Startle and Pre-Pulse Inhibition

The startle task is used to measure a number of behaviors, including basic startle, pre-pulse inhibition, and fear potentiation of the startle response.  The apparatus can be used to measure basic physiology as well as learning and memory.


Subjects are placed in a restraint tube mounted on a startle measuring platform.  The startle response to a stimulus of loud noise is recorded.

Basic Startle Response

In basic startle, startle stimuli of various intensities are presented unexpectedly. Varying startle response and habituation are recorded.

Pre-Pulse Inhibition

In Pre-Pulse Inhibition (PPI), the startle stimulus is paired with a predictive cue. In normal subjects, the “pre-pulse” cue reduces the startle amplitude.  This inhibition of the startle response is known as PPI.  Humans and animal models of several disease states are known to have pre-pulse inhibition deficits, including schizophrenia, Alzheimer’s, and PTSD.

Fear-Potentiated Startle

In Fear-Potentiated Startle, the subjects are trained to associate a neutral stimulus, such as a light cue, with an aversive stimulus.  When the startle response is tested in the presence of the light cue, the startle amplitude should be potentiated, or increased.

Equipment Capabilities

Our current system has the capability of producing sound stimuli, light stimuli and shock stimuli. We are in the process of acquiring an additional module which will allow us to also produce tactile stimuli (air puff to the animal’s back). Our equipment can be used on up to 4 mice or rats at the same time.