Brain development does not occur uniformly across the brain, but follows a newly identified developmental sequence, according to a new Penn Medicine study. Brain regions that support cognitive, social, and emotional functions appear to remain malleable—or capable of changing, adapting, and remodeling—longer than other brain regions, rendering youth sensitive to socioeconomic environments through adolescence. The findings are published in Nature Neuroscience.
Researchers charted how developmental processes unfold across the human brain from the ages of 8 to 23 years old through magnetic resonance imaging (MRI). The findings indicate a new approach to understanding the order in which individual brain regions show reductions in plasticity during development.
Brain plasticity refers to the capacity for neural circuits—connections and pathways in the brain for thought, emotion, and movement—to change or reorganize in response to internal biological signals or the external environment. While it is generally understood that children have higher brain plasticity than adults, this study provides new insights into where and when reductions in plasticity occur in the brain throughout childhood and adolescence.
The findings reveal that reductions in brain plasticity occur earliest in “sensory-motor” regions, such as visual and auditory regions, and occur later in “associative” regions, such as those involved in higher-order thinking (problem solving and social learning). As a result, brain regions that support executive, social, and emotional functions appear to be particularly malleable and responsive to the environment during early adolescence, as plasticity occurs later in development.
“Studying brain development in the living human brain is challenging. A lot of neuroscientists’ understanding about brain plasticity during development actually comes from studies conducted with rodents. But rodent brains do not have many of what we refer to as the association regions of the human brain, so we know less about how these important areas develop,” says corresponding author Theodore D. Satterthwaite,the McLure Associate Professor of Psychiatry in the Perelman School of Medicine, and director of the Penn Lifespan Informatics and Neuroimaging Center (PennLINC).
Lydon-Staley started out studying English and Psychology in his undergraduate education, going on to pursue a Ph.D. from Penn State University in Human Development and Family Studies. What brought him to Bassett’s lab was his interest in using cognitive neuroscience to understand the brain patterns and behaviors behind substance abuse and addiction. There, Lydon-Staley examined networks of nicotine withdrawal behaviors, how those behaviors impact each other, and what information they might hold about how to help smokers in their quit attempts. “David’s breadth of interest is only rivalled by his expansive expertise and bottomless enthusiasm,” says Bassett. “I feel incredibly lucky to have had the chance to work with him.”
In his new role at Annenberg, Lydon-Staley will launch the Addiction, Health, and Adolescence Lab, or “AHA!” for short. “My recent work examines engagement with new media during the course of daily life, and how the information sought and encountered relates to both curiosity and substance use,” he says. Lydon-Staley’s new lab will use methods like experience-sampling and functional Magnetic Resonance Imaging to understand brain and behavior, while drawing on theories and tools from communication, psychology, cognitive neuroscience, network science, and more.
Even though Lydon-Staley will be working out of a new school at Penn, he still has plans to continue collaborating with the Bassett Lab. One ongoing project he has with the lab involves studying how curiosity works in everyday life, and another looks at moment-to-moment patterns of cigarette withdrawal in daily smokers. “Working in the Bassett Lab gave me the confidence and ability to stretch my wings, chase ideas across traditional disciplinary lines, learn new skills, and collaborate with creative and capable scientists every day,” says Lydon-Staley. Those are opportunities he hopes to keep chasing and fostering in his new position.
Beyond continuing his prior research from a communication-based angle, Lydon-Staley is also excited to develop new classes in the Annenberg School. “Annenberg is a very special place. It is an active school, with frequent seminars and many vibrant research centers,” he says. Informed and inspired by the breadth of research from Annenberg scholars, Lydon-Staley hopes that he can create classes that focus on the psychology of time and timing in everyday life—topics that he spends a lot of time thinking about himself.
Above all, Lydon-Staley is excited by the opportunity to stay at Penn and continue the kind of versatile and multi-faceted studies that have been the bedrock of his research so far. He hopes to continue expanding his previous work with not only the Engineering School, but the School of Medicine and the Graduate School of Education as well. “The opportunities for interdisciplinary collaboration at Penn are unrivaled, and I am constantly in awe of the quality of students here.”
Seven-tesla MRI of the porcine mitral valve showing the papillary muscle (PM) and chordae tendinae (CT).
Since its invention in the early 1970s, magnetic resonance imaging (MRI) has played an increasingly important role in the diagnosis of illness. In addition, over time, the technology of MRI has evolved enormously, with the ability to render more detailed three-dimensional images using stronger magnetic fields . However, imaging tissues under mechanical loads (e.g., beating heart, lung breathing) are still difficult to image precisely with MRI.
A new study in PLOS One, led by Morten Jensen, Ph.D., of the University of Arkansas, breaks an important technical barrier in high resolution imaging for tissues under mechanical load. Using 3D-printed mounting hardware and 7-tesla MRI, this group produced some of the highest quality images yet produced of the mitral valve exposed to physiological pressures (see above). In the longer term, this method could point to new corrective surgical procedures that would greatly improve the repair procedures for mitral valves.
Oncology Breakthroughs
Among the most significant challenges faced by surgical oncologists is developing a ‘clear margin,’ meaning that the tissue remaining after tumor excision is free of any tumor cells. If the margins are not free of tumor cells, the cancer is more likely to recur. However, until now, it has been impossible to determine if cancer cells were still present in tissue margins before finishing surgery because of the time required to test specimens.
At the University of Texas, Austin, however, scientists are getting closer to overcoming this obstacle. In a recent study published in Science Translational Medicine, this team of scientists presents the MasSpecPen — short for mass spectrometry pen. This device is capable of injecting a tiny drop of water into tissue, extracting the water after it mixes with the tissue, and quickly analyzing the sample’s molecular components. The authors, who included biomedical engineering faculty member Thomas E. Milner, Ph.D., tested the device using ex vivo samples from 253 patients with different varieties of cancer, including breast, lung, and thyroid cancers. The MasSpecPen provided sensitivity, specificity, and accuracy exceeding 96% in all cases. Although it has yet to be tested intraoperatively, if effective under those conditions, the device could become an essential part of the surgeon’s arsenal.
If the MasSpecPen could render surgical treatment of cancer more effective, a device developed at SUNY Buffalo could help doctors diagnose lung cancer earlier. Lung cancer is a particularly deadly variety of cancer because patients don’t feel any discomfort until the cancer has spread to other areas of the body. In collaboration with Buffalo’s Roswell Park Center Institute, microchip manufacturer Intel, and local startup Garwood Medical Devices, a team of scientists, including Professor Edward P. Furlani, Ph.D., from Buffalo’s Department of Chemical and Biomedical Engineering, was awarded a grant from the National Science Foundation to develop a subcutaneous implant incorporating a nanoplasmonic biochip to detect biomarkers of lung cancer. A wearable smart band would receive data from the biochip and would act as an early warning system for lung cancer. The biomarkers selected for the biochip would optimally predict lung cancer risk much earlier than the metastasis stage. If the system that the team develops is successful in diagnosing lung cancer before it spreads, it could greatly improve survival and cure rates.
Feverish Growth
Worldwide but particularly in the Global South, malaria remains a major public health concern. According to a Global Burden of Disease study in 2015, there were nearly 300 million cases of the disease in a single year, with 731,000 fatalities. One of the earliest treatments to combat malaria was invented by British colonialists, who added quinine to the tonic used in the gin and tonic cocktail. More recently the drug artemisinin was developed for fighting malaria. However, this drug and its derivatives are very expensive. The primary reason for this cost is that the drug is extracted from the sweet wormwood plant, which is in short supply. In hopes of producing a greater supply of artemisinin, scientists collaborating among Denmark, Malaysia, and the Netherlands report in Frontiers in Bioengineering and Biotechnology that transplanting the genes responsible for producing atremisinin into Physcomitrella patens, a common moss, led to a much faster production rate of the drug than what is possible with the wormwood plant. The process proved simpler and less expensive than earlier attempts to transplant genes into tobacco plants. If this potential is harnessed correctly, it could make an enormous difference in lessening the global burden of malaria.
Understanding Fear
We’ve known for years about the flight-or-fight response — the adrenergic response of our bodies to danger, which we share in common with a number of other animals. Once the decision to flee is made, however, we know far less about what determines the escape strategy used. According to Malcolm A. MacIver, professor of biomedical engineering and mechanical engineering in Northwestern University’s McCormick School of Engineering, part of the escape strategy depends on how far away the attacker is. In a paper he coauthored that was published in Current Biology, Dr. MacIver studied threat responses in larval zebrafish and found that a fast-looming stimulus produced either freezing or escape at a shorter interval following the threat perception; when the perceived threat was slow looming, longer latency following the perception of the threat was seen, resulting in a greater variety of types of escape behaviors. While it might seem a giant leap between observing behaviors in fish and higher life forms, the basic mechanism in the “oldest” parts of the brain, from an evolutionary standpoint, are less different than we might think.
People and Places
The University of Maryland has announced that construction on a new building to serve as the home of its Department of Bioengineering will be finished by the end of September. The building is to be named A. James Clark Hall, after a builder, philanthropist, and alumnus of Maryland’s School of Engineering. Further south, George Mason University in Fairfax, Va., has announced that the new chair of its Department of Engineering there will be Michael Buschmann, Ph.D., an alumnus of MIT and faculty member since the 1990s at École Polytechnique in Montreal. Congratulations, Dr. Buschmann!
