Monday, March 29, 2010

When memory-related neurons fire in sync with certain brain waves, memories last

When memory-related neurons fire in sync with certain brain waves, memories last

When memory-related neurons in the brain fire in sync with certain theta (3-8 Hz) brain waves, the resulting image recognition and memories are stronger than if this synchronization does not occur.
"Theta oscillations are known to be involved in memory formation, and previous studies have identified correlations between memory strength and the activity of certain neurons, but the relationships between these events have not been understood. Our research shows that when memory-related neurons are well coordinated to theta waves during the learning process, memories are stronger," said Adam N. Mamelak, M.D., a neurosurgeon at Cedars-Sinai Medical Center

War on Drugs? Meet the War on Cheesecake.

Dopamine D2 receptors in addiction-like reward dysfunction and compulsive eating in obese rats


    We found that development of obesity was coupled with emergence of a progressively worsening deficit in neural reward responses. Similar changes in reward homeostasis induced by cocaine or heroin are considered to be crucial in triggering the transition from casual to compulsive drug-taking. Accordingly, we detected compulsive-like feeding behavior in obese but not lean rats, measured as palatable food consumption that was resistant to disruption by an aversive conditioned stimulus. Striatal dopamine D2 receptors (D2Rs) were downregulated in obese rats, as has been reported in humans addicted to drugs. Moreover, lentivirus-mediated knockdown of striatal D2Rs rapidly accelerated the development of addiction-like reward deficits and the onset of compulsive-like food seeking in rats with extended access to palatable high-fat food. These data demonstrate that overconsumption of palatable food triggers addiction-like neuroadaptive responses in brain reward circuits and drives the development of compulsive eating. Common hedonic mechanisms may therefore underlie obesity and drug addiction.

Friday, March 26, 2010

Silencing the brain with light

Silencing the brain with light
A team led by neuroengineer Edward Boyden has found a class of proteins that, when inserted into neurons, allow them to be turned off with rays of yellow-green light. The silencing is near instantaneous and easily reversible.

This kind of selective brain silencing, reported in the Jan. 7 issue of Nature, could not only help treat brain disorders but also allows researchers to investigate the role of different types of neurons in normal brain circuits and how those circuits can go wrong.

“We hope to enable a broad platform of molecular tools for controlling brain activity, thus enabling new general therapeutic tools, and new ways of studying brain function,” says Boyden, the Benesse Career Development Professor in the MIT Media Lab and an associate member of the McGovern Institute for Brain Research at MIT.

‘Clean and digital’

Boyden first demonstrated the use of light to reduce brain activity in 2007. However, the feat was performed in cells, not living animals, and the silencing was not as precise. In the new study, the researchers used a different protein — one that inhibits neurons more strongly, silences more brain tissue and can be repeatedly activated because it returns to its original state within milliseconds of light activation.

With the new protein, called Arch, brain silencing is “extremely clean and digital,” says Boyden. “The other one was more like a volume knob turning up and down.”

Boyden and his colleagues combined genetic and optical techniques to control neuron activity, a strategy that has come to be called “optogenetic.” First, they engineered brain cells of living mice to express the gene for the Arch protein, which functions as a proton pump, moving protons across the cell membrane to alter the cell’s voltage. The proton pumps are light-sensitive, so they pump protons out of cells when activated by yellow-green light. That lowers voltage inside the cells, silencing their firing.

In their previous work, the researchers used a light-sensitive chloride pump called halorhodopsin, which changes neurons’ voltage by pumping chloride ions into the cell. However, they weren’t satisfied with it and started looking for a better chloride pump, examining proteins from a range of bacteria, plants and fungi. They couldn’t find a chloride pump that offered the kind of control they were seeking, but discovered the new Arch proton pump in a strain of archaebacteria called Halorubrum sodomense that lives in the Dead Sea.

“This is the result of mining the wealth of the natural world — genomic diversity and ecological variation — to discover new tools that can empower scientists to study complex systems like the brain,” says Boyden. “We're using natural tools isolated from the wild to help us understand how neural circuits work.” This strategy has long been used in molecular and cellular biology, resulting in tools like restriction enzymes, PCR and GFP, but Boyden's work only recently has been applied to tackle complex systems-level biological problems.

One major advantage of the new pumps is that they can be used over and over again: They recover their ability to be light-activated within seconds, rather than the minutes required for the old tool, halorhodopsin, to reprime itself. That is critical to neuroscientists who want to study the role of particular cell types in different tasks, says Edward Callaway, professor of systems neurobiology at the Salk Institute, who was not involved in the research.

“If you have to wait a long time to get recovery, you just can’t compare different conditions quickly,” says Callaway, who studies vision-processing circuits in the brain. The new channels offer a “much more practical” way to use optogenetics for animal studies such as testing which neurons are involved in different visual tasks, he says.

To achieve brain silencing in mice, the researchers implanted an externally controllable light source inside the mice’s brains. While the current device requires mice to be wired up to an external control, the researchers are designing a fully wireless system.

Boyden's group, working with the Desimone lab at the McGovern Institute at MIT, is now performing pre-clinical testing of this approach in non-human primates, to assess its safety as a potential therapy for epilepsy, chronic pain and post-traumatic stress disorder. The team has also developed, in collaboration with other groups at MIT, hardware for optical neural stimulation, which could be valuable for neural prosthetic purposes.

The MIT researchers have also discovered other proton pumps activated by different colors of light, combining these pumps with previously discovered tools allows researchers to selectively silence different brain regions using red and blue light. “One beautiful thing about this is we can inactivate different projections in the same brain,” says Boyden.

In future studies, the researchers plan to use their neuron-silencing tools to examine the neural circuits of cognition and emotion, and to determine whether the new pumps are safe and effective in monkeys — a critical step toward potentially using optical control to treat human diseases.

MIT TechTV – Ed Boyden: National Science Foundation interview

MIT TechTV – Ed Boyden: National Science Foundation interview

Posted using ShareThis

Thursday, March 11, 2010

Hot Stuff! Brand New Cranial Laser Reflex Technique Case Study Video!

Here is a new video of a patient that came in yesterday for the first time. She was referred by another chiropractor in town who sent her for evaluation and a Cranial Laser Reflex Technique treatment for spasms after a stroke 2.5 years ago. She has also been under the care of several MD's, PT's, neurologists, etc during this time. (Luckily she was very agreeable to me videoing the session, and luckily I had an extern handy to hold my iPhone.)

The total visit lasted about 25 minutes, but the video is edited to 10 minutes long as per the youtube limits. Most of what I cut was me talking, and repeating some of the same treatments again.

I start off with lasering the Cranial Reflex Pathways for the biceps and forearm muscles with a 200mW 650nm red laser (on half battery power, probably). This immediately reduced the tone of these muscles that had been in spasm for 2.5 years. I then perform some general cranial adjustments, both with my hands and with light taps from the Impulse adjusting instrument. I then release the traps, pecs, and rhomboids, etc with more CLRT.

Then I bust out the Resonant Frequency Wand and run the normalizing frequencies for biceps, forearm flexors, etc. The change was immediately apparent. The biceps frequency elongated that muscle and allowed me to straighten her arm, and the freq for pronator teres was especially helpful at untwisting her foream and wrist. After a few minutes of this, I was able to fully extend her arm, waaay farther than it had been for years. She reported that she felt a tingling in her arm as I was working on her head, and that the treatment felt "awesome."

The difficulty with a case like this lies in the fact that she has been stuck in rigid flexion so long and these muscles have shortened considerably, and she will have to un-learn all the coping strategies she has had to create along the way. But overall, her response after a single treatment makes me think she'll do very well if we keep this up.

There's no limit to the capacity of the human body to heal itself... if one is open to the possibilities.

Pretty cool stuff...Watch.