You feel yourself float up and out of your physical body. You glide toward the entrance of a tunnel, and a searing bright light envelops your field of vision.

Rather than an ascent into the afterlife, a new study says these features of a near-death experience may just be a bunch of neurons in your brain going nuts.

"A lot of people believed that what they saw was heaven," said lead researcher and neurologist Jimo Borjigin. "Science hadn't given them a convincing alternative."

Scientists from the University of Michigan recorded electroencephalogram (EEG) signals in nine anesthetized rats after inducing cardiac arrest. Within the first 30 seconds after the heart had stopped, all the mammals displayed a surge of brain activity that had features associated with consciousness and visual activation. The burst of electrical activity even exceeded levels during a normal, awake state.

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