Physiological and behavioral results of the fear conditioning task.

<p>Means and standard errors of skin conductance response (SCR, <i>panel A</i>), valence ratings (<i>panel B</i>), fear ratings (<i>panel C</i>), and unconditioned stimulus (UCS) expectancy ratings (<i>panel D</i>) in response to CS⁺ and CS⁻ across habituation (Hab), acquisition (Acq), and extinction (Ext) phases. See text for details.</p

ANOVA effects of the fear conditioning procedure for valence, fear, and unconditioned stimulus (UCS) expectancy ratings as well as skin conductance response (SCR).

<p><i>Note:</i> *significant at p<.05; n.s. = not significant. Note that the MANOVA for behavioral ratings during habituation did not display a significant main effect of CS-type and was thus not followed up by analyses for each single rating scale (see text for details).</p>a<p><i>F</i>(1,58) for factor CS-type, factor Time, and for interaction effect CS-type x Time.</p

Correlations between fear conditionability and aversive memories (as assessed by the IMQ) during the memory triggering task and ambulatory assessment.

<p><i>Note: cond.</i>: condition; <i>IMQ</i>: Intrusion Memory Questionnaire.</p><p>Non-parametric correlation coefficients (Spearman’s rho, <i>ρ</i>) are reported. See text for details.</p

Correlations between fear conditionability and aversive memories.

<p><i>Panel A</i>: Correlation between conditionability as measured by valence and aversive memories during CS⁺ cue condition of the memory triggering task. <i>Panel B</i>: Correlation between conditionability as measured by valence and ambulatorily assessed aversive memories. <i>Panel C</i>: Correlation between conditionability as measured by skin conductance response (SCR) and ambulatorily assessed aversive memories. Note: Values for aversive memories represent sum scores of the Intrusion Memory Questionnaire (IMQ) in T-scores. Variables did not fulfill bivariate normal distribution criteria and thus non-parametric correlational analyses were used. See text for details.</p

Relationship between Fear Conditionability and Aversive Memories: Evidence from a Novel Conditioned-Intrusion Paradigm

<div><p>Intrusive memories – a hallmark symptom of posttraumatic stress disorder (PTSD) – are often triggered by stimuli possessing similarity with cues that predicted or accompanied the traumatic event. According to learning theories, intrusive memories can be seen as a conditioned response to trauma reminders. However, direct laboratory evidence for the link between fear conditionability and intrusive memories is missing. Furthermore, fear conditioning studies have predominantly relied on standardized aversive stimuli (e.g. electric stimulation) that bear little resemblance to typical traumatic events. To investigate the general relationship between fear conditionability and aversive memories, we tested 66 mentally healthy females in a novel conditioned-intrusion paradigm designed to model real-life traumatic experiences. The paradigm included a differential fear conditioning procedure with neutral sounds as conditioned stimuli and short violent film clips as unconditioned stimuli. Subsequent aversive memories were assessed through a memory triggering task (within 30 minutes, in the laboratory) and ambulatory assessment (involuntary aversive memories in the 2 days following the experiment). Skin conductance responses and subjective ratings demonstrated successful differential conditioning indicating that naturalistic aversive film stimuli can be used in a fear conditioning experiment. Furthermore, aversive memories were elicited in response to the conditioned stimuli during the memory triggering task and also occurred in the 2 days following the experiment. Importantly, participants who displayed higher conditionability showed more aversive memories during the memory triggering task and during ambulatory assessment. This suggests that fear conditioning constitutes an important source of persistent aversive memories. Implications for PTSD and its treatment are discussed.</p></div

Results for aversive memories, state anxiety, and SCL during the memory triggering task.

<p><i>Note: cond.</i>: condition; <i>IMQ number</i>: number of aversive memories (“How often did memories (pictures or thoughts) of violence scenes pop into your mind during the last part of the experiment (the last 3 minutes)?”); <i>IMQ duration</i>: duration of aversive memories in % of total time of the respective condition (“How many percent of the time have you been mentally engaged with memories (pictures or thoughts) of the violence scenes during the last part of the experiment (the last 3 minutes)?”); <i>IMQ distress</i>: distress elicited by aversive memories, scale 0–100; 0 = not distressing at all, 100 = extremely distressing (“How distressing did you find these memories of the violence scenes during the last part of the experiment (the last 3 minutes)?”); <i>state anxiety</i>: assessed by STAI state scale; <i>SCL</i>: skin conductance level given as ln(1+SCL) in µS.</p>*<p>significant main effect of condition at <i>p</i><.05.</p>1 2 3<p>Different number superscripts indicate that conditions significantly differ from each other at <i>p</i><.05 in post-hoc tests.</p>a<p>Values represent sum scores of the IMQ in T-scores.</p>b<p>F(2,116).</p>c<p>F(2,114).</p

Schematic depiction of the conditioned-intrusion paradigm.

<p><i>Panel A:</i> Differential fear conditioning procedure with aversive film scenes as unconditioned stimuli (UCS) and sounds as conditioned stimuli (CS⁺ and CS⁻). See text for details. <i>Panel B:</i> Red line: Average skin conductance response to the CS⁺ and the UCS during the reinforced trials of the acquisition period. Blue line: Average skin conductance response to the CS⁻ during acquisition. The dashed line displays the boundary between CS and UCS presentation. Values are referenced to the respective baseline before CS onset; means and standard errors are displayed. <i>Panel C:</i> Memory triggering task. Neutral soundscape with superimposed CS⁺ cues (CS⁺ cue condition), CS⁻ cues (CS⁻ cue condition), or no superimposed sound cues (no-cue condition). See text for details.</p

Ambulatory assessment of aversive memories.

<p><i>Note: IMQ</i>: Intrusion Memory Questionnaire; <i>IES-R:</i> Impact of Event Scale – revised.</p>a<p>0 = not distressing at all, 100 = extremely distressing.</p>b<p>retrospective for day 0 until day 2; possible scores: intrusion 0–35, avoidance 0–40, hyperarousal 0–35.</p

Eyeblink startle magnitude (image – ITI) as a function of state (deprived, satiated) and food type (chocolate, food) (A).

<p>Startle magnitued, collapsed across food type, correlated negatively with state measures of frustration/depression (B), and attentional impulsiveness (BIS, Barrat Impulsiveness Scale) (C).</p

Subjective ratings as a function of state (deprived, satiated) and food type (chocolate, food): Picture-wise desire to eat (A), and palatability (B) ratings and block-wise ratings of frustration/depression (C).

<p>Subjective ratings as a function of state (deprived, satiated) and food type (chocolate, food): Picture-wise desire to eat (A), and palatability (B) ratings and block-wise ratings of frustration/depression (C).</p