Category: Brain Mechanisms

Cabbies’ brains

The BBC has a nice piece covering the continuing research of Prof. Eleanor Maguire (Wellcome Institute of Neurology, University College London) on the distinctive development of the hippocampus in the brains of London taxi drivers: Taxi drivers’ brains ‘grow’ on the job. Prof. Maguire’s research in this area is pretty extensive (see publication list). She’s found a great naturally occurring experiment in the brains of cabbies who have to navigate London’s notoriously byzantine downtown streets.

As the BBC report describes, driving a cab in London is difficult and demands a well-developed knowledge of urban geography:

In order to drive a traditional black cab in London drivers have to gain “the knowledge” – an intimate acquaintance with the myriad of streets in a six-mile radius of Charing Cross.

It can take around three years of hard training, and three-quarters of those who embark on the course drop out, according to Malcolm Linskey, manager of London taxi school Knowledge Point. “There are 400 prescribed runs which you can be examined on but in reality, you can be asked to join any two points,” he told BBC News Online.

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The Everyday Brain and Our Everyday Life

Earlier this week I wrote about Jean-Pierre Changeux and Gerald Edelman, drawing on the New York Review of Books essay by Israel Rosenfield and Edward Ziff, How The Mind Works: Revelations. As I blogged then, “In the end I was still left with a ‘So what?’ Their hints at subjective psychology, the acting brain, and relational representation remained the side dishes, rather than the main course. I’ll deal with that main course later this week.” It’s Saturday, so I better keep to that promise.

Let me begin by just giving you the essay excerpts.

In general, every recollection refers not only to the remembered event or person or object but to the person who is remembering. The very essence of memory is subjective, not mechanical, reproduction; and essential to that subjective psychology is that every remembered image of a person, place, idea or object invariably contains, whether explicitly or implicitly, a basic reference to the person who is remembering.

The “rigid divide,” [Giacomo] Rizzolatti and Corrado Sinigaglia write in their new book, Mirrors in the Brain, “between perceptive, motor, and cognitive processes, is to a great extent artificial; not only does perception appear to be embedded in the dynamics of action, becoming much more composite than used to be thought in the past, but the acting brain is also and above all a brain that understands.”

For Edelman, then, memory is not a “small scale model of external reality,” but a dynamic process that enables us to repeat a mental or physical act: the key conclusion is that whatever its form, memory itself is a [property of a system]. It cannot be equated exclusively with circuitry, with synaptic changes, with biochemistry, with value constraints, or with behavioral dynamics. Instead, it is the dynamic result of the interactions of all these factors acting together.

Together, subjective psychology, an acting and embedded brain, and representation and action that are dynamic and relational present us with a new starting point when we talk about the intersections of neuroscience and psychology with anthropology. Starting with their conclusions, making it the beginning of something better, that would have been a really exciting essay for me to read.

As I wrote a couple days ago, Howard Gardner does get us closer to this new individuality. “Gardner brings a refreshingly unique take, neither the individual of science, bounded and rational, or the individual of philosophy and art, lone thinker and creative genius. Nervous system, individual experience, and subjective interpretation move us into a radically different domain—an individuality that lies firmly in the continua Gardner describes.”

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Brain vs. Philosophy? Howard Gardner Gets Us Across!

Jean-Pierre Changeux and Paul Ricoeur, both French scholars, wrote a book together entitled What Makes Us Think?: A Neuroscientist and a Philosopher Argue about Ethics, Human Nature, and the Brain. It consists of a series of discussions and debates the two held, an oral approach to knowledge given to us as written and translated word.

Together these two ably illustrate the biology/culture and science/humanities divide we have discussed recently. Changeux sees brains as more than just the material substance of knowledge and self; neurons serve as author as well. In contrast, Ricoeur brings phenomenology, interpretation, and reflexivity to the table, as well as a keen appreciation of the limits of human knowledge (and thus materialist claims, like those made by Changeux). Yet the first chapter of their book is entitled A Necessary Encounter, and then covers topics such as Body and Mind, The Neuronal Model and The Test of Experience, and Desire and Norms.

It was a true pleasure to encounter a lengthy and excellent review of this book by Howard Gardner, the psychologist and educator whose best known work is Frames of Mind: The Theory of Multiple Intelligences (Gardner even gives us a 25th year retrospective on the work). Entitled Mind and Brain: Only the Right Connections, Gardner sets up the theoretical debate at stake, provides us background on both scholars, and then perceptively takes us through their entire debate.

Here’s one excerpt to give you a sense of how Gardner sees Changeux, riding triumphant science, and Ricoeur, on the defensive, debating the brain:

When Changeux explains that the nervous system is active as well as reactive, Ricouer cautions that one should first speak of mental activities and not of the brain: “The discourse of the mental includes the neuronal and not the other way around.” Changeux responds: “What we wish to do is to link up the two discourses (material and mental) with each other” (p. 44). Here as elsewhere, Changeux seeks to effect connections, while Ricoeur insists on the ontological separation of the two realms.

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Jean-Pierre Changeux, Gerald Edelman, and How the Mind Works

The nature of the brain’s “representations”—if there is such a thing—of the world, the self, the past and present, remains puzzling, as the very different approaches we have described suggest: Changeux’s view of “long-lasting global representations”; Edelman and Tononi’s view of memory as constructive recategorizations, and Rizzolatti’s stunning discovery of mirror neurons, suggesting that we know and understand others, to some extent, through neural imitation. And as these differing views show… we are still far from a full understanding of the nature of memory, perception, and meaning.

So Israel Rosenfield, a doctor and historian, and Edward Ziff, a biochemistry professor, conclude their review How The Mind Works: Revelations in a forthcoming New York Review of Books piece. What I liked about this essay is its clear statement on starting points to think about our brains and its insightful summaries and critique of recent work. But in the end I was still left with a “So what?” Their hints at subjective psychology, the acting brain, and relational representation remained the side dishes, rather than the main course. I’ll deal with that main course later this week, and in this post cover Changeux and Edelman.

Rosenfield and Ziff give us a quick historical summary of work on the neuron as a cell that uses electrochemical signaling. Early research by Hermann von Hermholtz and Santiago Ramon y Cajal contributed to defeating the notion that neurons functioned in a similar fashion to the dominate communication technology of that time, the telegraph. Neurons are slow in direct contrast to the speedy telegraph.

Today we still draw on an equally speedy but wrong view, the computer analogy. Jean-Pierre Changeux helped overturn the computer view using both basic research and basic biological theory, evolution by natural selection. (Still, I was left asking myself, why couldn’t we have learned from the failure of the telegraph model in the first place…)

As Rosenfield and Ziff note, Changeux’s research showed that “the human brain therefore does not make optimal use of the resources of the physical world; it makes do instead with components inherited from simpler organisms… that have survived over the course of biological evolution.”

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Wednesday Round Up #10

Hierarchy

Anthropology.Net, The Social Brain Hypothesis: Are Our Brains Hardwired to Deal with Hierarchies?
Subconsciously processing dominance hierachies

Marc Dingman, Neuroimaging and the Social Ladder
Social hierarchy: can we see it in an fMRI?

Ira Flatow, Mapping the Social Brain
How the brain responds to social status

Constance Holder, A Head for Social Hierarchy
More on the work by Caroline Zink: superior players change our own thinking

Free Will

Cognitive Daily, Changing Belief in Free Will Can Cause Students to Cheat
No free will, more likely to cheat—if responsibility doesn’t count, who cares?

Foolish Green Ideas, Tight Fit
Very funny take on the “no free will” research

Brain Mechanisms

Chris/Mixing Memory, Emotion, Reason and Moral Judgment
Brain damage, moral scenarios, and general vs. personal rationality

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More on Brainbow

Since I posted Jeff Lichtman’s Brainbows, with all those wonderful images of the fluorescent brain, I’ve gotten questions from people about two basic things: first, how do they get those colors? and second, how do they get those images?

For the colors, genetic recombination techniques are used to insert pigment-expressing genes into the genomes of developing mice. The cool part? Those extra genes come from coral and jellyfish. The red color comes from coral, while the blue and cyan come from modifying a fluorescent green pigment in jellyfish.

For the images, the fluorescent hues only appear under fluorescent light. The Lichtman group has used two techniques, both using confocal microscopy (focused image taking, rather than a normal broad view from a typical microscope). First, brain slices are taken from mice and then examined in the lab. Second, for live shots, the Lichtman group works on the “neuromuscular junctions in a very accessible neck muscle in mice,” which permits taking a series of images over several days.

In the older post I blogged on how Lichtman’s approach to his research is reminiscent of what we try to do here—a naturalist concerned with the processes, mechanisms and connections of life and an understanding of the power of observation. But here I want to point out why these techniques are powerful. First, they permit an understanding of neuronal arrangements and connections through the greater discrimination provided by the many different colors. The image below from the original Nature article shows the differences between neuronal patterns in different parts of the brain.

Second, using computers to create 3-D videos from 2-D images, this research gives us maps that permits us stereoscopic humans to actually see fields of neurons as they are structured in the brain. This too represents a major advance over older images. So enjoy the video!

Finally, for your viewing pleasure, a composite image of brainbow pictures.