Pavlovian-to-instrumental transfer after human threat conditioning

Abstract

Threat conditioning is a common associative learning model with translational relevance. How threat-conditioned cues impact on formally unrelated instrumental behavior in humans is not well known. Such an effect is known as Pavlovian-to-instrumental transfer (PIT). While PIT with aversive primary Pavlovian reinforcers is established in nonhuman animals, this is less clear in humans, where secondary reinforcers or instructed instrumental responses are most often investigated. We modified an existing human PIT procedure to include primary reinforcers. Participants first learned to obtain (or avoid losing) appetitive instrumental reinforcement (chocolate) by appropriate approach or avoidance actions. They either had to act (Go) or to withhold an action (NoGo), and in the Go condition either to approach a reward target to collect it or to withdraw from the reward target to avoid losing it. Then they learned to associate screen color (CS) with aversive Pavlovian reinforcement (electric shock US). In the transfer phase, we conducted the instrumental task during the presence of Pavlovian CS. In a first experiment, we show that the aversive Pavlovian CS+, compared to CS−, increased response rate in Go-Withdraw trials, i.e., induce conditioned facilitation of avoidance responses. This finding was confirmed in a second and independent experiment with an increased number of Go-Withdraw trials. Notably, we observed no appreciable conditioned suppression of approach responses. Effect size to distinguish CS+/CS− in Go-Withdraw trials was d = 0.42 in the confirmation sample. This would require n = 37 participants to demonstrate threat learning with 80% power. Thus, the effect size is on a practically useful scale although smaller than for model-based analysis of autonomic measures. In summary, our results indicate conditioned facilitation of formally unrelated instrumental avoidance behavior in humans and provide a novel behavioral threat learning measure that requires only key presses.

Saccadic Scanpath Length: An Index for Human Threat Conditioning

“…The corresponding confidence interval was computed using bootci in Matlab (biascorrected and accelerated bootstrapping). We also computed Akaike Information Criterion (AIC) as in previous work (Xia et al, 2019a). Log Bayes Factor (LBF) was then calculated from AIC values by formula LBF = (AIC -AICref)/2.…”

“…We developed this threat conditioning measure with an eye on concurrent pupil size recordings but we note that the lack of a fixation cross may decrease retrodictive validity of pupillary responses (Xia et al, 2019a). In order to combine both measures, more sophisticated correction of the pupil foreshortening error may be required (Hayes & Petrov, 2016).…”

“…We thus report data from 21 participants in Experiment 1 (12 females, mean age ± standard deviation 26.4±3.6 years), 35 participants in Experiment 2 (21 females, 24.7±3.8 years), 26 participants in Experiment 3 (15 females, 24.6±3.0 years), and 22 participants in Experiment 4 (15 females, 26.4±5.2 years). Experiments 1-2 were primarily conducted to assess Pavlovian-to-Instrumental transfer after threat conditioning; behavioural and psychophysiological data from these experiments are published in a previous report (Xia et al, 2019a; see for data sets: Xia, Gurkina, & Bach, 2019b, 2019c. Experiment 4 had been conducted during development of a model for threat-conditioned pupil size responses (Korn et al, 2017); psychophysiological results from this experiment are also published (see for data set: Korn, Staib, Tzovara, Castegnetti, & Bach, 2018).…”

“…Finally, we compare psychometric properties of different threat conditioning measures( Figure 5). We did not include PSR in this comparison as these are compromised by the lack of an explicit instruction to fixate (Xia et al, 2019a). Our main development criterion was retrodictive validity, which gives an estimate of combined trueness and precision of a measure.…”

“…This includes overt behavior such as freezing (Bouton & Bolles, 1980;Roelofs, Hagenaars, & Stins, 2010), autonomic nervous system responses, measured as changes in skin conductance (Bach, Daunizeau, Friston, & Dolan, 2010;Staib, Castegnetti, & Bach, 2015), pupil size (Korn, Staib, Tzovara, Castegnetti, & Bach, 2017), heart period (Castegnetti et al, 2016) or respiration amplitude (Castegnetti, Tzovara, Staib, Gerster, & Bach, 2017), and the modulation of externally elicited behaviours, such as fear-potentiated startle (Blumenthal, 1988;Blumenthal et al, 2005;Khemka, Tzovara, Gerster, Quednow, & Bach, 2017) or Pavlovian-to-instrumental transfer (Xia, Gurkina, & Bach, 2019a). While all of these measures have specific advantages and disadvantages (see Ojala & Bach, 2020 for a review), a common limitation is their modest retrodictive validity.…”