The BRAIN Initiative is marking a milestone—10 years of advancing neuroscience and neurotechnology research by funding innovative projects. As part of a rotating series of blog posts, the directors of the BRAIN Initiative-partnering Institutes and Centers share their voice and perspectives on the impact BRAIN has made on their respective missions—and vice versa.
By Michael F. Chiang, MD, Director, NEI
How has NEI participated in the NIH BRAIN Initiative?
The National Eye Institute has been part of BRAIN since its beginning. Over the past 10 years, vision-related projects have comprised a substantial portion (20-30%) of the BRAIN portfolio. One reason is that the retina—an extension of the brain—is more accessible than other parts of the brain. The retina is easy to image using new tools such as optical coherence tomography, a non-invasive imaging approach that uses light waves to take detailed pictures and surgically access the layers of the retina. In addition, the eye is easily accessible surgically, and many methods exist to measure retinal function. These factors make the eye and the visual system an outstanding model system for developing and testing new tools and methods. Vision-related BRAIN projects have helped explain neural information processing: the components and processes that help us think, move, and experience the world around us. It has been fascinating to see vision science and neuroscience move each other forward.
Why do you think it’s important for NEI to participate in the NIH BRAIN Initiative?
A unique benefit of studying the visual system through the BRAIN Initiative is that we can trace a stimulus (an object or other image such as motion or change in contrast) to the specific brain region, cell type, or even individual neuron that processes the stimulus. This approach is most useful when we understand exactly where the stimulus has fallen on the retina—optimally in a natural environment as individuals move freely. Research initially funded by NEI revealed that as humans navigate different types of terrain, movement of the head and eyes adapts to the challenges of the environment—producing unique patterns as the retina fixates on particular objects or points within a natural scene. BRAIN-funded projects have begun to explore how understanding eye motion and gaze in a variety of experimental systems—including in mice and non-human primates—can enhance our study of visual processing.
What major BRAIN-funded scientific advancements or conversations has NEI been a part of?
One of our most exciting BRAIN collaborations has been the BRAIN Atlas and the Cell Census Network. Through this work, we have unearthed the ancient evolution of retinal cells as well as discovered species-specific cell types in the retina. For example, bipolar retinal neurons, which transmit visual information within the retina, tend to be highly conserved across species. In contrast, retinal ganglion cells, which transmit visual information from the eye to the brain, are much more diverse. Deepening our knowledge of the cell types in the retina helps us understand signal processing and may provide new approaches to preserving and restoring sight.
How has the BRAIN Initiative advanced or shaped your mission?
The NIH BRAIN Initiative has spurred the development of novel resources and tools that will support vision research for years to come. One example is the Allen Brain Map, which houses a set of cell atlases and brain maps at the BRAIN-supported Allen Institute in Seattle. BRAIN-supported projects have developed transformational methods and technologies that have opened many new areas of exploration.
One of NEI’s goals over the past decade has been to find ways to restore vision through tissue regeneration or prosthetic devices. Restoring signal transmission from the retina to other parts of the brain has turned out to be even more complex than we thought, driving the development of new devices, tools, and strategies to establish or regenerate eye-brain connections.
Some BRAIN researchers are exploring the lateral geniculate nucleus as a prosthetic connection point. This region, which relays visual information from the retina to the primary visual cortex (at the back of the brain), may be more accessible than deeper regions of the visual cortex. Researchers have also developed a thin, flexible film that can record thousands of connections over a wide area of the cortex. Still others are exploring multimodal technologies to stimulate neurons in the retina or the brain. For example, “optoacoustics” allows light entering through the eye’s lens to activate ultrasound waves that stimulate retinal neurons. This low-energy process can control neuronal activity with high precision while minimizing heat damage to the retina.
These and other advances from BRAIN-funded research are catalyzing ongoing basic research at NEI and are paving the way for the next chapter in understanding and potentially restoring vision.
Image: Michael F. Chiang, MD, Director, NEI