title: Uncertainty of trial timing enhances acquisition of conditioned eyeblinks in anxiety vulnerable individuals.
abstract: Recent work has found that behaviorally inhibited (BI) individuals exhibit enhanced eyeblink conditioning in omission and yoked training as well as with schedules of partial reinforcement. We hypothesized that spacing CS-US paired trials over a longer period of time by extending and varying the inter-trial interval (ITI) would facilitate learning. All participants completed the Adult Measure of Behavioural Inhibition (AMBI) and were grouped as behaviorally inhibited (BI) and non-behaviorally inhibited (NI) based on a median split score of 15.5. All participants received 3 US alone trials and 30CS-US paired trials for acquisition training and 20CS alone trials for extinction training in one session. Conditioning stimuli were a 500 ms tone conditioned stimulus (CS) and a 50-ms air puff unconditional stimulus (US). Participants were randomly assigned to receive a short ITI (mean=30+/- 5s), a long ITI (mean=57+/- 5s) or a variable long ITI (mean=57 s, range 25-123 s). No significant ITI effects were observed for acquisition or extinction. Overall, anxiety vulnerable individuals exhibited enhanced conditioned eyeblink responses as compared to non-vulnerable individuals. This enhanced acquisition of CRs was significant in spaced training with a variable long ITI, but not the short or long ITI. There were no significant effects of ITI or BI on extinction. These findings are interpreted based on the idea that uncertainty plays a role in anxiety and can enhance associative learning in anxiety vulnerable individuals.
authors.affiliation: School of Psychological Sciences, University of Northern Colorado, Greeley, CO, United States; Stress and Motivated Behavior Institute, Syracuse, NY, United States. Electronic address: michael.allen@unco.edu.
authors.forename: M T
authors.initials: MT
authors.lastname: Allen
authors.affiliation: Neurobehavioral Research Laboratory, Department of Veterans Affairs, VA New Jersey Health Care System, East Orange, NJ, United States; Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers the State University of New Jersey, Newark, NJ, United States.
authors.forename: C E
authors.initials: CE
authors.lastname: Myers
authors.affiliation: Stress and Motivated Behavior Institute, Syracuse, NY, United States; Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers the State University of New Jersey, Newark, NJ, United States; Syracuse VA Medical Center, Department of Veterans Affairs, Syracuse, NY, United States.
authors.forename: R J
authors.initials: RJ
authors.lastname: Servatius
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001007:Anxiety / Q000503:physiopathology* / Q000523:psychology*; D003214:Conditioning, Classical; D003215:Conditioning, Eyelid / Q000502:physiology*; D004576:Electromyography; D005108:Extinction, Psychological; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D011594:Psychometrics; D055815:Young Adult
keywords: Anxiety; Associative learning; Classical conditioning; Eyeblink; Trial timing; Uncertainty