As a child, Doris Tsao spent long hours musing on the mechanics and philosophy of vision with her father, who owns a company that designs artificial vision systems. "He made vision seem like the greatest scientific problem," she says. By the time Tsao was 11 or 12, she'd been hit by "the realization that your sense of vision is created by your brain" - and her fate as a brain researcher was sealed.
Tsao studied biology and math as an undergraduate at the California Institute of Technology, and in 1996 began her doctorate at Harvard Medical School, working on stereopsis (depth perception) with vision neuroscientist Margaret Livingstone. Researchers were just beginning to use functional MRI to study maps of human brain activation, and Livingstone sent Tsao to Massachusetts General Hospital to work with fMRI expert Roger Tootell and establish the technique in monkeys. Tsao thought she could also electrophysiologically probe activated areas of monkey's brains, thus combining fMRI's birds-eye view with the fine detail of single neuron recording.
"The big challenge was getting the monkey in the scanner," says Tsao, since they can't lie on their backs, as human scanners require, and are startled by the machine's loud clangs. Tsao had a friend taking a class at MIT's Media Lab build her a 'monkey chair,' and by 2001 she was running her first experiments.
Tsao began with stereopsis, but soon moved on to a topic that had also captured her imagination. In 1997, then Harvard University researcher Nancy Kanwisher used fMRI to identify a human cortical area specialized for face recognition. It wasn't clear, though, whether monkeys had such a dedicated module: Single-neuron studies had suggested that their face cells were scattered throughout the temporal cortex.
In 2003, Tsao and Winrich Freiwald, a monkey electrophysiologist
and at the time a postdoc with Kanwisher (now at MIT), identified
face-selective patches in monkeys using fMRI.
"It's lovely when someone takes a whole history of the field and
says, 'No, it's not quite like you think it is,' and twists it back around"
to present a new view, says Livingstone. In
2004, the Alexander von Humboldt Foundation
awarded Tsao €900,000 to start a lab
in Germany, and in 2006 she moved to the
University of Bremen, where Freiwald was
already working. The duo went on to identify
six distinct cortical regions involved in face
processing, each containing neurons with
characteristically different firing patterns.
Next year, Tsao will return to Caltech as an assistant professor in biology. She intends to return to stereopsis and other aspects of 3- dimensional vision, but there's no turning back with her work on face processing. Already, says Freiwald, "We are opening all these possibilities - almost too many for us to study them all."
Title: Head of Independent Research Group, Brain Research Institute, University of Bremen, Germany
1. D.Y. Tsao et al., "Faces and objects in macaque cerebral cortex," Nat Neurosci, 6:989-95, 2003. (Cited in 74 papers) 2. D.Y. Tsao et al., "A cortical region consisting entirely of face-selective cells," Science, 311: 670-4, 2006. (Cited in 96 papers) 3. S. Moeller et al., "Patches with links: a unified system for processing faces in the macaque temporal lobe," Science, 320:1355-9, 2008