Pain’s Benefit to Squid May Hold Clues to Chronic Human Pain

For the longfin inshore squid, pain can mean the difference between life and death, according to a new study. That’s because pain prompts injured squid to behave in ways that help it survive encounters with a fish predator, researchers said.

That finding may also provide hints as to why other animals, including humans, experience long-lasting or chronic pain, behavior experts say.

It’s long been thought that pain causes an animal to act self-protectively, says Robert Elwood, an animal behavior researcher at Queen’s University Belfast who was not involved in the study. Pain teaches an organism to avoid situations that will bring it on. It seems obvious, but it hasn’t really been tested until now, Elwood said in an email interview.

In a study published today in Current Biology, researchers report that the sensitivity with which injured squid reacted to aggressive moves from a predator, in this case a black sea bass, gave the squid better odds of surviving an attack.

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Your brain on speed: Walking doesn’t impair thinking and multitasking

When we’re strolling down memory lane, our brains recall just as much information while walking as while standing still—findings that contradict the popular science notion that walking hinders one’s ability to think.

University of Michigan researchers at the School of Kinesiology and the College of Engineering examined how well study participants performed a very complex spatial cognitive task while walking versus standing still.

"We’re saying that at least for this task, which is fairly complicated, walking and thinking does not compromise your thinking ability at all," said Julia Kline, a U-M doctoral candidate in biomedical engineering and first author on the study, which appears online in Frontiers in Human Neuroscience.

The finding surprised researchers, who expected to see decreased thinking performance with increased walking speed, Kline said. The 2011 best-selling book “Thinking Fast and Slow” suggests that because walking requires mental effort, walking may hinder our ability to think when compared to standing still.

"Past studies that have compared mental performance at a slow walking speed and standing have not found any differences, but our study is the first to show that the walking speed doesn’t matter," said Daniel Ferris, professor of kinesiology and biomedical engineering and senior author of the paper.

"Given the health benefits of walking, we should not discourage people from walking and thinking when they want."

Ferris offered one caveat: previous research has shown that walking performance can be impaired in the elderly when they dual-task during gait.

Ferris, Kline and Katherine Poggensee of U-M’s Human Neuromechanics Laboratory measured the ability of young, healthy participants to memorize numbers and their placement on a grid, and then enter those numbers correctly with a keypad while walking different speeds and standing still.

"Think of filling numbers one through nine on a tic-tac-toe grid and then remembering where they all are," Ferris said. "At every walking speed and standing still, participants entered about half the numbers correctly."

While speed didn’t change task performance, people took wider steps when performing the task than when they were only walking, which may be to compensate and stay balanced while concentrating, Kline said.

All participants showed increased activity in areas of the brain associated with spatial relationships and short-term memory during the cognitive task. In keeping with the U-M findings, a recent Stanford study suggested that walking fueled creativity.

In addition to good news for treadmill-desk users or people who like to think on the move, the study provides a useful scientific tool by demonstrating that it’s possible to collect accurate EEG data on moving subjects, Kline said.

This is important to researchers who study the brain and are concerned about getting accurate results when the subjects aren’t perfectly still. U-M researchers achieved their EEG results by applying different signal-processing techniques to eliminate the movement “noise” from the EEG signal.

FDA allows marketing of first prosthetic arm that translates signals from person’s muscles to perform complex tasks

The U.S. Food and Drug Administration (FDA) today allowed marketing of the DEKA Arm System, the first prosthetic arm that can perform multiple, simultaneous powered movements controlled by electrical signals from electromyogram (EMG) electrodes.

EMG electrodes detect electrical activity caused by the contraction of muscles close to where the prosthesis is attached. The electrodes send the electrical signals to a computer processor in the prosthesis that translates them to a specific movement or movements.

The EMG electrodes in the DEKA Arm System convert electrical signals into up to 10 powered movements, and it is the same shape and weight as an adult arm. In addition to the EMG electrodes, the DEKA Arm System contains a combination of mechanisms including switches, movement sensors, and force sensors that cause the prosthesis to move.

“This innovative prosthesis provides a new option for people with certain kinds of arm amputations,” said Christy Foreman, director of the Office of Device Evaluation at the FDA’s Center for Devices and Radiological Health. “The DEKA Arm System may allow some people to perform more complex tasks than they can with current prostheses in a way that more closely resembles the natural motion of the arm.”

The FDA reviewed clinical information relating to the device, including a 4-site Department of Veterans Affairs study in which 36 DEKA Arm System study participants provided data on how the arm performed in common household and self-care tasks. The study found that approximately 90 percent of study participants were able to perform activities with the DEKA Arm System that they were not able to perform with their current prosthesis, such as using keys and locks, preparing food, feeding oneself, using zippers, and brushing and combing hair.

The DEKA Arm System can be configured for people with limb loss occurring at the shoulder joint, mid-upper arm, or mid-lower arm. It cannot be configured for limb loss at the elbow or wrist joint.

Data reviewed by the FDA also included testing of software and electrical and battery systems, mitigations to prevent or stop unintended movements of the arm and hand mechanisms, durability testing (such as ability to withstand exposure to common environmental factors such as dust and light rain), and impact testing.

The FDA reviewed the DEKA Arm System through its de novo classification process, a regulatory pathway for some novel low- to moderate-risk medical devices that are first-of-a-kind.

The DEKA Arm System is manufactured by DEKA Integrated Solutions in Manchester, N.H.

Listening to bipolar disorder: Smartphone app detects mood swings via voice analysis

A smartphone app that monitors subtle qualities of a person’s voice during everyday phone conversations shows promise for detecting early signs of mood changes in people with bipolar disorder, a University of Michigan team reports.

While the app still needs much testing before widespread use, early results from a small group of patients show its potential to monitor moods while protecting privacy.

The researchers hope the app will eventually give people with bipolar disorder and their health care teams an early warning of the changing moods that give the condition its name. The technology could also help people with other conditions.

"We only ask that an individual use his or her smart phone as he or she normally would," said Emily Mower Provost, assistant professor of computer science and engineering who co-led the project. "We collect speech data from the smart phone and process the data in a privacy preserving manner to learn the acoustic patterns associated with harmful mood variations."

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The science behind rewards and punishment

In a neuroimaging study, a UQ psychologist has examined whether having allegiances with someone can affect feelings of empathy when punishing and rewarding others.

An international team of researchers, including Dr Pascal Molenberghs from UQ’s School of Psychology, mapped the brain activity while volunteers where giving electroshocks or money to members within or outside their group.

Dr Molenberghs said the research was a first of its kind and demonstrated that different neural responses were involved when delivering rewards or punishment to others.

“When we reward others we activate similar brain areas as when we receive rewards ourselves,” he said.

“However, these areas become more active when we reward members from our own group.

“Previous research has shown that we prefer to give more money to people from our own group, now we can actually show that this is associated with increased activation in reward-related brain areas, which is really exciting.

“The brain responses for punishing others directly revealed a different pattern of activation, one that was typically associated with receiving and seeing others in pain,” Dr Molenberghs said.

The study also found that personality traits influenced activity in these punishment-related brain areas.

People who did not care as much about others, showed less activation in these areas when shocking others, especially when they were shocking out-group members.

Co-author Professor Jean Decety, from the University of Chicago, said the results provided important insights into why some people don’t care as much when hurting others.

“Empathy and sympathy are necessary abilities to understand the potential consequences decisions will have on the feelings and emotions of others, even if the recipients of those decisions belong to a different group,” he said.

Students ‘print’ pink prosthetic arm for teen girl

Thirteen-year-old Sydney Kendall had one request for the Washington University in St. Louis students building her a robotic prosthetic arm: Make it pink.

Kendall Gretsch, Henry Lather and Kranti Peddada, seniors studying biomedical engineering in the School of Engineering & Applied Science, accomplished that and more. Using a 3-D printer, they created a robotic prosthetic arm out of bright-pink plastic. Total cost: $200, a fraction of the price of standard prosthetics, which start at $6,000.

“Currently, prosthetics are very expensive, and because kids keep growing, it is too costly for them to have the latest technology,” said Sydney’s mother, Beth Kendall. “With the 3-D printer, a prosthetic can be made much less expensive. The possibilities of what can be done to improve prosthetics using this technology is very exciting.”

Sydney lost her right arm in a boating accident when she was six years old. She learned to write with her left hand, but found most tasks difficult to accomplish with her prosthetic arm. Sydney said her new arm is easy to manipulate. By moving her shoulder, she can direct the arm to throw a ball, move a computer mouse and perform other tasks.

Peddada said it was thrilling to observe Sydney use her arm.

“It really showed us the great things you can accomplish when you bridge medicine and technology,” Peddada said.

The students developed the robotic hand as part of their engineering design course with Joseph Klaesner, PhD, associate professor of physical therapy at the School of Medicine. Several local medical practitioners, including orthopedic hand surgeons Charles A. Goldfarb, MD, and Lindley Wall, MD, both associate professors of orthopaedic surgery at the School of Medicine, served as mentors.

“They brought their engineering expertise, and we shared our practical experience with prosthetics and the needs of children,” Goldfarb wrote in a recent blog post about the project. “It was a valuable experience as Kendall, Henry and Kranti had no prosthetic experience and were able to think about the issues in a very different way.”

As Goldfarb explained, the WUSTL student design offers two key design differences that set it apart from similar “Robohand” devices that have been invented recently — the motor and the working thumb.

This prosthetic is battery-powered and controlled with an accelerometer (like in the iPhone). The thumb moves with a slightly different trigger (compared with finger motion).

Prosthetic limbs are tricky for patients of any age, and especially for children, noted Goldfarb, because they’re still growing and need to move to larger-sized devices on a regular basis. Since prosthetics have no sensation, some kids are more comfortable making do with their existing natural limbs, he added.

While 3-D printers can cost about $2,500, they are capable of producing artificial limbs at a relatively low individual cost.

“These prosthetic hands are really exciting because they are inexpensive, can be remade when the child grows, and they do offer functional abilities,” he said.

Researchers capture handoff of tracked object between brain hemispheres

When tracking a moving object, the two halves of the human brain operate much like runners successfully passing a baton during a relay race, says a University of Oregon researcher.

In a study online ahead of print in Current Biology, electroencephalogram (EEG) measured brainwaves from healthy young adults revealed how information about an attended object — one being watched closely — moves from one brain hemisphere to the other.

Such handoffs are necessary because the human visual system is contralateral; objects on the left side of space are processed by the right hemisphere and vice versa. When objects change sides, the two hemispheres must coordinate so that the tracked object isn’t lost during the exchange.

"Attentional tracking is something we do on a regular basis when driving in traffic or walking through a crowd," said Edward K. Vogel, professor of psychology. "Our world is dynamic. We’re moving. Our eyes are moving. Objects are moving. We need to use our attention to follow objects of interest as they move so that we can predict where they are going.”

People experience a smooth and seamless visual world despite information quickly being transferred back and forth between the hemispheres. “A car in your rearview mirror that moves from one lane to the other doesn’t suddenly disappear and then reappear on the other side,” he said. “The exchange is smooth, in part, because often the hemispheres coordinate a soft handoff.”

That means, he said, that before the object crosses into the other side of space, the new hemisphere picks it up, and the old hemisphere continues to hang on to it until it crosses well into the other side of space. Both hemispheres grab hold of the object during the exchange — much like in a relay race when two runners both briefly have hold of the baton to assure it isn’t dropped.

Eventually, Vogel said, such research may help us better understand individual differences in people’s visual tracking abilities. Some people, for instance, have trouble picking up a moving vehicle seen in a rearview mirror once it enters a blind spot. “This new technique allows us to watch the brain as information about a target is handed off from one side to the other, and it may provide insights into why attention is so limited,” Vogel said.

While psychological studies have often looked at attention and awareness, there has been little focus on how the two hemispheres interact. Interestingly, Vogel said, cellphone companies have long studied a similar problem: how to best transfer a call’s signal while a customer moves from one zone of a cell tower to another.

Cellular carriers using Code Division Multiple Access (CDMA) such as Sprint and Verizon utilize a soft handoff between towers, similar to the new findings. Global System for Mobile (GSM) carriers, such as T-Mobile and ATT, use a hard handoff in which a signal leaving a tower’s coverage is rapidly shut off and then turned on by the next tower — a scenario that tended to, before the technology improved, result in more dropped calls.

"Researchers at the University of Oregon are using cutting-edge techniques to examine important mechanisms of cognitive functioning," said Kimberly Andrews Espy, vice president for research and innovation and dean of the UO Graduate School. "This research by Dr. Vogel and his team provides a window on the process of attentional tracking that furthers our understanding of how the two hemispheres of the brain work together to process visual information."

(Image caption: This ribbon diagram shows three ankyrin repeats, a common structure found in receptor proteins that sense either cold or hot temperatures. A Duke team has identified three single-point mutations that can invert temperature-sensitivity, turning a cold-sensor into a heat-sensor. All three of these mutations are located in on a single ankyrin repeat. Credit: Grandl Lab, Duke University)

Small Mutation Changes Brain Freeze to Hot Foot

Ice cream lovers and hot tea drinkers with sensitive teeth could one day have a reason to celebrate a new finding from Duke University researchers. The scientists have found a very small change in a single protein that turns a cold-sensitive receptor into one that senses heat.

Understanding sensation and pain at this level could lead to more specific pain relievers that wouldn’t affect the central nervous system, likely producing less severe side effects than existing medications, said Jorg Grandl, Ph.D., an assistant professor of neurobiology in Duke’s School of Medicine who led the research team.

Temperature-induced pain, also called thermal pain, occurs when the body’s sensory neurons come in contact with temperatures above or below a certain threshold, such as plunging a limb into freezing water.

"We want to understand how either hot or cold temperatures can activate the sensors of hot and cold temperatures in the body," Grandl said.

Previous research has identified transient receptor potential (TRP) ion channels as being highly sensitive to either cold or hot temperatures. TRP ion channels are porous proteins that play a role in initiating electrical signals by controlling the flow of charged ions across the cell membrane.

It’s still unclear how temperatures make this happen, but the Grandl team’s research reveals that single-letter changes in DNA, called point mutations, are sufficient to make cold-sensitive TRP ion channels become sensitive to hot temperatures instead.

"There is strong interest in understanding temperature-sensitive molecules from a functional perspective because they are promising targets for developing analgesic compounds to treat chronic pain," said Grandl, who is also a member of the Duke Institute for Brain Sciences. "It is something we currently do not treat well. So, one promising strategy is to stop pain where it is initially sensed — at that first molecule that functions as a sensor of pain."

In a study appearing online early May 8 in the journal Neuron, Grandl’s team focused on TRPA1, an ion channel best known as a sensor for pain caused by environmental irritants and pungent chemicals, such as mustard oil, the active compound found in wasabi.

Grandl’s colleagues, postdoctoral fellow Sairam Jabba and research technician Raman Goyal, investigated whether single-point mutations could change cold-activated mouse TRPA1 into heat-activated. They formed this hypothesis because, in some other animals, including Drosophila fruit-flies and rattlesnakes, TRPA1 is naturally heat-activated.

To identify these structures, the team created a library of 12,000 mutant clones of the cold-activated mouse TRPA1 ion channel and randomly inserted one or two point mutations into each clone. After placing single clones into the individual slots of a 384-well plate and heating it from 25 degrees Celsius to 45 C in a matter of seconds, they were able to measure the thermal sensitivity of each mutant protein.

This screening pinpointed seven clones that showed strong activation when exposed to heat. Gene sequencing of these clones revealed 12 mutations that could potentially be responsible for changing the mouse TRPA1 from cold-activated to heat-activated. Out of these 12 mutations, Jabba and Goyal identified three mutations powerful enough to individually make that switch in TRPA1.

The mutations all turned out to be located within a single small domain of the ion channel protein known as ankyrin repeat six, indicating this domain plays a role in determining cold or heat activation. Ankyrin repeats are often responsible for managing protein-to-protein interactions, but their precise function in TRPA1 had not been previously known.

Interestingly, these single-point mutations didn’t change the ion channels’ responses to chemicals, such as mustard oil.

"This was very surprising and it demonstrates that making a single-point mutation produced a profound change in the temperature sensitivity of the protein, but it did not affect the chemical sensitivity," Grandl said. "It shows these mechanisms are to some degree distinct."

Grandl said that taken together, the findings also suggest that the effectiveness of such a small mutation might have been key to a single ancestral ion channel evolving into the wide diversity of temperature-activated ion channels we see today.