Slow brain waves play key role in coordinating complex activity

UCSF neurosurgeons place 64-electrode grids on the surface of the brain's temporal and frontal lobes to locate regions where epileptic seizures originate. These grids allowed UC Berkeley neuroscientists to study the interaction of brain waves during simple tasks, such as word recognition or hand movements. (Images courtesy the Knight Lab)

UCSF neurosurgeons place 64-electrode grids on the surface of the brain’s temporal and frontal lobes to locate regions where epileptic seizures originate. These grids allowed UC Berkeley neuroscientists to study the interaction of brain waves during simple tasks, such as word recognition or hand movements. (Images courtesy the Knight Lab)

While it is widely accepted that the output of nerve cells carries information between regions of the brain, it’s a big mystery how widely separated regions of the cortex involving billions of cells are linked together to coordinate complex activity. Now a new study by neuroscientists at the University of California, Berkeley, and neurosurgeons and neurologists at UC San Francisco (UCSF) is beginning to answer that question.

“One of the most important questions in neuroscience is: How do areas of the brain communicate?” said Dr. Robert Knight, professor of psychology, Evan Rauch Professor of Neuroscience and director of the Helen Wills Neuroscience Institute at UC Berkeley. “A simple activity like responding to a question involves areas all over the brain that hear the sound, analyze it, extract the relevant information, formulate a response, and then coordinate your lips and mouth to speak. We have no idea how information moves between these areas.”

By measuring electrical activity in the brains of pre-surgical epilepsy patients, the researchers have found the first evidence that slow brain oscillations, or theta waves, “tune in” the fast brain oscillations called high-gamma waves that signal the transmission of information between different areas of the brain. In this way, the researchers argue, areas like the auditory cortex and frontal cortex, separated by several inches in the cerebral cortex, can coordinate activity.

“If you are reading something, language areas oscillate in theta frequency allowing high-gamma-related neural activity in individual neurons to transmit information,” said Knight. “When you stop reading and begin to type, theta rhythms oscillate in motor structures, allowing you to plan and execute your motor response by way of high gamma. Simple, but effective.”

The findings are reported in the Sept. 15 issue of Science.

Read more at UC Berkeley News

Gabrielle Giffords’ neurosurgeon speaks about her surgery

 

G. Michael Lemole Jr., M.D., keynote speaker at Health Journalism 2011

G. Michael Lemole Jr., M.D., chief of neurosurgery at the University of Arizona Department of Surgery and University Medical Center, found himself in the media spotlight after he performed brain surgery on U.S. Rep. Gabrielle Giffords after she sustained a gunshot wound to the head in Tucson on Jan. 8.

As the keynote speaker at Health Journalism 2011, he recounted the treatment of the congresswoman earlier this year and his experience working with the media:

Everyone made a big deal of what we did, but it’s what we do everyday … This is academic medicine at its best

In the operation, Lemole and Martin E. Weinand, M.D., removed part of Gifford’s skull to allow her brain to swell, as well as removing dead brain tissue and skull fragments caused by the bullet.

 “We basically take part of the skull off and let the swollen brain relax,” explained Lemole. The procedure can relieve pressure on the brain but it can also worsen edema – the build-up of fluid that can cause an “outward herniation.” They also had to remove damaged parts of the brain to “save the good brain underneath.”

The procedure is informed by data gathered during surgery on soldiers injured in the Iraq war, he said. At some point, surgeons will replace the bone or use a prosthetic.

On Jan. 15, Lemole repaired Giffords’ orbital roof fracture through a skull base approach.  The last surgery that Giffords received was a ventriculostomy, which measured intracranial pressure and drained fluid in the brain. He credits the use of growing use of simulation in surgical training for allowing doctors to successfully perform operations like the ventriculostomy. In addition to simulation training, Lemole said the “flawless” EMT response and the multidisciplinary nature of trauma team combined to improve Giffords’ odds.

Lemole supervised the congresswoman’s care until she was released to a Houston rehabilitation hospital on Jan. 21 and during  this time, was available to the media. “We strategized with ourselves, administrators, and with the family. The family asked us to get the correct information out,” he said. Lemole said he chose his words carefully. “I don’t think I gave a rosy account,” he said, describing his careful use of the term “functional recovery” instead of terms like “full recovery” or “back to normal.”

Giffords Progress

Giffords outcome was impossible to predict at the outset of her injury. Generally, the odds of dying from a gunshot wound to the head range from 56 to 94 percent, Lemole said. If the path of the bullets goes through the geographic center of the brain, through the ventricles or through multiples lobes, the prognosis is not good. In Giffords’ case, the bullet did not cross from one side of the brain to the other, but travelled through the left side. The patient’s level of consciousness at admission is another factor –  at the time, Lemole was quoted as saying that Giffords was able to follow simple commands from the doctors.

The Arizona Republic newspaper reports “that she can stand on her own and walk a little but is working to improve her gait.” The use of her right arm and leg “is limited but improving” . Longer sentences frustrate her and she speaks most often in a single word or declarative phrases. She longs to leave the rehab center, repeating “I miss Tucson” and wheeling herself to the doors at the end of the hall to peer out. When that day comes, Giffords told her nurse, she plans to “walk a mountain.”

Sources:

Boston Blog

Health Journalism Blog

The Arizona Republic

Pioneering brain surgery to treat Tourette’s

 

Brain structures implicated in Tourette syndrome

 The BBC UK health website carries a story this week of a Devon man with Tourette’s syndrome who is to undergo a pioneering form of brain surgery.

Mike Sullivan, 32, who was diagnosed with the condition at the age of 12, has elected to undergo deep brain stimulation to help reduce his involuntary tics.

Tourette syndrome is an inherited neuropsychiatric disorder which begins in childhood. It is characterised by multiple physical (motor) tics and at least one vocal (phonic) tic

Mr Sullivan has tried a number of different medications. None has relieved his symptoms but many have given him serious and unpleasant side effects.

For deep brain stimulation a local anaesthetic is used and electrodes are put into the brain through the skull.

These are linked to a pacemaker-type battery in the patient’s chest then electrical impulses are sent to the brain to block the damaging signals.

A common perception of Tourette’s is that it is a bizarre condition, most often marked by the involuntary exclamation of obscene words, but actually this symptom is present in only a small minority of people with Tourette’s.[1]  Between 1 and 10 children per 1,000 have Tourette’s;[2] as many as 10 per 1,000 people may have tic disorders,[3] with the more common tics of eye blinking, coughing, throat clearing, sniffing, and facial movements.  The severity of the tics decreases for most children as they pass through adolescence, and extreme Tourette’s in adulthood is a rarity.

The exact cause of Tourette’s is unknown, but it is well established that both genetic and environmental factors are involved.[4]   Gender appears to have a role in the expression of the genetic vulnerability: males are more likely than females to express tics.[5]

Tourette syndrome is a spectrum disorder—its severity ranges over a spectrum from mild to severe. The majority of cases are mild and require no treatment.

However Mr Sullivan said he has to work hard to suppress the almost continual tics while working with the public at Exeter Register Office. He describes this experience as exhausting and mentally draining. He says he is aware of the risks involved in undergoing brain surgery, but if it led to any improvement in his condition it would be worth it.

“Whilst I’m scared and it’s not something I’d choose to do, it’s more than worth the risk,” he said. “If it improves me even by 5% or 10%, it will make such a massive difference to my quality of life.”

Doctors at the National Hospital for Neurology and Neurosurgery in London are trialling the use of deep brain stimulation to treat not only Tourette’s Syndrome, but Obsessive Compulsive Disorder, which many Tourette’s patients including Mr Sullivan also suffer from.

Only a few procedures have so far been carried out worldwide, but Mr Sullivan has been recommended for treatment by Dr Tim Harrower, a consultant neurologist at the Royal Devon and Exeter Hospital.

Tourette Support Ireland hopes to develop a countrywide network to support adults with the condition at its annual general meeting at 11am on Saturday, February 19th, in the Ashling Hotel, Dublin. Dr Tara Murphy, clinical psychologist at Great Ormond Street Hospital, will offer advice on behaviour therapies for the condition, and there will be a music workshop for young people. Tel: 087-2982356 or e-mail support@tsireland.ie. Advance registration on tsireland.ie.

Notes

[1] Schapiro NA. “Dude, you don’t have Tourette’s:” Tourette’s syndrome, beyond the tics. Pediatr Nurs. 2002 May–Jun;28

[2] Lombroso PJ, Scahill L. “Tourette syndrome and obsessive–compulsive disorder”. Brain Dev. 2008 Apr;30(4):231–7. doi:10.1016/j.braindev.2007.09.001 PMID 17937978

.[3] Tourette Syndrome Fact Sheet. National Institute of Neurological Disorders and Stroke/National Institutes of Health (NINDS/NIH), February 14, 2007. Retrieved on May 14, 2007

[4]Walkup JT, Mink JW, Hollenback PJ, (eds). Advances in Neurology, Vol. 99, Tourette Syndrome. Lippincott, Williams & Wilkins, Philadelphia, PA, 2006, p. xv. ISBN 0-7817-9970-8

[5] Black, KJ. Tourette Syndrome and Other Tic Disorders.eMedicine (March 30, 2007). Retrieved on August 10, 2009.

How did Gabrielle Giffords survive gunshot wound to head?

Rep Gabrielle Giffords

Rep Gabrielle Giffords

Initial reports on the shooting of American politician, Gabrielle Giffords, at the weekend, implied that she had been shot dead. The fact that she had received a gunshot wound through the back of her head made it seem sadly likely that this was the case. However, Giffords, although in a critical condition has survived the shooting, and her doctors are “cautiously optimistic” about her survival.

While around two-thirds of patients with a gunshot wound to the head don’t live, one-third do (although only 50% of those patients survive longer than 30 days).  Of course long-term neurological function in the survivors is another story.

In Giffords’ case, the bullet shot through the back of the left side of her head. If it had passed through the midline, the likelihood of survival would have been less likely.

According to CNN’s Chief Medical Correspondent Dr. Sanjay Gupta, the injury was a “through and through” injury, meaning there was both an entry and exit wound – meaning  some of the energy of the bullet was dissipated into space, as opposed to all within her cranial cavity.

Dr Gupta also reports that neurosurgeon, Dr. Michael Lemole, performed a craniectomy (surgical removal of a portion of the cranium) to prevent the brain swelling.  By removing portions of the skull, the brain has extra room to swell. Incidentally, the bone that’s removed is saved, and put back in the head during a future operation.

While Giffords is clearly not out of danger yet, let us hope that the signs are good for her recovery.