Learning about threat from friends and strangers is equally effective: An fMRI study on observational fear conditioning

Integrating behavioral and neurophysiological insights: High trait anxiety enhances observational fear learning

Observational fear learning delineates the process by which individuals learn about potential threats through observing others' reactions. Prior research indicates that individuals with high trait anxiety (HTA) manifest pronounced fear responses in direct fear learning scenarios. However, the specific influence of trait anxiety on observational fear learning remains insufficiently explored. This study aimed to fill this gap by examining 64 university students, divided equally between those with HTA and low trait anxiety (LTA), selected from an initial pool of 483 participants. Participants were subjected to observational fear learning tasks, and their behavioral responses, physiological reactions, and brain activations were recorded. Results demonstrated that HTA participants exhibited differentiated skin conductance responses to threat and safety stimuli during the observational fear acquisition phase, notwithstanding prior assurances against shock delivery. Furthermore, during the direct test phase, HTA participants reported significantly elevated fear and shock expectancy ratings for both types of stimuli, in contrast to their LTA counterparts. Neuroimaging data, derived via functional near-infrared spectroscopy (fNIRS) revealed heightened medial prefrontal cortex activation in HTA participants when directly facing threats. This study systematically explores the influence of high trait anxiety on observational fear learning, uncovering that HTA individuals exhibit excessive fear responses. These findings highlight the critical role of trait anxiety as a significant risk factor in the development of anxiety disorders.

Observational learning of threat-related attentional bias

Attentional bias to threat has been almost exclusively examined after participants experienced repeated pairings between a conditioned stimulus (CS) and an aversive unconditioned stimulus (US). This study aimed to determine whether threat-related attentional capture can result from observational learning, when participants acquire knowledge of the aversive qualities of a stimulus without themselves experiencing aversive outcomes. Non-clinical young-adult participants (N = 38) first watched a video of an individual (the demonstrator) performing a Pavlovian conditioning task in which one colour was paired with shock (CS+) and another colour was neutral (CS-). They then carried out visual search for a shape-defined target. Oculomotor measures evidenced an attentional bias toward the CS+ colour, suggesting that threat-related attentional capture can ensue from observational learning. Exploratory analyses also revealed that this effect was positively correlated with empathy for the demonstrator. Our findings extend empirical and theoretical knowledge about threat-driven attention and provide valuable insights to better understand the formation of anxiety disorders.

Understanding Others' Distress Through Past Experiences: The Role of Memory Engram Cells in Observational Fear

For individuals to survive and function in society, it is essential that they recognize, interact with, and learn from other conspecifics. Observational fear (OF) is the well-conserved empathic ability of individuals to understand the other's aversive situation. While it is widely known that factors such as prior similar aversive experience and social familiarity with the demonstrator facilitate OF, the neural circuit mechanisms that explicitly regulate experience-dependent OF (Exp OF) were unclear. In this review, we examine the neural circuit mechanisms that regulate OF, with an emphasis on rodent models, and then discuss emerging evidence for the role of fear memory engram cells in the regulation of Exp OF. First, we examine the neural circuit mechanisms that underlie Naive OF, which is when an observer lacks prior experiences relevant to OF. In particular, the anterior cingulate cortex to basolateral amygdala (BLA) neural circuit is essential for Naive OF. Next, we discuss a recent study that developed a behavioral paradigm in mice to examine the neural circuit mechanisms that underlie Exp OF. This study found that fear memory engram cells in the BLA of observers, which form during a prior similar aversive experience with shock, are reactivated by ventral hippocampal neurons in response to shock delivery to the familiar demonstrator to elicit Exp OF. Finally, we discuss the implications of fear memory engram cells in Exp OF and directions of future research that are of both translational and basic interest.

Rats respond to aversive emotional arousal of human handlers with the activation of the basolateral and central amygdala

Reading danger signals may save an animal's life, and learning about threats from others allows avoiding first-hand aversive and often fatal experiences. Fear expressed by other individuals, including those belonging to other species, may indicate the presence of a threat in the environment and is an important social cue. Humans and other animals respond to conspecifics' fear with increased activity of the amygdala, the brain structure crucial for detecting threats and mounting an appropriate response to them. It is unclear, however, whether the cross-species transmission of threat information involves similar mechanisms, e.g., whether animals respond to the aversively induced emotional arousal of humans with activation of fear-processing circuits in the brain. Here, we report that when rats interact with a human caregiver who had recently undergone fear conditioning, they show risk assessment behavior and enhanced amygdala activation. The amygdala response involves its two major parts, the basolateral and central, which detect a threat and orchestrate defensive responses. Further, we show that humans who learn about a threat by observing another aversively aroused human, similar to rats, activate the basolateral and centromedial parts of the amygdala. Our results demonstrate that rats detect the emotional arousal of recently aversively stimulated caregivers and suggest that cross-species social transmission of threat information may involve similar neural circuits in the amygdala as the within-species transmission.

The Relationship Between Fear Avoidance Belief and Threat Learning in Postoperative Patients After Lung Surgery: An Observational Study

Background

The role of fear-avoidance beliefs (FAB) in patients with chronic pain has been widely confirmed. However, few conclusions have been drawn about its role in postoperative patients.

Objective

To explore the characteristics of FAB in postoperative patients after lung surgery as well as the effect of threat learning on FAB.

Methods

Between May and September 2022, this study recruited 150 participants who had undergone thoracoscopic surgery. Variables such as age, gender, education, chronic pain, fear of pain, surgery method, pain intensity, FAB, cough, ambulation and threat learning were collected and subjected to correlation analysis and stepwise regression.

Results

The correlation analysis revealed that FAB was associated with age (r = -0.183, p < 0.05), gender (r = -0.256, p < 0.01), and preoperative FOP-9 (r = 0.400, p < 0.01). Postoperative variables such as pain intensity (r = 0.574, p < 0.01), initiation day of ambulation (r = 0.648, p < 0.01), total numbers of ambulation (r = -0.665, p < 0.01), and cough performance (r = -0.688, p < 0.01) were correlated with FAB. Furthermore, FAB was highly correlated with indicators of threat learning: direct (r = 0.556, p < 0.01), observation (r = 0.655, p < 0.01), and instruction (r = 0.671, p < 0.01). The highest variance explanation model of stepwise regression which explained 52.8% of the variance including instruction (B=1.751; p<0.01), direct (B=1.245; p<0.01), observation (B=0.768; p<0.01), age (B=-0.085; p<0.01), and surgery method (B=1.321; p<0.05).

Conclusion

Patients commonly experience FAB after lung surgery, which can directly affect their recovery behaviors such as ambulation and active coughing. The formation of FAB is influenced by threat learning, which suggests that controlling threat learning is important in preventing postoperative FAB.