Personality Correlates of Prepulse Inhibition of the Startle Reflex at Three Lead Intervals

Abstract

Abstract The acoustic startle reflex (ASR) is modulated by a number of experimental factors, the most important of which in the field of psychopathology is weak prestimulation: The ASR is reliably reduced if preceded briefly by a weaker stimulus (i. e., the prepulse), an effect known as prepulse inhibition (PPI). PPI is thought to reflect centrally-mediated sensorimotor gating of stimuli, preventing cognitive overload and behavioural confusion. PPI is impaired in a variety of psychiatric disorders, notably schizophrenia, as well as in individuals who score high on psychometric measures of psychosis proneness. Two experiments examined the association of personality (trait emotionality) and PPI at three prepulse-to-pulse intervals (30, 60 and 120 ms). Consistent with previous reports, findings from both experiments showed highly significant PPI (defined as percentage reduction in the amplitude of the ASR), which increased with prepulse-to-pulse interval (30 < 60 < 120 ms). A novel finding was that, in both experiments 1 (N = 36) and 2 (N = 63), the trait of neuroticism was negatively correlated with PPI; in addition, a measure of positive incentive motivation (i. e., Behavioural Activation System, Drive subscale; BAS-Drive) was also negatively correlated with PPI. These trait emotionality associations were independent of gender. Possible causal explanations of these personality associations are outlined. It is concluded that, in order to clarify the aetiological role of sensorimotor gating in psychopathological conditions (e. g., schizophrenia, often entailing emotional activation), trait emotionality variance should be routinely examined in future PPI studies.