Delay and trace fear conditioning in a complex virtual learning environment-neural substrates of extinction.

Extinction is an important mechanism to inhibit initially acquired fear responses. There is growing evidence that the ventromedial prefrontal cortex (vmPFC) inhibits the amygdala and therefore plays an important role in the extinction of delay fear conditioning. To our knowledge, there is no evidence on the role of the prefrontal cortex in the extinction of trace conditioning up to now.

The BDNF Val66Met polymorphism modulates the generalization of cued fear responses to a novel context.

Brain-derived neurotrophic factor (BDNF) has a crucial role in activity-dependent synaptic plasticity and learning and memory. The human functional single-nucleotide BDNF rs6265 (Val66Met) polymorphism has been found to be associated with alteration in neural BDNF release and function correlating with altered emotional behavior. Here, we investigated for the first time the hypothesis that this polymorphism in humans modulates the context dependency of conditioned fear responses.

Contextual fear conditioning in virtual reality is affected by 5HTTLPR and NPSR1 polymorphisms: effects on fear-potentiated startle.

The serotonin (5-HT) and neuropeptide S (NPS) systems are discussed as important genetic modulators of fear and sustained anxiety contributing to the etiology of anxiety disorders. Sustained anxiety is a crucial characteristic of most anxiety disorders which likely develops through contextual fear conditioning. This study investigated if and how genetic alterations of the 5-HT and the NPS systems as well as their interaction modulate contextual fear conditioning; specifically, function polymorphic variants in the genes coding for the 5-HT transporter (5HTT) and the NPS receptor (NPSR1) were studied.

Enhanced discrimination between threatening and safe contexts in high-anxious individuals.

Trait anxiety, a stable personality trait associated with increased fear responses to threat, is regarded as a risk factor for the development and maintenance of anxiety disorders. Although the effect of trait anxiety has been examined with regard to explicit threat cues, little is known about the effect of trait anxiety on contextual threat learning. To assess this issue, extreme groups of low and high trait anxiety underwent a contextual fear conditioning protocol using virtual reality.

Contextual fear conditioning predicts subsequent avoidance behaviour in a virtual reality environment.

Avoidance behaviour is a crucial component of fear and is importantly involved in the maintenance of anxiety disorders. Presumably, fear conditioning leads to avoidance of the feared object or context. A virtual reality contextual fear conditioning paradigm was used to investigate the association between explicit conditioning effects and subsequent avoidance behaviour.

Does pre-exposure inhibit fear context conditioning? A Virtual Reality Study.

Several studies in animals and humans have indicated that familiarity toward cues reduces cue-conditioning effects. The influence of familiarity of a context on context conditioning has been confirmed in animal studies only. Thus, this study examined contextual fear conditioning in humans depending on pre-exposure to the to-be-conditioned context.