An evoked potential (or "evoked response") is an electrical potential recorded from the nervous system of a human or other animal following presentation of a stimulus, as distinct from spontaneous potentials as detected by electroencephalography (EEG) or electromyography (EMG).

Evoked potential amplitudes tend to be low, ranging from less than a microvolt to several microvolts, compared to tens of microvolts for EEG, millivolts for EMG, and often close to a volt for ECG. To resolve these low-amplitude potentials against the background of ongoing EEG, ECG, EMG, and other biological signals and ambient noise, signal averaging is usually required. The signal is time-locked to the stimulus and most of the noise occurs randomly, allowing the noise to be averaged out with averaging of repeated responses.

Signals can be recorded from cerebral cortex, brain stem, spinal cord and peripheral nerves. Usually the term "evoked potential" is reserved for responses involving either recording from, or stimulation of, central nervous system structures. Thus evoked compound motor action potentials (CMAP) or sensory nerve action potentials (SNAP) as used in nerve conduction studies (NCS) are generally not thought of as evoked potentials, though they do meet the above definition.

John Felix Anthony Cena (/ˈsiːnə/; born April 23, 1977) is an American professional wrestler and actor. He is currently signed to WWE as a member of its Raw brand.

In WWE, Cena has won 19 championships in total, including 12 world titles (having won the WWE Championship a record 10 times and the World Heavyweight Championship twice). In addition, Cena has also won the WWE United States Championship three times, and is a four-time Tag Team Champion, having held the World Tag Team Championship twice (once each with Shawn Michaels and Batista), and the WWE Tag Team Championship twice (once each with David Otunga and The Miz). Cena also won the 2008 Royal Rumble match, and is a two-time Superstar of the Year Slammy Award winner (2009 and 2010). He also has the fourth highest number of combined days as WWE Champion behind Bob Backlund, Hulk Hogan and Bruno Sammartino.

Cena started his professional wrestling career in 2000, wrestling for Ultimate Pro Wrestling, where he held the UPW Heavyweight Championship. In 2001, Cena signed a contract with the World Wrestling Federation (WWF) and was sent to Ohio Valley Wrestling (OVW) where he held the OVW Heavyweight Championship and the OVW Southern Tag Team Championship (with Rico Constantino).