Theta wave

Theta waves were a type of brain wave usually experienced just before or after a period of deep sleep.

In 2154, Phlox determined that Jonathan Archer's theta wave levels were fine while he was comatose. 

The Altonian brain teaser responded to neural theta waves. 

In 2367, Doctor Beverly Crusher tried inducing theta waves into the entorhinal cortices of the USS Enterprise (NCC-1701-D) to help them achieve REM sleep, with no effect. .

Cortical inhibitors were used to control theta wave activity. 

In 2373, B'Elanna Torres' theta wave pattern indicated she was experiencing implanted memories, having received them telepathically from Jora Mirell.