Tuesday, March 8, 2016

Highlights and new discoveries in Neuroscience (February 2016)

In the second issue of this monthly digest series you can find out what happened at COSYNE 2016, how to cryonically freeze and recover a brain, why brains fold up the way they do, how to restore memory function in Alzheimer's, and much more.


New Alzheimer's treatment fully restores memory function

Australian researchers have come up with a noninvasive ultrasound technology that clears the brain of neurotoxic amyloid plaques—structures that are responsible for memory loss and a decline in cognitive function in Alzheimer's patients.

Published in Science Translational Medicine, the team describes the technique as using a particular type of ultrasound called a focused therapeutic ultrasound, which noninvasively beams sound waves into the brain tissue. By oscillating super-fast, these sound waves are able to gently open up the blood-brain barrier, which is a layer that protects the brain against bacteria, and stimulate the brain’s microglial cells to activate. Microglila cells are basically waste-removal cells, so they’re able to clear out the toxic beta-amyloid clumps that are responsible for the worst symptoms of Alzheimer's.

© Science Translational Medicine

The team reports fully restoring the memory function of 75 percent of the mice they tested it on, with zero damage to the surrounding brain tissue. They found that the treated mice displayed improved performance in three memory tasks - a maze, a test to get them to recognise new objects, and one to get them to remember the places they should avoid.

Source: Science Alert.

Mammal's brain has been cryonically frozen and recovered for the first time

For the first time, researchers have cryonically frozen a whole mammalian brain and recovered it in near-perfect condition, with the cell membranes, synapses, and intracellular structures all intact.

What this means is that all the components we think are required to form a personal identity—including memory and personality—could potentially be preserved for a long period of time, before either being uploaded to a computer for perpetuity, or reanimated some time in the future. "It's the first time that we have a procedure that can protect everything neuroscientists think is involved with learning and memory", says John Smart, co-founder of the non-profit Brain Preservation Foundation. "Given the results announced today, it seems to me that long-term memories are successfully preserved by this technique. This is not yet certain or universally agreed, but seems highly likely from my position."

The Brain Preservation Foundation awarded its five-year old "Small Mammal Brain Preservation Prize" to 21st Century Medicine—an independent research group lead by MIT graduate, Robert McIntyre—for coming up with the best technique to bring a frozen mammal's (a rabbit) brain back to life. The researchers have pocketed US$26,735 for their efforts.

The team dispersed a chemical compound called glutaraldehyde into the internal structures of a rabbit's brain at the same time to stablise it and prevent decay. Then as it was undergoing cooling, they slowly added a cryoprotectant liquid to ensure that the connectome—the complex map of connections that keep the 86 billion neurons or so humming along—and synaptic structure weren’t damaged in the process. This internal damage has been the number one reason why cryopreservation of the brain has failed so consistently in the past. The whole thing was converted into a near glass-like structure by cooling it to -130 Celsius (-210 degrees Fahrenheit) over 4 hours, which prepared it for some serious long-term storage. When the team wanted to thaw it out, they just had to gently reheat the brain and flush out the cryoprotectant chemicals.

Sources: Science Alert, Motherboard.

COSYNE 2016

This year's COSYNE meeting (Feb25–28) brought together leading theoretical and computational scientists to study fundamental problems in systems neuroscience, including keynote speakers such as Xiao-Jing Wang (NYU), Paul Smolensky (Johns Hopkins), Mala Murthy (Princeton), Leslie Vosshall (Rockefeller), Greg DeAngelis (Rochester), Richard Mooney (Duke), Marisa Carrasco (NYU), and Blaise Ag├╝era y Arcas (Google).

Last year's meeting caused some controversy about declining acceptance rates, but the organizers decided to keep the size of the meeting the same this year. As a fun fact, they performed some statistical analyses on the submitted abstracts, effectively putting to rest the myth of "If it weren't for that darn 3rd reviewer!!". Turns out that excluding the least favorable review from the decision process led to mostly the same number and selection of accepted abstracts. These results suggest that the 3rd reviewer does not just categorically hate you more than all the others, but might instead simply be another independent reviewer... ;-)

Talks from the main meeting as well as the workshops are covered at length in this blog post.

The physics of brain folding

The cortex is immediately recognizable by its characteristic pattern of ridges and furrows: Although it is just several millimeters thick, it has a surface area of about two-and-a-half square feet. The folding of the brain has so far been assumed to be the result of genetics, but researchers from the University of Jyväskylä in Finland have now found evidence that the brain folds up because of physical forces.

According to a model that Harvard researchers put forward forty years ago, the brain's folds form as a result of differential growth which causes the cortex to grow in size far more quickly than other brain structures, leading it to buckle and fold as its surface area increases, due to the constraints of the skull. To test this, Tuomos Tallinen of the University of Jyväskylä and his colleagues used magnetic resonance images to create a 3D-printed cast of an unfolded 22-week-old human brain. When immersed in a liquid, the surface of the outer layer tissue swells up, leading to small compression forces that make it crease, buckle up, and fold in on itself. All of this occurs as a consequence of the mechanical instability produced by constrained expansion, leading to a pattern of convolutions that is remarkably similar in appearance to that seen in the adult human brain (see video).

Source: The Guardian.

Miscellaneous

Researchers at the University of Wisconsin-Madison have discovered a subcortical pathway for rapid, goal-driven, attentional filtering. In this framework, goal representations in prefrontal cortex (PFC) can influence sensory processing in posterior brain regions via multi-synaptic feedback pathways extending to primary sensory cortex, and subsequently the thalamic reticular nucles (TRN). (Trends in Neurosciences)

Funded by DARPA, a research team at the University of Melbourne developed a "neural interface" device which, if inserted into the brain, could allow humans to control computers using nothing but thought. The device is already used as a means of clearing blood vessels (known as a stentrode) but the team found that they could easily modify it to have electrodes attached. This would effectively allow soldier 'cyborgs' to connect directly to computers and 'talk' to them. (Huffington Post)

A new discovery by Tel Aviv University, Technion (Rambam Medical Center), and Harvard University researchers suggests that levels of activity-dependent neuroprotective protein (ADNP) in the blood stream of patients is a reliable biomarker of Alzheimer's disease. The study also found that ADNP levels tested in the blood correlate with higher IQ in healthy older adults. (Neuroscientist News)

The brains of the elderly and younger people with autism and schizophrenia may share a common link: Both have low levels of vitamin B12. The findings, reported last month in the journal PLOS ONE, support an emerging theory that the human brain uses vitamin B12 in a tightly regulated manner to control gene expression and to spur neurological development at key points during life, from the brain's high-growth periods during fetal development and early childhood, through the refining of neural networks in adolescence, and then into middle and old age. (Fox News)

Similar to the Human Connectome Project, a new large-scale, cross-disciplinary academic collaborative has been launched, called the Human Affectome Project. The initiative will make use of teams of scientists to develop a comprehensive, integrated and holistic model of affect (i.e., one that can coherently map the complete landscape of feelings and emotions to individual needs, motivation, attention, arousal, and behavior). The initiative will involve an initial workshop that will take place in Halifax, Nova Scotia, Canada this summer (4th-5th August of 2016) where participants will present on various topics and explore and refine the initial framework. Following the workshop 12 teams will then engage in the production of a series of review articles that will be prepared for a top-tier peer-reviewed neuroscience journal. The program is scheduled to complete in 2018.

A Ph.D candidate at Tufts University in Massachusetts has created a tool that helps students learn the instrument faster and with more accuracy than they would under the watchful eye of a traditional teacher, or while practicing on their own. Called BACh, for Brain Automated Chorales (and an obvious nod to one of history's most prolific composers), the system can tell how hard a student's brain is working by measuring cognitive load, and only releases a new line of music once the learner's cognitive load is light, indicating they've mastered the first line with ease. (Fast Company)

The age at which an adolescent begins using marijuana may affect typical brain development, according to researchers at the Center for BrainHealth at The University of Texas at Dallas. In a paper recently published in Developmental Cognitive Neuroscience, scientists describe how marijuana use, and the age at which use is initiated, may adversely alter brain structures that underlie higher order thinking. (Neuroscientist News)

Next month

Anything I missed? Sound away in the comment section! Have something of interest or want your discovery to be considered for next month's issue? Let me know via mbeyeler (at) uci (dot) edu.