, however, the elevated microglia activation was not changed by either of the cell types.In summary, the data presented in this thesis contribute to the development of the growing field of novel therapeutic approaches for epilepsy which may in the future benefit those patients whose seizures cannot be controlled by conventional drugs, or even prevent seizures from occurring

Neurofly 2008 abstracts : the 12th European Drosophila neurobiology conference 6-10 September 2008 Wuerzburg, Germany

This volume consists of a collection of conference abstracts