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The neural correlates of consciousness: an analysis of cognitive skill learning (Marcus E. Raichle) Jafar Eljesani

The paper • Shows a functional brain-imaging strategy designed to isolate neural correlates of consciousness in human. • The strategy is based on skill learning. • Presenting (rapidly generating verbs for visually presented nouns) and after checking the cognitive skill before and after the practice.

Why? • Two components of the human conscious behavior are “content” and “arousal” • We would understand the consciousness more if we find the brain system which is responsible for these components. • Research on arousal and alert wakefulness have been made but we don´t know which cortical system are responsible for the content of our consciousness.

Why? • One approach is to study patients with lesions that deprive them of some aspect of their normal conscious experience. “ Blind sight” • Second approach is to examine normal activities in which consciousness in transiently suspended. An example is saccadic suppression which mean an analysis of the suppression of conscious visual experience during eye movements.

Third approach To identify the brain systems supporting a task when it is novel and effortful and compare these system with those engaged when the task is routine and reflexive. The performance demands would than require conscious attention or willed action. The task would than involve motor as well cognitive skills which can be transformed from reflective, effortful task o reflexive within is short time which can be made by Modern functional imaging techniques. The transformation give us important insight into those brain system concerned with conscious elements of na誰ve task performance.

Why this approach? • To indentify brain activity changes associated with task-related conscious behavior. The strategy is to measure the PET images of blood flow change obtained in a novel reading task (verb generation) with those obtained during a well practiced task with identical perceptual and motor requirement (word reading). The comparison hypothesis was regions of the brain concerned with conscious task performance could be isolated and indentified.

Results • Regional changes in brain activity associated with conscious effortful performance of verbgeneration were indentified. There were both increase and decreases in brain activity. • The is no necessary region (system) for consciousness under all circumstances . • The consciousness does not cease when task performance changes from naïve, effortless, attention-focusing experience to a practiced, effortless one requiring little attention.

Summary • They can´t seem to manage to pinpoint the exact location of consciousness or isolate it as a separate entity. • They can only speculate about processes related to consciousness.

The end

The neural correlates of consciousness: an analysis of cognitive skill learning