Constructing Your Own Cartesian Theatre

Cartesian Theater
The Cartesian Theatre is the place inside your head where you sit and watch the world unfold before your very eyes. Well, not really. In order for cognitive scientists to better understand how our brains create an interactive conscious experience, they actually had to demolish the Cartesian Theatre in order to assemble a structure of brain and mind that better fit with the research.

The search for the seat of consciousness has been a long and tumultuous journey, and by no means have humans come near the hidden prize. But some ideas are better than others -- some have thought the thing through more clearly than others, incorporating more of the confirmed research data into more elegant theories.

In "Self Comes to Mind," Antonio Damasio reveals some of his deepest and most recent ideas regarding the origin of the conscious self. It is worth quoting from Chapter 9 of the book to illustrate Damasio's search for the origin of self:

Several possible structures come to mind, but only a few can be seriously considered. An important candidate is the thalamus, a perpetual presence in any discussion of the neural basis of consciousness, specifically its collection of associative nuclei. The intermediate position of the thalamic nuclei, between the cerebral cortex and the brain stem, is ideal for signal brokering and coordination.

Although the associative thalamus is busy enough constructing the background fabric of any image, it plays a very important, albeit perhaps not the lead, role when it comes to coordinating the contents that define the autobiographical self. I will say more about the thalamus and coordination in the next chapter.

What are the other likely candidates? A strong contender is a composite collection of regions in both cerebral hemispheres that is distinguished by its connectional architecture. Each region is a macroscopic node located at a major crossroads of convergent and divergent signaling. I described them as convergence-divergence regions or CDRegions in Chapter 6 and indicated that they are made of numerous convergence-divergence zones. CDRegions are strategically located within high-order association cortices but not within the image-making sensory cortices. They surface in sites such as the temporoparietal junction, the lateral and medial temporal cortices, the lateral parietal cortices, the lateral and medial frontal cortices, and the posteromedial cortices. These CDRegions hold records of previously acquired knowledge regarding the most diverse themes. The activation of any of these regions promotes the reconstruction, by means of divergence and retroactivation into image-making areas, of varied aspects of past knowledge, including those that pertain to one’s biography, as well as those that describe genetic, nonpersonal knowledge.

...One of the main CDRegions, the posteromedial cortices (PMCs), appears to have a higher functional hierarchy relative to the others and exhibits several anatomical and functional traits that distinguish it from the rest. A decade ago I suggested that the PMC region was linked to the self process, albeit not in the role I now envision. Evidence obtained in recent years suggests that the PMC region is indeed involved in consciousness, quite specifically in self-related processes, and has provided previously unavailable information regarding the neuroanatomy and physiology of the region. (The evidence is discussed in the last sections of this chapter.)

...The final candidate is a dark horse, a mysterious structure known as the claustrum, which is closely related to the CDRegions. The claustrum, which is
located between the insular cortex and the basal ganglia of each hemisphere, has
cortical connections that might potentially play a coordinating role. Francis Crick was convinced that the claustrum was a sort of director of sensory operations charged with binding disparate components of a multisensory percept. The evidence from experimental neuroanatomy does reveal connections to varied sensory regions, thus making the coordinating role quite plausible. Intriguingly, it has a robust projection to the important CDRegion that I mentioned earlier, the PMC. The discovery of this strong link occurred only after Crick’s death and was thus not included in the posthumously published article that he wrote with Christof Koch, in which he made his case.1

The problem with the claustrum’s candidacy as coordinator resides in its small scale when we consider the job that needs to be performed. On the other hand, given
that we should not expect any of the structures discussed earlier to perform the
coordinating job single-handedly, there is no reason why the claustrum should not make a relevant contribution to the construction of the autobiographical self. _Self Comes to Mind

Damasio also describes a number of other key brain structures -- including the brain stem -- in connection with their role in constructing a conscious self. The path to consciousness is serpentine, and feeds back upon itself in intricate ways.

Antonio Damasio

What is the point to this? Simply, if you want to understand the mind -- your own or someone else's -- there are a number of things which you will need to process almost simultaneously, at various levels of basic and emergent logic. You cannot do that without having done a great deal of reading, thinking, experiencing, observing, and experimenting. Fortunately for non-scientists, the entire human world is a great experimental laboratory for studying cognition.

Secondarily, if you want to create a machine consciousness, you may want to understand how the only proof of concept in the known universe -- the human brain -- manages to achieve the task at variable levels of competence.

Readings:

For an introduction to consciousness, Susan Blackmore's intro to the topic is one of the best places to start.

Antonio Damasio's book, Self Comes to Mind, is an interesting progression beyond an introductory review on consciousness.

At a somewhat deeper level, Gyorgy Buszaki's Rhythms of the Brain will connect many elements of neuronal structure and activity with higher levels of brain function.

A Dynamic Collection of Integrated Neural Processes, Centered on the Representation of the Living Body, That Finds Expression in a Dynamic Collection of Integrated Mental Processes

B&NReview
Cognitive scientist Antonio Damasio has authored some of the most successful, influential, and widely read popular science books on the mind. His latest book, "Self Comes to Mind," is an attempt at "starting over." Damasio wants to re-draw his vision of consciousness and the mind, on a larger canvas, and with the advantage of recent research findings and more comprehensive thinking on his own part.

But can a middle-aged man truly start over? Will society allow it? The publication of Damasio's new book has spawned a large number of published responses, from the respectful Jonah Lehrer interview, to the somewhat bemused Barnes & Noble review by philosopher A C Grayling, to the quasi-temper tantrum thrown by psychologist Alison Gopnik, in Slate.

When a person accumulates a body of work and thought, it is difficult to start over. And despite his claim, Damasio is not actually beginning again at the beginning -- that would be impossible. He is taking much of the respect and credibility that he has earned from past research and writings, and risking it all in an attempt to create something quite magnificent -- the beginnings of a seminal vision of how human minds work.

Damasio makes a case for the necessity of a "self", or subjective element, in the mind. And he locates the self precisely within the body -- or at least the parts of the brain that sense and map the body. Despite Damasio's claims of "starting over," feelings and emotions play central roles in this embodied self, this anchor of higher consciousness. In fact, threads of his previous thoughts pervade his newest work.

The author builds his argument chapter by chapter, bringing the reader up to date on known brain functions, theories of mind, and new research findings which utilise the latest tools. So far, so good. But then, in connecting the threads of self, the body, feelings, consciousness, perception, movement, attention, and some types of memory, Damasio climbs far out onto the brain stem. By doing so, he may be providing jealous rivals -- some of them possessing psychological chain saws -- an opportunity to cut him off at the stump. Damasio does not care. To Damasio, the vision is the important thing, not necessarily what others might construe of it. If the vision is true, eventually it will come through.

Damasio looks at the mind from the level of brain centers and pathways, and from the higher level of mental processes up to the self. Some readers will be satisfied with his weaving of the two levels together, and others will not. It is worth the time and the struggle, in my opinion, as an introduction to cognition.

The truly hard work has yet to be done. And since an ultimate understanding of the human mind -- as far as modern humans are capable -- will require a monumental acquisition of concepts as well as a monumental erasing of mis-concepts, it is unlikely that many of the current crop of cognitive scientists will ever live to see the promised land. Starting over is much harder than one might think.

Update 27Dec2010: Philosopher Ned Block takes a shot at Damasio's book in the pages of the New York Times. I admit to being a bit puzzled by Block's obvious and repeated mischaracterisations of some of the basic ideas in Damasio's book, until I reached the final paragraph in Block's critique. It seems that Block is disturbed that some of Damasio's ideas may be used to justify suffering by cows and chickens in the livestock and food production business. Apparently, Block did not read the book at all, but rather seized upon a few sections which raised red flags in the minefield of Block's politically correct consciousness.

You would be amazed how common it is that busy book reviewers fail to read the books they are reviewing. I suppose when one is politically correct enough, one hardly has to read or think deeply about an idea in order to recognise it as heresy. Understanding such emotional and reflexive "thinking" is part of the reason why thinking people should read books such as Damasio's "Self Comes to Mind."