Dopamine Not About Pleasure (Anymore)

To John Salamone, professor of psychology and longtime researcher of the brain chemical dopamine, scientific research can be very slow-moving.

“It takes a long time for things to change in science,” he says. “It’s like pulling on the steering wheel of an ocean liner, then waiting for the huge ship to slowly turn.”

Salamone has spent most of his career battling a particular long-held scientific idea: the popular notion that high levels of brain dopamine are related to experiences of pleasure. As increasing numbers of studies show, he says, the famous neurotransmitter is not responsible for pleasure, but has to do with motivation.

He summarizes and comments on the evidence for this shift in thinking in a Nov. 8 review in the Cell Press journal Neuron.

Your Brain in Love

Men and women can now thank a dozen brain regions for their romantic fervor. Researchers have revealed the fonts of desire by comparing functional MRI studies of people who indicated they were experiencing passionate love, maternal love or unconditional love. Together, the regions release neuro­transmitters and other chemicals in the brain and blood that prompt greater euphoric sensations such as attraction and pleasure. Conversely, psychiatrists might someday help individuals who become dan­gerously depressed after a heartbreak by adjusting those chemicals.

Passion also heightens several cognitive functions, as the brain regions and chemicals surge. “It’s all about how that network interacts,” says Stephanie Ortigue, an assistant professor of psychology at Syracuse University, who led the study. The cognitive functions, in turn, “are triggers that fully activate the love network.”

(Graphics by James W. Lewis, West Virginia University (brain), and Jen Christiansen)

Origin of intelligence and mental illness linked to ancient genetic accident

Scientists have discovered for the first time how humans – and other mammals – have evolved to have intelligence. Researchers have identified the moment in history when the genes that enabled us to think and reason evolved.

This point 500 million years ago provided our ability to learn complex skills, analyse situations and have flexibility in the way in which we think. Professor Seth Grant, of the University of Edinburgh, who led the research, said: “One of the greatest scientific problems is to explain how intelligence and complex behaviours arose during evolution.”

The research, which is detailed in two papers in Nature Neuroscience, also shows a direct link between the evolution of behaviour and the origins of brain diseases. Scientists believe that the same genes that improved our mental capacity are also responsible for a number of brain disorders.

"This ground breaking work has implications for how we understand the emergence of psychiatric disorders and will offer new avenues for the development of new treatments," said John Williams, Head of Neuroscience and Mental Health at the Wellcome Trust, one of the study funders.

The study shows that intelligence in humans developed as the result of an increase in the number of brain genes in our evolutionary ancestors. The researchers suggest that a simple invertebrate animal living in the sea 500 million years ago experienced a ‘genetic accident’, which resulted in extra copies of these genes being made.

This animal’s descendants benefited from these extra genes, leading to behaviourally sophisticated vertebrates – including humans. The research team studied the mental abilities of mice and humans, using comparative tasks that involved identifying objects on touch-screen computers.

Researchers then combined results of these behavioural tests with information from the genetic codes of various species to work out when different behaviours evolved. They found that higher mental functions in humans and mice were controlled by the same genes.

The Brain: The Charlie Brown Effect

I am sitting in a darkened, closet-size lab at Tufts University, my scalp covered by a blue cloth cap studded with electrodes that detect electric signals from my brain. Data flow from the electrodes down rainbow-colored wires to an electroencephalography (eeg) machine, which records the activity so a scientist can study it later on.

Wearing this elaborate setup, I gaze at a television in front of me, focusing on a tiny cross at the center of the screen. The cross disappears, and a still image appears of Snoopy chasing a leaf. Then Charlie Brown takes Snoopy’s place, pitching a baseball. Lucy, Linus, and Woodstock visit as well. For the next half hour I stare at Peanuts comic strips, one frame at a time. The panels are without words, and while sometimes the action makes sense from frame to frame, at other times the Peanuts gang seems to be engaging in a series of unconnected shenanigans.

At the same time, a freshly minted Ph.D. named Neil Cohn is watching the readout from my brain, an exercise he has repeated with some 100 subjects to date. Many people would consider tracking Peanuts or Calvin and Hobbes comic strips unworthy of scientific inquiry, but Cohn begs to differ. His evidence suggests that we use the same cognitive process to make sense of comics as we do to read a sentence. They seem to tap the deepest recesses of our minds, where we bring meaning to the world.

Read more

Brain Cooling to Treat Epilepsy Moves Closer to Human Application

Neuroscientists from Japan’s Yamaguchi University today reported during the 66th annual scientific meeting of the American Epilepsy Society (AES) that chronic focal brain cooling suppresses seizures during wakefulness and achieves the effect without significantly affecting brain function. Their research, and that of others in the field, provides critical evidence that this approach to seizure control has reached a stage where testing in humans will soon be possible.

Focal brain cooling is well established as an effective method for suppressing seizures. But the technology for creating a practical device with potential clinical application has only recently become available and tested in rodents. More evidence from large animals and humans is needed prior to testing in clinical trials for drug-resistant epilepsy.

The Yamaguchi researchers implanted two feline and two non-human primates with a titanium cooling plate, or heat exchanger. The brain cooling device was placed in contact with the brain surface over cortex areas responsible for movement and sensation. Seizures were then induced in the motor cortex. Brain wave recordings to assess seizure activity and temperature recordings were performed under wakefulness.

According to Masami Fujii, M.D.,Ph.D., and Takao Inoue, Ph.D., and Michiyasu Suzuki, M.D., Ph.D., who presented the report, seizure discharges were significantly suppressed at 15˚C (59˚F).

“The results of our study suggest that focal brain cooling has a strong effect to suppress the epileptiform seizures under the awake condition,” Dr. Fujii said. “Moreover, implantation of the device for at least five months did not result in detrimental changes in brain tissue subjected to cooling compared to tissue from a similar site in the opposing hemisphere.”

Is “Deep Learning” a Revolution in Artificial Intelligence?

Can a new technique known as deep learning revolutionize artificial intelligence as the New York Times suggests?

The technology on which the Times focusses, deep learning, has its roots in a tradition of “neural networks” that goes back to the late nineteen-fifties. At that time, Frank Rosenblatt attempted to build a kind of mechanical brain called the Perceptron, which was billed as “a machine which senses, recognizes, remembers, and responds like the human mind.” The system was capable of categorizing (within certain limits) some basic shapes like triangles and squares. Crowds were amazed by its potential, and even The New Yorker was taken in, suggesting that this “remarkable machine…[was] capable of what amounts to thought.”

But the buzz eventually fizzled; a critical book written in 1969 by Marvin Minsky and his collaborator Seymour Papert showed that Rosenblatt’s original system was painfully limited, literally blind to some simple logical functions like “exclusive-or” (As in, you can have the cake or the pie, but not both). What had become known as the field of “neural networks” all but disappeared.

Read more

Research shows brain hub activity different in coma patients

A team of French and British researchers has found that brain region activity for coma patients is markedly different than for healthy people. In their paper published in the Proceedings of the National Academy of Sciences, the group describes the differences found when comparing fMRI scans of people in a coma with healthy volunteers.

To gain a better understanding of what goes on in the brain when a person is in a coma, and perhaps the nature of consciousness, the researchers performed fMRI brain scans on 17 people who had recently become comatose due to medical conditions that led to blockage of oxygen to the brain. They then compared those scans to those taken of 20 healthy volunteers.

In analyzing the results the team found that global comparisons between the two groups revealed very few if any differences. Blood continued to flow to all of the parts of the brain. When focusing on the brain as a network however, they found very large differences.

To look at the brain as a network requires looking at its different parts as regions that communicate with one another, forming hubs. In healthy people, certain regions or hubs are busier than others as evidenced by more blood flow. But for the people in a coma, the team found, the normally busy hubs grew less busy, while other hubs grew busier, indicating a major change in the flow of information.

The researchers suggest that the brain scans reveal that the normally busy hubs in healthy people are centers of consciousness and their reduced role in communications in comatose patients suggests that they are most likely not conscious of their existence. They point to prior research that has suggested that being in a coma is more likely closer to the experience of being under anesthesia than being asleep. They add that the their research indicates that regions of the brain that are responsible for conscience thought likely require more oxygen rich blood, and are thus likely to be more sensitive to oxygen deprivation than other areas of the brain, which might explain why people go into a coma when those regions are harmed.

Repeated Knocks to the Head Leads to Newly Recognized Brain Disease

Reports on the danger of head trauma in athletes and soldiers has pervaded the news in recent years. NFL and NHL player deaths have catapulted this problem into the limelight, with stories appearing in the New York Times, NPR, ESPN, 60 Minutes and even television entertainment shows. Media attention has raced far ahead of the science on this degenerative condition. But scientists are catching on. They have given this disease its own definition—chronic traumatic encephalopathy (CTE). Different from traumatic brain injury, Alzheimer’s, Parkinson’s, or ALS, they say CTE can strike adult and youths alike. Special coverage by Alzforum, the leading news source on Alzheimer’s and related diseases research, summarizes the status of research in this burgeoning field as researchers take steps to diagnose and treat CTE.

Read more