MEi:CogSci Conferences, MEi:CogSci Conference 2010, Dubrovnik

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Cognitive neurophysiologic models of conscious and nonconscious states
Roberto Cruz Murcia

Last modified: 2010-06-11

Abstract


Cognitive neurophysiologic models of conscious and nonconscious states

Roberto Cruz Murcia

Abstract

The idea that apart from the conscious processes of our common experience, there are nonconscious processes has a long history in psychology and philosophy. However is in the late twentieth century that most of the scientific research on conscious and unconscious process has been done. In the early twentieth century, the psychoanalysis proposed a series of speculative theories which were hard to address within a scientific-experimental paradigm with empirical orientation. But with the emergence of cognitive science came back again the interest in the nonconscious aspects of the human mind. Unlike previous attempts in the area, actual research has focused more on cognitive aspects such as implicit vs. explicit learning, or subliminal perception, rather than on psychopathology. In a typical situation simultaneous stimuli are presented to the subjects. Because they can only pay attention to one of the stimuli, the degree of processing or stimuli to which no attention has been paid is verified. Another paradigm is supraliminal or subliminal priming. The research suggests that there is nonconscious processing of information of non attended stimuli. I will address some cognitive neurophysiologic models including, Baar's global workspace, the dynamic core of Edelman and Tononi, thalamocortical rhythms, and CODAM, in order to try to give an explanation to the conscious and nonconscious phenomena. Explanations of consciousness can arise at two levels, the macro-level and micro-level. The first ones tend to be more modular. In general, explanations at the micro-level are more difficult to explore due to limitations of spatial and temporal resolution of current techniques. A theory or model of the consciousness should include: 1. an explanation of the conscious processes. 2. An explanation of unconscious processes. 3. An explanation of how the above are related. Some relevant questions are: How conscious and unconscious processes arise? What is the functional role of conscious and unconscious processes? How can be explained in neurophysiological or functional terms? How can be implemented in computational models? Global Workspace theory (Newman and Baars, 1993), is an architecture that seeks to explain conscious and unconscious processes, including psychological aspects such as memory, attention, automaticity, evaluation, verbal report, or subliminal priming, as well as neurological aspects such as coma. The main idea is that the content of consciousness is available globally to other cognitive processes in the brain. Llimas (2003) believe that the categorical implementation in the brain can hardly be explained by hierarchically connectivity due to the large number of possible categories, as for instance in the grandmother neuron hypothesis. Due to the topical organization of the sensory cortex, a better option is the dynamic interaction of maps based on temporal coherence that would enable faster change. For Llimas (1998) the common view of consciousness that consciousness this is based on inputs of sensory organs is not correct because consciousness is an intrinsic state rather than determined by sensory inputs. This state would be more dreamlike character and the senses play a moderating role and not a generating role in the genesis of consciousness. The thalamus can function like a hub for communication between different parts in the cortex. The large-scale temporal correlation of specific and non-specific thalamic activity and Rhythms at gamma-band frequencies (20-50 Hz) could explain the cognitive states of mind. CODAM tries to explain conscious and unconscious processes by a process of attention focusing. The attention will function like a "high level controller" that can give arise to phenomenal consciousness. It is supposed to increase the effectiveness of attention and it may help to explain the formation of the inner self. (Taylor, 2007) The model tries to explain several nonconscious phenomena like implicit learning and the blind sight perception. I think there is possible to see consciousness like function from a third point of view. But at the same time is possible to see it like phenomenological experience from a first person point of view. Differently from many authors I do not think there is two or many consciousness but one. I will explain a model of functional consciousness and how it can be related to phenomenological consciousness. I will show how a thalamocortical matrix could serve to bind the information of different modalities in one single experience. I will address topics of neurophysiology and psychology related with consciousness, memory, attention, etc. and some philosophical implications of the theories and some possible computational implementations.

References

[1]. Llinas, Rodolfo R. (2003). Consciousness and the thalamocortical loop.International Congress Series 1250 (2003) 409-416
[2]. Llinas, R., Ribary, U., Contreras, D. & Pedroarena, C. (1998). The neuronal basis for consciousness. Philosophical Transactions of the Royal Society of London, Series B, 353, 1841-1849
[3]. Newman, James and Bernard J. Baars, Bernard J. A neural attentional model for access consciousness. Concepts In NeuroScience, Vol. 4, No. 2 (1993) 255-290
[4]. Taylor, John G (2007). CODAM model: Through attention to consciousness. Scholarpedia, 2(11):1598