Memory Chip

Scientific American has a neat piece of news in its February 2007 issue (“Chipping In” by Anna Griffin; subscription required for full text). For some time, we have had technology that can pick up signals from neurons (brain and nerve cells), for instance, allowing paralyzed patients rudimentary control over a computer or prosthesis.

But a team at the University of Southern California, led by Theodore W. Berger, have taken this a step further. For twenty years he and his team studied the brains of rats; specifically, how neurons communicate in the hippocampus, a region of the brain involved in memory. They developed a model of how the neurons responded to various inputs and built it into a chip. They then took slices of hippocampal tissue, removed part of it, and replaced it with the chip, “[restoring] function by processing incoming neural signals into appropriate output with 90 percent accuracy,” according to the Scientific American article.

I find this to be very exciting. This sort of research could one day lead to devices to help humans with brain damage or memory problems, for instance, though of course that is still far away. Even at this stage, it took some interesting engineering work to figure out how to make a silicon chip interact with brain tissue. The next step will be to design a chip to work with a living brain, instead of tissue slices.

But what really fascinates me is that they were able to model the function of that brain tissue mathematically, to calculate how the section of neurons would respond to various inputs. This brings us closer to understanding just how brain functions such as memory and consciousness arise from the biology and chemistry of the brain.

It does suggest some future ethical and philosophical puzzles, though. Will we eventually be able to reproduce the functioning of the entire rat brain? How about that of a human? Might we one day be able to calculate the functioning of a human mind, to reproduce a mind as software?

My brain looks forward to future advances.

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Learning to Walk

Scientists watch the robot attempt to walk
Credit: Lindsay France/Cornell University. Source: PhysOrg.com.

Josh Bongard and his colleagues at Cornell write in the November 17, 2006, edition of Science (see abstract) about a new robot they have built. As reported on PhysOrg.com (thanks to Food not Bourgeoisie for spotting this), the robot develops a model of self to learn how to move, perhaps somewhat similar to the way human babies learn:

Nothing can possibly go wrong … go wrong … go wrong … The truth behind the old joke is that most robots are programmed with a fairly rigid “model” of what they and the world around them are like. If a robot is damaged or its environment changes unexpectedly, it can’t adapt.

So Cornell researchers have built a robot that works out its own model of itself and can revise the model to adapt to injury. First, it teaches itself to walk. Then, when damaged, it teaches itself to limp.

(continue reading at PhysOrg.com)

The robot is programmed with a list of its parts, but not how they are connected or used. Instead, it uses a process that is a mixture of scientific method and evolution to learn how to move. It activates a single random motor, then, based on the results, it constructs fifteen varying internal models of how it might be put together. Next, it decides on commands to send to its motors, selecting commands that will produce the largest variation between models. It activates its motors and based on the results, the most likely model is selected. Variations on this model are constructed, and the robot again determines which test movement will produce the largest difference in movement between models. (This sort of repeated variation and selection is sometimes called evolutionary computation.) After sixteen cycles, the robot uses its best model of self to determine how to move its motors to move the farthest. It then attempts to move (usually awkwardly, but functional).

In a second part of the experiment, the researchers simulated injury by removing part of a leg. When the robot detects a large discrepancy between its predicted movement and its actual movement, it repeats the sixteen-cycle process, generating a new model of self and new way to walk.

Continue reading “Learning to Walk”

Artificial Sun

Cutaway of ITER
Cutaway schematic of ITER. Note the size of the human for scale. Published with permission of ITER.

I strongly support international collaboration, so I was excited to read on Bainite’s blog that ITER has been formally announced. ITER is a project to demonstrate the feasibility of fusion power on a large scale; it is a joint project between the European Union, Japan, the People’s Republic of China, India, the Republic of Korea, the Russian Federation, and the United States.  The planned location is in Cadarache in southern France (approximate location 43°41’55.65″N 5°44’30.61″E). ITER will fuse deuterium and tritium, contained by magnetic fields. The resultant high-energy neutrons will produce heat. In a fusion power plant, this heat would then be used to produce electricity; however, as ITER intended for research and demonstration, the heat will be allowed to escape.

Fusion is a form of nuclear energy. In fact, it’s the way our sun and all the stars produce energy, which means that ultimately, it’s the source for almost all energy on Earth. The energy from the sun powers solar panels, heats air to produce wind currents, and evaporates water which flows back down to produce hydroelectric power. Plants capture sunlight to make their food in a process called photosynthesis; animals (including humans) eat those plants or eat animals who ate those plants to obtain food. Similarly, our fossil fuels—such as coal, oil, and natural gas—are formed from the remains of plants and animals that died millions of years ago.

The form of nuclear energy used in today’s power plants is fission, in which a large atomic nucleus is split into smaller pieces, releasing energy. While this results in millions of times at much energy as conventional chemical methods like burning coal and avoids producing greenhouse gases, it still produces radioactive waste products. On the other hand, fusion combines two small atomic nuclei: this releases even more energy than fission, and does not produce any toxic waste products. However, the trick is that it is technically much more difficult to control and harness the energy. Of course, we already possess the ability for uncontrolled fusion—the hydrogen bomb—which releases its energy all at once.

Continue reading “Artificial Sun”

Research on New Hemostatic Agent

The December issue of Scientific American mentions a new protein solution that, in animal tests, has been able to quickly stop bleeding in a way that’s fundamentally different from previous methods. The research, by Dr. Ellis-Behnke and colleagues, was published online in the journal Nanomedicine on 13 October 2006 (see abstract); the article is still in press.

It’s a solution of peptides (proteins) that is injected over the wound and stops the bleeding in seconds. It’s unclear precisely how it works; the peptides apparently self-assemble into some sort of fibrous network, different from normal blood clots (no platelets are present). No apparent toxic effects have been observed, and the gel is long-lasting. What’s especially neat is that the sustance eventually breaks down into its constituent amino acids, the building blocks of proteins, which can then be used by the body.

Obviously, research is still in the initial stages. Even if it is shown to be safe in humans, its effectiveness will have to be compared to standard methods of stopping bleeding. But it could add to our collection of hemostatic tools, potentially displacing the methods we currently use.

J. R. Minkel discusses the development in an expanded article on Scientific American’s web site. It also features a short clip demonstrating the use of the substance after making an incision in the liver of some type of rodent.