Neuroscientists Reconstruct Visual Experiences Using fMRI Data

Imagine tapping into the mind of a coma patient, or watching one’s own dream on YouTube. With a cutting-edge blend of brain imaging and computer simulation, scientists at the University of California, Berkeley, are bringing these futuristic scenarios within reach.

Using functional Magnetic Resonance Imaging (fMRI) and computational models, UC Berkeley researchers have succeeded in decoding and reconstructing people’s dynamic visual experiences - in this case, watching Hollywood movie trailers.

As yet, the technology can only reconstruct movie clips people have already viewed. However, the breakthrough paves the way for reproducing the movies inside our heads that no one else sees, such as dreams and memories, according to researchers.

“This is a major leap toward reconstructing internal imagery” said Professor Jack Gallant, a UC Berkeley neuroscientist and coauthor of the study published on September 22th in the journal Current Biology. “We are opening a window into the movies in our minds.”

Eventually, practical applications of the technology could include a better understanding of what goes on in the minds of people who cannot communicate verbally, such as stroke victims, coma patients and people with neurodegenerative diseases.

It may also lay the groundwork for brain-machine interface so that people with cerebral palsy or paralysis, for example, can guide computers with their minds.

However, researchers point out that the technology is decades from allowing users to read others’ thoughts and intentions, as portrayed in such sci-fi classics as “Brainstorm”, in which scientists recorded a person’s sensations so that others could experience them.

In their latest experiment, researchers say they have solved a much more difficult problem by actually decoding brain signals generated by moving pictures. Previously, Gallant and fellow researchers recorded brain activity in the visual cortex while a subject viewed black-and-white photographs. They then built a computational model that enabled them to predict with overwhelming accuracy which picture the subject was looking at.

“Our natural visual experience is like watching a movie” said Shinji Nishimoto, lead author of the study and a post-doctoral researcher in Gallant’s lab. “In order for this technology to have wide applicability, we must understand how the brain processes these dynamic visual experiences.” 

Nishimoto and two other research team members served as subjects for the experiment, because the procedure requires volunteers to remain still inside the MRI scanner for hours at a time.

They watched two separate sets of Hollywood movie trailers, while fMRI was used to measure blood flow through the visual cortex, the part of the brain that processes visual information. On the computer, the brain was divided into small, three-dimensional cubes known as volumetric pixels, or “voxels”.

“We built a model for each voxel that describes how shape and motion information in the movie is mapped into brain activity” Nishimoto said.

The brain activity recorded while subjects viewed the first set of clips was fed into a computer program that learned, second by second, to associate visual patterns in the movie with the corresponding brain activity. 

Brain activity evoked by the second set of clips was used to test the movie reconstruction algorithm. This was done by feeding 18 million seconds of random YouTube videos into the computer program so that it could predict the brain activity that each film clip would most likely evoke in each subject.

Finally, the 100 clips that the computer program decided were most similar to the clip that the subject had probably seen were merged to produce a blurry yet continuous reconstruction of the original movie.

Reconstructing movies using brain scans has been challenging because the blood flow signals measured using fMRI change much more slowly than the neural signals that encode dynamic information in movies, researchers said. For this reason, most previous attempts to decode brain activity have focused on static images.

“We addressed this problem by developing a two-stage model that separately describes the underlying neural population and blood flow signals” Nishimoto said.

Ultimately, Nishimoto said, scientists need to understand how the brain processes dynamic visual events that we experience in everyday life.

“We need to know how the brain works in naturalistic conditions” he said. “For that, we need to first understand how the brain works while we are watching movies”.

Other coauthors of the study are Thomas Naselaris with UC Berkeley’s Helen Wills Neuroscience Institute, An T. Vu with UC Berkeley’s Joint Graduate Group in Bioengineering; and Yuval Benjamini and Professor Bin Yu with the UC Berkeley Department of Statistics.

Source: Journal Current Biology

Transforming drug delivery

Ellis Meng, an associate professor of biomedical and electrical engineering at the USC Viterbi School of Engineering, stands at the bold crossroads of medical research. She seeks new ways to deliver and monitor drugs for patients through nanotechnology and wireless communication.

Through a grant from the U.S. Army Telemedicine and Advanced Technology Research Center (TATRC) and Qualcomm Wireless Health, Meng is working on a system for chronic pain medication for Army veterans, ultimately allowing them to return home and to productive lives.

“It is a challenge to monitor and control chronic pain in patients,” Meng said. “The patient often has to return to the doctor to adjust and assess the pain medication, and doctors need to ensure that pain medications are being delivered consistently and with the right dosage.”

Meng’s team is developing and testing an implanted drug delivery device connected to a wireless network by an external controller for remote monitoring and modification of drug dosage levels. The infusion pumps will allow physicians to track compliance and control of drug delivery regimens in patients remotely.

The challenge for Meng’s team is twofold: develop small, effective drug delivery systems and find ways for those systems to communicate wirelessly with health care teams. Current pumps used to administer drugs for chronic pain are the size of a hockey puck; Meng is developing pumps that are the size of three quarters stacked together - and they can be even smaller, if necessary.

The tiny pumps she is developing are more accurate and have a smaller footprint but similar capacities than traditional pumps. Meng’s goal is to revolutionize drug delivery by delivering the right dose at the right time and place so that patients can receive the maximum benefit without side effects.

The implications of Meng’s research extend well beyond chronic pain. The new medical frontier is moving toward targeted, specialized treatments for conditions ranging from eye disease to cancer to epilepsy. Her research could be used, for example, to deliver drugs directly to tumors for cancer patients or treatments for neurological disease that could avoid traditional and risky surgery.

“We are working to break the mold of what’s been done conventionally in terms of drug delivery - it doesn’t make sense to take a drug orally when a problem is very localized,” Meng said.

The TATRC/Qualcomm Wireless Health Innovation Challenge represents an important step for Meng and her colleagues in the ongoing quest to transform health care through engineering. “The challenge awardees are pioneering new breakthroughs in health science that could significantly benefit the U.S. military community,” said Don Jones, vice president of wireless health strategy and market development at Qualcomm Labs. “Qualcomm is pleased to help enable these important research projects, which align closely with our goal of speeding the diagnosis, treatment and self-management of health conditions via cellular wireless networks.”


Source: USC Viterbi School of Engineering

IBV evaluates the anthropometric data of Cristiano Ronaldo

The Institute of Biomechanics of Valencia (IBV) is the only Spanish research center has participated in a documentary that examines the physical and mental qualities of Cristiano Ronaldo.

Specifically, the IBV researcher, Dr. Luis Garcés, has scanned Cristiano Ronaldo in three dimensions to obtain its anthropometric measurements. The data obtained from Ronaldo confirmed that his body balance of height and muscle mass are those that allow him to excel different aspects as such as jumping, speed or kicking the ball.

The 3D data was performed with a cabin that records by an optical system the body three-dimensional surface. This technology allows to obtain hundreds of thousands of points on the body surface in seconds without coming into contact with him.

According to the researcher Luis Garcés, Cristiano Ronaldo concentrates muscle mass on the trunk and thighs, making the mass of the lower extremities relatively minor compared to the athletes of the same height.

This is a competitive advantage because allows Ronaldo to move faster to run, jump or kick the ball with less physical demands. Furthermore, "he excels for having a high center of gravity, ie, long thin legs in relation to the mass of his torso. These characteristics are similar to the sprinter Usain Bolt. Thanks to them, it achieves a greater stride length and powerful motion of the lower limbs".

The Institute of Biomechanics of Valencia is a research center that has become an international expert in anthropometric characterization of the population and the transfer of this information to the ergonomic design of products. Since 1994 it has worked on the creation of Spanish and European population anthropometric databases and its application in the development of tools design and ergonomic evaluation of products.

In addition, the IBV provides an Athlete Evaluation Service that uses a set of biomechanical tests and technological tools, applied to the analysis and study of the many variables surrounding the sport. These tests allow IBV to assess the athlete's physical condition and offering the possibility of obtaining the evolution of different objective variables of interest to improve the athlete training.

Source: Institute of Biomechanics of Valencia (IBV)

New MRI technique could mean fewer breast biopsies in high-risk women

A University of Wisconsin-Madison biomedical engineer and colleagues have developed a method that, applied in MRI scans of the breast, could spare some women with increased breast cancer risk the pain and stress of having to endure a biopsy of a questionable lump or lesion.

The universal technology will give radiologists greater confidence in visually classifying a lesion as malignant or benign.

The American Cancer Society recommends that women with certain breast cancer risk factors - including inherited genetic mutations, family or personal history of breast cancer, or previous radiation therapy to the chest - receive an annual MRI screening in addition to their yearly mammogram.

During a breast MRI, which lasts about a half hour, the technician injects a contrast agent into a vein in the patient's arm. Over time, the contrast agent flows throughout the body, including the breasts. Because they are growing quickly, cancerous lesions often have immature vasculature, and the contrast agent flows in and "leaks" out quickly. Conversely, benign lesions show more gradual in and out flow.

"The tricky ones are the ones that enhance quickly and then fall off more slowly," says Wally Block, a UW-Madison associate professor of biomedical engineering and medical physics. "Many of these lesions turn out to be difficult to classify and lead to biopsy."

Yet, it turns out that with the right kind of MRI scan, radiologists can visually identify a cancerous lesion based on characteristics about its shape. For example, breaks or interruptions in a lesion can indicate a benign fibroadenoma. Lumps with smooth edges often are benign, while those with jagged edges can signal cancer.

To generate the kind of crisp, three-dimensional images necessary for such a diagnosis, Block, UW-Madison radiology associate professor Fred Kelcz and graduate student Catherine Moran are capitalizing on their unique MRI data-acquisition method.

An MR image is made up of thousands of smaller pieces of information. The conventional data-acquisition method gathers that information slowly, and it's designed to be viewed from a single imaging plane. "What people do now is they compromise," says Block. "They don't get resolution in the other planes to make it a reasonable scan time. We found a way around that."

With the team's powerful technique, an MRI machine acquires data radially and generates a high-resolution, three-dimensional image that radiologists can turn, slice and view from many perspectives - enabling them to study a lesion's physical characteristics more carefully. Machines equipped with the technique also acquire more data in less time.

In addition, the method also makes it possible for radiologists to view fat images and water images separately, which is particularly useful because fat composes a large portion of the breast. "Rarely is disease associated with fat," says Block. "Most of the time radiologists are concentrating on water images, but sometimes our fat images of the breast are also useful. The boundaries of a lesion often stand out very clearly when embedded in fat."

Block and his colleagues currently are gathering data on the efficacy of the technique. They have tested the method on 20 patients at the University of Wisconsin Hospital and have shared it with colleagues at the University of Toronto for additional assessment. They also are working with Michigan State University researchers to test the technique.

Collaborating with Scott Reeder, a UW-Madison assistant professor of biomedical engineering and radiology, Block and colleagues also are refining ways to image both breasts simultaneously — a development that could slash scan time and free valuable MRI space for additional patients. "If you have a screening procedure that you want people to participate in regularly, you want to make it convenient for them," says Block.

Funding from the Wallace H. Coulter Translational Research Partnership in biomedical engineering at UW-Madison supported the research, as well as grants and in-kind support from GE Healthcare. In addition to Block, Kelcz, Moran and Reeder, UW-Madison collaborators also include research scientist Alexey Samsonov and assistant researcher Ethan Brodsky.

Source: University of Wisconsin-Madison

Drug-loaded brain electrode could prevent seizures

Neuroscientists implant microelectrode arrays in brains to eavesdrop on - and sometimes influence - the electrical activity of neurons. Why not chemically influence the brain alongside this electrical manipulation, thought Xinyan Tracy Cui at the University of Pittsburgh, Pennsylvania, and her colleagues.

A new polymer-covered electrode has the potential to monitor and deliver drugs to out-of-sync brain cells. If trials in animals are successful, it could one day help people to control epilepsy.

So the team coated microelectrodes with an electrically conductive polypyrrole film. Then they loaded pockets within the film with different drugs and neurotransmitters such as glutamate, GABA and dopamine, and attached the arrays to samples of rat brain tissue.Applying an electrical current to the polymer caused it to change shape and release its drug cargo, which then acted on surrounding cells. Cui is currently working on replicating this demonstration in living rodents.

Polypyrrole-coated microelectrode arrays, like ordinary arrays, could not only monitor neurons for unusual electrical activity but also deliver electrical impulses to keep neurons firing at the right tempo, like the brain pacemakers sometimes used to treat epilepsy. With the polypyrrole coating, however, microelectrode arrays could release drugs when they detect unusual activity – such as the haphazard electrical firing that characterises a seizure. Because electrodes reach into specific regions of the brain, the drugs would affect only neighbouring neurons.

"Theoretically you could use the electrode arrays to monitor neural activity and once you detect a sign of a seizure you could pump anticonvulsive drugs at just the right location," Cui says.

One difficulty, however, is that once the polymer sheds its drugs it has no more to offer. One solution might be to add carbon nanotubes as drug reservoirs.

"We have the proof of concept for a simple but powerful technology that can be used with a variety of different drugs or biochemical molecules," Cui says. "Because of its versatility, the potential applications are limitless."

Saleem Nicola at the Albert Einstein College of Medicine in New York City says he is impressed with the study, but notes that in Cui's tests some of the powerful drugs that inhibit neural activity did not seem as effective as one might expect, although it is unclear why.

"In theory it's a great idea, but ultimately we want to see it working in electrodes implanted in the brain for a fair amount of time," he says. "This is a first pass, but it could be extremely powerful if it lives up to its promise."

Source: Journal of Neural Engineering

Subdermal sensor for glucose monitoring through its brightness level

Researchers at the Institute of Industrial Science at the University of Tokyo have found a way to monitor glucose levels using tiny implanted wireless fluorescent sensors that glow relative to blood sugar levels. Considering that nearly 26 million people in the United States have diabetes, this is big news for those who would love to do away with bothersome finger pricks.

While others have looked for ways to monitor glucose concentrations using subdermal sensors, no one has been able to create one that can be implanted and left under a person’s skin over an extended period. Studies reported that this sensor is better than existing subdermal glucose sensors that are limited by poor accuracy, stability and are oxygen dependent.

The Japanese researchers found that the polyethylene glycol (PEG)-bonded polyacrylamide (PAM) hydrogel fibers they used reduced inflammation compared with regular PAM hydrogel fibers. They also found that the sensor continuously responded to blood glucose concentration changes for up to 140 to 160 days, showing its potential application for long-term in vivo continuous glucose monitoring.

According to the same studies, further calibration and testing of the sensor is needed, but the researchers hope their findings will foster the development of long-term, fluorescent, implanted continuous glucose sensors that can be used in people.

The study was published online earlier this month in the Proceedings of the National Academy of Sciences.

Source: Exame Informática

Teenager receives the world's most advanced bionical hand

A teenage racing fan got a helping hand from his favorite Formula One team - literally.

Matthew James, 14,  was born without a left hand and unable to afford a costly top-of-the-line prosthetic hand that could do more than the claw-like prosthesis that he had been using. So last June the Wokingham, England, boy wrote to Mercedes F1 boss Ross Brawn to ask for help, joking that in exchange for "sponsoring" the hand, he'd plaster the prosthesis with Mercedes ads.

Matthew's condition isn't particularly rare. About one in 20 children are born with some sort of congenital hand "differences," according to the American Society for Surgery of the Hand. In addition to missing hands, common defects include webbed fingers and missing or extra fingers (a condtion known as polydactyly).

But Brawn's team came through for Matthew anyway. It struck a deal with Touch Bionics, the Scottish firm that makes the $40,000 prosthesis, to fit the teen with one.

What does Matthew say about his new i-LIMB Pulse prosthesis?

"It is just amazing," he told the Telegraph."'My old artificial hand was not great. It had a pretty basic open close mechanism similar to a clamp. But with this one I can do everything, it is just like the real thing."

The new hand attaches to Matthew's left wrist with a silicone socket and features an individual motor for each finger. That makes it much more like a real hand. Matthew can use it to tie his shoelaces, catch a ball, and hold a pen to draw pictures, the Telegraph reported.

But the extra versatility isn't all good news for Matthew.

"Unfortunately, there's one downside to it," he told the BBC. "I'm having to do more chores."


 Source: CBS News

Electrocardiogram technology can reduce mistakes and runs on smart phones

Xiaopeng Zhao, assistant professor in the Department of Mechanical, Aerospace, and Biomedical Engineering at the University of Tennessee, Knoxville, developed an algorithm that improves the effectiveness of electrocardiograms, according to a university announcement.

Zhao - a BMES member - and his team of graduate and undergraduate students and physicians developed the award-winning technology.

The ECG is the most commonly performed screening tool for a variety of cardiac abnormalities. However, it is estimated that about 4 percent of all ECGs are taken with misplaced electrodes, leading to faulty diagnoses and mistreatments, according to the announcement.

Zhao’s algorithm examines interferences that result from electrode misplacement and disturbances, including patient motion and electromagnetic noise. Unlike conventional algorithms used to evaluate ECGs, Zhao’s algorithm is more reliable because it is based on a matrix which simultaneously tests for irregular patterns caused by such interferences. Therefore, instead of a typical “yes-no” type of classification result, Zhao’s produces a more accurate A-F letter grade of the ECG that targets specific weaknesses in the test. The algorithm also makes recommendations as to where to accurately place the electrodes.

Zhao’s team has implemented the algorithm in a java program, which can be installed and operated on a smart phone. The program takes only a split second to execute on a smartphone and assess a ten-second ECG. The speed is key in situations where a second can mean the difference between life and death

The goal is for users in remote areas to be able to know which ECGs are accurate to decrease misdiagnoses and ultimately save lives. The algorithm is also helpful in intensive care units where medical staff may be overworked, as well as for novice health professionals.

“There is a large population that does not receive good health care because they live in rural communities,” said Zhao. “This algorithm helps to bring the doctor to their home through the help of mobile phone technology. We hope our invention brings their health care quality more in line with that of the developed world by reducing errors and improving the quality of ECGs.”

The algorithm recently won top honors in Physionet Challenge 2011 - two first-place finishes and one third-place finish.

Sponsored by the National Institutes for Health, Physionet and the annual Computing in Cardiology conference jointly host a series of challenge problems that are either unsolved or not well-solved. Starting in 2000, a new challenge topic is announced each year, aiming to stimulate work on important clinical problems and to foster rapid progress towards their solution.

Zhao and his team will receive an award of $2,000 and present their work at the Computing in Cardiology 2011 conference on September 18-21, at Hangzhou, China. (For further information, http://physionet.org/challenge/ )

This work was in part supported by the National Science Foundation and the National Institute for Mathematical and Biological Synthesis (NIMBioS). Zhao worked with graduate students Henian Xia, Joseph McBride, Adam Sullivan, and Thibaut De Bock, undergraduate student Gabriel Garcia, and physicians Dr. Jujhar Bains and Dr. Dale Wortham.


Source: Biomedical Engineering Society