claustrum :: Neurosurgeons find small brain region that turns consciousness on and off, like the key in a car's ignition

reposted from

Neurosurgeons find small brain region that turns consciousness on and off, like the key in a car's ignition

The 54-year-old epilepsy patient - her name remains concealed to protect her privacy - was lying on the operating table while surgeons explored inside her brain with electrodes. They were looking for the source of her epileptic seizures. Suddenly, after they applied electricity to a small region, buried deep, near the front of the brain, the woman froze and her eyes went blank. She was awake, but entirely unresponsive.

The precise area the surgeons had zapped included a sliver of tissue known as the claustrum, which is part of a network that supports awareness.Mohamad Koubeissi and his colleagues state that nobody has ever examined the effects of stimulating this specific brain region before, despite this kind of surgical procedure having been performed for decades. Just as geographers still surprise us with reports of having discovered previously unchartered parts of the earth, it takes one aback to hear of unexplored areas of neural terrain.

Intrigued by the woman's response to the stimulation of this specific brain region, the surgeons investigated further. Ten further stimulations, and on every occasion zapping the claustrum had the same effect. By contrast, zapping an area just 2.7mm away did not.

Perhaps the woman was simply paralysed by the electrical stimulation? The effects are more intriguing than that. If given an instruction prior to the stimulation, such as words to utter or movements to make, she continued this for a few seconds after the stimulation began, but then descended into still, unresponsive stupor. It was also striking to observe that as soon as the stimulation ended, the woman regained consciousness. However, she had no memory of the preceding moments during the stimulation period.

The researchers also examined the synchronisation of activity across the brain during the stimulation of the claustrum. They found that it increased synchronisation across the brain, possibly to a debilitating level. If so, this would match the situation observed in epileptic seizures that trigger loss of consciousness.

Caution is required - after all, this is a single case study, and the patient in question was missing part of one hippocampus, removed during earlier treatment for epilepsy. Nonetheless this is an intriguing finding. "... [T]he disruption of consciousness that we herein describe has never been precipitated by electrical stimulation of any other site in the human brain," the researchers said.

Speaking to New Scientist magazine, lead author Koubeissi likened the claustrum to a car's ignition. While both the brain and the car are made up of many functioning parts, "...there's only one spot where you turn the key and it all switches on and works together," he told them. "So while consciousness is a complicated process created by many structures and networks - we may have found the key." If these results can be replicated, the hope is that stimulation of the claustrum may offer a way to treat disorders of consciousness associated with epileptic seizures.

_________________________________ 

Mohamad Z. Koubeissia, Fabrice Bartolomei, Abdelrahman Beltagy, Fabienne Picard. (2014). Electrical stimulation of a small brain area reversibly disrupts consciousness.  Epilepsy & Behavior Volume 37, August 2014, Pages 32–35

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

reposted from.
Thanks Jen.

Changing Faces: Stimulating the Brain Morphs People’s Faces Before Patient’s Eyes

Researchers find the region in the brain responsible for recognizing faces—and manipulate it for the first time

By Maia Szalavitz @maiaszOct. 24, 20121 Comment

• •  
  •  
  •  
  • inShare 
• Read Later

RELATED

• Exercise Trumps Brain Games in Keeping Our Minds Intact
• Q&A With UK Scientist Who Gave Out Ecstasy on Live TV
• Facial Recognition Abilities Peak Later Than Scientists Thought
• Brain Zapping Study Sheds Light on Facial Blindness ABC News
• Electric Brain Stimulation Warps Your Perception Of FacesPopular Science

• Email
• Print
• Share
• Comment

 Follow @TIMEHealth

The patient sits on the bed, his head wrapped in thick gauze bandages.  He looks his doctor in the eye and says, “You just turned into somebody else… You almost look like somebody I’ve seen before, but somebody different.  That was a trip.”

No, 47-year-old Ron Blackwell hadn’t taken any psychedelic drugs.  He wasn’t delirious or psychotic following the brainsurgery he had recently undergone. Instead, he was responding to signals from electrodes implanted in his brain to help determine the source of his seizures. By coincidence, the test electrodes had been placed in his fusiform gyrus, the brain region involved in recognizing faces.

MORE: Could Deep Brain Stimulation Fend Off Alzheimer’s?

“Your nose got saggy and went off to the left,” Blackwell said, describing the changes he was seeing in his doctor Josef Parvizi’s face in a video released along with a new study. The research, published in the Journal of Neuroscience, was led by Parvizi, who is an associate professor of neurology at Stanford.

While having surgery to treat epilepsy, Blackwell agreed to take part in an experiment led by Parvizi aimed at understanding what the fusiform region actually does and how specific it is to recognizing faces.

MORE: A Flicker of Consciousness

While most people recognize familiar faces rapidly— even if we can’t always put a name to them— up to 3% of the population has a genetic disorder that interferes with recognition, known as prosopagnosia. The condition can also occur after stroke or other brain injury.

In extreme cases, people with prosopagnosia can’t even recognize their own spouses or parents:  they simply don’t have the ability to match the visual signals of a person’s face and merge them with the brain’s memory banks to indicate something familiar, and experts presumed this deficit was caused by damage to the fusiform.

Neurologist and bestselling author Oliver Sacks publicly discussed his experience with the disorder, saying that it hascontributed to his shyness and avoidance of social situations.  Author Heather Sellers wrote about her life with the condition, describing including the havoc it caused in her social life when she once sat down with the wrong date in a bar without realizing it— confusing the individual she had mistaken for her date and infuriating the man she was supposed to be seeing.

MORE: Found! The Seat of Embarrassment in Your Brain

The new study provides the strongest evidence for the potential source of prosopagnosia’s confusing symptoms. The scientists found that the fusiform is specialized for recognizing faces and that stimulating it produces massive distortions in facial perception. Blackwell described seeing faces metamorphose into other faces when the electrodes were turned on.  In one case, he said, “It’s like the shape of your face, your features, drooped.”  But nothing else was affected.  “Only your face changed,” he said, “Everything else was the same.”

When the electrodes were turned off, Blackwell had no unusual reactions.  And when he looked at other things like the TV or a balloon, while there was slight distortion, it was nothing like the complete metamorphosis he experienced when he looked at faces.

MORE: The Brain: What the Mouse Brain Tells Us

“These findings provide evidence for the causal role of these fusiform face regions in face perception,” the authors write.  Unfortunately for Blackwell, however, the cause of his seizures was too close to important areas involved in vision for it to be removed.  The work does, however, provide intriguing new information about how the fusiform area works, and potentially for how it might be manipulated to help those suffering from not just prosopagnosia but related disorders as well.

Those include Capgras’ Syndrome, in which people are convinced that their friends and family members— sometimes even their pets— have been replaced by identical imposters. While the conditions sounds more like a psychiatric condition, in these cases the problem likely results from a disconnect between the fusiform area and the brain’s emotional regions.  When people with Capgras’ Syndrome see people they love— but don’t feel the love and warmth they normally experience — they compensate for the gap by convincing themselves that the people around them are “fake,” or even robots.  If their real family members or spouses were there, they reason, they wouldn’t seem so cold and odd.

MORE: New York State of Mind? Research Reveal Brain Wiring Is Laid Out Like a Grid

For these patients and potentially others who suffer from related symptoms following stroke and brain trauma, the electrical stimulation opens a window into an area of the brain that had been out of reach, and provides hope that their seemingly untreatable symptoms may someday be relieved by less invasive treatments.