Showing posts with label brain. Show all posts
Showing posts with label brain. Show all posts

Saturday, February 19, 2011

Spectacularly Complex

Whole ColumnComputer model of a single neocortical column from a rat's brain (Photo: IBM)

Excerpt from Portraits of the Mind: Visualizing the Brain from Antiquity to the 21st Century by Carl Schoonover:

This image shows the three-dimensional configuration of ten thousand simulated neurons that constitute a single neocortical column—an anatomical unit barely wider than the head of a pin. The neocortical column, believed to be a building block of the cerebral cortex, is a mere millimeter cubed, and is repeated countless times across the expanse of the human neocortex.

Since there is simply no way to gain full experimental insight into a process at this large a scale, the Blue Brain Project was launched in 2005 in collaboration with IBM to produce a computer simulation of it. It is so spectacularly complex that a dedicated state-of-the-art supercomputer is required to keep track of all the phenomena as they recurrently influence one another; even with this computational firepower, it still takes about one hundred seconds to simulate a single second of activity.

In order to make it as realistic as possible, a wide variety of factors in included in the simulation: genetics, the shape of the dendrites, and the neurophysiological characteristics imparted by their ion channel composition. Here we see the Blue Brain’s cortical column in action: Each dendrite is simulated individually and rendered so that its color (ranging from blue to red) represents its voltage at one moment in time.

The long-term goal of the project is to uncover the broad principles of the brain function and dysfunction by simulating the entire brain of mammals, including that of humans.

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Zooming Out, Highlighting a Single Neuron
Blue Brain Project video

Sunday, January 16, 2011

The Holy Grail of Brain Training


Illustration by Peter Arkle for Newsweek

Excerpt from “Can You Build a Better Brain?” by Sharon Begley, Newsweek, Jan. 10 & 17, 2011:

The rule that “neurons that fire together, wire together” suggests that cognitive training should boost mental prowess. Studies are finding just that, but with a crucial caveat. Training your memory, reasoning, or speed of processing improves that skill, found a large government-sponsored study called ACTIVE. Unfortunately, there is no transfer: improving processing speed does not improve memory, and improving memory does not improve reasoning. Similarly, doing crossword puzzles will improve your ability to?.?.?.?do crosswords. “The research so far suggests that cognitive training benefits only the task used in training and does not generalize to other tasks,” says Columbia’s Yaakov Stern.

The holy grail of brain training is something that does transfer, and here there are three good candidates. The first is physical exercise. Simple aerobic exercise, such as walking 45 minutes a day three times a week, improves episodic memory and executive-control functions by about 20 percent, finds Art Kramer of the University of Illinois at Urbana-Champaign. His studies have mostly been done in older adults, so it’s possible the results apply only to people whose brain physiology has begun to deteriorate—except that that happens starting in our 20s. Exercise gooses the creation of new neurons in the region of the hippocampus that files away experiences and new knowledge. It also stimulates the production of neuron fertilizers such as BDNF, as well as of the neurotransmitters that carry brain signals, and of gray matter in the prefrontal cortex. Exercise stimulates the production of new synapses, the connections that constitute functional circuits and whose capacity and efficiency underlie superior intelligence. Kramer finds that a year of exercise can give a 70-year-old the connectivity of a 30-year-old, improving memory, planning, dealing with ambiguity, and multitasking. “You can think of fitness training as changing the molecular and cellular building blocks that underlie many cognitive skills,” he says. “It thus provides more generalizable benefits than specifically training memory or decision making.”

The second form of overall mental training is meditation, which can increase the thickness of regions that control attention and process sensory signals from the outside world. In a program that neuroscientist Amishi Jha of the University of Miami calls mindfulness-based mind-fitness training, participants build concentration by focusing on one object, such as a particular body sensation. The training, she says, has shown success in enhancing mental agility and attention “by changing brain structure and function so that brain processes are more efficient,” the quality associated with higher intelligence.

Finally, some videogames might improve general mental agility. Stern has trained older adults to play a complex computer-based action game called Space Fortress, which requires players to shoot missiles and destroy the fortress while protecting their spaceship against missiles and mines. “It requires motor control, visual search, working memory, long-term memory, and decision making,” he says. It also requires that elixir of neuroplasticity: attention, specifically the ability to control and switch attention among different tasks. “People get better on tests of memory, motor speed, visual-spatial skills, and tasks requiring cognitive flexibility,” says Stern. Kramer, too, finds that the strategy-heavy videogame Rise of Nations improves executive-control functions such as task switching, working memory, visual short-term memory, and reasoning in older adults.

Read the entire article…