Jill Bolte Taylor has always been fascinated by the brain.
"I've always been thinking about who am I as a brain, as a mind," Taylor told "Nightline" co-anchor Terry Moran. "To me, it's absolutely phenomenal that this collection of cells is capable of creating for us a perception of the world that seems real and that feels safe. To me that is just a mind-blowing concept."
Taylor's own perception of the world was shattered in an instant on Dec. 10, 1996, when the then 37-year-old suffered a left hemisphere stroke. As a scientist, the stroke offered a Taylor a rare opportunity to experience what she studied.
She has since shared that experience with the world in a best-selling book, "My Stroke of Insight: A Brain Scientist's Personal Journey," and a presentation she gave at the Technology, Entertainment, Design conference in February that has caught on like wildfire on the Internet.
The stroke was the moment that "everything changed," Taylor now says.
"In the course of four hours I watched my mind completely deteriorate in its ability to process all information coming in through my sensory systems," she said. "I had no ability to connect what was going on inside of my nervous system with the external world. I shifted away from being the person I was before."
Who Taylor was before the stroke was a Harvard-trained and published neuroanatomist who devoted her life to studying the brain at the cellular level. Her experience growing up with a sibling who suffered from mental illness shaped her future profession.
"Eventually [my brother] was diagnosed with chronic schizophrenia," Taylor said. "So his brain was organizing information very differently than mine, was and that fascinated me."
She chose to study the brain because, she says, "I knew I would never be bored." Still fascinated by her subject matter, Taylor calls the space inside our heads "the great frontier."
Most people would expect a stroke to be a frightening, even painful experience, but Taylor describes it differently, using words such as "bliss" and "euphoria" and adding that she didn't initially realize what was happening.
"There was no fear," she said. "I'm observing myself feeling detached from my normal perception of reality."
She calls it an "incredible education" for a scientist, because the stroke allowed her to live what she had learned about how the left and right hemispheres of the brain function.
Taylor's stroke occurred in the left hemisphere of her brain, where the language center is primarily located. The left hemisphere controls the ability to create sound and to understand words; it controls the internal organization of every detail of your life. The right hemisphere controls what Taylor calls "the big picture."
"The right hemisphere is the big contextual landscape of your life," she said. "You're not focusing on all the details. You're experiencing the whole context … So you have both of these beautiful hemispheres. One is designed to do the big picture. The other is designed to take the detail out of that, and then you walk into the world and you have both."
Taylor says her stroke of insight, her epiphany, occurred when her right hemisphere took over.