Neuroscience and Experience

Sample Lecture

EXECUTIVE SUMMARY :
Even before Descartes, and exemplified in Burton’s “Anatomy of Melancholy”, attempts were being made to explain even relatively complicated subjective states like depression on the basis of the “neuroscience” of the day. While such attempts may now seem to us to be laughably naïve, it is actually an open question whether we are not ourselves guilty of premature closure on this topic. In particular, some of  our  current neuroscience may be superceded; similarly, the recent attempt to bootstrap a new science of consciousness from diverse findings in neuroscience and psychology in the past decade has been considerably delayed by the restatement in new guise of old questions such as  whether the world external to us is an illusion, or indeed unreal.

This course is above all an attempt to provide tools to talk and think about these issues and does not presume to give ultimate answers. It starts by considering the explananda of a theory of consciousness. How is it that many patients who have lost the use of a whole side of their body refuse to acknowledge this, and insist that they are still intact? Pathologies of conscious perception like Capgras, which compels the patient to consider his next of kin and friends to be imposters pretending to be the real thing, are then discussed. On occasion, patients have gone so far as to kill these “imposters”. Other patients lose conscious access to part of their visual field by lesions to the V1 area of the brain. These patients, though unaware of this area, show under testing that they are processing it. “Mirror neurons” in the brain show activity when one is doing a particular task, as when watching someone else do it. So do we really think that is us on the movie screen?

At the level of individual neurons as that of the concerted action of groups thereof, the course considers alternatives to the standard paradigm such as resonate and fire, and how the subthreshold oscillations ubiquitous in the brain may be exploited for neural computation. We look at methodologies such as fMRI and EEG. We then go on to consider the relatively certain knowledge we have about neural representation of the individual sensory worlds and multimodal mapping. We focus on the work of Walter Freeman Jr., whose schema allows for the fact that consciousness may just be a sample of much faster brain processes than we are aware of.

Theories of consciousness and evidence for them are then introduced. We discuss the work of Damasio, Laberge, and “blackboard architecture” theorists, as well as considering researchers like Schachter who rightly focus on how necessarily serial human agency can function in a system as noisy and parallel as the brain. With this equipment, we then consider the history of theories of the mind, and consider whether there are historical universals that give us clues, however tantalising, as to who we are. Descartes crisis of belief is contrasted with Vedantin meditations, which come to a completely different conclusion. That tension allows us access to reposing the fundamental questions in the light of modern brain science.

 © 2010,2011 Seán O Nuallain