A Single Neuron Can Change the Activity of the Whole Brain

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A Single Neuron Can Change the Activity of the Whole Brain

(PhysOrg.com) -- The pulsing of a single neuron can switch a brain’s waves from the equivalent of a big ocean swell to ripples on a pond, according to new research from Howard Hughes Medical Institute investigator Yang Dan of the University of California, Berkeley.

The study reveals important new information about how the brain controls large-scale activity patterns and suggests that an individual cell has more influence than previously thought. The findings, published in the May 1, 2009, issue of the journal Science , could ultimately shed light on how chaotic brain patterns can lead to sleep disorders such as sleepwalking.

Brain cells use electrical pulses to talk with one another and guide functions ranging from heart rate and breathing to decision-making and navigation. Like the din of a crowd, the chatter of 100 billion neuronal cells in the human brain creates larger patterns of activity commonly called brain waves.

These patterns reveal the brain’s general state of arousal. For instance, large, slow brain waves that are synchronized throughout the brain are indicative of deep sleep. “Many neurons are doing the same thing at the same time,” says Dan. During so-called rapid eye movement (REM) sleep, on the other hand, different brain areas are less synchronized, firing in smaller and more frequent oscillations. And in an awake person, the brain broadcasts a rapid, uncoordinated pattern.

Dan and her colleagues wanted to understand how large-scale wave patterns influence the connection between two neurons. They knew that neuronal connections could strengthen or weaken over time, and these changes seem to underlie learning and memory. They wondered whether the overall pattern of brain activity altered nerve cells ’ ability to change their connection strength.

Studying anesthetized rats, they used one electrode to ...

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