The Ravenous Brain - Daniel Bor

The Ravenous Brain

Bor loves the "Prefrontal parietal cortex" PPC, which he identifies as the seat of "working memory". In turn, the concept of awareness, consciousness and working memory a so closely intertwined that research in any of these subjects is, by default, research in all the others.

In this book, he makes a strong case. It turns out that we can be conscious while missing big chunks of our brain. Evidence from such sad situations, along with EEG and fMRI studies, allow us to zero in on the brain functions that are necessary and sufficient for consciousness. Bor provides extensive examples of experiments that reveal the limits of consciousness and how it can be "taken apart" in various ways.

One of is central ideas is "chunking". He visualizes working memory has having a limited capability to handle "chunks" - perhaps just 4 at a time (whatever "chunks" are). To deal with this limit, the brain (mainly the PPC), detects patterns (chunks) that can be manipulated as one. For example, 4 lines may be lumped together as a rectangle. In his sense, Bor's "chunks" are what we'd call "patterns". Once formed, such chunks can be stored (somehow) in the rest of the brain and re-used in subsequent tasks performed in working memory. Thus, General Relativity can become just one "thing" in some situations.

Other examples in the book invite a different analogy. The "chunk" can be a "subroutine", such as an algorithm for muscle movements that form a good tennis swing. Once formed, the whole swing can be "packed away" and executed as a single "chunk'.

As I understand it, the theory is that the prefrontal lobes (what's usually though of as the seat of "executive function" or decision making) get involved only if we need to puzzle out a new way of "chunking" current experience. On the other hand, it seems like Bor is claiming that this part of the brain is always active when a person is conscious.

Comparing to Hofstader's claim that analogy is the fuel of thought, it would appear that the formation and application of categories by analogy would be compatible with Bor's theory, although Bor would quite reasonably regard categories (as chunks) and analogy (as the process that creates chunks) as special cases. Bor claims words as "chunks" but makes no extensive claims about language in general.

Interestingly, Bor is a big fan of meditation as a way to "flex our consciousness muscle" and improve general mental health. He ties many mental illnesses to problems with working memory and discusses the effect that various drugs have on these conditions.

Bor's theories are necessarily confined to his experimental tools, meaning that his core theories are about brain regions that "light up" in fMRI studies. This gives a relatively static picture of the brain and leads to a lot of talk about brain regions such as the PPC. More recent methods allow Susan Greenfield to watch "chunks"(active neural assemblies) fly around in the cortex in real time, hinting at somewhat different ways to visualize what Bor talks about mainly in broad generalizations about hypothetical communication between neurons. The resulting picture gets away from regions "lighting up" to something more akin to a huge fireworks display with "chunks" flying all over the brain, igniting other "chunks" in a spectacular chain reaction. Susan Greenfield's work also ties in closely with Bor's ideas about the effects of neurotransmitters, since a closer look at "chunk" activation shows that certain neurotransmitters are elevated in physically nearby brain regions on a very short time scale. Brain regions "lighting up" on fMRI scans are blurry image resulting in a time exposure of several seconds, when the real events are a light show something like those revealed at microsecond intervals.