Unconditioned,<unk> , and conditioned stimuli as well as unconditioned and conditioned responses in Ivan Pavlov's research on digestion. A<unk>  is a<unk>  which initially produces no specific response other than focusing attention. In classical conditioning, when used together with an unconditioned<unk> , the<unk>  becomes a conditioned<unk> . With repeated presentations of both the<unk>  and the unconditioned<unk> , the<unk>  will elicit a response as well, known as a conditioned response. Once the<unk>  elicits a conditioned response, the<unk>  becomes known as a conditioned<unk> . The conditioned response is the same as the unconditioned response, but occurs in the presence of the conditioned<unk>  rather than the unconditioned<unk> .
Neutral stimulus
Tetanic contraction
Stimulant
Adequate stimulus
Endogenous agonist
Co-stimulation
Overpressure
Exertion