MIT News - School of Science MIT News is dedicated to communicating to the media and the public the news and achievements of the students, faculty, staff and the greater MIT community. en Tue, 10 Mar 2020 00:00:00 -0400 How the brain encodes landmarks that help us navigate Neuroscientists discover how a key brain region combines visual and spatial information to help us find our way. Tue, 10 Mar 2020 00:00:00 -0400 Anne Trafton | MIT News Office <p>When we move through the streets of our neighborhood, we often use familiar landmarks to help us navigate. And as we think to ourselves, “OK, now make a left at the coffee shop,” a part of the brain called the retrosplenial cortex (RSC) lights up.</p> <p>While many studies have linked this brain region with landmark-based navigation, exactly how it helps us find our way is not well-understood. A new study from MIT neuroscientists now reveals how neurons in the RSC use both visual and spatial information to encode specific landmarks.</p> <p>“There’s a synthesis of some of these signals — visual inputs and body motion — to represent concepts like landmarks,” says Mark Harnett, an assistant professor of brain and cognitive sciences and a member of MIT’s McGovern Institute for Brain Research. “What we went after in this study is the neuron-level and population-level representation of these different aspects of spatial navigation.”</p> <p>In a study of mice, the researchers found that this brain region creates a “landmark code” by combining visual information about the surrounding environment with spatial feedback of the mice’s own position along a track. Integrating these two sources of information allowed the mice to learn where to find a reward, based on landmarks that they saw.</p> <p>“We believe that this code that we found, which is really locked to the landmarks, and also gives the animals a way to discriminate between landmarks, contributes to the animals’ ability to use those landmarks to find rewards,” says Lukas Fischer, an MIT postdoc and the lead author of the study.</p> <p>Harnett is the senior author of the study, which appears today in the journal <em>eLife</em>. Other authors are graduate student Raul Mojica Soto-Albors and recent MIT graduate Friederike Buck.</p> <p><strong>Encoding landmarks</strong></p> <p>Previous studies have found that people with damage to the RSC have trouble finding their way from one place to another, even though they can still recognize their surroundings. The RSC is also one of the first areas affected in Alzheimer’s patients, who often have trouble navigating.</p> <p>The RSC is wedged between the primary visual cortex and the motor cortex, and it receives input from both of those areas. It also appears to be involved in combining two types of representations of space — allocentric, meaning the relationship of objects to each other, and egocentric, meaning the relationship of objects to the viewer.</p> <p>“The evidence suggests that RSC is really a place where you have a fusion of these different frames of reference,” Harnett says. “Things look different when I move around in the room, but that’s because my vantage point has changed. They’re not changing with respect to one another.”</p> <p>In this study, the MIT team set out to analyze the behavior of individual RSC neurons in mice, including how they integrate multiple inputs that help with navigation. To do that, they created a virtual reality environment for the mice by allowing them to run on a treadmill while they watch a video screen that makes it appear they are running along a track. The speed of the video is determined by how fast the mice run.</p> <p>At specific points along the track, landmarks appear, signaling that there’s a reward available a certain distance beyond the landmark. The mice had to learn to distinguish between two different landmarks, and to learn how far beyond each one they had to run to get the reward.</p> <p>Once the mice learned the task, the researchers recorded neural activity in the RSC as the animals ran along the virtual track. They were able to record from a few hundred neurons at a time, and found that most of them anchored their activity to a specific aspect of the task.</p> <p>There were three primary anchoring points: the beginning of the trial, the landmark, and the reward point. The majority of the neurons were anchored to the landmarks, meaning that their activity would consistently peak at a specific point relative to the landmark, say 50 centimeters before it or 20 centimeters after it.</p> <p>Most of those neurons responded to both of the landmarks, but a small subset responded to only one or the other. The researchers hypothesize that those strongly selective neurons help the mice to distinguish between the landmarks and run the correct distance to get the reward.</p> <p>When the researchers used optogenetics (a tool that can turn off neuron activity) to block activity in the RSC, the mice’s performance on the task became much worse.</p> <p><strong>Combining inputs</strong></p> <p>The researchers also did an experiment in which the mice could choose to run or not while the video played at a constant speed, unrelated to the mice’s movement. The mice could still see the landmarks, but the location of the landmarks was no longer linked to a reward or to the animals’ own behavior. In that situation, RSC neurons did respond to the landmarks, but not as strongly as they did when the mice were using them for navigation.</p> <p>Further experiments allowed the researchers to tease out just how much neuron activation is produced by visual input (seeing the landmarks) and by feedback on the mouse’s own movement. However, simply adding those two numbers yielded totals much lower than the neuron activity seen when the mice were actively navigating the track.</p> <p>“We believe that is evidence for a mechanism of nonlinear integration of these inputs, where they get combined in a way that creates a larger response than what you would get if you just added up those two inputs in a linear fashion,” Fischer says.</p> <p>The researchers now plan to analyze data that they have already collected on how neuron activity evolves over time as the mice learn the task. They also hope to perform further experiments in which they could try to separately measure visual and spatial inputs into different locations within RSC neurons.</p> <p>The research was funded by the National Institutes of Health, the McGovern Institute, the NEC Corporation Fund for Research in Computers and Communications at MIT, and the Klingenstein-Simons Fellowship in Neuroscience.</p> MIT neuroscientists have identified a “landmark code” that helps the brain navigate our surroundings.Image: Christine Daniloff, MITResearch, Brain and cognitive sciences, McGovern Institute, School of Science, Neuroscience, National Institutes of Health (NIH) Events postponed or canceled as MIT responds to COVID-19 Changes follow new Institute policies on travel, events, and visitors; some large classes to move online. Mon, 09 Mar 2020 14:48:39 -0400 MIT News Office <p>MIT schools, departments, labs, centers, and offices have acted swiftly to postpone or cancel large events through May 15 in the wake of the Institute’s <a href="">announcement last week</a> of new policies&nbsp;regarding gatherings likely to attract 150 or more people.</p> <p>To safeguard against COVID-19, and the spread of the 2019 novel coronavirus, many other MIT events have been modified both on campus and elsewhere, with increased opportunities offered for livestreaming.</p> <p>The guidelines put forth last week have also now been expanded to include some large classes: The Institute will move classes with more than 150 students online, starting this week.</p> <p><strong>Impacts on classes and student travel</strong></p> <p>Following consultation with senior academic leadership and experts within MIT Medical, the Institute has suspended in-person meetings of classes with more than 150 students, effective tomorrow, Tuesday, March 10. The approximately 20 classes impacted by the decision will continue to be offered in virtual form.</p> <p>“We are being guided by our medical professionals who are in close contact with state and national public health officials,” Ian Waitz, vice chancellor for undergraduate and graduate education, wrote today in a letter to deans and department heads. “They have advised us that while the risk to the community is low and there are no cases on campus as of now, we need to move quickly to help prevent the potential transmission of the disease and to be ready if and when it impacts our campus.”</p> <p>“Our approach is to be aggressive, but to move forward in stages,” Waitz added, “while keeping in mind that some individual faculty and departments may be moving faster than others, that the level of comfort with remote teaching varies, and that some classes may translate better than others to alternative formats.”</p> <p>As of now, midterm examinations will proceed as scheduled, but the plan for large courses is to run midterms in several rooms simultaneously so the number of students in each room remains well below 150. The Registrar’s Office is working on room scheduling strategies to best accommodate that approach.&nbsp;</p> <p>The Institute has also decided that all MIT-sponsored student domestic travel of more than 100 miles will have to go through the Institute’s high-risk travel waiver process.</p> <p><strong>Impacts on undergraduate and graduate admissions</strong></p> <p>As shared in President L. Rafael Reif’s <a href="">letter of last Thursday</a>, MIT’s new policy on events will apply to <a href="">Campus Preview Weekend</a>, ordinarily an on-campus gathering for students admitted to the incoming first-year undergraduate class. In the coming weeks, the Admissions Office will be connecting with admitted students, current students, and campus partners to discuss what to do instead of a conventional CPW. For more information, please see:&nbsp;<a href="" title=""></a></p> <p>The Admissions Office will not host any programming for K-12 students, including admitted students and their families, between now and May 15, regardless of the size of the event.&nbsp;All scheduled admissions sessions and tours have been canceled between now and May 15, and MIT Admissions is canceling all scheduled admissions officer travel to domestic and international events in that time window.&nbsp;</p> <p>Additionally, all graduate admissions visit days have been canceled, effective immediately.&nbsp;“Based upon reducing risk, we ask all departments to cancel all remaining graduate open houses and visit days, and to move to virtual formats,” Waitz says. “Many departments have already done this.”</p> <p>Despite the cancellation of these formal events, the MIT campus currently remains open for visits by prospective students. However, in keeping with suggested best practices for public health, visitors from countries that the U.S. Centers for Disease Control and Prevention (CDC) finds&nbsp;<a href="">have “widespread sustained (ongoing) transmission” of COVID-19</a> cannot visit campus until they have successfully completed 14 days of self-quarantine.</p> <p><strong>Impacts on major campus events</strong></p> <p>The <strong>MIT Excellence Awards and Collier Medal</strong> celebration, scheduled for this Thursday, March 12, has been postponed; a rescheduled date will be announced as soon as it is confirmed. The Excellence Awards and Collier Medal recognize&nbsp;the work of service, support, administrative, and sponsored research staff. The Excellence Awards acknowledge the extraordinary efforts made by members of the MIT community toward fulfilling the goals, values, and mission of the Institute. The Collier Medal is awarded to an individual or group exhibiting qualities such as a commitment to community service, kindness, selflessness, and generosity; it honors the memory of MIT Police Officer Sean Collier,&nbsp;who lost his life&nbsp;while protecting the MIT campus.&nbsp;<a href="" title="">A full list of this year’s honorees is available</a>.</p> <p>Career Advising and Professional Development is working on plans to change the format of the <strong>Spring Career Fair</strong>, previously scheduled for April 2, to a virtual career fair for a date to be announced in April. All other large-scale employer engagement events — such as career fairs, mixers, symposiums, and networking events — will also be canceled; adopt a virtual model; be postponed beyond May 15; or adopt other models that meet the new policies involving large events.&nbsp;</p> <p>MIT is postponing the remaining two <strong>Climate Action Symposia</strong>, “<a href="">MIT Climate Initiatives and the Role of Research Universities</a>” and “<a href="" title="">Summing Up: Why Is the World Waiting?</a>” — previously scheduled for April 2 and April 22, respectively. These symposia will be rescheduled; new dates will be announced on <a href="applewebdata://7840DF2E-F494-42B9-B4DA-510B4A5DE3D9/" title=""></a>.&nbsp;</p> <p><strong>Solve at MIT</strong> on May 12-14 will be virtual. In addition to a livestream on <a href="">this page</a>, Solve will continue to bring together its cross-sector community via interactive online workshops and more. Participants can also contribute&nbsp;<a href="">a solution</a>&nbsp;or&nbsp;<a href="">a donation</a>&nbsp;to the&nbsp;<a href="">Health Security and Pandemics Challenge</a>.</p> <p><strong>Impacts on athletics and intercollegiate athletics events</strong></p> <p>The Department of Athletics, Physical Education and Recreation (DAPER) is taking steps to safeguard student-athletes, staff, and community members who utilize DAPER facilities for club sports, intramurals, and recreation. Unless otherwise announced, MIT’s intercollegiate athletics events will continue as scheduled. However, visiting teams are asked to bring only student-athletes and essential team personnel to events at MIT. </p> <p>Additionally, DAPER has requested that only MIT students, faculty, and staff members attend upcoming home athletic events through May 15. All other spectators, including parents, are asked to watch events using&nbsp;<a href="" target="_blank">DAPER’s video streaming service</a>.</p> <p><strong>Other impacted events and activities</strong></p> <p>Discussions are ongoing about many additional events scheduled between now and May 15. The list below will be updated as more information becomes available. Among the affected events and activities announced so far:</p> <ul> <li>Use of the pillars in Lobby 7 for community discussion is suspended for the rest of the spring semester, to minimize close contact and sharing of writing implements.</li> <li><strong>SpaceTech 2020,</strong>&nbsp;scheduled for Wednesday, March 11, has been postponed until a later date. The all-day event, part of MIT Space Week, will highlight the future of space exploration by featuring lightning talks from current students; talks and panels from alumni; and an interactive guided tour along the Space Trail to visit Department of Aeronautics and Astronautics (AeroAstro) labs and ongoing research projects. Visit <a href=""></a> for the latest information.</li> <li><strong>MIT Getfit has</strong> canceled both of its midpoint events originally scheduled for Wednesday, March 11. Organizers are working to contact participants with more information.</li> <li>The March 13 lecture titled<strong> “Fateful Triangle: How China Shaped US-India Relations During the Cold War,” </strong>by Tanvi Madan of the Brookings Institution, has been postponed. More information is available at <a href="" target="_blank" title=""></a>.</li> <li><strong>To the Moon to Stay Hackathon</strong>, scheduled for Saturday, March 14, has been postponed until a later date. MIT AeroAstro and the MIT Media Lab’s Space Exploration Initiative are partnering to design and build an experiment to go to the moon on board Blue Origin’s inaugural lunar mission. The goal of the hackathon is to bring the MIT community together to think about lunar missions and habitation through a variety of challenges. To receive updates,&nbsp;<a href="">join their email list</a>&nbsp;or visit <a href=""></a>.</li> <li>The Koch Institute is limiting attendance at the&nbsp;<a href="">SCIENCE with/in/sight: 2020 Visions</a>&nbsp;event on March 17. This event is now for invited guests only.</li> <li>All <a href="">MIT Communications Forum</a> events have been postponed until the fall. This includes <a href="">Science Under Attack</a>, originally scheduled for March 19, and <a href="">David Thorburn’s presentation</a> as part of the William Corbett Poetry Series, originally scheduled for April 8.</li> <li>The <strong>MIT de Florez Award Competition</strong>,&nbsp;scheduled for April 15, will be conducted virtually. Additional information will be sent to the Mechanical Engineering community via email.&nbsp;</li> <li><strong>The Mechanical Engineering Graduate Student Gala</strong>,&nbsp;scheduled for April 19, has been canceled and will be rescheduled for the fall.</li> <li>The <strong>Mechanical Engineering Student Awards Banquet</strong>,&nbsp;scheduled for May 15, has been canceled. Awards will be announced virtually.</li> <li>The&nbsp;<a href="" title="">Office of Engineering Outreach Programs</a>&nbsp;(OEOP) has canceled its&nbsp;<a href="">SEED Academy program</a>&nbsp;through May 15. This includes the SEED Academy Spring Final Symposium on May 9. OEOP will continue to communicate with SEED Academy students and parents via email and through The Sprout newsletter to offer information on course, project, and engagement options.</li> <li><strong>The 2020 Brazil Conference at MIT and Harvard</strong>&nbsp;has been canceled. More information can&nbsp;be found at&nbsp;<a href=""></a>.</li> <li>The March 12 Starr Forum, titled <strong>“Russia’s Putin: From Silent Coup to Legal Dictatorship,”</strong> has been changed to a <a href="">live webcast</a>.</li> <li>The March 13 Myron Weiner Seminar on International Migration, titled <strong>“Future Aspirations Among Refugee Youth in Turkey Between Integration &amp; Mobility,”</strong> has been canceled.</li> <li>The MIT Sloan&nbsp;School of Management is&nbsp;canceling all international study tours and treks. Student conferences are either being cancelled or modified: The March 7 <strong><a href="">Robo-AI Exchange Conference</a></strong>, the March 13 <strong><a href="">New Space Age</a> Conference</strong>, and the April 2 <strong><a href="">Golub Center for Finance and Policy</a> discussion</strong> on equity market structure with the SEC are canceled. The March 13<strong> <a href="">ETA Summit</a></strong> and the April 17 <strong><a href="">Ops Sim Competition</a> </strong>are proceeding, with virtualization. The March 16 <strong><a href="">Entrepreneurship and Innovation Alumni gathering</a></strong> in San Franciso is also canceled.</li> <li>The 2020 MIT Scholarship and UROP Brunch that was scheduled for April 4 has been canceled.</li> <li>The MIT Campaign for a Better World event in Toronto, originally set for April 29, will be postponed.</li> <li>The Program in Science, Technology, and Society’s <strong>Morison Lecture and Prize in Science, Technology, and Society,</strong> originally scheduled for April 14, 2020, 4 p.m.; E51-Wong Auditorium,&nbsp;has been rescheduled for Oct. 1, 2020.</li> <li>The Women's and Gender Studies Program's <a href="">Women Take the Reel Series</a> film event,"<strong>Warrior Women</strong>,” scheduled for March 12 at 6:30 p.m., has been postponed until fall 2020.</li> <li>The <strong>MIT Graduate Alumni Gathering</strong>, scheduled for March 20–21 in Cambridge, has been postponed, with plans for rescheduling to a later date in 2021.</li> <li>The <strong>MIT Student Alumni Association’s Dinner</strong> with 12 Strangers event series, set to be held in Cambridge and Boston, has been cancelled for the spring semester.</li> </ul> <p><em>This article will be updated as more information on impacted events becomes available.</em></p> Community, Faculty, Staff, Students, Administration, MIT Medical, Health, Chancellor, School of Engineering, School of Science, Sloan School of Management, School of Humanities Arts and Social Sciences, School of Architecture and Planning, Program in STS, Campaign for a Better World, Alumnai/ae A new model of vision Computer model of face processing could reveal how the brain produces richly detailed visual representations so quickly. Wed, 04 Mar 2020 14:00:00 -0500 Anne Trafton | MIT News Office <p>When we open our eyes, we immediately see our surroundings in great detail. How the brain is able to form these richly detailed representations of the world so quickly is one of the biggest unsolved puzzles in the study of vision.</p> <p>Scientists who study the brain have tried to replicate this phenomenon using computer models of vision, but so far, leading models only perform much simpler tasks such as picking out an object or a face against a cluttered background. Now, a team led by MIT cognitive scientists has produced a computer model that captures the human visual system’s ability to quickly generate a detailed scene description from an image, and offers some insight into how the brain achieves this.</p> <p>“What we were trying to do in this work is to explain how perception can be so much richer than just attaching semantic labels on parts of an image, and to explore the question of how do we see all of the physical world,” says Josh Tenenbaum, a professor of computational cognitive science and a member of MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and the Center for Brains, Minds, and Machines (CBMM).</p> <p>The new model posits that when the brain receives visual input, it quickly performs a series of computations that reverse the steps that a computer graphics program would use to generate a 2D representation of a face or other object. This type of model, known as efficient inverse graphics (EIG), also correlates well with electrical recordings from face-selective regions in the brains of nonhuman primates, suggesting that the primate visual system may be organized in much the same way as the computer model, the researchers say.</p> <p>Ilker Yildirim, a former MIT postdoc who is now an assistant professor of psychology at Yale University, is the lead author of the paper, which appears today in <em>Science Advances</em>. Tenenbaum and Winrich Freiwald, a professor of neurosciences and behavior at Rockefeller University, are the senior authors of the study. Mario Belledonne, a graduate student at Yale, is also an author.</p> <p><strong>Inverse graphics</strong></p> <p>Decades of research on the brain’s visual system has studied, in great detail, how light input onto the retina is transformed into cohesive scenes. This understanding has helped artificial intelligence researchers develop computer models that can replicate aspects of this system, such as recognizing faces or other objects.</p> <p>“Vision is the functional aspect of the brain that we understand the best, in humans and other animals,” Tenenbaum says. “And computer vision is one of the most successful areas of AI at this point. We take for granted that machines can now look at pictures and recognize faces very well, and detect other kinds of objects.”</p> <p>However, even these sophisticated artificial intelligence systems don’t come close to what the human visual system can do, Yildirim says.</p> <p>“Our brains don’t just detect that there’s an object over there, or recognize and put a label on something,” he says. “We see all of the shapes, the geometry, the surfaces, the textures. We see a very rich world.”</p> <p>More than a century ago, the physician, physicist, and philosopher Hermann von Helmholtz theorized that the brain creates these rich representations by reversing the process of image formation. He hypothesized that the visual system includes an image generator that would be used, for example, to produce the faces that we see during dreams. Running this generator in reverse would allow the brain to work backward from the image and infer what kind of face or other object would produce that image, the researchers say.</p> <p>However, the question remained: How could the brain perform this process, known as inverse graphics, so quickly? Computer scientists have tried to create algorithms that could perform this feat, but the best previous systems require many cycles of iterative processing, taking much longer than the 100 to 200 milliseconds the brain requires to create a detailed visual representation of what you’re seeing. Neuroscientists believe perception in the brain can proceed so quickly because it is implemented in a mostly feedforward pass through several hierarchically organized layers of neural processing.</p> <p>The MIT-led team set out to build a special kind of deep neural network model to show how a neural hierarchy can quickly infer the underlying features of a scene — in this case, a specific face. In contrast to the standard deep neural networks used in computer vision, which are trained from labeled data indicating the class of an object in the image, the researchers’ network is trained from a model that reflects the brain’s internal representations of what scenes with faces can look like.</p> <p>Their model thus learns to reverse the steps performed by a computer graphics program for generating faces. These graphics programs begin with a three-dimensional representation of an individual face and then convert it into a two-dimensional image, as seen from a particular viewpoint. These images can be placed on an arbitrary background image. The researchers theorize that the brain’s visual system may do something similar when you dream or conjure a mental image of someone’s face.</p> <p>The researchers trained their deep neural network to perform these steps in reverse — that is, it begins with the 2D image and then adds features such as texture, curvature, and lighting, to create what the researchers call a “2.5D” representation. These 2.5D images specify the shape and color of the face from a particular viewpoint. Those are then converted into 3D representations, which don’t depend on the viewpoint.</p> <p>“The model gives a systems-level account of the processing of faces in the brain, allowing it to see an image and ultimately arrive at a 3D object, which includes representations of shape and texture, through this important intermediate stage of a 2.5D image,” Yildirim says.</p> <p><strong>Model performance</strong></p> <p>The researchers found that their model is consistent with data obtained by studying certain regions in the brains of macaque monkeys. In a study published in 2010, Freiwald and Doris Tsao of Caltech recorded the activity of neurons in those regions and analyzed how they responded to 25 different faces, seen from seven different viewpoints. That study revealed three stages of higher-level face processing, which the MIT team now hypothesizes correspond to three stages of their inverse graphics model: roughly, a 2.5D viewpoint-dependent stage; a stage that bridges from 2.5 to 3D; and a 3D, viewpoint-invariant stage of face representation.</p> <p>“What we show is that both the quantitative and qualitative response properties of those three levels of the brain seem to fit remarkably well with the top three levels of the network that we’ve built,” Tenenbaum says.</p> <p>The researchers also compared the model’s performance to that of humans in a task that involves recognizing faces from different viewpoints. This task becomes harder when researchers alter the faces by removing the face’s texture while preserving its shape, or distorting the shape while preserving relative texture. The new model’s performance was much more similar to that of humans than computer models used in state-of-the-art face-recognition software, additional evidence that this model may be closer to mimicking what happens in the human visual system.</p> <p>“This work is exciting because it introduces interpretable stages of intermediate representation into a feedforward neural network model of face recognition,” says Nikolaus Kriegeskorte, a professor of psychology and neuroscience at Columbia University, who was not involved in the research. “Their approach merges the classical idea that vision inverts a model of how the image was generated, with modern deep feedforward networks. It’s very interesting that this model better explains neural representations and behavioral responses.”</p> <p>The researchers now plan to continue testing the modeling approach on additional images, including objects that aren’t faces, to investigate whether inverse graphics might also explain how the brain perceives other kinds of scenes. In addition, they believe that adapting this approach to computer vision could lead to better-performing AI systems.</p> <p>“If we can show evidence that these models might correspond to how the brain works, this work could lead computer vision researchers to take more seriously and invest more engineering resources in this inverse graphics approach to perception,” Tenenbaum says. “The brain is still the gold standard for any kind of machine that sees the world richly and quickly.”</p> <p>The research was funded by the Center for Brains, Minds, and Machines at MIT, the National Science Foundation, the National Eye Institute, the Office of Naval Research, the New York Stem Cell Foundation, the Toyota Research Institute, and Mitsubishi Electric.</p> MIT cognitive scientists have developed a computer model of face recognition that performs a series of computations that reverse the steps that a computer graphics program would use to generate a 2D representation of a face.Image: courtesy of the researchersResearch, Computer vision, Brain and cognitive sciences, Center for Brains Minds and Machines, Computer Science and Artificial Intelligence Laboratory (CSAIL), School of Science, School of Engineering, National Science Foundation (NSF), Artificial intelligence, Machine learning, Neuroscience Not your average science classroom MIT student volunteers host fifth annual Northeast Regional Middle School Science Bowl for over 100 middle schoolers. Wed, 04 Mar 2020 12:40:01 -0500 Fernanda Ferreira | School of Science <p>More than 100 middle schoolers gathered at MIT to compete in the annual&nbsp;<a href="">Northeast Regional Middle School Science Bowl</a>. The campus was filled with the sounds of buzzers going off, cheering, and lots of science, math, and engineering.</p> <p>The Saturday, Feb. 22, event brought together 24 teams from 11 middle schools in Massachusetts, Maine, and New Hampshire. The three teams representing the James F. Doughty School came from Bangor, Maine; they had to wake up at 4 a.m. to be on MIT’s campus in time to register for the competition.</p> <p>The middle school team from the Roxbury Latin School, an all-boys middle and high school in West Roxbury, Massachusetts, competed for the third time this year. According to Christopher Zhu, a senior at the school who leads the participating team’s weekly practices, the science bowl competitions are a great way to get middle schoolers involved in science. “I would say that one half of the people who do science bowl have a strong personal interest in science and the other half are trying things out,” says Zhu.</p> <p>“It’s not your stereotypical science classroom,” Zhu says. “It’s a fun and engaging competitive environment that a lot of the younger kids enjoy.” For Robert Moore, who coaches Roxbury Latin’s team, the appeal is the level of excitement generated. “It’s no different than a basketball tournament.”&nbsp;&nbsp;</p> <p>Those who have experienced the exhilaration of answering the right question and gaining points for their team find it hard to leave science bowl. The Northeast Regional was originated by former MIT undergraduate and alumna of the science bowl Kathleen Schwind. The event is now in its fifth year and, now that Schwind has graduated from MIT, was coordinated and executed by Paolo Adajar, a third-year majoring in mathematical economics; Alborz Bejnood, a computational biologist at the Broad Institute of MIT and Harvard; Andrew Gu, a second-year majoring in mathematics; Sujay Kazi, a third-year double majoring in mathematics and physics; Jushua Park, a second-year majoring in biological engineering; and Mihir Singhal, a second-year majoring in mathematics.</p> <p>“This is the only science bowl in the nation entirely run by veterans,” says Adajar, who adds that the majority of the volunteers are also alums. For many, organizing science bowl is their way to stay involved and give back to the competition that marked their middle and high school experiences. The MIT School of Science funds the event each year.</p> <p>The morning began with a series of round-robin style competitions, with the 24 teams divided into groups of six that play against each other, fielding questions from across the STEM universe. Each round involves a number of toss-up questions, which both teams can buzz to answer. These questions are heavily guarded prior to the event, but the U.S. Department of Energy, which organizes science bowl, has <a href="" target="_blank">sample questions online from previous years</a>. These vary from what type of process is used by nuclear power plants to generate energy (answer: fission) to which cellular organelle is responsible for photosynthesis (answer: chloroplast).&nbsp;</p> <p>A correctly answered question gains the team four points and the chance to answer a bonus question worth 10 points. While toss-up questions have to be answered individually, bonus questions involve teamwork, with the four team members whispering back and forth, trying to make the most of the 20 seconds they have to agree on an answer. One bonus question from 2017, for instance, asked a team to solve the following equation for x: x2 – 7x – 120 = 0 (Answer: Both -8 and 15, and the team was required to give both answers in order to receive points).</p> <p>Practice at Roxbury Latin, which started in January, focuses on teaching contestants how to play the game. “The team knows what they know, but they need to learn to listen carefully, to not buzz in too early, to not blurt,” says Moore. “For me, that’s why we practice.”</p> <p>After a break for lunch, the top two teams from each group headed to the single-elimination bracket, which decided who proceeded to the semi-finals. In the middle of the afternoon, the final winning and third place-deciding matches brought this year’s annual Regional Middle School Science Bowl to a close.</p> <p>This year, both first and second place went to two teams from Jonas Clarke Middle School in Lexington, Massachusetts. Clarke Team 2 came in first, while Clarke Team 1 came in second. The winning team received not only the “fame and glory of winning the coolest science bowl in all the nation,” according to Adajar, but they will also go on to represent the Northeast in the&nbsp;<a href="" target="_blank">National Science Bowl</a> in Washington in April.</p> <p>Roxbury Latin’s team did not go to the single-elimination round and over lunch, two of the team’s eighth-graders analyzed their performance. “We were zero-to-two after the first two rounds, then came back to two-for-two, and the last round was really close,” said one student. “That was a confidence hit, but the questions got easier and we got more aggressive with the buzzing,” added another team member. Ending the tournament two wins to three losses may have been disappointing, but when asked about their plans for next year there was no hesitation. “We’re definitely doing science bowl in high school.”</p> Over 100 middle schoolers from Maine, New Hampshire, and Massachusetts came to the MIT campus to compete in the fifth annual Northeast Regional Middle School Science Bowl. Photo: Paolo AdajarSchool of Science, Broad Institute, STEM education, K-12 education, Community, Contests and academic competitions QS World University Rankings rates MIT No. 1 in 12 subjects for 2020 Institute ranks second in five subject areas. Tue, 03 Mar 2020 19:01:01 -0500 MIT News Office <p>MIT has been honored with 12 No. 1 subject rankings in the QS World University Rankings for 2020.</p> <p>The Institute received a No. 1 ranking in the following QS subject areas: Architecture/Built Environment; Chemistry; Computer Science and Information Systems; Chemical Engineering; Civil and Structural Engineering; Electrical and Electronic Engineering; Mechanical, Aeronautical and Manufacturing Engineering; Linguistics; Materials Science; Mathematics; Physics and Astronomy; and Statistics and Operational Research.</p> <p>MIT also placed second in five subject areas: Accounting and Finance; Biological Sciences; Earth and Marine Sciences; Economics and Econometrics; and Environmental Sciences.</p> <p>Quacquarelli Symonds Limited subject rankings, published annually, are designed to help prospective students find the leading schools in their field of interest. Rankings are based on research quality and accomplishments, academic reputation, and graduate employment.</p> <p>MIT has been ranked as the No. 1 university in the world by QS World University Rankings for eight straight years.</p> Afternoon light streams into MIT’s Lobby 7.Image: Jake BelcherRankings, Computer science and technology, Linguistics, Chemical engineering, Civil and environmental engineering, Mechanical engineering, Chemistry, Materials science, Mathematics, Physics, Economics, EAPS, Business and management, Accounting, Finance, DMSE, School of Engineering, School of Science, School of Architecture and Planning, Sloan School of Management, School of Humanities Arts and Social Sciences, Electrical Engineering & Computer Science (eecs), Architecture, Biology, Aeronautical and astronautical engineering Undergraduate Teaching Lab wins SafetyStratus College and University Health and Safety Award The award is given annually by the American Chemical Society. Tue, 03 Mar 2020 15:20:01 -0500 Danielle Randall Doughty | Department of Chemistry <p>The Department of Chemistry’s&nbsp;<a href="" target="_blank">Undergraduate Teaching Laboratory</a>&nbsp;has been awarded the&nbsp;<a href="" target="_blank">2020 SafetyStratus College and University Health and Safety Award</a> by the American Chemical Society (ACS). ACS gives this award in recognition of the most comprehensive chemical safety programs in higher undergraduate education.</p> <p>The process of submitting the Undergraduate Teaching Laboratory for this illustrious prize was initiated by Whitney Hess, manager of safety systems and programs at MIT.Nano, who worked diligently with laboratory Director John Dolhun to complete the comprehensive application required for the award.</p> <div> <p>“We feel very honored, this represents our collective efforts to strive for the highest standards in fostering a safe teaching lab and in enhancing the chemical safety education of our undergraduates,” said Dolhun and Hess in a joint statement. “We are motivated to continuously improve our lab operations and safety, in alignment with the research advances happening in the chemistry department that inspire our lab modules.”</p> <div> <p>Winners of the SafetyStratus College and University Health and Safety Award receive a $1,000 honorarium and an engraved plaque, which are presented at the 2020 CHAS Awards Symposium at the ACS Fall national meeting. The recipients will deliver a 15- to 20-minute presentation on any topic pertaining to chemical safety at the symposium.</p> <div> <p>MIT previously received this award in 2005 and 1991.</p> </div> </div> </div> Whitney Hess (left) and John DolhunPhoto: Danielle DoughtyChemistry, Awards, honors and fellowships, School of Science, Safety, Health, MIT.nano, Nanoscience and nanotechnology Empowering faculty partnerships across the globe MISTI Global Seed Funds program has delivered $22 million to faculty since 2008. Tue, 03 Mar 2020 12:20:01 -0500 MISTI <p>MIT faculty share their creative and technical talent on campus as well as across the globe, compounding the Institute’s impact through strong international partnerships. Thanks to the MIT Global Seed Funds (GSF) program, managed by the MIT International Science and Technology Initiatives (<a href="" target="_blank">MISTI</a>), more of these faculty members will be able to build on these relationships to develop ideas and create new projects.</p> <p>“This MISTI fund was extremely helpful in consolidating our collaboration and has been the start of a long-term interaction between the two teams,” says 2017 GSF awardee Mehrdad Jazayeri, associate professor of brain and cognitive sciences and investigator at the McGovern Institute for Brain Research. “We have already submitted multiple abstracts to conferences together, mapped out several ongoing projects, and secured international funding thanks to the preliminary progress this seed fund enabled.”</p> <p>This year, the 28 funds that comprise MISTI GSF received 232 MIT applications. Over $2.3 million was awarded to 107 projects from 23 departments across the entire Institute. This brings the amount awarded to $22 million over the 12-year life of the program. Besides supporting faculty, these funds also provide meaningful educational opportunities for students. The majority of GSF teams include students from MIT and international collaborators, bolstering both their research portfolios and global experience.</p> <p>“This project has had important impact on my grad student’s education and development. She was able to apply techniques she has learned to a new and challenging system, mentor an international student, participate in a major international meeting, and visit CEA,” says Professor of Chemistry Elizabeth Nolan, a 2017 GSF awardee.</p> <p>On top of these academic and research goals, students are actively broadening their cultural experience and scope. “The environment at CEA differs enormously from MIT because it is a national lab and because lab structure and graduate education in France is markedly different than at MIT,” Nolan continues. “At CEA, she had the opportunity to present research to distinguished international colleagues.”</p> <p>These impactful partnerships unite faculty teams behind common goals to tackle worldwide challenges, helping to develop solutions that would not be possible without international collaboration. 2017 GSF winner Emilio Bizzi, professor emeritus of brain and cognitive sciences and emeritus investigator at the McGovern Institute, articulated the advantage of combining these individual skills within a high-level team. “The collaboration among researchers was valuable in sharing knowledge, experience, skills and techniques … as well as offering the probability of future development of systems to aid in rehabilitation of patients suffering TBI.”</p> <p>The research opportunities that grow from these seed funds often lead to published papers and additional funding leveraged from early results. The next call for proposals will be in mid-May.</p> <p>MISTI creates applied international learning opportunities for MIT students that increase their ability to understand and address real-world problems. MISTI collaborates with partners at MIT and beyond, serving as a vital nexus of international activity and bolstering the Institute’s research mission by promoting collaborations between MIT faculty members and their counterparts abroad.</p> Left to right: The Machu Picchu Design Heritage project is a past Global Seed Fund recipient. Paloma Gonzalez, Takehiko Nagakura, Chang Liu, and Wenzhe Peng pose with a panoramic view of Machu Picchu in Peru. They are part of an MIT team that has worked to digitally document the site.Photo: MISTIMISTI, McGovern Institute, Brain and cognitive sciences, School of Humanities Arts and Social Sciences, Research, Faculty, Funding, Global, Center for International Studies MIT students dominate annual Putnam Mathematical Competition Participating MIT students make history by taking all top five spots — the first time this has happened for any school. Tue, 03 Mar 2020 11:55:02 -0500 Sandi Miller | Department of Mathematics <p>Each December, thousands of undergraduates participate in the <a href="">William Lowell Putnam Mathematical Competition</a>, the premier math contest in the United States and Canada. The 80th annual exam was held on Dec. 7, 2019, and results were announced Feb. 18. For the first time in Putnam’s history, all five of the top spots in the contest, known as Putnam Fellows, came from a single school — MIT.</p> <p>MIT students also dominated the rest of the scoreboard: nine of the next 11, eight of the next 12, and 33 of the following 80 honorable mention rankings. Among the top 192 test-takers overall, 76 were MIT students.</p> <p>The 2019 Putnam Fellows, listed in alphabetical order, are seniors Ashwin Sah and Kevin Sun, junior Yuan Yao, sophomore Shengtong Zhang, and first-year Daniel Zhu. Yao and Zhang were 2018 Putnam Fellows, and Sah was a 2017 Putnam Fellow. Among the three top scorers — Sah, Zhang, and Zhu — two earned a nearly perfect score, and one (who prefers not to be named) earned a perfect score of 120 points. This is only the fifth time in Putnam's history that a test-taker received a perfect score.</p> <p>Competitors were also ranked by participating institution. Starting in 2019, the ranking is based on the three top scorers from each institution (while in previous years, it was based on the scores of three preselected individuals). MIT came in first as a team since the three top scorers, Sah, Zhang, and Zhu, are all from MIT. This is the MIT team’s fifth first-place win in the past seven years. This year, Harvard University came in second and Stanford University came in third.</p> <p>The Department of Mathematics will also honor two top-scoring female students, first-year Dain Kim and junior Qi Qi, at an awards dinner that will be held in the spring. Qi was one of three recipients for the 2019 Elizabeth Lowell Putnam Prize, given to top female contestants. She is the fourth MIT student to receive this honor since the award began in 1992.&nbsp;</p> <p>The honors come with cash awards. The institution with the first-place team receives $25,000, and each member of the team receives $1,000. Each Putnam Fellow receives $2,500, the next 11 highest-ranking individuals each receive $1,000, and the next 12 highest-ranking individuals each receive $250. The Elizabeth Lowell Putnam Prize carries a $1,000 award, and the Department of Mathematics will also give a $1,000 special prize to Dain Kim.</p> <p>“This was unprecedented,” says <a href="">Yufei Zhao</a>, Class of 1956 Career Development Assistant Professor of Mathematics, who coaches first-year students for the competitions via the Putnam Seminar in the fall, and also oversees the competition at MIT. “It was a pretty surreal result. I am extremely proud of our students’ phenomenal performance at the Putnam Competition. We are very happy to see that our undergraduate community is home to such an exceptional group of students.”</p> <p>The Department of Mathematics’ <a href="">PRIMES</a> program, which attracts many top high school math-inclined students to its STEM classes, also boasted of many alumni among the top scorers, including Zhu and 15 other MIT students, and three Harvard students — including a "next-12" finisher, Franklyn Wang, and an Elizabeth Lowell Putnam co-winner Laura Pierson.</p> <p>Many MIT Putnam competitors have prepared for the exam by participating in the first-year Putnam Seminar <a href="">18.A34 (Mathematical Problem Solving, Putnam Seminar)</a>, taught by Zhao, who was a three-time Putnam Fellow when he was an undergraduate at MIT. Through the seminar, Zhao encourages students to “use their experience in math competitions as a springboard onto higher mathematics,” and emphasizes the importance of good communication and presentation skills.</p> <p>A number of Putnam competitors go on to have successful research careers. Several faculty members of the Department of&nbsp;Mathematics were Putnam Fellows: Davesh Maulik, Bjorn Poonen, Peter Shor, David Vogan, and Zhao. In <a href="">Putnam’s history</a>, only eight participants were four-time Putnam Fellows, including Poonen, and three of them were MIT students. In fact, the first four-time Putnam Fellow was former MIT student Don Coppersmith '72, who went on to have a successful research career in cryptography.</p> <p>Success at math competitions “is neither necessary nor sufficient to becoming a good research mathematician,” according to Zhao. Nevertheless, he believes that the skills promoted by math competitions can be useful in research mathematics. Zhao regularly works with MIT undergraduate students to produce <a href="">cutting-edge research results</a>. “I am very fortunate to work with these amazing students,” says Zhao.</p> <p>Administered by the Mathematical Association of America, the competition included 150 MIT students among 4,229 test-takers from 570 U.S. and Canadian institutions. The six-hour exam, taken over two sessions on the first Saturday of December each year, consists of 12 problems worth 10 points each. Fewer than a fourth of all participants of this competition scored more than 10 points total, and the median score was 2.</p> <p>Complete results from the competition can be found on the <a href="">MAA website</a>. For more history on the competition, former MAA President Joseph A. Gallian wrote an interesting <a href="">2015 overview</a>.&nbsp;</p> MIT students set records at this year’s Putnam Competition: (left to right) Shengtong Zhang, Yuan Yao, Kevin Sun, Daniel Zhu, Qi Qi, and Dain Kim. Not pictured: Ashwin Sah. Photo: Sandi MillerMathematics, School of Science, Awards, honors and fellowships, Contests and academic competitions, Students, Undergraduate, Women in STEM Answering “Why?” MLK Visiting Scholar Benjamin McDonald uses synthetic organic chemistry in the Swager lab to answer questions with more questions. Mon, 02 Mar 2020 13:00:01 -0500 Fernanda Ferreira | School of Science <p>Everyone knows a kid who constantly asks, “Why?” “Why is the sky blue?” “Why do people have teeth?” “Why are hurricanes given names?” According to Benjamin McDonald, he was that kid. “I kept asking ‘Why?’ to the point of exasperation on the part of my parents,” he says. Because McDonald always wanted to get to the root of things, each answer was met with another “why” question. “I saw science as a clear mechanism for trying to answer some of those questions,” he explains.</p> <p>Currently, McDonald is a postdoc and the self-described “regular old organic chemist learning new tricks and new questions” in Professor Tim Swager’s lab. The Swager lab uses concepts from basic chemistry to create new applications such as materials that react to different chemicals. This has led McDonald to flip the question from “Why?” to “Why not?” He’s still interested in why substances behave as they do, but he has also begun tinkering with these substances. Specifically, he’s modifying polymers to give them new applications.</p> <p><strong>The language of chemistry</strong></p> <p>For as long as McDonald can remember, he always knew he wanted to be a chemist. He took a short detour during his first year at the University of North Carolina at Asheville after a disappointing general chemistry class. “I was like ‘I’m going to be a biologist,’” McDonald remembers. He hedged his bets, choosing to double major in biology and chemistry. “And then I took organic chemistry my sophomore year and something just clicked,” McDonald says.</p> <p>Organic chemistry introduced McDonald to what he calls the hieroglyphic language of molecules. The two-dimensional sketch of a molecule is the hieroglyphic, and reading it allows you to picture the molecule in three dimensions in your head. “We can then understand some of the properties of the molecule, such as the collagen in your skin, based on its structure and how that relates to how our body works and even how the universe works.” He dropped biology, graduating with a bachelor's degree in chemistry in 2012.</p> <p>For McDonald, organic chemistry offered the perfect level of detail to understand questions like how different types of life processes work — without getting tied down by big-picture complexities such as appearance, behavior, and systematic taxonomy. “I was addicted to it,” he says. McDonald got involved with organic chemistry research, moving systematically from undergraduate research to a doctoral program at Northwestern University.</p> <p>“My PhD was in total synthesis and reaction development,” McDonald says. This is a field that harkens back to the 1960s, explains McDonald, when the magic-bullet concept developed by Nobel laureate Paul Ehrlich was in full force. Ehrlich believed that molecules could be developed to specifically target a germ while leaving the rest of the body unscathed. “Total synthesis is the art and science of making these small organic molecules, and reaction development is figuring out how to make a specific chemical bond,” McDonald says.</p> <p>“I was trained in that, which a lot of times sets you up to be a chemist in a pharmaceutical company, which wasn’t that appealing,” McDonald says. Becoming a postdoc in the Swager lab allowed him to find an application for that training outside of the focused approach of the pharmaceuticals industry, he says. “Tim [Swager] is particularly unique because he knows a lot of organic chemistry, but he also knows polymer chemistry, material science, even some electrical engineering,” says McDonald. “As he says, he knows enough about many things to be dangerous.”</p> <p>Swager, the John D. MacArthur Professor of Chemistry, also makes sure his lab members represent a number of scientific fields. “I strive to bring in a mix of all different types of people,” he says. To this mix, McDonald brings the pure synthetic chemistry. “It takes a lot of skill to make complicated molecules, do multi-step reactions, and to do these fast,” Swager explains. The molecules McDonald is synthesizing require dozens of steps in a row and the yield goes down with each step added. “You need really good chemistry to get any material out, and Ben brings that skill.”</p> <p>Coming to Swager’s lab was, according to McDonald, a paradigm shift: “to go from being exquisitely focused on one specific space, to seeing someone who is able to use it simply as a tool towards more interesting applications.”</p> <p>These applications are wide-ranging, from responsive polymers on the surface of materials that can create uniforms that protect against chemical warfare to polymers that can act as functional surfactants, changing the surface tension of droplets in an emulsion. McDonald is one of the polymer chemists in the lab, but these projects are collaborative, involving work with chemists with other specialties, as well as engineers. “Our group is very interdisciplinary, and that is also great training for modern science,” he says. “No one has the one skill set to rule them all.”</p> <p><strong>Bringing in voices</strong></p> <p>The same way no scientist can master every skill set, no single person can represent every perspective or human experience, which is why McDonald is concerned with increasing representation in chemistry. “For me, diversity in research is necessary to keep fresh ideas and questions in science,” says McDonald. And when it comes to technological progress, diversity guarantees that as many of society’s stakeholders are involved in the process. “This is important for an equitable society, but also for an&nbsp; informed and engaged one.”</p> <p>During his PhD, McDonald was involved in a number of initiatives focused on diversity and inclusion, particularly through the graduate-student-led NU BonD (Northwestern University’s Building on Diversity). “It’s still going on, and it’s an effort to make chemistry more reflective of the general population and bring in more voices.” NU BondD organized workshops, seminar series, and monthly social events that promoted diversity and focused on how microaggressions and implicit bias can impact scientific research.</p> <p>At MIT, McDonald has focused his efforts on the question of “How?”&nbsp;— How do people get to MIT? “I noticed that a lot of people at MIT always do summer research rotations here,” he says, which allows future graduate students to start building connections at MIT while still in college. “If we want to make the community more balanced, an obvious answer is to have programs that get people who are not the majority in the door,” he adds.</p> <p>Last year, Swager nominated McDonald for the MLK Visiting Professors and Scholars Program, which enhances and recognizes the contributions of scholars in the community, and in October 2019 McDonald was <a href="">announced as one of the six MLK Visiting Scholars</a> for 2019-20. “Ben is an outstanding scholar and he’s doing a lot for diversity at MIT,” says Swager.</p> <p>Recently, McDonald has started talking with the MIT Chemistry Alliance for Diversity and Inclusion (CADI) to create a program that gets more underrepresented groups in the summer research rotations. Similar programs exist in other departments at MIT; <a href="">the MIT Summer Research Program</a>, for instance, brings underrepresented minorities and underserved students to MIT for nine weeks of research on campus in fields including biology and brain and cognitive science. “I think this is the simplest way to affect bottom-up change,” says McDonald.</p> MLK Scholar Ben McDonald uses his synthetic chemistry skills set to develop new applications in Tim Swager’s lab.Photo: Danielle Randall DoughtySchool of Science, Chemistry, MLK visiting scholars, Diversity and inclusion, Profile, Graduate, postdoctoral The neural basis of sensory hypersensitivity A new study may explain why people with autism are often highly sensitive to light and noise. Mon, 02 Mar 2020 11:00:00 -0500 Anne Trafton | MIT News Office <p>Many people with autism spectrum disorders are highly sensitive to light, noise, and other sensory input. A new study in mice reveals a neural circuit that appears to underlie this hypersensitivity, offering a possible strategy for developing new treatments.</p> <p>MIT and Brown University neuroscientists found that mice lacking a protein called Shank3, which has been previously linked with autism, were more sensitive to a touch on their whiskers than genetically normal mice. These Shank3-deficient mice also had overactive excitatory neurons in a region of the brain called the somatosensory cortex, which the researchers believe accounts for their over-reactivity.</p> <p>There are currently no treatments for sensory hypersensitivity, but the researchers believe that uncovering the cellular basis of this sensitivity may help scientists to develop potential treatments.</p> <p>“We hope our studies can point us to the right direction for the next generation of treatment development,” says Guoping Feng, the James W. and Patricia Poitras Professor of Neuroscience at MIT and a member of MIT’s McGovern Institute for Brain Research.</p> <p>Feng and Christopher Moore, a professor of neuroscience at Brown University, are the senior authors of the paper, which appears today in <em>Nature Neuroscience</em>. McGovern Institute research scientist Qian Chen and Brown postdoc Christopher Deister are the lead authors of the study.</p> <p><strong>Too much excitation</strong></p> <p>The Shank3 protein is important for the function of synapses — connections that allow neurons to communicate with each other. Feng has previously shown that mice lacking the Shank3 gene display many <a href="">traits associated with autism</a>, including avoidance of social interaction, and compulsive, repetitive behavior.</p> <p>In the new study, Feng and his colleagues set out to study whether these mice also show sensory hypersensitivity. For mice, one of the most important sources of sensory input is the whiskers, which help them to navigate and to maintain their balance, among other functions.</p> <p>The researchers developed a way to measure the mice’s sensitivity to slight deflections of their whiskers, and then trained the mutant Shank3 mice and normal (“wild-type”) mice to display behaviors that signaled when they felt a touch to their whiskers. They found that mice that were missing Shank3 accurately reported very slight deflections that were not noticed by the normal mice.</p> <p>“They are very sensitive to weak sensory input, which barely can be detected by wild-type mice,” Feng says. “That is a direct indication that they have sensory over-reactivity.”</p> <p>Once they had established that the mutant mice experienced sensory hypersensitivity, the researchers set out to analyze the underlying neural activity. To do that, they used an <a href="">imaging technique</a> that can measure calcium levels, which indicate neural activity, in specific cell types.</p> <p>They found that when the mice’s whiskers were touched, excitatory neurons in the somatosensory cortex were overactive. This was somewhat surprising because when Shank3 is missing, synaptic activity should drop. That led the researchers to hypothesize that the root of the problem was low levels of Shank3 in the inhibitory neurons that normally turn down the activity of excitatory neurons. Under that hypothesis, diminishing those inhibitory neurons’ activity would allow excitatory neurons to go unchecked, leading to sensory hypersensitivity.</p> <p>To test this idea, the researchers genetically engineered mice so that they could turn off Shank3 expression exclusively in inhibitory neurons of the somatosensory cortex. As they had suspected, they found that in these mice, excitatory neurons were overactive, even though those neurons had normal levels of Shank3.</p> <p>“If you only delete Shank3 in the inhibitory neurons in the somatosensory cortex, and the rest of the brain and the body is normal, you see a similar phenomenon where you have hyperactive excitatory neurons and increased sensory sensitivity in these mice,” Feng says.</p> <p><strong>Reversing hypersensitivity</strong></p> <p>The results suggest that reestablishing normal levels of neuron activity could reverse this kind of hypersensitivity, Feng says.</p> <p>“That gives us a cellular target for how in the future we could potentially modulate the inhibitory neuron activity level, which might be beneficial to correct this sensory abnormality,” he says.</p> <p>Many other studies in mice have linked defects in inhibitory neurons to neurological disorders, including Fragile X syndrome and Rett syndrome, as well as autism.</p> <p>“Our study is one of several that provide a direct and causative link between inhibitory defects and sensory abnormality, in this model at least,” Feng says. “It provides further evidence to support inhibitory neuron defects as one of the key mechanisms in models of autism spectrum disorders.”</p> <p>He now plans to study the timing of when these impairments arise during an animal’s development, which could help to guide the development of possible treatments. There are existing drugs that can turn down excitatory neurons, but these drugs have a sedative effect if used throughout the brain, so more targeted treatments could be a better option, Feng says.</p> <p>“We don’t have a clear target yet, but we have a clear cellular phenomenon to help guide us,” he says. “We are still far away from developing a treatment, but we’re happy that we have identified defects that point in which direction we should go.”</p> <p>The research was funded by the Hock E. Tan and K. Lisa Yang Center for Autism Research at MIT, the Stanley Center for Psychiatric Research at the Broad Institute of MIT and Harvard, the Nancy Lurie Marks Family Foundation, the Poitras Center for Psychiatric Disorders Research at the McGovern Institute, the Varanasi Family, R. Buxton, and the National Institutes of Health.</p> MIT neuroscientists have discovered a brain circuit that appears to contribute to the sensory hypersensitivity often seen in people with autism spectrum disorders.Image: Jose-Luis Olivares, MITResearch, Autism, Brain and cognitive sciences, McGovern Institute, Neuroscience, School of Science, National Institutes of Health (NIH)