When you get up in the morning and just before sleep, you are naturally in this state. When you close your eyes your brain automatically starts producing more alpha waves. Many studies monitoring the EEG activity of experienced meditators have revealed strong increases in alpha activity.
Bottom-up processing happens when someone tries to understand language by looking at individual meanings or grammatical characteristics of the most basic units of the text, (e.g. sounds for a listening or words for a reading), and moves from these to trying to understand the whole text.
get to the bottom of something. to discover the truth about something The electric company has not yet gotten to the bottom of why we had such a huge blackout. get to the bottom of something. to discover the truth about a situation (often + question word) The family finally got to the bottom of why their boy was killed. How will investigators get to the bottom of the affair with so little evidence? See also: bottom, get, of.