Human Cognition and Language Processing with Neural-Lexicon Hypothesis

Cognition and language seem closely related to the human cognitive process, although they have not been studied and investigated in detail. Our brain is too complex to fully comprehend the structures and connectivity, as well as its functions, with the currently available technology such as electro-encephalography, positron emission tomography, or functional magnetic resonance imaging, and neurobiological data. Therefore, the exploration of neurobiological processes, such as cognition, requires substantially more related evidences, especially from in-vivo human experiments. Cognition and language are of inter-disciplinary nature and additional methodological support is needed from other disciplines, such as deep learning in the field of artificial intelligence, for example. In this paper, we have attempted to explain the neural mechanisms underlying "cognition and language processing" or "cognition or thinking" using a novel neural network model with several newly emerging developments such as neuronal resonance, in-vivo human fiber tractography or connectivity data, Engram and Hebbian hypothesis, human memory formation in the high brain areas, deep learning, and more recently developed neural memory concepts, the neural lexicon. The neural lexicon is developed via language by repeated exposure to the neural system, similar to multilayer signal processing in deep learning. We have derived a neural model to explain how human "cognition and language processing" or "cognition and thinking" works, with a focus on language, a universal medium of the human society. Although the proposed hypothesis is not fully based on experimental evidences, a substantial portion of the observations in this study is directly and indirectly supported by recent experimental findings and the theoretical bases of deep learning research.