neurodudes

Haim Sompolinsky has written an excellent book chapter on the scientific view of free will and choice, pulling in good ideas from physics and neuroscience along with contemporary philosophical commentary.

I think this chapter might be helpful for neuroscientists outside of the lab. Often a dinner table discussion has moved to the idea of “quantum consciousness” or “quantum free will”. Often, someone will mention Roger Penrose, who has become something of a poster boy for this idea that quantum indeterminacy (eg. Heisenberg’s uncertainty principle) is one possible way that free will is really free. And then, people look around and say, “Well, you’re a neuroscientist. Do we have free will?” (And that’s when I take another big drink or bite while I figure out something semi-coherent to say.)

Sompolinsky does a nice job of evaluating such claims (in the end, he says we cannot rule out the possibility that the brain is an indeterministic system but it seems unlikely) and provides nice scientific insight. In his view, it is far more likely that the brain’s apparent randomness (eg. individual cell spike rasters vary across repeated presentations of the same stimulus) is more simply explained by thermal noise (think of varying channel gating properties) and chaotic brain dynamics. (Recall, a chaotic system is still deterministic; it simply exhibits aperiodic behavior due to exquisite sensitivity to initial conditions. It is difficult to predict the long-term behavior of chaotic systems. The more we know the initial conditions in detail, the better our prediction.) On the other hand, he argues that the relevant length and time scales for neurons (micrometers and milliseconds) are far larger by many orders of magnitude than those of quantum noise. Chaos might amplify such quantum events, but this is far from being the simplest, most parsimonious explanation. Given the current level of neuroscience understanding, this is almost idle speculation. Regardless of the (in)determinacy of the world, Sompolinsky effectively argues against any non-physical, purely mental (ie. dualistic) agent of causation.

Thus, in sum, the world and our brains might not be determined but, even given that, there’s no reason to believe we have any causative ability to change things in the sense of traditional free will. These observations seem right on the mark to me. I hope they bring some insight for others. Or at least a way to fend off the dinner-table-free-will-conversation barrage of questions.

Jonathon Keats (no, not that one) has written a scorching review of neuro grad student Jonah Lehrer’s new book, Proust was a Neuroscientist.

I saw this somewhat more favorable review a few weeks in the NYT and was intrigued by the book. As an undergrad, I majored in cognitive science and English and, naturally, was fascinated by the cultural differences of academics in these disparate fields.

As in the Salon article, I also think attempts to unify the “two cultures” (ie. arts and sciences) are misguided. A work like Lehrer’s book (which I have not read) will need to work hard to “prove” its thesis and likely sound very forced. What can we really say about arts vs. sciences? For that matter, is it important to make value judgments on this topic? I’d say, no. We seem to have a natural urge to categorize our activities and then try to order them. Science is more worthwhile. Art is a more creative endeavor. Are these blanket generalizations productive?

But there is overlap between the two cultures and those regions seem more and more important to me. And I think neuroscience in particular has a lot to say here, too. If we know what makes good art good (in a scientific way), will we stop appreciating it or enjoying it? (This is similar to the idea that if someone told you free will was simply an illusion would the illusion be any less powerful than it is right now?) Often, the surprise of creative thought underlies the best science and the best art. Okay, there’s my attempt at a unification!

On a separate note, there certainly seems to be a hunger amongst the reading public for neuroscience books, despite our incomplete picture of how the brain works. For those frustrated with slow progress in research, maybe we should just go write a book.

The relatively recently discovered cannabinoid receptors has me wondering how many other neuroreceptors may be left to discover. One way to estimate the number of these is to screen the genome and look for sequences that look like receptors. This paper says that people have done that for the special case of G protein-coupled receptors (GPCRs), and that the result is that, excluding receptors involved in “chemosensory responses such as taste and olfaction”, there are “367 receptors (1), of which some 200 have been shown to bind known transmitters (3). This leaves about 160 orphan GPCRs that are not activated by any known transmitters and thus are genes with unknown function.”

I didn’t notice this before, but in a study of about 4000 subjects, people who took Rimonabant (marketed as Acomplia), a selective antagonist of the cannabinoid type 1 receptor (CB1), apparently had a 3.2% incidence of depressive disorders where placebo-takers apparently had a 1.6% incidence. Also, irritability went from .6% to 1.9%, parasomnia from .2% to 1.5%, nervousness from .2% to 1.2%, sleep disorders from .4% to 1.0%, memory loss from .9% to 1.6%, hypoesthesia from .6% to 1.6%, and sciatica from .4% to 1.0%. Psychiatric adverse events were dose-dependent.

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Pascual-Marqui has posted a preprint and would like comments. Read on for details.

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In this paper at arXiv, Yin et al. report on an analysis of the abstracts from the SfN meetings from 2001 to 2006. It sounds like their analysis uncovered several interesting trends: Two they mention in their abstract are that 60% of authors appear in only one year’s abstracts over the studied period, and that systems neuroscience seems to be on the rise relative to cellular and molecular neuroscience.

-John O’Leary

Salon features an interview today with Steve Pinker and Rebecca Goldstein:

Proud atheists: Steven Pinker, Rebecca Goldstein interview | Salon Books

After reiterating the physicalist view of the mind, the article ends with this quote from Pinker (reminiscent of Marr’s levels of analysis):

[...] But just by looking at the brain itself, will you ever be able to understand the creative mind?

PINKER: I suspect not. In fact, the reason I’m not a neurobiologist but a cognitive psychologist is that I think looking at brain tissue is often the wrong level of analysis. You have to look at a higher level of organization. For the same reason that a movie critic doesn’t focus a magnifying glass on the little microscopic pits in a DVD, even though a movie is nothing but a pattern of pits in a DVD. I think there’s a lot of insight that you’ll gain about the human mind by looking at the whole human behaving, thinking and reporting on his own consciousness. And that might be true of creativity as well. It may be that the historian, the cognitive psychologist and the biographer working together will give us more insight than someone looking at neurons and brain chemistry.

I think the analogy with the DVD is disingenuous. In the case of the DVD, we know precisely how the low-level pits are combined to form the high-level representation (the movie). The system is not mysterious. To be fair, Pinker doesn’t say that neurobiology is always the wrong level of analysis. Maybe he would have been correct 50 or 100 years ago, but I think it’s clear now that neurobiology is on the path to providing a complete synthesis (certainly, with the help of cognitive psychology) that cannot be achieved without it.

Third Annual Computational Cognitive Neuroscience Conference. Program.

Nytimes article.

Summary after the break.

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Emotiv is a company trying to do a neuro (EEG) interface to game platforms.

Emotiv Home

Seems ambitious. Do EEG interfaces have a fast enough information transfer rate (bits/sec) for gaming? Maybe it’s not necessary if the game is just detecting your “mood” in conjunction with a standard keypad controller but seems to me you’d want to try and boost bit rates (as several EEG groups, like this one at Fraunhofer, are doing) as much as possible.

Anyone used this device?