Prepulse Inhibition and Startle Reflex Test

Prepulse inhibition (PPI), also termed as startle reduction or reflex modification, is a phenomenon in which a weak stimulus (Prepulse) can suppress the startle response to a subsequent stronger startle stimulus (pulse). Impairment in PPI is believed to be linked to a dysfunction in the sensorimotor gating mechanism. Clinical studies in humans have shown that patients with schizophrenia, schizotypal personality disorder, obsessive-compulsive disorder, and Huntington’s disease have impairment in PPI. The nucleus accumbens, hippocampus, amygdala, medial prefrontal cortex, pedunculotegmental nucleus, and ventral and caudodorsal striatum play important roles in PPI. Several neurotransmitters such as dopamine, acetylcholine, serotonin, glutamate, GABA and nor epinephrine also have a role in regulating PPI.