Glimpses into the Brain through the Senses

This month, the eyes were a focus at two Kavli Institutes: Jeremy Nathans team at the Kavli Neuroscience Discovery Institute at Johns Hopkins University developed an atlas of the cells in the iris; and, Matthias Nau, Markus Frey and Christian Doeller at the Kavli Institute for Neural Systems at the Norwegian University of Science and Technology have developed a user-friendly, camera-free method of tracking eye movement— gathering a rich source of information about how behavior connects to cognition and brain health.

New View of the Iris

The cellular tapestry of the iris is no longer in the eye of the beholder. A team of researchers from Johns Hopkins University has mapped the cell types in the mouse iris—the many-hued ring of tissue surrounding the pupil. The cell-by-cell map will serve as a foundational resource for others studying the iris’ structure and function, development and role in disease. It could also help scientists engineer cell therapies to replace damaged tissue. The team was led by Jeremy Nathans, a member of the Kavli Neuroscience Discovery Institute, who said in a recent news article, “The basic biology of the iris had kind of languished.” No longer. In a study published in eLife, Nathans and his colleagues identified eight iris cell types, including two that had not been described before. They also discovered the developmental origin of iris cells and observed major changes in gene expression in the cells that constrict or dilate the pupil, changing the amount of light that hits the retina. The cellular atlas will serve as a resource for other researchers studying the intricacies of the eye and disease of the iris.

Viewing Habits

The eyes give away a lot. Tracking how the eyes move can actually tell researchers a lot about our cognitive processes and help them diagnose brain diseases. For decades, neuroscientists have used eye-tracking cameras to study subtle shifts in gaze and their relationship to the brain and mind. But the technology is expensive and difficult to use. As a result, eye tracking has not become routine in the clinic in the same way we monitor heart rate or blood pressure to gauge health and disease. Fortunately, researchers at the Kavli Institute for Systems Neuroscience at the Norwegian Science and Technology University have now developed DeepMReye (pronounced “deep M-R-I”), a user-friendly eye tracker that monitors eye movements using functional magnetic resonance imaging (fMRI) scans. It is an analytical technique that decodes eye movement and gaze direction from new or previously collected scans, including those taken when the eyes are closed. In a news article, Dr Matthias Nau, a researcher in Christian Doeller’s lab, said he hopes the camera-free tracking tool will be a “plug-and-play” solution that allows more scientists and clinicians to tap into the power of the eyes. DeepMReye is open source and freely available on Github, where it could be used to answer questions related to attention, decision making, social behavior and more.

Dance Dance Evolution

Why do humans dance? That is the question at the center of a new research project by Sadye Paez and Constantina Theofanopoulou, two members of Erich Jarvis’s Laboratory of Neurogenetics of Language at The Rockefeller University. Paez and Constantina are both experts in neuroscience and genomics, as well as accomplished dancers—Paez in Latin dance and Theofanopoulou in Flamenco. In collaboration with New York University’s Center for Ballet and the Arts, they will study the purpose of dance in human evolution. Whereas humans can hear a sound and tap out a rhythm, our closest relatives, the Great Apes, struggle to do so. The researchers will also explore the connections between the neuroscience of vocal learning and of rhythmic movement across species. “The impulse to move is innate, and the continuum of movement is as vast and infinite as the numbers and types of species.… But the ability to move rhythmically, what we call ‘dance’ or ‘movement to sound’, is unique. This distinct ability to purposefully control and coordinate our bodies in response to cadence or tempo has exciting applications,” said Paez, in a news release. Jarvis is a member of the Kavli Neural Systems Institute at Rockefeller.

Scent-sational!

Mind-reading happens every day in the lab of Sreekanth Chalasani at the Salk Institute for Biological Studies. His target isn’t the human brain; it’s the worm’s. With just 302 neurons, the nematode C.elegans makes it possible for researchers like Chalasani to study how individual cells react to stimuli. In a recent study, he watched how networks of neurons in the worm’s nervous system reacted to five different odors, including salt. The goal was to see beyond the handful of neurons known to directly sense odor and capture the organism’s brain-wide response. When Chalasani and his colleagues imaged the worm’s nervous system, they saw 50 or 60 neurons respond to a puff of each chemical odorant. Then they used mathematical methods to identify patterns in the neural activity that corresponded to each chemical. While they didn’t identify a unique neural fingerprint for each odorant, they showed that the approach may be helpful in unravelling how neurons encode complex information and how that these processes may go awry in sensory and cognitive disorders. Chalasani is a member of the Kavli Institute for Brain and Mind (KIBM) at the Salk.

Reading List

Gabriel Silva leads the Mathematical Neuroscience Lab at the University of California San Diego, where he is also associate director of the Kavli Institute of Brain and Mind. Silva and his team use mathematics and engineering to understand the brain, and are developing brain-inspired machine learning techniques. In an article on Medium, Silva calls for Theoretical Neuroscience 2.0, arguing that computational neuroscience will not lead us to a better understanding of brain function unless the mathematical models it produces can be experimentally tested. On Medium and as a contributor to Forbes, Silva draws on his expertise in neuroscience and engineering to cover topics like: How nanotechnology is impacting neuroscience, how new technologies could help restore vision, and space travel might impact the brain.