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Posts Tagged ‘optogenetics’

Using optogenetics--essentially, bioengineering different clusters of nerve cells to respond to certain frequencies of light--a team of Stanford researchers has found a way to test an established yet untested hypothesis about social dysfunction. This hypothesis holds that social-behavior deficits are linked to the propensity of excitatory nerve cells versus inhibitory nerve cells to fire.

That is, when facing social stimulus people with social disorders experience an imbalance wherein too many excitatory nerves fire (or not enough inhibitory nerves fire) resulting in a kind of over-responsiveness. This lines up nicely with empirical evidence (for instance, autistic people becoming agitated by loud noises or by too many people talking at the same time) as well as a certain anomalous brain-wave pattern known as gamma-oscillation that is detected in many people suffering from autism or schizophrenia.

In their mice, the researchers used optogenetics to bioengineer excitatory and inhibitory nerve cells in the parts of the brain responsible for social function to fire on command. That is, using different frequencies of light they could bias excitability. They then introduced them into social environments and tested them against a control group.

The researchers found that when they amped up the excitability in their optogenitically modified mice, the test subjects became almost instantly antisocial--and they also exhibited that heretofore inexplicable gamma-oscillation pattern in their brain waves. When the researchers restored balance by turning up the inhibitory nerve cell firing, the mice regained a significant amount of social function almost immediately.

Of course, this is significant because it might just get at the root of antisocial behavior brought on by social disorders like autism and schizophrenia. From a nervous system standpoint, mice and humans aren’t all that different (it’s thought that we shared a common ancestor some 75 million years ago). So these findings could be quite relevant to research into treatment for those suffering from schizophrenia and autism spectrum disorders.

In a newly released video from this year’s TED conference, Miesenboeck, a professor at Oxford, explains his pioneering work in the field of optogenetics, which involves genetically modifying nerve cells to react to light. Pulsing lasers at modified neurons mimics a brain impulse, allowing Miesenboeck and his colleagues to study what happens next.

As he explains in the video below, the flies’ neurons were modified to develop light-sensitive “pores,” which open when exposed to light. The opened pore allows electrical current to flow, and the neuron fires an electrical impulse. Others have used optogenetics to make fruit flies smell bananas when they see blue light, for instance.

It even works with brainless flies — Miesenboeck’s former graduate student, Susana Lima, lopped off optogenetically modified flies’ heads and stimulated the fly equivalent of the spinal cord with a laser pulse. The headless flies flew, meaning Miesenboeck and Lima were able to remotely control brainless flies by simulating a brain impulse.

The headless fly research was first published five years ago, and since then, scientists have come a long way, Miesenboeck says — they can now interfere with the animals’ psychology. His interpretation of psychology involves an “actor,” the brain’s decision-making center, and a “critic,” which continually provides commentary on the actor’s decisions.

“You can think of this nagging inner voice as the brain's equivalent of the Catholic Church, if you’re an Austrian like me ... or your mother, if you’re Jewish,” Miesenboeck says.
Following this logic, Miesenboeck figures the cells that make up the “critic” are a key ingredient in intelligence. He figured if he could identify the critic cells and modify them, he could artificially nag the actor cell cluster into changing its behavior. So the fly should learn from mistakes that it thought it had made, which in reality it had not, he explains.

In one series of experiments, he caused a fruit fly to "remember" to avoid a certain smell as it flew around. Through various fly-behavior experiments, Miesenboeck narrowed down the critic center to a clump of just 12 cells. This knowledge can lead neurologists and psychologists to a much greater understanding of the physiological networks that drive behavior. Much more work remains to be done — for instance, no one has yet figured out how the critic cells actually work — but it’s exciting, promising work.

“I find it exhilarating to see how vague psychological notions evaporate and give rise to a physical, mechanistic understanding of the mind — even if it’s the mind of a fly,” Miesenboeck says.

The implants would use light pulses to activate certain brain regions and reroute function

Such brain implants made from electrodes or optical fibers would sit on the brain's surface and monitor the electrical signals sent among neurons. They would also beam light pulses to stimulate specific parts of the brain in response, and ideally help the brain function normally despite having damaged areas.

The appropriately-named REPAIR (Reorganization and Plasticity to Accelerate Injury Recovery) project involves a team led by Stanford and Brown universities working with a two-year budget of $14.9 million. First up for the optogenetic tests are mice, rats and eventually monkeys.

Learning how to manage the human brain has been a top priority for DARPA in recent years, given the mad science lab's orders for technology such as cryogenic methods to freeze traumatic brain injury in its tracks. But they also seek to co-opt the brain's power for directly controlling prosthetic limbs usable by wounded warfighters. Even if this latest venture does not directly heal, it may at least help negate the effects of brain injuries so that it's as if they never existed.

[via Wired's Danger Room]

The implants would use light pulses to activate certain brain regions and reroute function

Such brain implants made from electrodes or optical fibers would sit on the brain's surface and monitor the electrical signals sent among neurons. They would also beam light pulses to stimulate specific parts of the brain in response, and ideally help the brain function normally despite having damaged areas.

The appropriately-named REPAIR (Reorganization and Plasticity to Accelerate Injury Recovery) project involves a team led by Stanford and Brown universities working with a two-year budget of $14.9 million. First up for the optogenetic tests are mice, rats and eventually monkeys.

Learning how to manage the human brain has been a top priority for DARPA in recent years, given the mad science lab's orders for technology such as cryogenic methods to freeze traumatic brain injury in its tracks. But they also seek to co-opt the brain's power for directly controlling prosthetic limbs usable by wounded warfighters. Even if this latest venture does not directly heal, it may at least help negate the effects of brain injuries so that it's as if they never existed.

[via Wired's Danger Room]

The implants would use light pulses to activate certain brain regions and reroute function

Such brain implants made from electrodes or optical fibers would sit on the brain's surface and monitor the electrical signals sent among neurons. They would also beam light pulses to stimulate specific parts of the brain in response, and ideally help the brain function normally despite having damaged areas.

The appropriately-named REPAIR (Reorganization and Plasticity to Accelerate Injury Recovery) project involves a team led by Stanford and Brown universities working with a two-year budget of $14.9 million. First up for the optogenetic tests are mice, rats and eventually monkeys.

Learning how to manage the human brain has been a top priority for DARPA in recent years, given the mad science lab's orders for technology such as cryogenic methods to freeze traumatic brain injury in its tracks. But they also seek to co-opt the brain's power for directly controlling prosthetic limbs usable by wounded warfighters. Even if this latest venture does not directly heal, it may at least help negate the effects of brain injuries so that it's as if they never existed.

[via Wired's Danger Room]

The implants would use light pulses to activate certain brain regions and reroute function

Such brain implants made from electrodes or optical fibers would sit on the brain's surface and monitor the electrical signals sent among neurons. They would also beam light pulses to stimulate specific parts of the brain in response, and ideally help the brain function normally despite having damaged areas.

The appropriately-named REPAIR (Reorganization and Plasticity to Accelerate Injury Recovery) project involves a team led by Stanford and Brown universities working with a two-year budget of $14.9 million. First up for the optogenetic tests are mice, rats and eventually monkeys.

Learning how to manage the human brain has been a top priority for DARPA in recent years, given the mad science lab's orders for technology such as cryogenic methods to freeze traumatic brain injury in its tracks. But they also seek to co-opt the brain's power for directly controlling prosthetic limbs usable by wounded warfighters. Even if this latest venture does not directly heal, it may at least help negate the effects of brain injuries so that it's as if they never existed.

[via Wired's Danger Room]

The implants would use light pulses to activate certain brain regions and reroute function

Such brain implants made from electrodes or optical fibers would sit on the brain's surface and monitor the electrical signals sent among neurons. They would also beam light pulses to stimulate specific parts of the brain in response, and ideally help the brain function normally despite having damaged areas.

The appropriately-named REPAIR (Reorganization and Plasticity to Accelerate Injury Recovery) project involves a team led by Stanford and Brown universities working with a two-year budget of $14.9 million. First up for the optogenetic tests are mice, rats and eventually monkeys.

Learning how to manage the human brain has been a top priority for DARPA in recent years, given the mad science lab's orders for technology such as cryogenic methods to freeze traumatic brain injury in its tracks. But they also seek to co-opt the brain's power for directly controlling prosthetic limbs usable by wounded warfighters. Even if this latest venture does not directly heal, it may at least help negate the effects of brain injuries so that it's as if they never existed.

[via Wired's Danger Room]