Davidsen, JörnYaghoubi, Mohammad Hassan2019-01-032019-01-032018-12-27Yaghoubi, M. H. (2018). Neuronal avalanche dynamics and criticality in neuronal cultures (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/109405The brain is often thought to be organized in a way that it optimizes its information processing and storage capabilities, supported by studies indicating that neuronal networks self-organize to a critical state. This is characterized by the emergence of scale-free statistics in neuronal avalanches close to those predicted by mean-field theory, suggesting that neuronal avalanches propagate in a tree-like network. Here, we use optical imaging techniques to study neuronal avalanches in different preparation of neuronal cultures and different dynamical regimes. We present an experimental case study where the avalanche statistics is significantly different from mean-field, suggesting that feed-back loops play a leading role in propagation of neuronal avalanches. Another phenomenon is that cortical and hippocampal neurons alternate between high and low activity regimes (up and down states) characterized by distinct firing rates. In contrast with previous theoretical works, our experimental findings suggest both states exhibit scale-free behavior with different intrinsic time scales.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.NeurosciencePhysicsmaster thesis10.11575/PRISM/35680