Better Memory Associated With Larger Posterior Brain Hippocampus

Scientists have revealed that the sizes of the posterior and anterior segments of the hippocampus could predict individual's ability to remember past events. Hippocampus is an important brain structure associated with recollection memory.

They found that a larger posterior hippocampus and a smaller anterior hippocampus were associated with better recollection.

Although research has generally linked smaller hippocampi with worse recollection in neuropsychological patients and during aging, this relationship has not held up among healthy young adults.

"There is some evidence that extensive spatial memory acquisition leads to enlargement of the posterior hippocampus and a decrease in the anterior hippocampus," explained lead study author, Dr. Jordan Poppenk who conducted the study at Baycrest's Rotman Research Institute.

"This suggested to us that the crucial predictor of individual differences in recollection ability might not be the overall size of the hippocampus but the separate contributions of the posterior and anterior segments of the hippocampus," he said.

Dr. Poppenk and co-author Dr. Morris Moscovitch analysed high-resolution magnetic resonance imaging brain scans of healthy adults who had participated in recollection memory tests.

The result showed that better recollection was linked with a larger posterior hippocampus and a smaller anterior hippocampus.

The overall size of the hippocampus did not predict recollection, as larger posterior hippocampi were offset by smaller anterior hippocampi.

The researchers went on to show that the link between the posterior hippocampus and recollection depended on interactions with other parts of the brain between the times that memories were learned and retrieved, particularly regions involved in perception which form the basis of recollected experience.
"Our results show for the first time that the size of the posterior hippocampus, especially when expressed as a ratio to the size of the anterior hippocampus, reliably predicts recollection in healthy adults," Dr. Poppenk stated.

"This finding explains the longstanding failure to correlate the overall size of the hippocampus with memory.

"We also provide evidence that it is the functional connections, possibly related to memory consolidation, between the posterior hippocampus and other parts of the brain that may underlie enhanced memory recollection," he added. 

Habit Formation Linked to 'Gateway' to Brain Cells

A new study has revealed that key receptors on brain cells that function like 'gateways' are essential to enable habit formation.

Research showed that NMDA receptors on dopamine neurons in the brain's basal ganglia function like gateways to the brain cells, letting in electrically charged ions to increase the activity and communication of neurons.

Their pivotal role reminded neuroscientist Dr. Lei Phillip Wang of a computer's central processing unit.

"The NMDA receptor is a commander, which is why it's called a master switch for brain cell connectivity," said Wang, the study's first author.

To determine their role in habit formation, GHSU researchers used a genetic trick to selectively disable the NMDA receptors on dopamine neurons and found, for example, mice could be trained to push a lever for food without it becoming an automatic response.

Dopamine is a chemical that helps brain cells in communication.

If they were full, they would not push the lever. But just as humans cannot refrain from flipping a light switch during a power outage, satiated mice with receptors could not pass up the lever.

When they compared the firing of the dopamine neurons in regular versus the mutant mouse, they found a dramatic spike in response to a cue that signals food in the normal mouse and a significantly dampened one in the mutant, Wang said.

"We think this reduced response is probably sufficient for other types of learning, but not for habit learning," he said.

The finding that the receptors are critical to turning learned behaviour into a habit provides new direction for therapy to better treat diseases such as Parkinson's, which in addition to the hallmark shaking, causes the loss of some old habits and impedes the ability to make new ones.

It also opens the door to speeding up the process of forming good habits and, possibly, selectively removing bad ones such as drug addiction or smoking since the same circuits are seemingly involved in both.

"Dopamine neurons regulate circuits all over the brain but they need to be regulated too," said Dr. Joe Z. Tsien, Co-Director of the Brain and Behavior Discovery Institute at Georgia Health Sciences University.

"The questions become how and whether regulation of dopamine neurons is important. Our study shows it's important and it's through the NMDA receptors," Tsien added.

Tumor removed, life embraced: SCSU instructor's survival strengthens outlook

When he was diagnosed with Marfan syndrome at age 15, Kristian Twombly knew he’d eventually need heart surgery.
The genetic defect that causes him to have elongated fingers and limbs also caused his heart valves to flap loosely rather than close properly. He put off surgery until his mid-30s, and in August 2009 the St. Cloud State University music professor had mechanical valves installed during open heart surgery.
That fixed one problem that Twombly had carried with him from his youth. But he continued to have migraine headaches that he remembered first experiencing in his 10th-grade English class.
Admittedly not a fan of visiting the doctor, Twombly suffered through the headaches with ibuprofen and aspirin. Then it wasn’t just the headaches and the blurred vision that came with each episode.
“Since heart surgery, I noticed that I would have a migraine headache, and while this visual thing was happening, my right foot would go numb,” he said. “Not like pins-and-needles numb. I could move it, but I just couldn’t feel it.”
He first thought it was one of the many odd side effects he had been experiencing after coming off the heart/lung machine. His heart condition prevented him from taking the drug routinely prescribed for migraines, so his physician decided to rule out other causes of the headaches before turning to a different medication.
That led to an MRI in February — “Just a routine brain MRI,” he recalls.
Afterward, he was waiting in the lobby at the Center for Diagnostic Imaging, waiting for the packet of pictures that he would take back to his physician. After an unusually long wait, a nurse asked him to come back and see the doctor. He recalls clearly what happened next and what the doctor said.
“Well, it’s been there for about 20 years we think, and it’s sitting right on top of your head. And we’ve taken the liberty of calling a neurosurgeon and setting an appointment with a neurosurgeon. We’ll just take you up right now. Have you eaten anything today?”
Just 18 months after open heart surgery, Twombly again was facing a potentially life-altering procedure. He had a baseball-sized brain tumor that had been growing in his head since his grade-school days. St. Cloud neurosurgeon Dr. Gregory Sherr removed the tumor in March, and Twombly has emerged with little, if any, lasting effects of the surgery.
The heart surgery caused him to reassess what was important in life, he said. He had been reluctant to take out a loan to buy a car or a house because he thought the Marfan syndrome would kill him before he could pay off those loans. The heart surgery made him grow up a bit, he confesses. The brain surgery 18 months later only confirmed those feelings.
“In many ways, it was similarly life-changing. My girlfriend has three kids. We went through Thanksgiving and Christmas last year together. But it was very important to me that we, that WE, cook Thanksgiving and that WE have Christmas together,” he said. “My commitment to family and to life in general and to improving myself and to being a positive influence on the world is, if not redoubled, certainly is a huge priority to me.”
Critical stage
Sherr got the call from a radiologist he knows who works downstairs in the building where Sherr works.
You won’t believe it, Sherr was told. This guy is walking around with a baseball-sized tumor in his head. Can I send him right up?
“My initial impression once I saw the pictures was that this was a slow-growing lesion, 20 years maybe,” Sherr said in an email interview.
Twombly’s brain had dealt with the lesion long enough and now the growth was “pissing his brain off,” Sherr said. It had reached a critical stage.
“I have seen and operated on bigger, so it didn’t surprise me,” Sherr said of the tumor. “But it was located right within and pressing on the area of the left brain that controls his right side, arm and leg, a dangerous location for surgery.”
On the midline of the brain is one of its most essential veins, and the tumor likely began along that wall, Sherr said. That presented another challenge: how to take it out without injuring that critical vein. If that vein is injured, a person can die within minutes.
What’s next?
Heidi Perreault was studying at her Zimmerman home when she received a text message from her boyfriend.
It was bad news. That’s all Twombly’s message said.
 I think I have a brain tumor, he replied.
“It was good that we now had an idea what it was,” Perreault said during a recent interview, “but it was scary having something in his brain.”
Still, questions remained. How do we get it out? What are the possible negative outcomes of operating on the brain? Will he be the same Kristian Twombly after the surgery that he is now?
Because the tumor was entwined with the tissues that control his right-side movement, Sherr needed to find a path to the tumor and a path to getting it out.
“We knew we would have to use functional and diffusion tensor imaging MRI sequences to accurately discover the areas around the tumor that were functional and find a path into the tumor,” Sherr said.
Those new types of MRIs “are just being adopted,” he said, and both St. Cloud Hospital and CDI have recently acquired the expensive technologies. They allow the surgeon to see the brain in 3-D, to identify where the tumor is and where the vital brain tissues are that control movement.
Twombly’s confidence in Sherr, whom he jokingly calls Dr. Sure Of Himself, made it easier for him to decide that he could have his brain surgery in St. Cloud rather than at the Mayo Clinic where he had his heart surgery.
“It was really sort of affirming in that regard,” Twombly said. “There was no question that he was going to be able to do it and that, yeah, I could have gone to the Mayo where I had my heart surgery. I had no worries about doing it in St. Cloud, and I’m glad that I did.”
Friend feels concern
Mark Springer taught the History of Rock ’n’ Roll class at St. Cloud State before Twombly was hired about six years ago. Twombly took over teaching that class and became close friends with Springer, who is interim dean of the university’s College of Liberal Arts.
Springer and Twombly crossed a few items off Twombly’s “bucket list” before the 2009 heart surgery. Later, Springer was one of a handful of people in a tight-knit circle of music friends who would learn about the brain tumor.
Springer’s thoughts immediately turned to a teacher he once had who was diagnosed with a brain tumor and died soon after.
“My first reaction honestly was that I was concerned that he was a dead man walking,” Springer said. “That’s just from my own experience. It heightened my concern dramatically. And then I wanted to know where it was and could they operate?”
Twombly scheduled the surgery for the Friday before spring break, partly because he wanted to limit the number of days of work he would miss.
“There was more tumor than cyst,” Sherr said. “It was a meticulous and difficult tumor to remove.”
The surgery took several hours, during which doctors used a microscope to guide their moves.
Springer was in South Africa on a study-abroad trip during his friend’s surgery.
“That was tough,” he said. “It was hard to be at a distance knowing that our friend was going through this.”
The postsurgery concerns soon would turn to the quality of life that Twombly would have once he recovered.
New perspective
“Every day I am amazed that he is exactly what I knew before the surgery,” Perreault said. “It is humbling that humans have the ability to remove from his brain what was inside there and return him to me as he was before, joking around with us and loving us. It’s truly amazing.”
About the only lasting effect of the surgery is that Twombly has a void, or space, in his brain where the tumor used to be. The brain doesn’t grow or expand to fill that space, and Twombly and his friends had some fun with that.
There was a contest to decide what best to put in the void where the tumor once resided.
Suggestions ranged from a golf ball to some new electronic musical component to a Wi-Fi hot spot.
Sherr told him the void actually would fill with a fluid mixture of sugars and some proteins.
“I was drinking a lot of apple juice at the time,” Twombly said, “so I joked that it was going to be filled with apple juice.”
Reality is that he’ll have to have regular brain scans to see if the tumor, which wasn’t cancerous, grows back. Twombly believes his heart condition and Marfan syndrome pose bigger threats down the road than his brain.
Trained as a composer, he writes music but also loves to perform. He admits that he could probably have made due with some loss of motor control without it having a severe impact on his research or his teaching.
Springer also is amazed at the fact that Twombly came out of brain surgery the same person.
“I was surprised. I figured there would be some lasting effect,” Springer said. “Even if it was that they couldn’t take care of the migraines. But Kristian is certainly no different than he was before he went in. He may be harboring this inside, but it hasn’t changed his spirit.”
But Twombly has changed. His initial Marfan’s diagnosis came with a life expectancy of about 40 years. That’s why he had such a nonchalant attitude about the future and how much there was going to be for himself.
Medical advances have extended that life expectancy for those with Marfan’s. And Perreault and her three children also have given Twombly greater perspective on life and what’s important.
“I might have been a little bit more living in the instant before the surgeries,” he said. “It’s a tough thing to grapple with. But the sort of double whammy of these things coming together and the potential severity, it’s a lot to consider. But I can say this. At no point have I sat down and said, ‘Why me?’ ”
“I think he’s done a better job putting importance on the things that matter to him and less time sweating the smaller things,” Perreault said.
And to his friends, he’s a unique example of the resilience of the human spirit.
“To see friend go through this once, and then to see it twice? It’s really hard,” Springer said. “But I’m just amazed at modern medicine and the ability that these amazing doctors have. And also the power of the human spirit, not only to see it in Kristian and his recovery, but in his friends and family. Just to see that on display is amazing. You read about it. You know, people will read your paper and say, ‘That’s nice.’ But until you live it and see it ...”
Editor’s note: Twombly is a member of the Opinion Pages’ Times Writers Group.

Why eating less helps brain to stay young

Eating less activates a molecule for ‘brain longevity’ and thus helps the brain stay young, a new study has revealed.

Many studies suggest that obesity is bad for our brain, slows it down, causes early brain aging, making it susceptible to diseases typical of older people as the Alzheimer’s and Parkinson’s. In contrast, caloric restriction keeps the brain young.

A team of Italian researchers at the Catholic University of Sacred Heart in Rome have discovered that this molecule, called CREB1, is triggered by ‘caloric restriction’ (low caloric diet) in the brain of mice. They found that CREB1 activates many genes linked to longevity and to the proper functioning of the brain.

CREB1 mediates the beneficial effects of the diet on the brain by turning on another group of molecules linked to longevity, the ‘sirtuins’.

This finding is consistent with the fact that CREB1 is known to regulate important brain functions as memory, learning and anxiety control, and its activity is reduced or physiologically compromised by aging.

Moreover, Italian researchers have discovered that the action of CREB1 can be dramatically increased by simply reducing caloric intake, and have shown that CREB is absolutely essential to make caloric restriction work on the brain. In fact, if mice lack CREB1 the benefits of caloric restriction on the brain (improving memory, etc.) disappear.

So the animals without CREB1 show the same brain disabilities typical of overfed and/or old animals.

“Thus, our findings identify for the first time an important mediator of the effects of diet on the brain,” Dr Giovambattista Pani, lead researcher.

“This discovery has important implications to develop future therapies to keep our brain young and prevent brain degeneration and the aging process. In addition, our study shed light on the correlation among metabolic diseases as diabetes and obesity and the decline in cognitive activities.”

“Our hope is to find a way to activate CREB1, for example through new drugs, so to keep the brain young without the need of a strict diet,” Dr Pani added.

Caloric restriction means the animals can only eat up to 70 percent of the food they consume normally, and is a known experimental way to extend life, as seen in many experimental models.

Advances in 'Brain Reading'

Researchers are using functional MRI brain scans to observe brain signal changes that take place during mental activity at UCLA's Laboratory of Integrative Neuroimaging Technology.

They then employ computerized machine learning (ML) methods to study these patterns and identify the cognitive state — or sometimes the thought process — of human subjects. The technique is called "brain reading" or "brain decoding."

In a new study, the UCLA research team describes several crucial advances in this field, using fMRI and machine learning methods to perform "brain reading" on smokers experiencing nicotine cravings.

The research, presented last week at the Neural Information Processing Systems' Machine Learning and Interpretation in Neuroimaging workshop in Spain, was funded by the National Institute on Drug Abuse, which is interested in using these method to help people control drug cravings.

In this study on addiction and cravings, the team classified data taken from cigarette smokers who were scanned while watching videos meant to induce nicotine cravings. The aim was to understand in detail which regions of the brain and which neural networks are responsible for resisting nicotine addiction specifically, and cravings in general, said Dr. Ariana Anderson, a postdoctoral fellow in the Integrative Neuroimaging Technology lab and the study's lead author.

"We are interested in exploring the relationships between structure and function in the human brain, particularly as related to higher-level cognition, such as mental imagery," Anderson said. "The lab is engaged in the active exploration of modern data-analysis approaches, such as machine learning, with special attention to methods that reveal systems-level neural organization."

For the study, smokers sometimes watched videos meant to induce cravings, sometimes watched "neutral" videos and at sometimes watched no video at all. They were instructed to attempt to fight nicotine cravings when they arose.

The data from fMRI scans taken of the study participants was then analyzed. Traditional machine learning methods were augmented by Markov processes, which use past history to predict future states. By measuring the brain networks active over time during the scans, the resulting machine learning algorithms were able to anticipate changes in subjects' underlying neurocognitive structure, predicting with a high degree of accuracy (90 percent for some of the models tested) what they were watching and, as far as cravings were concerned, how they were reacting to what they viewed.

"We detected whether people were watching and resisting cravings, indulging in them, or watching videos that were unrelated to smoking or cravings," said Anderson, who completed her Ph.D. in statistics at UCLA. "Essentially, we were predicting and detecting what kind of videos people were watching and whether they were resisting their cravings."

In essence, the algorithm was able to complete or "predict" the subjects' mental states and thought processes in much the same way that Internet search engines or texting programs on cell phones anticipate and complete a sentence or request before the user is finished typing. And this machine learning method based on Markov processes demonstrated a large improvement in accuracy over traditional approaches, the researchers said.

Machine learning methods, in general, create a "decision layer" — essentially a boundary separating the different classes one needs to distinguish. For example, values on one side of the boundary might indicate that a subject believes various test statements and, on the other, that a subject disbelieves these statements. Researchers have found they can detect these believe–disbelieve differences with high accuracy, in effect creating a lie detector. An innovation described in the new study is a means of making these boundaries interpretable by neuroscientists, rather than an often obscure boundary created by more traditional methods, like support vector machine learning.

"In our study, these boundaries are designed to reflect the contributed activity of a variety of brain sub-systems or networks whose functions are identifiable — for example, a visual network, an emotional-regulation network or a conflict-monitoring network," said study co-author Mark S. Cohen, a professor of neurology, psychiatry and biobehavioral sciences at UCLA's Staglin Center for Cognitive Neuroscience and a researcher at the California NanoSystems Institute at UCLA.

"By projecting our problem of isolating specific networks associated with cravings into the domain of neurology, the technique does more than classify brain states — it actually helps us to better understand the way the brain resists cravings," added Cohen, who also directs UCLA's Neuroengineering Training Program.

Remarkably, by placing this problem into neurological terms, the decoding process becomes significantly more reliable and accurate, the researchers said. This is especially significant, they said, because it is unusual to use prior outcomes and states in order to inform the machine learning algorithms, and it is particularly challenging in the brain because so much is unknown about how the brain works.

Machine learning typically involves two steps: a "training phase" in which the computer evaluates a set of known outcomes — say, a bunch of trials in which a subject indicated belief or disbelief — and a second, "prediction" phase in which the computer builds a boundary based on that knowledge.

In future research, the neuroscientists said, they will be using these machine learning methods in a biofeedback context, showing subjects real-time brain readouts to let them know when they are experiencing cravings and how intense those cravings are, in the hopes of training them to control and suppress those cravings.

But since this clearly changes the process and cognitive state for the subject, the researchers said, they may face special challenges in trying to decode a "moving target" and in separating the "training" phase from the "prediction" phase.

Woman is cured of Tourette's by electrodes in the brain

A woman suffering from Tourette's syndrome has said she is cured after having electrodes implanted in her brain as part of a trial.

Jayne Bargent said the treatment worked within an hour of the electrodes being switched on, six weeks after she underwent surgery to have them implanted and a pacemaker placed in her chest to provide the power. Until the experimental technique was tried this week, Ms Bargent couldn't read, drive or walk properly because of the constant convulsive twitches caused by the condition.

"It is absolutely amazing," she said. "This is going to give me my life back. I've had three years of gradually getting worse and they press a few little buttons and everything improves dramatically." She said the condition had been so debilitating that food would fall out of her mouth as she tried to eat.

The trial is being conducted by the UCL National Hospital for Neurology and Neurosurgery where doctors believe the impulses from the electrodes dampen down disorganised and mistaken messages passing through the brain that cause the convulsions. The technique is already used for conditions such as Parkinson's.
Tom Foltynie, a consultant neurologist, said the speed of response to the treatment experienced by Ms Bargent was unusual: "We generally see effects over days rather than minutes."

Scientists find a gene that controls memory formation

Washington: A team led by an Indian-origin neuroscientist has found a gene that "turns on" when memories are stored in the brain, a discovery they believe could help pinpoint the exact locations of memories in the brain.

It`s known that when one witnesses a new event, the brain encodes a memory of it by altering the connections between neurons. This needs turning on many genes in those neurons.

Now, neuroscientists at the Massachusetts Institute of Technology (MIT) have identified a gene, called Npas4, which is very active in the hippocampus -- a brain structure known to be critical in forming long-term memories.

The findings, described in the journal Science, would be a breakthrough in pinpointing the exact locations of memories in the brain and might open up new avenues for altering or even creating memory, the researchers said.

"We think of Npas4 as the initial trigger that comes on, and then in turn, in the right spot in the brain, it activates all these other downstream targets," Kartik Ramamoorthi, a MIT graduate student who led the study, said in a statement.

"Eventually they are going to modify synapses in a way that`s likely changing synaptic inhibition or some other process that we are trying to figure out," Ramamoorthi said.

The scientists, who carried out their research on mice, found that Npas4 turns on a series of other genes that modify the brain`s internal wiring by adjusting the strength of synapses, or connections between neurons.

"This is a gene that can connect from experience to the eventual changing of the circuit," said Yingxi Lin, a member of the McGovern Institute for Brain Research at MIT where the study was carried out.

The researchers gave mice mild electric shock when they enter a specific chamber. Within minutes, the mice learn to fear the chamber and the next time they enter it, they freeze.
The researchers found that Npas4 is turned on very early during this conditioning. "This sets Npas4 apart from many other activity-regulated genes. A lot of them are ubiquitously induced by all these different kinds of stimulations; they are not really learning-specific," Lin said.

So far, the researchers have identified only a few of the genes regulated by Npas4, but they suspect there could be hundreds more. The experiments showed that Npas4 binds to the activation sites of specific genes and directs an enzyme called RNA polymerase II to start copying them.

When the researchers knocked out the gene for Npas4, they found that mice could not remember their fearful conditioning.

They also found that this effect could be produced by knocking out the gene in the CA3 region of the hippocampus. Knocking it out in other parts of the hippocampus, however, had no effect.

Though they focused on contextual fear conditioning, the researchers believe that Npas4 will also prove critical for other types of learning.

"We`re hunting for the memory, and we think we can use Npas4 to mark where it is," Ramamoorthi said.

"That`s because it`s turned on specifically and now we can label the cells and maybe fish out where in the brain the memory is sitting."

Determined to thrive, a little boy battles a brain disorder

Dylan is nearly 2. Because of radical surgery more than a year ago, he talks, goes to preschool and inspires his family with hope.

By Molly Hennessy-Fiske By Molly Hennessy-Fiske

Dylan is nearly 2. Because of radical surgery more than a year ago, he talks, goes to preschool and inspires his family with hope.

At left, three-month-old Dylan recovers from surgery in April, 2010. At right, Dylan, now nearly 2 years old, at his home in Los Angeles earlier this month. (Francine Orr / Los Angeles Times) More Photos

By Molly Hennessy-Fiske, Los Angeles Times

December 25, 2011

Dylan Catania turns 2 next month. He likes pasta with red sauce, playing catch or wrestling with his dad, sitting on slick leather chairs at Starbucks to greet strangers and holding his breath underwater. He does not like baby food, sitting in his car seat or taking naps.

Video: Dylan's journey

When he is really, really happy, Dylan likes to sit on the ground, crack a smile exposing his fledgling teeth and spin like a top.
The faint scar on his right temple is invisible under a cap of downy brown hair. He was born with half of his brain enlarged and malformed, a disorder known as hemimegalencephaly that occurs in fewer than two dozen births a year.
When he was nearly 3 months old, neurosurgeons at UCLA severed the right hemisphere of Dylan's brain from the left in a seven-hour hour operation, radical surgery to stop him from suffering as many as a hundred seizures each day.
Neurologists who see him now, scooting across the floor propelled by his right hand, recognize the telltale "hemi scoot." His family and friends see a determined boy who has grown not only stronger but more trusting, empathetic and brave.
He can say more than two dozen words. He does not cry for his mother at the preschool near his family's home in Beverly Glen, but if another child wails, he joins in solidarity. He favors classical music and anything Elmo, waving his right hand to the beat, but has been known to watch in awe as his sister and cousins groove along to their Wii. He has yet to make peace with his left side, slightly paralyzed by the surgery, but if his parents ask nicely, he will kiss his left hand, known as "lefty."

Quieting Dylan's brain

Photos: Dylan's journey

From the Archive:

A journey of risk, hope for baby with a "big, bad brain"
Video | Photos

The right side of Dylan's brain was triggering seizures that worsened steadily after his birth in January 2010, even when he was heavily medicated. Specialists at UCLA recommended operating as soon possible, before the seizures could damage Dylan's brain. But they warned that the surgery might paralyze Dylan's left side and still not stop his seizures.
The Catanias chose to try to save Dylan's mind. Still, they worried if they were doing the right thing for their infant son. The Times documented their decision to operate and Dylan's long recovery in an article that was published last Christmas Day.
Before the surgery, Ellen and Jeff Catania had lived on the edge. Dylan's seizures grew increasingly frequent. His tiny body would tense, arms clenched, and he would wail. When it was over, they would give him a cocktail of anti-seizure drugs that left him sluggish, eyelids at half-mast. They kept him close by, never moving him into his nursery.
More than a year and a half after the operation, Dylan has not suffered another seizure. He still has trouble sleeping through the night (Elmo helps) and beds down in his parents' room. But he stopped taking his anti-seizure medication months ago. His brown eyes, once hooded, are now open wide, taking in the world.
"If you ask him to press a button, he does it. He knows exactly what you're talking about," Jeff Catania, 61, says. "He lays down when asked, and when we go to leave the house, he lifts up his legs to put on his shoes."

Interactive Graphic:

To stop seizures that cannot be controlled by medication, doctors at UCLA use a radical surgery that removes deep brain-tissue structures to isolate areas generating the seizures. Without surgery, Dylan Catania's rare disorder, known as hemimegalencephaly, could have left him severely retarded. Here's a look at how surgeons used the procedure for Dylan:

Sources: Gary W. Mathern, M.D.; The CIBA Collection of Medical Illustrations. Graphics reporting by Tom Reinken and Paul Duginski

Graphics by Paul Duginski, interactivity by Itzu Chen, Los Angeles Times

Dylan's right arm is so strong, when they play catch, he slings the ball over his father's head.
"I don't underestimate him anymore," Jeff Catania says. "So I give back a little bit."
The Catanias do not measure their son's progress in the typical childhood milestones. Doctors say Dylan's development is delayed but that he is making good progress.
"He'll need support and all the things that go with it, but he's already achieving a level of activity that we would not have expected if we had not gotten seizure control," says Dr. Gary Mathern, the UCLA neurosurgeon who operated on Dylan. "He's already beating expectations."
Mathern is working with the Catanias and other parents through the nonprofit Brain Recovery Project to develop therapies for children who have the same surgery as Dylan.
The Catanias, who both work as fundraisers, still have a mountain of medical bills from Dylan's care. They just learned that he will need surgery in order to correct the crossing in his right eye. Ellen Catania, 48, sits up at night reading stories on the Internet about other children who had Dylan's surgery.
"Some go all the way to 15 and have a seizure," she says, grimacing. "You feel so joyful for every day with him, but then you still worry about his future."
His pediatric neurologist, Dr. Raman Sankar, said there is no guarantee that Dylan will remain seizure-free. But at a time when his brain is rapidly developing, stopping the seizures has given Dylan's mind space to grow, Sankar said.
"I wanted him to be able to make his own decisions, and he does," Jeff Catania said as he watched Dylan repeatedly punching a button to activate an electronic Santa Claus set up next to the tree in their living room.
Dylan's 11 year-old sister, Isabella, rolled her eyes as Santa danced and sang for the umpteenth time.
"He sure knows a lot of ways to say no!" she said as Dylan shot her a grin and began spinning.

Royal Institution Royal Institution Christmas lectures will unwrap the human brain

In this year's Christmas lectures on BBC Four, Professor Bruce Hood aims to reveal the brain in all its mystery and complexity

Prof Bruce Hood wants people to come away from his Christmas lectures with a greater appreciation of their white and grey matter.

Human beings are the most intelligent species on the planet because our brains have evolved to cope with complex social situations, according to this year's Royal Institution Christmas lecturer, Professor Bruce Hood. This important function takes decades to develop properly, however, and explains why we humans spend a much larger proportion of our lifespan as children than any other animal.
In three one-hour lectures – entitled Meet Your Brain – Hood will examine how the brain is constructed and creates the world we perceive around us. He also hopes to inspire a new generation of neuroscientists from among his audience of schoolchildren by showing that scientists are only beginning to understand the workings of the brain.
"I'm going to leave open a lot of questions and, hopefully, they'll see that this has got many years of work in future," says Hood, an experimental psychologist at the University of Bristol.
Whether or not they (or the millions watching at home) end up studying the brain, Hood hopes that people come away from the lectures with a deeper appreciation of the white and grey matter. "We take it for granted – the things we do every day. We don't understand how complicated they really are. I want people to come away with a sense of wonder about how a thing like the brain has such flexibility and such powerful processing capability to create this experience we have."
The Royal Institution's Christmas lectures were initiated by Michael Faraday in 1825 as an attempt to bring science to young people. They have run every year since (except during the second world war) and lecturers have included David Attenborough, Richard Dawkins and Dame Nancy Rothwell.
From a set that resembles a 1950s horror movie, Hood plans to take viewers on a trip through the capabilities of our most important organ. "The brain is seven times heavier than you would imagine for an animal our size. It's full of billions upon billions of brain cells," he says. "It's not the number of cells that's really fascinating, it's the connection between the cells because that's the secret of the processing power of the brain. It's connections that encode information."
Babies are born with almost their full complement of brain cells, so it's the increase in the number of connections between the cells that explains the change in the size and weight of the brain as it matures. All of this helps to create a representation of the external world.
"You're encoding experiences and storing that," says Hood. "When the brain brings these back to think about them, it's almost recreating the original experience. It's not a photograph captured in time, these things are constantly dynamic and changing."
Hood will also discuss a uniquely human capability that our brains have evolved: the ability to be social. "Childhood used to be thought of as a time of immaturity," he says. "But we now realise that this is the period where we're becoming social. The species which have the longest periods of childhood tend to be the ones which are more flexible or intelligent."
Not only do human children learn from others, they learn to become like others. "We spend up to 15-20 years in childhood and that's a large proportion of human lifespan and that can only be because it serves a really important process, which I think is learning from others and learning to communicate and share information," says Hood. "We don't simply read behaviours, we put ourselves in other humans' shoes, we take their perspectives, we can empathise, we can see their points of view. This is a whole area called 'theory of mind'. Without that you cannot anticipate what other people are thinking and doing."
The human desire to socialise, to see people around us, can also trick us. "Seeing faces [in inanimate objects] is a very common thing because faces are the most important social stimuli to humans. We have areas of our brain dedicated to processing faces," says Hood. "The problem is that we're trip-wired to seeing anything that could be face-like. This has often explained why people have seen faces in clouds or trees. Often, religious deities are the things that people spot."
Hood's own research involves examining the human ability to form connections with objects by inferring some internal property that gives them a specific character. "Children at 3-4 years of age will know that cats are different from dogs but they can do that over and beyond the outward appearance. They start to think there must be something inside a cat that makes them different to a dog – a catty essence," he says. "They're starting to infer a deeper property to the living world."
In recent experiments, Hood has found that people wanted to wash their hands after touching or wearing a cardigan that they have been told once belonged to a murderer; but they wanted to hold a pen that had been told had belonged to Albert Einstein. "I think this is the basis of why we go to museums and collections: we want to see the original objects," says Hood. "As soon as we discover it's not the original, our regard for it disappears."