You're standing near an airport luggage carousel and your
bag emerges on the conveyor belt, prompting you to spring into action. How does
your brain make the shift from passively waiting to taking action when your bag
appears?
A new study from investigators at the University of Michigan
and Eli Lilly may reveal the brain's "switch" for new behavior. They
measured levels of a neurotransmitter called acetylcholine, which is involved
in attention and memory, while rats monitored a screen for a signal. At the end
of each trial, the rat had to indicate if a signal had occurred.