When I was studying Psychology we did some alpha wavelength "training" using bio feedback methods
Alpha is characterized as 8-13 CPS and is associated with unfocused attention or a relaxed mental and physical state.

"Alpha is generated during meditation or generally when the mind and body is in a quiet and relaxed position; either sitting or lying down with the eyes closed" but nevertheless allows full awareness of the environment - it relieves tension and is often referred to as "active rest" in Yoga.

I still use this method today to achieve a state of mental and physical relaxation during a hectic time; I don't consider it's ever made me "overly receptive!