作者单位:Univ Calif San Francisco, Dept Bioengn & Therapeut Sci, San Francisco, CA 94143 USA[1]Curtin Univ, Fac Hlth Sci, GPO Box U1987, Perth, WA 6845, Australia[2]Univ Utah, Dept Neurosurg, Salt Lake City, UT USA[3]Univ Western Australia, Fac Med, Perth, WA, Australia[4]