Anxious responses to predictable and unpredictable aversive events.
Anxiety induced by 2 types of predictable and unpredictable aversive stimuli, an unpleasant shock or a less aversive airblast to the larynx, were investigated in a between-group design. Participants anticipated predictable (signaled) or unpredictable (not signaled) aversive events, or no aversive event. Unpredictable, relative to predictable, contexts potentiated the startle reflex in the shock group but not in the airblast group. These data suggest that unpredictability can lead to a sustained level of anxiety only when the pending stimulus is sufficiently aversive. Because predictable and unpredictable danger may induce different types of aversive responses, the proposed design can serve as a useful tool for studying the neurobiology and psychopharmacology of fear and anxiety.
Grillon
Christian
C
Mood and Anxiety Disorder Program, National Institute of Mental Health, 15K North Drive, Bldg. 15K, Room 113, MSC 2670, Bethesda, MD 20892-2670, USA. christian.grillon@nih.gov.
Baas
Johanna P
JP
Lissek
Shmuel
S
Smith
Kathryn
K
Milstein
Jean
J
D000328:Adult; D000704:Analysis of Variance; D001007:Anxiety / Q000503:physiopathology* / Q000523:psychology; D001362:Avoidance Learning / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D013216:Reflex, Startle / Q000502:physiology*