Difference between conditioned freezing, shock sensitization to startle and conditioned fear potentiation to startle?

Question

I am reading paper-listed below-that talks about three terms, Conditioned freezing; Shock sensitization to startle; Conditioned fear potentiation to startle.

I understand that conditioned freezing takes place when the subject (rat) learns to associate a neutral stimulus (CS) with an aversive stimulus (US), such that when the CS is presented alone, the subject will freeze in the form of defensive behavior. However, I do not understand its relation to the other two terms listed above.

The paper citation is below,

Richardson, R., & Vishney, A. (2000). Shock sensitization of startle in the developing rat. Developmental Psychobiology: The Journal of the International Society for Developmental Psychobiology, 36(4), 282-291.

Answer 1

The first sentence of the abstract is:

Rats given a series of shocks exhibit a potentiated startle response to a loud acoustic stimulus compared to nonshocked animals

Shock sensitization to startle refers to how giving a series of shocks results in a stronger startle in response to a startling acoustic stimulus.

The first sentence of the introduction is:

Presentation of a stimulus (e.g., a tone or a light) that had been previously paired with an aversive stimulus (e.g., shock) markedly enhances the unconditioned startle response to a loud, unexpected noise. This effect is referred to as fear potentiation of startle

Fear potentiation of startle is a more general case of "shock sensitization to startle" - animals who are made fearful respond more strongly to a startling cue. This is probably something you are familiar with as a human, too: think about jump scares in a haunted house, being startled by something while watching a scary movie, a sudden noise when walking in the dark, etc.

When reading a paper you might start at the beginning and find the first places that terms you are interested in are mentioned - that's usually where they will be defined.