Teams of Memes, bursting from the seams

Image courtesy of the googles.

Daniel Dennett’s From Bacteria to Bach and Back is a lengthy and winding journey. It is characterized (including by its publisher) as a general explanation of the evolution of minds and various peculiar mental functions, consciousness and language being the two most hotly discussed by philosophers, but there’s a better way to read it. As its best, the book is a tour of Dennett’s personal philosophical repertoire, illustrating how ideas from his books and papers fit together.

Dennett’s general theory of the development of genetics stems from his broad theory of memes, where a meme is any informational entity that can be transmitted and replicated. The rough idea is that minds are meme-machines in the way that organisms are gene-machines (in Dawkins’ analogy of the gene’s-eye-view). This is a fruitful analogy, in some respects, though I think it can and should draw some skepticism from readers. I’ll return to those worries later.

The basic building blocks of Dennett’s view are indicated by gestures and short explanations, which is a challenge since he’s spent so much time discussing and arguing for them elsewhere in his work. In any case, there are really two that it is important to understand.

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I was compelled to post this

I said I didn’t want to say anything about free will, and I still don’t, but Massimo Pigliucci weighed in, and Jerry Coyne responded, and so did Sean Carroll, and of course I created a free will thread for everyone else to talk about it, so I guess there’s a fair bit of momentum behind it all.

I don’t understand why free will was getting all tangled up in indeterminacy vs. determinism, since that seems to be a completely independent issue. I’ll sum up my opinion by agreeing with Jerry Coyne:

Of course, whether the laws of physics are deterministic or probabilistic is, to me, irrelevant to whether there’s free will, which in my take means that we can override the laws of physics with some intangible “will” that allows us to make different decisions given identical configurations of the molecules of the universe. That kind of dualism is palpable nonsense, of course, which is why I think the commonsense notion of free will is wrong.

My mind is a product of the physical properties of my brain; it is not above them or beyond them or somehow independent of them. It doesn’t even make sense to talk about “me”, which is ultimately simply yet another emergent property of the substrate of the brain, modifying the how the brain acts. It is how the brain acts.

I think consciousness is a product of self-referential modeling of how decisions are made in the brain in the absence of any specific information about the mechanisms of decision-making — it’s an illusion generated by a high-level ‘theory of mind’ module that generates highly simplified, highly derived models of how brains work that also happens to be applied to our own brain.

(Also on FtB)

What have the students been up to this week?

It’s another update on the bloggin’ students in my Neuroscience course, and what they’ve been thinking about.

They all welcome visits and comments!

(Also on FtB)

What have my students been thinking about lately?

I gave them an exam, that’s what. That and long boring lecturings at 8am on pattern formation in the nervous system. But otherwise, I’ve had them blogging, so we can take a peek into the brain of a typical college student and see what actually engages them.

I understand these are all the things all college students everywhere are contemplating.

(Also on FtB)

What have my students been thinking about this week?

I’ve got my neurobiology students blogging — all I ask is that they write something relevant to understanding how brains work. Let’s see where their minds are at this week, shall we?

(Also on FtB)

Wiring the brain

This story is some kind of awesome:

For those who don’t want to watch the whole thing, the observation in brief is that color perception is affected by color language. The investigators compare Westerners with our familiar language categories for color (red, blue, green, yellow, etc.) to the people of the Himba tribe in Africa who have very different categories: they use “zoozu”, for instance, for dark colors, which includes reds, greens, blues, and purples, “vapa” for white and some yellows, “borou” for specific shades of green and blue. Linguistically, they lump together some colors for which we have distinct names, and they also discriminate other colors that we lump together as one.

The cool thing about it all is that when they give adults a color discrimination test, there are differences in how readily we process and recognize different colors that corresponds well to our language categories. Perception in the brain is colored (see what I did there?) by our experiences while growing up.

The study is still missing one part, though. It’s presented as an example of plasticity in wiring the brain, where language modulates color perception…but we don’t know whether people of the Himba tribe might also have subtle genetic differences that effect color processing. The next cool experiment would be to raise a European/American child in a Himba home, or a Himba child in a Western home (this latter experiment is more likely to occur than the former, admittedly) and see if the differences are due entirely to language, or whether there are some actual inherited differences. It would also be interesting to see if adults who learned to be bilingual late experience any shifts in color perception.

(Also on FtB)

Neuro student articles

I’m teaching an upper-level course in neurobiology this term, and as I usually do, I made all the poor suffering students go out and create blogs, and I also told them they had to write one post a week about neuroscience. Today I was asked if I was going to pharyngulate their blogs, and of course I said I would. So go forth and harrass them! A word of warning, though: as many people learned last time I did this, these are not passive, cowed students, but feisty upperclassmen who are comfortable with biting back; the worst thing you can do is be condescending or patronizing.

(Also on FtB)

How am I going to fit an MRI in the bedroom?

Maybe you’ve seen this before: it’s a diagram of the sensory and motor cortex of the brain, with a little man or homunculus drawn over it to illustrate the somatic areas associated with each region. You see where the little man’s knee is on the left image of the sensory cortex? Stick an electrode in there and zap it, and a patient/victim will feel a sensation in his knee. Put the patient in an MRI and tickle his knee, and that region of the brain will light up. Cool, huh?

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Another cute feature: look in the medial longitudinal fissure. You see the homunculus’s toes, and right down there, located beyond the toes, is where the genital sensory area is located. Poke at that with an electrode and…we’re talking happy time at the Mad Scientists’ convention. But notice, though, that in the diagram of the homunculus, the poor creature’s genitals are drawn, and they’re male. It’s a bit sexist, don’t you think?

This bias has now been corrected.

a team led by Lars Michels at University Children’s Hospital in Zurich, Switzerland, used functional magnetic resonance imaging to confirm that the position of the clitoris on the homunculus was in approximately the same position as the penis in men. Barry Komisaruk at Rutgers University in Newark, New Jersey, and his colleagues have now used the same method to map the position of the clitoris, vagina and cervix on the sensory cortex as women stimulated themselves.

I read these things, and I think to myself that I really went into the wrong research field. Oh, well.

They also discovered something else.

Komisaruk also checked what happened when women’s nipples were stimulated, and was surprised to find that in addition to the chest area of the cortex lighting up, the genital area was also activated. “When I tell my male neuroscientist colleagues about this, they say: ‘Wow, that’s an exception to the classical homunculus,'” he says. “But when I tell the women they say: ‘Well, yeah?'” It may help explain why a lot of women claim that nipple stimulation is erotic, he adds.

Now, as a true nerd and as a typical male who has always been mystified by the female sexual response, I feel a deep craving to plumb the mysteries with my own personal fMRI scanner. It’ll also be a research project that will go over well at the next Mad Scientists’ convention.

(Also on FtB)

What’s the matter with Andrew Brown’s brain?

He’s completely lost me again. Brown has a couple of posts up complaining about people referring to mental illness as a “brain disease” and confusing mind with brain — he seems to deplore the growing recognition that the mind is entirely a product of the brain, and that psychology is built on a physical substrate, which leads to what he thinks is a premature reduction of mind to brain. He’s not making an argument from dualism, though; the gist of his complaint is that you can’t deduce thoughts from the structure of the brain, therefore it’s an invalid approach.

That doesn’t make any sense. We also don’t have a consistent, predictable way of deriving the structure of the brain from behavior, but we don’t use that as an excuse to dismiss studying behavior, and it’s not an argument that we need to distinguish mind from brain. We’ll never have a complete description of any brain sufficient to derive thoughts from physiology; so? Time to face the truth and recognize that your mind is entirely produced by chemistry and electrophysiology and molecular biology of the brain, nothing more, and I find no reason to take offense when people are aware that a cup of coffee, the sun shining in your face, or a hug from your children cause biological changes to your brain.

I find the prospects exciting, not annoying. Here’s an example: scientists have created an artificial hippocampal nucleus on a chip. What they did was record the electrical activity from area CA1 of the hippocampus while rats were learning a memory task, and then stuck a device in their brains that played back that sequence into the hippocampus. When they pharmaceutically silenced CA1, which normally inhibits learning, and ran the chip instead, learning was restored. When they used the chip without the CA1 inhibitor, learning was enhanced.

Nobody understands exactly how this works, but there’s no denying that the function of this part of the brain is produced by patterned electrical activity. Incomplete understanding shouldn’t be a barrier to recognizing the reality staring us in our face.

Besides, I’d love to augment my brain with silicon. Although, to be honest, I’d rather test it on my students first — they won’t mind getting a chip implanted to help them learn, right?