Author: Julie Pryor

Are eyes the window to the soul?

Anne Trafton |

Covert attention has been defined as shifting attention without shifting the eyes. The notion that we can internally pay attention to an object in a scene without making eye movements to it has been a cornerstone of the fields of psychology and cognitive neuroscience, which attempt to understand mental phenomena that are purely internal to the mind, divorced from movements of the eyes or limbs. A study from the McGovern Institute for Brain Research at MIT now questions the dissociation of eye movements from attention in this context, finding that microsaccades precede modulation of specific brain regions associated with attention. In other words, a small shift of the eyes is linked to covert attention, after all.

Seeing the world through human eyes, which have a focused, high-acuity center to the field of vision, requires saccades (rapid movements of the eyes that move between points of fixation). Saccades help to piece together important information in an overall scene and are closely linked to attention shifts, at least in the case of overt attention. In the case of covert attention, the view has been different since this type of attention can shift while the gaze is fixed. Microsaccades are tiny movements of the eyes that are made when subjects maintain fixation on an object.

“Microsaccades are typically so small, that they are ignored by many researchers.” says Robert Desimone, director of MIT’s McGovern Institute for Brain Research and lead author on the study. “We went in and tested what they might represent by linking them to attentional firing in particular brain regions.”

In the study from Desimone and his team, the authors used an infrared eye-tracking system to follow microsaccades in awake macaques. The authors monitored activity in cortical regions of the brain linked to visual attention, including area V4. The authors saw increased neuronal firing in V4, but only when preceded by a microsaccade toward the attended stimulus. This effect on neuronal activity vanished when a microsaccade was directed away from the stimulus. The authors also saw increased firing in the inferior temporal (IT) cortex after a microsaccade, and even found that attention to an object amongst a ‘clutter’ of different visual objects, finding that attention to a specific object in the group was preceded by a microsaccade.

“I expected some links between microsaccades and covert attention,” says lead author of the study Eric Lowet, now a postdoctoral fellow at Boston University. “However, the magnitude of the effect and the precise link to microsaccade onset was surprising to me and the lab. Furthermore, to see these effects also in the IT cortex, which has large receptive fields and is involved in higher-order visual cognition, was striking”.

Why was this strong effect previously missed? The separation of eye movement and attention is so core to the concept of covert attention, that studies often actively seek to separate the visual stimulus by directing attention to a target outside the receptive field of vision, while the subject’s gaze is maintained on a fixation stimulus. The authors are the first to directly test microsaccades toward and away from an attended stimulus, and it was this set up, and the difference in neuronal firing upon separating these eye movements, that allowed them to draw the conclusions made.

“When we first separated attention effects on V4 firing rates by the direction of the microsaccade relative to the attended stimulus,” Lowet explains, “I realized this analysis was a game changer.”

The study suggests several future directions of study that are being pursued by the Desimone lab. Low frequency rhythmic (in the delta and theta range) sampling has been suggested as a possible explanation for attentional modulation. According to this idea, people sample visual scenes rhythmically, with an intrinsic sampling interval of about a quarter of a second.

“We do not know whether microsaccades and delta/theta rhythms have a common generator,” points out Karthik Srinivasan, a co-author on the study and a scientist at the McGovern Institute. “But if they do, what brain areas are the source of such a generator? Are the low frequency rhythms observed merely the frequency-analytic manifestation of microsaccades or are they linked?”

These are intriguing future steps for analysis that can be addressed in light of the current study which points to microsaccades as an important marker for visual attention and cognitive processes. Indeed, some of the previously hidden aspects of our cognition are revealed through our motor behavior after all.

Does our ability to learn new things stop at a certain age?

by The Brain |

This is actually a neuromyth, but it has some basis in scientific research. People’s endorsement of this statement is likely due to research indicating that there is a high level of synaptogenesis (formation of connections between neurons) between ages 0-3, that some skills (learning a new language, for example) do diminish with age, and some events in brain development, such as connections in the visual system, are tied to exposure to a stimulus, such as light. That said, it is clear that a new language can be learned later in life, and at the level of synaptogenesis, we now know that synaptic connections are plastic.

If you thought this statement was true, you’re not alone. Indeed, a 2017 study by McGrath and colleagues found that 18% of the public (N = 3,045) and 19% of educators (N = 598) believed this statement was correct.

Learn more about how teachers and McGovern researchers are working to target learning interventions well past so-called “critical periods” for learning.

Yanny or Laurel?

Anne Trafton |

“Yanny” or “Laurel?” Discussion around this auditory version of “The Dress” has divided the internet this week.

In this video, brain and cognitive science PhD students Dana Boebinger and Kevin Sitek, both members of the McGovern Institute, unpack the science — and settle the debate. The upshot? Our brain is faced with a myriad of sensory cues that it must process and make sense of simultaneously. Hearing is no exception, and two brains can sometimes “translate” soundwaves in very different ways.

Feng Zhang elected to National Academy of Sciences

Anne Trafton |

Feng Zhang has been elected to join the National Academy of Sciences (NAS), a prestigious, non-profit society of distinguished scholars that was established through an Act of Congress signed by Abraham Lincoln in 1863. Zhang is the Patricia and James Poitras ’63 Professor in Neuroscience at MIT, an associate professor in the departments of Brain and Cognitive Sciences and Biological Engineering, an investigator at the McGovern Institute for Brain Research, and a core member of the Broad Institute of MIT and Harvard. Scientists are elected to the National Academy of Sciences by members of the organization as recognition of their outstanding contributions to research.

“Because it comes from the scientific community, election to the National Academy of Sciences is a very special honor,” says Zhang, “and I’m grateful to all of my colleagues for the recognition and support.”

Zhang has revolutionized research across the life sciences by developing and sharing a number of powerful molecular biology tools, most notably, genome engineering tools based on the microbial CRISPR-Cas9 system. The simplicity and precision of Cas9 has led to its widespread adoption by researchers around the world. Indeed, the Zhang lab has shared more than 49,000 plasmids and reagents with more than 2,300 institutions across 62 countries through the non-profit plasmid repository Addgene.

Zhang continues to pioneer CRISPR-based technologies. For example, Zhang and his colleagues discovered new CRISPR systems that use a single enzyme to target RNA, rather than DNA. They have engineered these systems to achieve precise editing of single bases of RNA, enabling a wide range of applications in research, therapeutics, and biotechnology. Recently, he and his team also reported a highly sensitive nucleic acid detection system based on the CRISPR enzyme Cas13 that can be used in the field for monitoring pathogens and other molecular diagnostic applications.

Zhang has long shown a keen eye for recognizing the potential of transformative technologies and developing robust tools with broad utility. As a graduate student in Karl Diesseroth’s group at Stanford, he contributed to the development of optogenetics, a light-based technology that allows scientists to both track neurons and causally test outcomes of neuronal activity. Zhang also created an efficient system for reprogramming TAL effector proteins (TALEs) to specifically recognize and modulate target genes.

“Feng Zhang is unusually young to be elected into the National Academy of Science, which attests to the tremendous impact he is having on the field even at an early stage of his career, “ says Robert Desimone, director of the McGovern Institute for Brain Research at MIT.

This year the NAS, an organization that includes over 500 Nobel Laureates, elected 84 new members from across disciplines. The mission of the organization is to provide sound, objective advice on science to the nation, and to further the cause of science and technology in America. Four MIT professors were elected this year, with Amy Finkelstein (recognized for contributions to economics) as well as Mehran Karder and Xiao-Gang Wen (for their research in the realm of physics) also becoming members of the Academy.

The formal induction ceremony for new NAS members will be held at the Academy’s annual meeting in Washington D.C. next spring.

Ann Graybiel wins 2018 Gruber Neuroscience Prize

Anne Trafton |

Institute Professor Ann Graybiel, a professor in the Department of Brain and Cognitive Sciences and member of MIT’s McGovern Institute for Brain Research, is being recognized by the Gruber Foundation for her work on the structure, organization, and function of the once-mysterious basal ganglia. She was awarded the prize alongside Okihide Hikosaka of the National Institute of Health’s National Eye Institute and Wolfram Schultz of the University of Cambridge in the U.K.

The basal ganglia have long been known to play a role in movement, and the work of Graybiel and others helped to extend their roles to cognition and emotion. Dysfunction in the basal ganglia has been linked to a host of disorders including Parkinson’s disease, Huntington’s disease, obsessive-compulsive disorder and attention-deficit hyperactivity disorder, and to depression and anxiety disorders. Graybiel’s research focuses on the circuits thought to underlie these disorders, and on how these circuits act to help us form habits in everyday life.

“We are delighted that Ann has been honored with the Gruber Neuroscience Prize,” says Robert Desimone, director of the McGovern Institute. “Ann’s work has truly elucidated the complexity and functional importance of these forebrain structures. Her work has driven the field forward in a fundamental fashion, and continues to do so.’

Graybiel’s research focuses broadly on the striatum, a hub in basal ganglia-based circuits that is linked to goal-directed actions and habits. Prior to her work, the striatum was considered to be a primitive forebrain region. Graybiel found that the striatum instead has a complex architecture consisting of specialized zones: striosomes and the surrounding matrix. Her group went on to relate these zones to function, finding that striosomes and matrix differentially influence behavior. Among other important findings, Graybiel has shown that striosomes are focal points in circuits that link mood-related cortical regions with the dopamine-containing neurons of the midbrain, which are implicated in learning and motivation and which undergo degeneration in Parkinson’s disorder and other clinical conditions. She and her group have shown that these regions are activated by drugs of abuse, and that they influence decision-making, including decisions that require weighing of costs and benefits.

Graybiel continues to drive the field forward, finding that striatal neurons spike in an accentuated fashion and ‘bookend’ the beginning and end of behavioral sequences in rodents and primates. This activity pattern suggests that the striatum demarcates useful behavioral sequences such, in the case of rodents, pressing levers or running down mazes to receive a reward. Additionally, she and her group worked on miniaturized tools for chemical sensing and delivery as part of a continued drive toward therapeutic intervention in collaboration with the laboratories of Robert Langer in the Department of Chemical Engineering and Michael Cima, in the Department of Materials Science and Engineering.

“My first thought was of our lab, and how fortunate I am to work with such talented and wonderful people,” says Graybiel.  “I am deeply honored to be recognized by this prestigious award on behalf of our lab.”

The Gruber Foundation’s international prize program recognizes researchers in the areas of cosmology, neuroscience and genetics, and includes a cash award of $500,000 in each field. The medal given to award recipients also outlines the general mission of the foundation, “for the fundamental expansion of human knowledge,” and the prizes specifically honor those whose groundbreaking work fits into this paradigm.

Graybiel, a member of the MIT Class of 1971, has also previously been honored with the National Medal of Science, the Kavli Award, the James R. Killian Faculty Achievement Award at MIT, Woman Leader of Parkinson’s Science award from the Parkinson’s Disease Foundation, and has been recognized by the National Parkinson Foundation for her contributions to the understanding and treatment of Parkinson’s disease. Graybiel is a member of the National Academy of Sciences, the National Academy of Medicine, and the American Academy of Arts and Sciences.

The Gruber Neuroscience Prize will be presented in a ceremony at the annual meeting of the Society for Neuroscience in San Diego this coming November.

Beyond the 30 Million Word Gap

Anne Trafton |

At the McGovern Institute for Brain Research at MIT, John Gabrieli’s lab is studying how exposure to language may influence brain function in children.

The Beautiful Brain: The Drawings of Santiago Ramón y Cajal

Anne Trafton |

Opening May 3, 2018

Santiago Ramón y Cajal made transformative discoveries of the anatomy of the brain and nervous system, work that led to his receiving a Nobel Prize in 1906. This founder of modern neuroscience was also an exceptional artist. His drawings of the brain were not only beautiful, but also astounding in their capacity to illustrate and understand the details of brain structure and function.

The Beautiful Brain: The Drawings of Santiago Ramón y Cajal at the MIT Museum is part of a traveling exhibit that will include approximately 80 of Cajal’s drawings, many rarely before seen in the U.S.

These historical works will be complimented by a contemporary exhibition of neuroscience visualizations that are leading to new insights, aided by technologies, many pioneered here at MIT’s McGovern Institute, that allow increasingly more detailed and precise understandings.

The exhibit is scheduled to open on May 3, 2018.

The Beautiful Brain: The Drawings of Santiago Ramón y Cajal was developed by the Frederick R. Weisman Art Museum, University of Minnesota with the CSIC’s Cajal Institute, Madrid, Spain.

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Major exhibition support provided by:

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Sustaining exhibition support provided by:

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Contributing exhibition support provided by:

spanishembassymibrpilm

 

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This exhibition is generously supported by the Associate Provost for the Arts, Philip Khoury. Additional support has been provided by the Council for the Arts at MIT.

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Warm Wishes for 2018!

Anne Trafton |

This year, we hope you enjoy “Postcards from the Brain” — an illustrative journey featuring brain regions studied by McGovern researchers.

For a closer look at these postcards, including a description of how our researchers are studying these particular regions of the brain, please visit our image gallery.

McGovern Institute 2017 Halloween Party

Anne Trafton |

See below for a full gallery of images from our annual Halloween party.

How Biological Memory Really Works: Insights from the Man with the World’s Greatest Memory

Anne Trafton |

 

Jim Karol exhibited no particular talent for memorizing anything early in his life. Far from being a savant, his grades in school were actually pretty bad and, after failing to graduate from college, he spent his 20’s working in a factory. He only started playing around with mnemonic techniques at the age of 49, merely as a means to amuse himself while he worked out on the treadmill. Then, in one of the most remarkable cognitive transformations in human history, he turned himself into the man with the world’s greatest memory. Whatever vast body of information is put before him — the US zip codes, the day of the week of every date in history, the first few thousand digits of pi, etc. — he voraciously commits to memory using his own inimitable mnemonic techniques. Moreover, unlike most other professional memorists, Jim has mastered the mental skill of permanently storing that information in long-term memory, as opposed to only short or medium-term memory. How does he do it?

To be sure, Jim has taken standard menmonic techniques to the next level. That said, it has been well-documented for over 2500 years that mnemonic techiques — such as the “Method of Loci” or the “Memory Palace” — dramatically enhance the memory capacity of anyone who uses them regularly. But is there any point to improving one’s memory in the age of the computer? Tony Dottino, the founder/executive director of the USA Memory Championship and a world reknown memory coach, will describe his experiences of teaching these techniques to all age groups.

Finally, does any of this have anything to do with the neuroscience of memory? McGovern Institute neuroscientist Robert Ajemian argues that it does and that one of the great intellectual misunderstandings in scientific history is that modern-day neuroscientists largely base their conceptualization of human memory on the computer metaphor. For this reason, neuroscientists usually talk of read/write operations, traces, engrams, storage/retrieval distinctions, etc. Ajemian argues that all of this is wrong for the brain, a highly distributed system which processes in parallel. The correct conceptualization of human memory is that of content-addressable memory implemented by attractor networks, and the success of mnemonic techniques, though largely ignored in current theories of memory, constitutes the ultimate proof. Ajemian will briefly outline these arguments.