Developing a mechanism for social buffering: social support as a safety signal One explanation for these stressbuffering effects is that social support signals safety and consequently mitigates the experience of threat. Neural investigations of social support provide some evidence for this view, indicating that experiencing or being reminded of social support leads to the activation of safety-related neural regions and reduces activation in regions known to be involved in pro cessing pain and distress. Of par tic u lar interest is the link between both received and perceived social support and activity in the ventromedial prefrontal cortex (vmPFC), a region associated with pro cessing safety (Delgado, Olsson, & Phelps, 2006; Eisenberger et al., 2011). For example, the vmPFC shows greater activity in response to safety cues (Phelps, Delgado, Nearing, & LeDoux, 2004) and even tracks differ ent types of safety cues (dissociation between cues that were always safe vs. cues that switched from being threatening to safe: Schiller, Levy, Niv, LeDoux, & Phelps, 2008). Importantly, the vmPFC is also known to play a role in inhibiting threat responding and extinguishing learned fear via inhibitory connections with the amygdala (Phelps et al., 2004), a region that is crucial during fear learning and influences downstream fear-related activity in both the SNS and the HPA axis (Adolphs, Tranel, Damasio, & Damasio, 1995; Delgado, Olsson, & Phelps, 2006). Social support has also been linked to decreased activity in the dorsal anterior cingulate (dACC) and anterior insula (AI), regions associated with the distressing experience of both physical (Lieberman & Eisenberger, 2015; Price, 2000) and social pain (Eisenberger, 2012; Eisenberger, Lieberman, & Williams, 2003)(see Figure 81.1, left panel). Mirroring findings in behavioral research showing that social support can decrease subjective distress during painful experiences (Brown, Sheffield, Leary, & Robinson, 2003; Che et al., 2018; Master et al., 2009), neural investigations have demonstrated that simply viewing pictures of a social-support figure while receiving pain leads to increased activity in the vmPFC and decreased activity in the dACC and AI, suggesting that social support may lead to increased perceptions of safety and a decreased subjective experience of pain (Eisenberger, 2011; Younger, Aron, Parke, Chatterjee, & Mackey, 2010). Given the previously discussed inhibitory connection between the vmPFC and the amygdala, these findings also suggest that social-support figures may be acting as a type of safety signal, leading to reduced perceptions of threat. This link between social-support impact of social support on stress-response systems can be found within the animal and human lit er a ture. In animals, the presence of a conspecific reduces escape or avoidance be hav ior to a threatening context (Baum, 1969; Hall, 1955), decreases freezing be hav ior in the face of threats (Davitz & Mason, 1955), increases tolerance for novel environments (Liddell, 1950, 1954), and mitigates anxious be hav ior following social defeat (Nakayasu & Ishii, 2008; Nakayasu & Kato, 2011). In addition to effects on behavioral responses to threat, the presence of familiar others ameliorates physiological stress responses to threatening events or contexts. For example, guinea pigs placed in novel environments exhibit dampened HPA axis activity when with a familiar conspecific (Hennessy, Zate, & Maken, 2008; Sachser, Durschlag, & Hirzel, 1998).

Similarly, research in humans demonstrates that receiving social support alleviates stress to threatening or stressful events. For example, receiving social support during a stressful event …