Libet v. recent neuroscience

Consciousness isn’t all about you, you know  ::  New Scientist, 15 August 2015  ::

Summary and review of the above article

A source of despair in consciousness studies is the way in which popular science writers continue to plough ahead making pronouncements that are flatly contradicted by the neuroscientific data of recent years. In particular, consciousness students might be forgiven for screaming every time Libet’s veteran 1980s experiment is trundled out. Halligan and Oakley writing in a recent issue of ‘New Scientist’ go down this predictable route. nrn2497-i1The brain prepares for actions such as reaching out prior to awareness of the intention to reach. However, this ignores the now abundant research showing that a separate visual stream projects to other areas of the brain involved in more deliberative evaluation and reasoning. Any model that depends only on the Libet experiment can be seen as false.

The authors go on to correctly describe how our conscious experience of the world is formed by unconscious processing in the earlier parts of the sensory cortex. However, they ignore totally what the brain does with these unconsciously formed experiences; this is to evaluate the adaptive or reward/punisher features
of the stimuli that have been brought into consciousness, as a guide to subsequent action and behaviour.

This process is most connected with brain regions such as the orbitofrontal, the anterior cingulate, and parts of the basal ganglia, knowledge of whose functions has in recent years moved into the mainstream of neuroscience. nrn2497-f1Here, however, their now well established processing is completely ignored, rendering the authors’ approach one that by-passes cores sections of the more recent scientific data. In particular, the claim that consciousness has no cognitive function is falsified by evidence that the evaluative/feeling/processing performed by these regions influences the subsequent activity of the dorsolateral prefrontal area of reasoning/planning, and also the selection of working memory and the direction of top-down attention.

The authors claim that ‘everything’ has been performed back stage by the unconscious is falsified by the evidence that brain regions associated with the generation of conscious feelings and experience lie upstream of those driving more deliberated actions and behaviour.

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