There’s little mystery in what our visual system does: the brain takes a pattern of photons hitting the retina and creates a coherent representation of what we see.
But how does the brain do this? And how was it wired to perform this computational marvel during development?
Cristopher Niell, who joined the faculty last fall as an assistant professor of biology in the University of Oregon Institute of Neuroscience, uses microscopy and electrical recordings to study patterns of activity and connections between neurons, the structural units of the nervous system.
Niell recorded a scientific first in 2004 with direct observation of neurons making connections in a vertebrate, the zebra fish. The nerve cells don’t grow like the branches of a tree, Niell discovered; the process is dynamic, with neurons extending and retracting as they probe areas of the brain in search of reaching one another.
Niell helped pioneer methods to label synapses in the brain and manipulate individual neurons. That’s akin to opening up a computer microprocessor to expose the wiring; furthermore, Niell can turn on or off individual cells to learn how the entire circuit works together.
Despite the fact that mice are often thought of as blind, Niell discovered that the mouse visual system performs similar computations to those in our brain, ushering in a new age of research in visual neuroscience.
“Modern genetic tools provide the opportunity to see the structure of a defined visual cell type, map its connections, record its activity in response to visual stimulation and then selectively silence or activate that cell type in a reversible manner,” said Niell and collaborator Andrew Huberman, in a recent review of vision research.
Through optogenetics, Niell uses light to stimulate specific visual neurons while recording electrical activity from others. He measures the activity of individual neurons when they fire – audible, with sound equipment, as a “pop!”
A better understanding of these neural connections will help scientists resolve abnormalities that create visual and behavioral disorders such as dyslexia, autism and schizophrenia.
In April, Niell was named a 2012 Searle Scholar (one of 15 chosen nationally), which entitles him to $300,000 in support during the next three years. In February, he received a $50,000 Sloan Research Fellowship, awarded annually to select early-career scientists and scholars by the Sloan Foundation.
“Cris is well positioned to make major contributions to our understanding of the neuronal basis of vision,” said Shawn Lockery, a UO biology professor and director of the institute. “His work will be highly attractive to national institutes that focus on the development and function of neuronal circuitry relating to mental health, vision, neurological diseases and stroke.”
Niell’s research may one day help bridge the gap between visual prosthetics developed by industry and the understanding necessary to incorporate that technology into the human experience.
“The therapeutic applications are years down the road,” university biology professor Chris Doe said. “But Cris is one of the people working toward that end.”
Said Niell: “I’ve always had an interest in how the brain works. It’s so fundamental to who we are.”