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. The brain prepares for actions such as reaching out prior to awareness of the intention to reach.
Posts Tagged ‘orbitofrontal’
The brain’s resting state activity accounts for about 80% of its energy consumption. Anaesthesia, in which consciousness is removed, involves a 40-50% reduction in energy consumption, implying that part of the resting state’s high level of energy consumption is used to sustain consciousness. The resting state also overlaps with the reward system which is based on midline structures, as distinct from lateral regions that are more involved in planning and reasoning.
This study demonstrates how neurons that are active when the subject chooses whether to have a small reward now or a larger reward in the future are inactive when the choice is made for the subject, implying a physical brain distinction between freewill and its absence.
Neural antecedents of self-initiated actions in secondary motor cortex Murikami, M. Vicente, Gil Costa & Z. Mainen Nature Neuroscience, vol. 17, No. 11, pp. 1574-82, November 2014 www.nature.com/neuro Summary and review of the above paper INTRODUCTION: In a very guarded fashion, the authors of this paper cast doubt on the Libet-based orthodoxy where pre-conscious activity in the brain precludes the possibility of conscious will. Their research suggests that a simple threshold Read more […]
Orthodox theories are not successful in explaining the causal interaction between mental experiences and events in the brain. Since the year 2000, neuroimaging studies have shown that the activity of brain regions involved in emotional processing can be consciously and volitionally altered. This paper seeks to demonstrate the causal influence of such phenomena as thoughts, on the brain, and on subsequent behaviour. Thus beliefs, goals and expectations are seen as being related to behaviour.
The orbitofrontal cortex and ventral striatum encode expected outcomes during decision taking. Activity in these brain regions also reflects the perception of missed opportunities. Neural signals related to regret at missed opportunities are encoded here.
Even at the very early stage of the retina, an important division arises between two parallel visual streams, the dorsal stream and the ventral stream. The dorsal stream projects to the parietal cortex, and is responsible for movements in relation to objects, many of them of a routine or reflex nature. It is also seen as an answer to the ‘where is it?’ location question. The processing of the dorsal is unconscious, and is faster than the consciousness-related processing of the ventral stream.
Stephen Baxter’s short article in the science magazine, Focus, highlights some of the problems that arise in dealing with consciousness in a scientific forum. Baxter suggests that Turing made a correct, or at least insightful decision, in deciding to aim at a test as to whether robots/computers could think like humans, while avoiding the possibly unscientific or undefined area of consciousness. This is not strictly speaking true. Turing appeared to have believed that having a robot/computer that Read more […]
Response to a debate on Fate, Freedom and Neuroscience at the Institute of Arts and Ideas, London This debate highlighted some of the problems that bedevil modern consciousness studies. One such problem is the tendency to elide the self with consciousness. A more detailed analysis suggests that the self is not the same thing as consciousness, but instead merely a part of the contents of consciousness. The main components of the self are, firstly the necessary distinction between the body and the Read more […]
The Orbitofrontal Cortex David Zald & Scott Rauch Oxford University Press (2006) ISBN 978-0-19-856575-8 Keywords: orbitofrontal, sensory qualia, sub-cortical structures, limbic structures The papers in this book deal most of all with the links between the orbitofrontal cortex and the amygdala plus other parts of the limbic system that instantiate emotional processing in the brain. There is scant mention of consciousness, qualia or how these relate to emotional experience. However, Read more […]