title: P50 suppression in human discrimination fear conditioning paradigm using danger and safety signals.
abstract: Auditory P50 suppression, which is assessed using a paired auditory stimuli (S1 and S2) paradigm to record the P50 mid-latency evoked potential, is assumed to reflect sensory gating. Recently, P50 suppression deficits were observed in patients with anxiety disorders, including panic disorder, post-traumatic stress disorder and obsessive-compulsive disorder, as we previously reported. The processes of fear conditioning are thought to play a role in the pathophysiology of anxiety disorders. In addition, we found that the P50 sensory gating mechanism might be physiologically associated with fear conditioning and extinction in a simple human fear-conditioning paradigm that involved a light signal as a conditioned stimulus (CS+). Our objective was to investigate the different patterns of P50 suppression in a discrimination fear-conditioning paradigm with both a CS+ (danger signal) and a CS- (safety signal). Twenty healthy volunteers were recruited. We measured the auditory P50 suppression in the control (baseline) phase, in the fear-acquisition phase, and in the fear-extinction phase using a discrimination fear-conditioning paradigm. Two-way (CSs vs. phase) Analysis of variance with repeated measures demonstrated a significant interaction between the two factors. Post-hoc LSD analysis indicated that the P50 S2/S1 ratio in the CS+ acquisition phase was significantly higher than that in the CS- acquisition phase. These results suggest that the auditory P50 sensory gating might differ according to the cognition of the properties (potentially dangerous or safe) of the perceived signal.
authors.affiliation: Research Center for Child Mental Development, Graduate School of Medicine, Chiba University, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Kurayama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Matsuzawa
authors.forename: Zen
authors.initials: Z
authors.lastname: Komiya
authors.forename: Ken
authors.initials: K
authors.lastname: Nakazawa
authors.forename: Susumu
authors.initials: S
authors.lastname: Yoshida
authors.forename: Eiji
authors.initials: E
authors.lastname: Shimizu
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology*; D003617:Dangerous Behavior; D004192:Discrimination, Psychological / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology*; D005239:Fear / Q000502:physiology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D055815:Young Adult