Posts tagged Brain Activity Map
Articles and news from the latest research reports.
Is Obama’s Plan to Map the Human Brain this Generation’s Equivalent to Landing a Man on the Moon?
President John F. Kennedy’s mission in the 1960s was to land a man on the moon. President Bill Clinton made cracking the human genome one of his top priorities. Now, President Barack Obama says a detailed map of the human brain is necessary to understand how it works and what needs to be done when it’s not working properly. The president is expected to unveil his plans for an estimated $3 billion, decade-long commitment to the Brain Activity Map project next month in his 2014 budget proposal.
Rutgers Today talked with Rutgers University behavioral neuroscientist Timothy Otto, professor and director of the Behavioral and Systems Neuroscience program in the Department of Psychology, about what we know about the brain, how much we still need to discover and if spending billions of dollars in research will enable scientists to develop new treatments for debilitating neurological diseases like Alzheimer’s, Parkinson’s and autism.
Nanotools for neuroscience and brain activity mapping
The ambitious and controversial Brain Activity Map (BAM), initiative instituted by a small group of researchers last year, has been steadily gaining momentum. Earlier this week, a proof-of-principle Zebrafish BAM was demonstrated with astounding clarity by a pair of researchers at the Howard Hughes Medical Institute.
Following on the heels of that work, an exhaustive 17-page compendium of current and soon-to-be brain mapping tools was published yesterday in ACS Nano by a rapidly snowballing list of disciples.
The BAM roster has been a carefully manicured player list from the beginning, and the role it has as ship wheel to this diffuse effort should not be underestimated. With the ranks now swelling to 27, each contributor to the paper has, in word or in spirit, contributed notably to the 185 referenced technologies on the paper. What we have here is not a research release, this is a textbook for the new neuroscience, and the journal choice, though not publicly accessible, hints at the desire to draw even more nanoscale researchers into the effort.
Media attention has channeled formative criticism to the effort in a way we have not seen before. Those sentiments on the cautionary take at least, might be summarized by likening the BAM scientists to cavemen having just discovered fire. Now sitting in the sand, they appear to be chartering a course to the internal combustion engine as they scribe on the ground with blunt bone instruments. The problem is that having just fleshed out how the brain’s wiring, the connectome, might be extracted, the community elites just leapfrogged to the full activity map, or at least one for some of the lesser animals.
The most extravagant technology proposed is undoubtedly the DNA tickertape. It appears to have been developed initially, at least in part, by Northwestern University’s Konrad Kording. Some of the earlier BAM papers show however that George Church, of human genome project fame, actually holds a patent that might cover some aspects of Kording’s idea. In particular, Church seems responsible for the wickedly unique concept of engineering DNA polymerases to produce predictable errors that would in effect record conditions within the cell or device onto DNA tapes. Fortunately Church, having entered neuroscience some time ago, is also a BAM founding father. His “nucleic acid memory device” could be the means by which the spike activity of each neuron would be recorded.
Among the other wild exotica hinted at in the ACS Nano paper is the DNA barcode proposed by Anthony Zador, from the Cold Spring Harbor Lab. This device would use a genetically modified rabies virus to infiltrate the nervous system, and record every connection in the process, web-crawl style. While Zador is not an author on this or the previous BAM papers, his techniques would not only provide a way to deliver a connectome of a complex brain, they potentially could do it non-destructively. Furthermore, the barcode mechanism would perhaps be the ideal way to propagate the Kording-Church tickertape machinery from cell to cell, bundling topology and activity together.
Many of the neurotools mentioned in the ACSNano paper are logical extensions of current technologies, just slightly smaller and a little higher in resolution. Recording cell activity with voltage-sensitive or calcium-imaging dyes, as was done in the Zebrafish map, may or may not be the process used ten years from now. Other ideas, like accessing neurons through fiber optic probes threaded through the vasculature to the capillaries, were re-invigorated, as were new sensors altogether like nanodiamond and nanogold devices.
Glaringly absent from this paper however, is a clear consensus of what exactly is to be done with these tools. The Zebrafish calcium map, for example, does not discriminate between neuron bodies, axons, dendrites, or synapses. The question of what level of detail is to be the goal of new studies still needs to be asked. This is a tough question because an activity map, like the connectome that would couch it, is rewritten on scales beneath our direct perception—not only is it a moving target, its trajectory is largely unknown. A long-term project such as this based in a set of technologies, as opposed to hypothesis-driven scientific inquiry, needs to balance fluidity with credibility.
Imagining what you would want to do if you were making a BAM of your own brain may emerge as the best way to set the project’s goals. In that case, the researchers may not be going for the whole BAM right away—just the things they would want to know in enough detail to get some answers in the least destructive way possible. If they plow through a bunch of animal studies generating terabytes of data, but cannot then use those methods used to learn about our brains, they will not have been successful. Priority then is to be the nondestructive BAM, focused on those high-interest, highly accessible areas with the highest density of observables wherein the observation risks are low. How to do this is the question of the next BAM installment.
Researchers explain the goals and structure of a new brain-mapping project
A proposed effort to map brain activity on a large scale, expected to be announced by the White House later this month, could help neuroscientists understand the origins of cognition, perception, and other phenomena. These brain activities haven’t been well understood to date, in part because they arise from the interaction of large sets of neurons whose coördinated efforts scientists cannot currently track.
“There are all kinds of remarkable tools to study the microscopic world of individual cells,” says John Donoghue, a neuroscientist at Brown and a participant in the project. “And on the macroscopic end, we have tools like MRI and EEG that tell us about the function of the brain and its structure, but at a low resolution. There is a gap in the middle. We need to record many, many neurons exactly as they operate with temporal precision and in large areas,” he says.
An article published Thursday in Science online expands the project’s already ambitious goals beyond just recording the activity of all individual neurons in a brain circuit simultaneously. Researchers should also find ways to manipulate the neurons within those circuits and understand circuit function through new methods of data analysis and modeling, the authors write.
Understanding how neurons communicate with one another across large regions of the brain will be critical to understanding how the brain works, according to participants in the project. Other efforts to map out the physical connections in the brain are already under way (see “TR10: Connectomics” and “Mapping the Brain on a Massive Scale”), but these projects look at static brains or can only get a rough view of how regions of the brain communicate. The new project will probably start applying its novel and yet unknown technologies on simpler brains, such as those of flies, and will probably take decades to achieve its goals.
Numerous leaders from the fields of neuroscience, nanotechnology, and synthetic biology are expected to collaborate on the effort. “We need something large scale to try to build tools for the future,” says Rafael Yuste, a neurobiologist at Columbia University and a member of the project. “We view ourselves as tool builders. I think we could provide to the scientific community the methods that could be used for the next stage in neuroscience.”
In addition to deepening fundamental understanding of the brain, the project may also lead to new treatments for psychiatric and neurological disorders. “If we truly understand how things like thoughts, cognition, and other features of the brain emerge, then we should have a better understanding of mood disorders, Parkinson’s, epilepsy and other conditions that are thought to arise from brain-wide circuitry problems,” says Donoghue.
Details about which technology ideas will be given the green light and how much money will support their development are expected to be revealed in the White House announcement that is still to come. The project is likely to be supported by the National Institutes of Health, the National Science Foundation, the Defense Advanced Research Projects Agency, the Office of Science and Technology Policy, and private foundations, participants say. It’s not yet clear how much money will be needed or which technologies will be given priority.
Whichever particular technologies emerge, nanotechnology is likely to be involved, in part because of the need for smaller and faster sensors to record neuronal activity across the brain. Existing sensors can record the electrical activity of neurons, but these chips can typically monitor fewer than 100 neurons at a time and can’t record activity from neighboring neurons, which would be necessary to understand how neurons interact with one another. Paul Weiss, director of the California NanoSystems Institute at the University of California, Los Angeles, a participant in the project, says that nanofabrication techniques could address this problem, with smaller chips bearing smaller electrical and even chemical probes. “We’ve had over a decade a fairly substantial investment in science and technology to develop the capability … to control how what we make interacts with the chemical, physical, and biological worlds,” he says.
Novel optical techniques could also aid the mapping project. Currently, many research groups use calcium-sensitive fluorescent dyes to study neuron firing, but Yuste wants to develop an optical technique that uses voltage-sensitive fluorescent dyes for a faster readout. “Neurons communicate using voltage,” he says. “We would like to develop voltage imaging so we will be able to measure neuronal activity directly.”
While many things about the project are uncertain, one thing is clear—there is going to be a lot of data to store, share, and analyze. “We have just begun to scratch the surface of how you deal with data in high-dimensional spaces,” says Terry Sejnowski, a computational neuroscientist at the Salk Institute. “If you are talking about one million neurons, no one can even imagine what that looks like–it is way beyond what we can perceive in three dimensions.”
The Science article also sketches out a rough time line. Within five years, it should be possible to monitor tens of thousands of neurons; in 15 years, one million neurons should be possible. A fly’s brain has about 100,000 neurons, a mouse’s about 75 million, and a human’s about 85 billion. “With one million neurons, scientists will be able to evaluate the function of the entire brain of the zebrafish or several areas from the cerebral cortex of the mouse,” the authors write.