The Quest for Consciousness: A Neurobiological Approach

used book in really good shape bought in europe and arrived really fast

This is a great book that describes where we stand in the search for neuronal correlates of consciousness (NCC). The problem has been attacked by people from various different fields. Still, it has to be a biology problem. Consciousness clearly resides in the brain. If only we had plenty of examples of brain-damaged people ... some of whom clearly lacked consciousness, some who were almost conscious, some who were certainly conscious, some who were uncertainly conscious .... then maybe we'd work out what the key was. Luckily, we don't have all that many brain-damaged subjects. Koch takes this sort of approach to the problem of discovering the NCC: he tries "to quantitatively correlate the receptive field properties of individual neurons to conscious perception." If there's no map between certain cells and the structure of a conscious perception, then it's unlikely that these cells are sufficient for that conscious percept. That means looking at what we'd normally think of as vision problems, optical illusions, attention loss, long and short term memory, and various automatic and semi-automatic responses to stimuli. What amazed me most was that the work on this subject is still easily readable by the layman. One of the more interesting questions Koch raises is this: since consciousness resides in the brain, do we get two consciousnesses when we split the brain in two? Actually, (as Koch explains) this was studied by Roger Sperry, whose split-brain experiments on monkeys and other animals in the 1950s and 1960s showed that the two sides of the brain easily learn different responses to stimuli, indicating that these animals effectively possess two separate minds. There are, of course, as Koch describes, some human split-brain patients who also demonstrate this. It's an interesting book that is easy to read. It's sobering to realize how little progress we've made on such a fundamental question.

This is the best popular neuroscience book that I have read, and I've read a couple dozen of them over the last 15 years. I can say without hesitation that it rasies the bar for popular neuroscience writing. It's not so much that Koch is the best writer, although he's very good. The strength of Koch here is that he provides a great deal of detail about the processes he talks about, and he organizes the information in such a way that you don't get lost in anatomical terminology. A lot of neuroscience books may such things as 'lesions in the posterior parietal cortex are known to be related to a condition called 'hemi-neglect' where the patient is unaware of objects in the left hemisphere, despite the fact they can see them if asked' - while that's interesting, it's usually presented as a brute fact with no real grounding of what the posterior parietal cortex does or how it fits into the larger scheme of sensory processing. But Koch does a marvelous job of explaining how various regions function and interconnect with others, and how that results in what you experience, or even what you don't experience. The word 'quest' in the title isn't just hyperbole, you really are on an adventure to find something very specific, which is laid out at the beginning of the book. What Koch is looking for is what is called the Neuronal Correlates of Consciousness (NCC), meaning specific neurons whose activity can be demonstrated to be causally linked to specific aspects of conscious awareness (i.e. subjective experience). In this case, because more is known about the visual system than almost anything else about the brain, and certainly any other sense, he narrows his search for the NCCs to those that underlie visual experience. So, in effect, this book is about the visual system, specifically how and where it generates conscious awareness of visual stimuli. His quest starts at the retina, where you get a wonderfully detailed and readable account of it's structure and activity, then you are whisked down the optic nerve to the Lateral Geniculate Nucleus (another structure I've read about many times before, but have never come away with a clear understanding of what it does until this book). After that you travel to the back of the brain to areas V1-V4 in the visual cortex which break down the signals from the retina into bits and pieces of contrast, lines, angles, shading, dark and light, color. Koch swiftly moves up the processing hierarchy, moving from basic perceptual bits and pieces to object recognition and attention. There is a revealing discussion of non-conscious visual processing that is compelling, giving the reader a glimpse of the enormous behind-the-scenes power that the brain brings to bear on perception, which we are fortuitously, and by design, never aware of. There's a good deal of detail throughout, but never does he get bogged down. It's written with clarity and always with a sense of how it all fits into the quest for the NCC.

ABSOLUTELY RECOMMENDABLE for anyone interested in how the brain works. The clear exposure and expertise of the author(s) makes of this book an extremely enjoyable read. Great for Neuroscience and Cognitive science students. With citations supporting every little detail exposed, it creates a library for future readings. For non-scientists interested in the brain and mind this book should be quite easy to understand.

Christof Koch takes the reader on a literal quest, starting where visual information enters at the eyes and proceeding as it is processed in successive layers of the brain, looking for the neural correlates of consciousness: neural activity corresponding in an explicit, easily understandable way, directly to our conscious percepts. Along the way we learn what is known (and what is still mysterious) about the various brain areas, neural organization, and information pathways, and about how this information has been gained. Understanding consciousness is a kind of holy grail, and the excitement of the author's personal chase rendered the book so gripping to me that I read it straight through.Many readers will find the most interesting sections to be those in which Koch goes beyond his more sober scientific publications to speculate on the nature of qualia, our sensations such as pain or redness, as arising through evolution and corresponding to "meaning". Unfortunately, beyond a few evocative paragraphs, Koch does not address the nature of meaning. He also explicitly defers judgement on questions such as why qualia feel like anything at all to us and whether we have free will. I don't think he should be faulted for these omissions -- while these subjects are not beyond the scope of science, they may well be beyond the scope of neurobiology.However, readers interested in the Quest for Consciousness will also enjoy What is Thought?, which brings ideas from computer science and other fields to bear on these questions. WIT? is organized around a computational theory of what meaning is and of how evolution discovers and exploits it. This theory suggests viewing the genome as source code that compiles into the brain as executable. Thus it is suggested that neurobiology is not the only or even the most straightforward path to understanding the mind: simple, understandable structure in source code often is blown up and obscured in the executable. What is Thought? analyzes computationally what it means to understand, how we understand, and what we can understand about understanding. Finally it offers a straightforward, principled theory of why qualia feel like something to us, and indeed why they feel like they do, as well analyzing in detail what free will is, how it arises, and what its limitations are. The computational theories of What is Thought? unify relevant data from a variety of fields but the book discusses relatively little neuroscientific data. Its theories and approach will ultimately be confirmed or falsified as technologic progress continues: as gene expression data and brain imaging improve, as new psychophysics experiments are developed, for example probing qualia illusions in unnatural circumstances. On my reading, they are consistent with the data and most of the theories in Quest for Consciousness, but also there is considerable potential for integrating the data and approaches of the two books into further experimentation and understan