Biomedical subjects

Frank Baeyens

Publications and source records attributed to Frank Baeyens.

14 recordsLinked to original sources

PubMed2006

The repeated confrontation with videotapes of spiders in multiple contexts attenuates renewal of fear in spider-anxious students.

In a treatment-analogue experiment, extinction of fear of spiders was investigated in a group of spider-anxious students. Two groups were created: in the single extinction group the extinction trials consisted of repeated presentations of a videotaped spider in one specific location of a house, whereas in the multiple extinction group the trials consisted of videotapes of the same spider in three different locations of a house. Also a control group was included that was exposed to videotapes of the location but without the spider. As reflected in skin conductance responses and self-report data, fear of spiders was significantly reduced in the two extinction groups compared to the control group. Moreover, when the extinction groups were confronted with the videotape of the spider in a new location, the single extinction group did not show generalisation of extinction, whereas the multiple extinction group did. These results corroborate the existing evidence for context dependence of extinction of fear and provide new evidence that the use of multiple contexts during extinction might improve the generalisability of extinction in humans. Implications for exposure therapy are discussed.

Adolescent↗

PubMed2006

Concomitant deficits in working memory and fear extinction are functionally dissociated from reduced anxiety in metabotropic glutamate receptor 7-deficient mice.

Metabotropic glutamate receptor 7 (mGluR7), a receptor with a distinct brain distribution and a putative role in anxiety, emotional responding, and spatial working memory, could be an interesting therapeutic target for fear and anxiety disorders. mGluR7-deficient (mGluR7-/-) mice showed essentially normal performance in tests for neuromotor and exploratory activity and passive avoidance learning but prominent anxiolytic behavior in two anxiety tests. They showed a delayed learning curve during the acquisition of the hidden-platform water maze, and three interspersed probe trials indicated that mGluR7-/- mice were slower to acquire spatial information. Working memory in the water maze task and the radial arm maze was impaired in mGluR7-/- mice compared with mGluR7+/+. mGluR7-/- mice also displayed a higher resistance to extinction of fear-elicited response suppression in a conditioned emotional response protocol. In a non-fear-based water maze protocol, mGluR7-/- mice displayed similar delayed extinction. These observed behavioral changes are probably not attributable to changes in AMPA or NMDA receptor function because expression levels of AMPA and NMDA receptors were unaltered. Extinction of conditioned fear is an active and context-dependent form of inhibitory learning and an experimental model for therapeutic fear reduction. It appears to depend on glutamatergic and higher-level brain functions similar to those involved in spatial working memory but functionally dissociated from those that mediate constitutional responses in anxiety tests.

Analysis of Variance↗

PubMed2006

Stronger renewal in human fear conditioning when tested with an acquisition retrieval cue than with an extinction retrieval cue.

It was previously demonstrated in our laboratory that conditioned fear in humans can renew after extinction, when this procedure took place in a different context (ABA-renewal [Vansteenwegen et al. (2005). Return of fear in a human differential conditioning paradigm caused by a return to the original acquisition context. Behaviour Research and Therapy, 43(3), 323-336]). Using the same experimental design, we now tested the power of retrieval cues to interact with this contextual renewal phenomenon. Two groups went through acquisition and extinction (in a different context). They were then tested in the original acquisition context and in the presence of a retrieval cue. In the acquisition-cue group, this cue previously featured during the acquisition procedure; in the extinction-cue group, the cue previously featured during the extinction procedure. As expected, renewal of conditioned electro-dermal responding and retrospective expectancy ratings was strongest in the acquisition-cue group. Theoretical and clinical implications of this finding are discussed.

Association Learning↗

PubMed2006

Determinants and predictive validity of direct and indirect measures of recently acquired food attitudes.

The present study examined whether the affective priming paradigm in the picture-picture naming task can be used to measure recently acquired food attitudes. Food (dis)likes were induced by an evaluative learning procedure in which real food items were contingently paired with sensory liking or expected consequences information. It was found that the picture-picture naming task is capable of measuring recently induced food attitudes irrespective of whether they were based on sensory liking or expected consequences information. In addition, we observed that affective priming effects that are obtained with the naming task can be used to predict food-related choice behaviour, irrespective of whether participants are given time to elaborate on their choice or not. The latter finding, however, emerged only when food attitudes were based on sensory liking.

Adult↗

PubMed2005

Evaluative conditioning is intact after unilateral resection of the anterior temporal lobe in humans.

Several lesion and functional imaging studies conducted in animals and humans suggest that structures within the amygdaloid nuclear complex (ANC) are important for the occurrence of fear conditioning. Whether this brain structure is also critical for evaluative conditioning, has been investigated less frequently. In the current experiment, a group of participants with unilateral resection of the anterior temporal lobe and a control group received a differential evaluative flavor-taste conditioning task. In the pre-acquisition phase, two fruit flavors (the conditioned stimuli (CSs)) were presented and participants were instructed to evaluate both. In the subsequent acquisition phase, one of these fruit flavors (CS+) was presented together with a bad tasting substance Tween20 (polysorbate 20, the US), while the other flavor (CS-) was never paired with Tween20. Finally, in the post-acquisition phase, the two flavors were presented again without Tween20 and participants were asked to evaluate both of them for a last time. The control group as well as the lesion group rated the CS+ in the post-acquisition phase less favorable than in the pre-acquisition phase, while the ratings of the CS- remained the same in both phases. We clearly demonstrated evaluative conditioning in both test groups. Because the lesion group had still one intact ANC it would be premature, however, to conclude that the ANC is not involved in evaluative conditioning. We conclude that despite evidence for impaired fear conditioning, unilateral damage to the ANC does not impair evaluative conditioning.

Adult↗

PubMed2005

Return of fear in a human differential conditioning paradigm caused by a return to the original acquistion context.

In a differential human fear conditioning paradigm evidence for ABA-renewal was obtained manipulating the lighting in the experimental room. During acquisition in either a dark or illuminated room, one neutral slide was sometimes paired with a loud aversive noise whereas another slide was not. Subsequently, extinction took place in the opposite lighting context. When afterwards the participants were tested again in the original acquisition context, measurements revealed a recovery of the conditioned electrodermal response and an increase in the retrospective verbal US-expectancy ratings. No response recovery was obtained in an AAA-group that received acquisition, extinction and test trials in one and the same context. Several theoretical explanations for this type of return of fear as well as implications for clinical practice are discussed.

Conditioning, Classical↗

PubMed2005

Return of fear in a human differential conditioning paradigm caused by a stimulus change after extinction.

In a human fear conditioning experiment, 32 participants were trained in a differential conditioning procedure with geometrical shapes as CS+ and CS- (four presentations each), and an electric shock as US. Measures of conditioned responding were skin conductance response (SCR) and retrospective US-expectancy ratings. For half of the participants (Generalization Group, GG), the subsequent extinction phase consisted of four nonreinforced presentations of generalization stimuli (GS+ and GS-). Participants from the Extinction control Group received an equal amount of nonreinforced presentations of the CSs. Finally, all participants were tested with the original CSs. The results from both measures clearly show an increase in the size of the discrimination upon the stimulus change after extinction in the GG. Because this pattern is not observed in the Extinction control Group, extinction performance appears to be somehow restricted to the perceptual characteristics of the extinction stimulus. Interestingly, the size of the conditioned SCR discrimination in the GG is not influenced by the stimulus change after acquisition. This observation points to a differential impact of stimulus change after acquisition vs. extinction treatment. The findings are discussed from the theoretical perspective of renewal and the clinical perspective of Return of Fear.

Analysis of Variance↗

PubMed2005

Reinstatement of fear responses in human aversive conditioning.

The treatment of choice for a number of anxiety disorders is exposure therapy. However, successful reduction of fear through exposure is sometimes followed by a (partial) return of symptoms of fear (return of fear, ROF; Clin. Psychol. Rev. 9 (1989) 147). Several possible learning mechanisms have been suggested to explain ROF (e.g. mechanisms related to spontaneous recovery, renewal, reacquisition and reinstatement). The present study focuses on reinstatement, which refers to the observation that mere US-only presentations can 'reinstate' previously extinguished fear responses. Although animal research has repeatedly demonstrated this phenomenon, little is known about fear reinstatement in humans. The present study employed a differential aversive conditioning procedure: after acquisition and a subsequent extinction procedure, a series of four unpredicted US-only trials was scheduled in the reinstatement group. The control group did not receive additional US presentations. A significant reinstatement effect was observed for US-expectancy ratings and fear ratings in the reinstatement group, but not in the control group. No differences were observed in a reaction time measure of resource allocation to the conditioned stimuli. These findings constitute a first demonstration of reinstatement of conditioned fear responses in humans. Implications for exposure treatment and suggestions for future research are discussed.

Adult↗

PubMed2005

Affective priming as an indirect measure of food preferences acquired through odor conditioning.

The present study aimed at investigating affective priming for originally neutral food stimuli that recently acquired their affective meaning through odor conditioning. In a first phase, pictures of different brands of yogurts (CSs) were contingently presented with a positive or negative odor (US). In a subsequent phase, the yogurt CSs were used as primes in an affective priming procedure. Rating data showed that the acquisition procedure resulted in a reliable evaluative learning effect. This could be corroborated by the results of the priming task. Participants responded faster to positive target words and made fewer errors when they were preceded by a CS that had been associated with a positive odor, as compared to a CS that was associated with a negative odor. A reversed pattern was present for negative targets. Based on these findings, it is suggested that affective priming might be used as a demand-free measure of evaluative learning.

Adult↗

PubMed2005

Avoidance behavior can function as a negative occasion setter.

The authors put forward the hypothesis that avoidance learning can result from the fact that participants learn (a) that a stimulus is followed by an unconditioned stimulus (US) when the avoidance behavior is not emitted and (b) that the stimulus is not followed by the US when the avoidance behavior is emitted. As such, avoidance behavior is assumed to function as a negative occasion setter. The results of a contingency judgment experiment involving 65 students showed that avoidance behavior indeed has the unique functional properties of a negative occasion setter (resistance to counterconditioning and selective transfer of modulation).

Association Learning↗

PubMed2004

An exploration of affective priming as an indirect measure of food attitudes.

During the last few years indirect measures of attitudes have been increasingly promoted. Because they are assumed to be less influenced by demand effects, these indirect measures would constitute a better basis to predict behaviour in some circumstances. In two studies, we examined the usefulness of the affective priming paradigm as an indirect measure of food likes and dislikes. Participants were asked to evaluatively categorize word targets, which were primed by individually selected positive and negative food pictures. The first experiment was a basic exploration of the usefulness of the affective priming paradigm to uncover food likes and dislikes, by making use of food stimuli that elicit strong evaluative reactions. The second experiment examined whether the paradigm can also be used in the context of weaker food (dis)likes. It could be demonstrated that both strongly (Experiments 1 and 2) and moderately (Experiment 2) evaluated food primes influenced the speed of responding to the positive and negative target words. No differential sensitivity for attitudes of moderate or extreme evaluative meaning could be demonstrated, however. The implications for future research and the applicability of this indirect index of food (dis)likes are discussed.

Adult↗

PubMed2002

Expectancy-learning and evaluative learning in human classical conditioning: affective priming as an indirect and unobtrusive measure of conditioned stimulus valence.

It has been argued that in classical conditioning two processes might be operative. First, one may learn that the conditioned stimulus (CS+) is a valid predictor for the occurrence of the biologically negative or positive event (US; expectancy-learning). Second, one may learn to perceive the conditioned stimulus itself as a negative or positive stimulus, depending on the valence of the event it has been associated with (evaluative learning). Until the present, however, both forms of learning have been investigated using rather different conditioning procedures. Using a differential aversive conditioning preparation with pictures of human faces as CSs and an electrocutaneous stimulus as US, we were able to demonstrate that both forms of learning can co-occur. Moreover, the extent of evaluative learning in this aversive conditioning procedure did not significantly differ from the amount of evaluative learning in an evaluative conditioning procedure with positive and negative adjectives as USs, which was administered to the same participants. In the present study evaluative learning was not only indexed by direct evaluative ratings, but we introduced affective priming as an indirect and unobtrusive, reaction time based measure of stimulus valence. Finally, imagery instructions during acquisition did not facilitate expectancy-learning nor evaluative learning.

Adult↗

PubMedDate not supplied

Reinstatement of extinguished conditioned responses and negative stimulus valence as a pathway to return of fear in humans.

The present study investigated reinstatement of conditioned responses in humans by using a differential Pavlovian conditioning procedure. Evidence for reinstatement was established in a direct (fear rating) and in an indirect measure (secondary reaction time task) of conditioning. Moreover, the amount of reinstatement in the secondary reaction time task was significantly correlated with the difference in valence between the conditioned stimulus (CS)+ and the CS-after extinction. These data provide clear evidence for reinstatement and for the role of negative stimulus valence in the return of conditioned responding after extinction.

Analysis of Variance↗

PubMedDate not supplied

Extinction and renewal of Pavlovian modulation in human sequential Feature Positive discrimination learning.

Using a conditioned suppression task, we investigated extinction and renewal of Pavlovian modulation in human sequential Feature Positive (FP) discrimination learning. In Experiment 1, in context a participants were first trained on two FP discriminations, X-->A+/A- and Y-->B+/B-. Extinction treatment was administered in the acquisition context a (aaa group) or in a new context b (aba group), and comprised X-->A- extinction and Y- control trials. Discriminative X-->A/A responding was lost in both groups when tested in the extinction context, but partially recovered in the aba and not in the aaa group when tested in the acquisition context, suggesting extinction and renewal of extinguished modulation. The same was observed for the Y-->B/B control pair, however, questioning whether the loss of discriminative X-->A/A responding represented genuine extinction of modulation. In Experiment 2, including only aba groups, participants were trained in context a on two FP discriminations, X-->A+/A- and Y-->B+/B-, after which the group "Extinction" was exposed to X-->A- extinction trials in context b, whereas the group "Control" was exposed to X- control trials; concurrently, both groups received further Y-->B+/B- training. In the group Control, differential Y-->B/B and X-->A/A responding were acquired and maintained throughout the experiment. In the group Extinction, while Y-->B/B responding was also maintained throughout, differential X-->A/A responding disappeared because of X-->A- extinction treatment when tested in the extinction context b, but partially reappeared when tested in the acquisition context a. This evidences aba-renewal of extinguished modulation.

Adolescent↗