Babinski response n : extension upward of the toes when the sole of the foot is stroked firmly on the outer side from the heel to the front; normal in infants under the age of 2 years but a sign of brain or spinal cord injury in older persons [syn: Babinski, Babinski reflex, Babinski sign, plantar responses are extensor] (Credit: Hypertext Webster Gateway at UCSD). CLICK HERE to see a movie of a Babinski reaction (Note: You need to have an MPEG movie player for your browser. If you don't, you can download CINEWEB.)