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Signal propagation in neural networks
Blaštík, Filip ; Šanda, Pavel (advisor) ; Bureš, Zbyněk (referee)
A proper account of signal propagation in neuronal networks is the key to developing a genuine understanding of information processing accomplished by the brain. The data can often be in the form of the complex activity of neuronal assemblies and their spiking patterns. Under particular circumstances, neuronal assemblies produce a coordinated synchronized activity with the profile of travelling waves. These have been shown to represent the information processing of, e.g., perceptual sensitivity. We decided to model the phenomenon of the travelling wave by using a spiking neural network model of 1mm2 of primate's early visual cortices. The modelled neural column was employed to generate synchronized activity. By interconnecting said columns, we were able to model the travelling wave. In order to describe its dynamics, we developed several event-detection algorithms to identify such a travelling wave from simulated neural columns. We discovered that methods based on the detection of local dynamics in moving windows rendered most adequately the intuitive idea of the travelling wave. After establishing our event-detection approach, we shifted the focus to causal inference. Signal propagation is commonly inferred by abstract theoretical concepts like the Granger causality or transfer entropy. In this work, we...
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Neural Correlates of Consciousness: Theoretical problems and Candidates
Blaštík, Filip ; Flegr, Jaroslav (advisor) ; Boschetti, Silvia (referee)
Consciousness is part of the world, which yet resisted a scientific inquiries for an ages. This work is mainly concerned around Neural Correlates of Consciousness program which should uncover a nature of the consciousness. It covers wide variety of a theoretical problems, the first part is concerned around the ambivalence of Neural Correlates of Consciousness definition and its alternatives. The second part asks a questions, whether the neural correlates of consciousness is only discourse creating entity and sheds a light on the dilemma, if the right correlations to form neural correlates of consciousness are possible. It is done on a basis of the experimental evidence and their attempts to form Neural Correlate of Consciousness. In third chapter the philosophical dilemma is exposed. The dilemma arises from conceptual decisions "What is to be conscious", how researchers philosophically pre-conceptualize the scientific question. This is tried to be reconciled by unification of the philosophical theories. Alas it is shown the unification of the theories of mind is impossible. From this is drawn a conclusion that the philosophical pre-conception is a necessary ingredient to form the neural correlate of consciousness. To breach from mere a correlation to a causality is a matter of choosing testable and...
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