Final answer:
Following REM sleep deprivation, John will likely experience REM rebound with increased duration and intensity of REM sleep due to the homeostatic regulation of sleep.
Step-by-step explanation:
If John was deprived of REM sleep during a sleep lab experiment last night, we could reasonably expect that tonight he will d) Enter REM rebound, having longer and more intense REM sleep. The phenomenon of REM rebound occurs as a compensatory increase in the frequency and depth of REM sleep following a period of REM deprivation. This reflects the homeostatic regulation of sleep, suggesting the importance of REM sleep for functions such as emotional processing, learning, and memory.