My brain arrived by mail

In my research, I study the brain and how it works. It's useful to have a feeling for the shape of the brain, and where the parts are. So, I purchased a brain model from AllHeart.com.

I was pleasantly surprised. It's approximately life-sized, solid rubber, and weighs over 3 pounds. Basically, close to a real human adult brain (except for the rubber). Here is a view from the bottom.

It also comes apart. Here is a sagittal view of the left hemisphere.

It has 8 pieces in total. These are the 4 pieces for each hemisphere.

And it even comes with a handy dandy stand, shaped especially to fit your cranial curves.

I'll use it when I teach about the brain.

Moving things with your mind: Neuroprosthetics

Miguel A. L. Nicolelis

Holy cow, what an amazing talk I just went to. I'm at a conference in Buenos Aires, called "Engineering in Medicine and Biology". It features many scientific and engineering advances in fields like medical imaging, bioinformatics, and neuroscience. I make it a habit to attend the plenary talks because they're meant for a general audience, and they're often a good way to see a nice overview of a field of research.

This afternoon, I attended a plenary keynote lecture called "Towards a Whole-Body Neuroprosthetic", by Miguel A. L. Nicolelis of Duke University. What an eye-opener!

The theme behind his research -- implantable arrays that can read electrical activity from thousands of neurons. This activity is used to derive numerical models of behaviour. For example, a monkey is trained to play a little computer game in which it has to move a cursor into a circular region on the screen by manipulating a joystick. While this is going on, an implanted probe in the monkey's motor cortex reads off the neural activity associated with the movements. Later on, the experimenters remove the joystick, and instead derive the INTENDED motions directly from the monkey's neural activity. And it works beautifully! The monkey is able to control the cursor with its mind (similar to classical EEG-based attempts, but no training is needed; the device reads your intentions from your brain's natural internal language).

This technology could be used in corporeal augmentation for the paralyzed (artificial limbs and other actuators could be controlled directly by the brain). That's the first application that comes to mind (no pun intended). But there are other applications, such as remote manipulation... controlling a limb over the internet.

In the talk, he also described experiments where they fed electrical activity INTO the brain. This could be thought of as an aditional form of sensory input. The example he gave was a mouse that lives in a cage with a complex magnetic field. The mouse has a magnetic field sensor that sends information into its brain. It will be interesting to see how the mouse's brain incorporates the new input. Presumably, the mouse will have a completely independent perception of where it is in its cage, so that if you gouged out its eyes and plugged up its ears, it would still be able to navigate in its cage without hesitation.  Sounds strange, but you've already got something similar. Most people don't realize that they have more than 5 senses; your inner ear houses your equilibrium, your sense of which way is down. Close your eyes, and stand on one foot. You can still stay upright because of your sense of equilibrium.  The mouse's magnetic sense is sorta like that.

Using these neuroprosthetic input and output devices, Prof. Nicolelis' goal is to have a quadraplegic walk onto the field to open the 2014 FIFA World Cup in Brazil (Nicolelis' native country). The person will be strapped into an exoskeleton robot, and implants in their brain will give the robot the complex instructions for walking.

Finally, Prof. Nicolelis urged us to loosen our grip on the idea that cognitive functions are localized in the brain. He said that this division of the brain is a model that we like because its easy to understand; he offered the rather paradoxical quip "our brains don't think the way we think". He also emphasized that the brain is a general-purpose statistical inference machine. No matter what input you feed it, it will start to build the structure of the input into its model of the world. I like the way Nicolelis thinks.

My brains, spread all around the world

Every now and then, I get an e-mail from someone asking if they can use my MRI data for their paper or project. In case you've never seen "My Brain" page, it has a link to download a 3D stack of slices of my head. One of the 129 slices is shown on the right.

A couple years ago, I was approached by the creators of ImageJ, a free image-processing application offered by the National Institute of Health in the U.S. They asked if I would agree to allow them to use my MRI data as a standard sample dataset. OF COURSE! So now anyone that has ImageJ can get my MRI slices by simply choosing "Open samples..." from the File menu. They can also see a volume rendering from that MRI stack. ... the scanner adds at least 10 pounds.

Brain Awareness Week: March 15-21

I just found out that next week is Brain Awareness Week. I guess that's the week your brain should be aware.

No wait! That's the week that your brain should be aware of brains (insert infinite regress here).

On Being Certain: A book review

The book: "On Being Certain: Believing You Are Right Even When You're Not" by Robert A. Burton, M.D.

This book shook the foundation of my epistemological world. The crux is that the sense of knowing something is a feeling like anger or pride. Thus, the fact that you "know" something does not mean it's true.

He gives an example. Right after the Challenger exploded on take-off (back in 1986), a psychology researcher collected statements from a number of people about what they were doing when they heard the news. A few years later, he asked them again. They all remembered vividly. Except, their memories didn't necessarily match what they'd written. When shown their statements, some continued to insist that the statement was wrong, but their memory was right. It's a vivid demonstration of how utterly convincing the feeling of certainty is. But, it's just a feeling.

He goes further. We don't even have any way of knowing what unconscious mental processes went into a belief or conclusion. So introspection is of little use for determining which beliefs are true and which are false.

He gives examples involving medical doctors. One proclaims, "I believe in the necessity of research, but I know that personal experience is the 'proof of the pudding.' " Like many doctors, this one leans heavily on his own personal judgement based on experience. But how do we know that the judgement is tied tightly to reality?

Science is the best bet.

... we should know when we are basing our decisions on science and when they are based upon unsubstantiated experience, hunches, and gut feelings. But, as we've seen, we aren't reliable assessors of such arbitrary distinctions.

His suggestion is that we modulate the conviction of our beliefs by attempting to consider the probability that each is correct, and reflect that uncertainty when we express our beliefs to others.

Toward the end of the book, Dr. Burton seems to suggest that our brains are equipped with a sensory system for perceiving a representation of brain state. This is nothing short of a theory of consciousness, and nothing short of fascinating. Just like we have a sensory cortex for processing tactile and visual information, we might also have a sensory cortex for processing mental information. He doesn't say it point-blank, but launches the notion for the reader. It blew my mind. I'm not sure I agree with it, but then again, this book makes it abundantly clear that we should not let the feeling of believing fool us.

Poor kitty, but nice neurons

My graduate student and I are working on a neural network model of the visual system. We've been learning a lot about neuroscience, and I'm loving it. I'm also sitting in on PSYCH 261 (Physiological Psychology), and this week we covered the visual system. The prof. showed us this short YouTube video:


It shows Hubel and Wiesel in the 1960s measuring how certain neurons react to different light stimuli. They clamped a cat's head down and stuck an electrode into its brain (OK, the sad part is over). They found that certain neurons reacted to particular patterns of light, not just brightness. It's those patterns that we're trying to get our computerized visual system to spontaneously generate, thereby positing a theory for how the visual system achieves this organization. We're getting there.

Synesthesia - kind of maybe

In the PSYCH 261 lecture today, the prof. mentioned synesthesia. It's a condition in which your sensory perceptions of objects become mixed. For example, some people see numbers as coloured, or automatically associate months with personalities. I'm not sure if I experience some of that or not; I expect everyone does to some extent.

Here is how I view the months of the year... every time I think about months, I see them arranged in this format.


I also used to associate emotions with letters and numbers (eg. f and 5 are angry, but b and 4 are calm), but that's faded somewhat over the years.

Anyone else?

[From intelligent-falling.blogspot.com]