A Single Neuron Can Change the Activity of the Whole Brain
May 1, 2009
(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 spur a neuron to fire rapidly and used another electrode nearby to activate the local neuronal connections. A third electrode was used to pick up the larger pattern emitted by all the neurons in the area. They wanted the overall brain state to remain constant during the experiment, but instead found that tickling one neuron could cause the entire brain state to change.
“Initially, this was very inconvenient,” says Dan. But then the researchers realized that the phenomenon deserved more attention. Looking more closely, they verified that a neuron firing at high frequency could switch the brain from a “non-REM pattern” of activity to a “REM pattern,” and vice versa.
The result was counterintuitive. “Every neuron makes connections to roughly 1,000 other neurons, but most of those are quite weak,” says Dan. A target cell won’t respond unless many, many neurons that connect to it fire at the same time and therefore she says it’s surprising that a single neuron could change the activity of the whole brain. “Single neurons have more weight than we used to think,” she says.
Dan doesn’t yet know how one cell could exert such power. The researchers had to repeatedly and rapidly fire a cell to cause the pattern to switch, so they might be emulating the effect of many cells firing at once. A neuron doesn’t normally fire in that way, so it is an open question whether the activity of a single neuron could change overall brain pattern under normal circumstances.
The findings add a new twist to how brain patterns are established. Researchers know that certain brain structures, such as the hypothalamus and the brain stem, play a part in setting the pace of global brain activity. In this study, Dan and her team were tickling brain cells in a different area: the cortex, the thin sheet of neurons on the surface of the brain involved in such abilities as moving and seeing.
Dan isn’t certain how cells in the cortex might control brain state, but she posits that signaling there could link back to the thalamus and spur it to set up a new pattern. “We know that a lot of circuits are involved in controlling brain state,” says Dan. “We’re saying that cortex is also part of that loop.”
By providing new information about how brain states are controlled, the study might ultimately lead to new knowledge about what causes certain sleep disorders. “In sleepwalking, there is a mixed-up boundary between slow-wave sleep and the awake state,” says Dan. “Your muscles move, but you aren’t consciously aware of your surroundings.” Understanding the circuitry that establishes brain states could ultimately reveal how that mixed-up situation is established.
Next, Dan wants to study animals that are naturally awake or sleeping, rather than anesthetized, to see if under normal conditions, a single neuron or a few neurons really can turn the tide on the entire brain.
-
For the first time, patterns of excitation waves found in brain's visual processing center
Jul 31, 2007 |
not rated yet |
0
-
Stem-cell therapies for brain more complicated than thought
Nov 27, 2007 |
not rated yet |
0
-
It's only a game of chance
Mar 27, 2007 |
not rated yet |
0
-
Rewiring the mammalian brain -- neurons make fickle friends
Aug 08, 2006 |
not rated yet |
0
-
Research shows the brain's processing speed is significantly faster than real time
Nov 15, 2007 |
not rated yet |
0
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (29) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (3) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (1) |
0
-
Is Everyday Technology Killing Us?
Feb 08, 2012
-
Exercise and weight loss
Feb 08, 2012
-
Why do we have head aches? Our brains can't feel anything.
Feb 07, 2012
-
"The end of diseases" by David Agus, interview from Daily Show with Jon Stewart
Feb 04, 2012
-
Oncolytic adenovirus
Feb 04, 2012
-
Nutrition label stuffs and diets
Feb 02, 2012
- More from Physics Forums - Medical Sciences
More news stories
Physically abused children report higher levels of psychosomatic symptoms
Children who display multiple psychosomatic symptoms, such as regular aches and pains and sleep and appetite problems, are more than twice as likely to be experiencing physical abuse at home than children who do not display ...
15 minutes ago |
not rated yet |
0
|
Heavy lifting for cancer research
Many patients with advanced cancer suffer from cachexia, a condition also called body-wasting or wasting syndrome, which causes significant weight loss, extreme fatigue and reduces quality of life.
1 hour ago |
not rated yet |
0
60 percent of Spanish adolescents state they do not take drugs and rarely drink alcohol
Despite the clichés surrounding the habits of adolescents, the results of a study by the University of Seville show that most young people do not fit the risk profile of taking substances. Some 60% of ...
16 minutes ago |
not rated yet |
0
Researchers develop gene therapy to boost brain repair for demyelinating diseases
(Medical Xpress) -- Our bodies are full of tiny superheroesantibodies that fight foreign invaders, cells that regenerate, and structures that ensure our systems run smoothly. One such structure is myelina ...
Medicine & Health / Neuroscience
1 hour ago |
not rated yet |
0
|
New target for Alzheimer's drugs
(Medical Xpress) -- Biomedical scientists at the University of California, Riverside have identified a new link between a protein called beta-arrestin and short-term memory that could open new doors for the ...
2 hours ago |
not rated yet |
0
|
Tidal forces could squeeze out planetary water
Alien planets might experience tidal forces powerful enough to remove all their water, leaving behind hot, dry worlds like Venus, researchers said.
Oracle to pay $1.9B for Taleo, extends SAP rivalry
(AP) -- Oracle Corp. is escalating its rivalry with German business-software maker SAP AG and plans to pay $1.9 billion for Taleo Corp., a company that helps businesses hire and manage their employees.
Can indigenous insects be used against the light brown apple moth?
The light brown apple moth (LBAM), Epiphyas postvittana (Walker), an invasive insect from Australia, was found in California in 2006. The LBAM feeds on apples, pears, stonefruits, citrus, grapes, berries and many other plants ...
Physics research suggests new pathways for cancer progression
Observing that certain cancer cells may exhibit greater flexibility than normal cells, some scientists believe that this capability promotes rapid tumor growth. Now computer simulations developed by Boston University Biomedical ...
NASA sees Tropical Cyclone Jasmine over Vanuatu and New Caledonia
NASA's Aqua satellite passed over Tropical Cyclone Jasmine on Feb. 8, 2012 as it was passing between Vanuatu and New Caledonia. NASA imagery showed Jasmine had a 20 nautical mile-wide eye.
New technology platform for molecule-based electronics
Researchers at the Nano-Science Center at the University of Copenhagen have developed a new nano-technology platform for the development of molecule-based electronic components using the wonder material graphene. At the same ...
May 01, 2009
Rank: 5 / 5 (1)
May 02, 2009
Rank: not rated yet
This is exactly what we've been doing in the field of neurofeedback for decades. You can train the brain to change it state by encouraging a different level of activity in the cortex. We posit that this then changes the thalamic regulators via the thalamocortical loops creating a new neural self-regulatory pattern leading to resolution of symptoms of conditions like ADHD, autism, anxiety, depression, traumatic brain injury and more.
This is a very interesting cellular level demonstration of the same effect.