Sine Wave

Muriel seemed to be a bit worked up as she pedaled along with the group on the regular social ride. "I think the mind has electrical currents". She said this like it was the first time it was ever said.
"Of course it does". Someone in the group chimed.
"Three kinds of current".
"Oh??"
"Yes, two, the happy emotion and the sad emotion each have a DC and Clarity of Thinking is AC". Matter of factly Muriel states.
"I can't wait to hear some more". From insided the rolling group, of which were cruising at a nice pace down the country road.
"The only trouble is that the AC current has breaks in it making it a weaker current, at least for the brain, which then makes clear thinking's duration so short, effective only at the peak of the sine wave".
"Hog Wash" Peleton's chorus.

Can anyone tell me who said this, or something like this?
"Everyone of us arrived here involuntarily and uninvited, for a short stay and not knowing why"
You get a prize if you can.

In her life she roamed the earth searching for here home, not knowing where it is. But when she gets there she will recognize it. The earth is a big place, but maybe that's what IS home.