Neuroimaging resilience to trauma: convergent evidence and challenges for future research

Abstract

Resilience, or the phenomenon of successful adaptation following significant trauma exposure, is a complex, multidimensional, and dynamic process. To date, research on neural mechanisms involved in human resilience has comprised of two major research streams – involving individuals with childhood and adulthood trauma exposure, respectively. Although there are systematic differences in how both trauma and resilience have been defined across these two bodies of work, some striking regions of convergence emerge when considering the literature as a whole. Here, we review neuroimaging studies of resilience in both trauma-exposed individuals and the general population, alongside discussion of some of the methodological difficulties involved in quantifying trauma and resilience in human participants. Results highlight the involvement of brain networks implicated in emotion regulation (medial prefrontal cortex and amygdala), responses to rewards (ventral striatum and ventromedial prefrontal cortex), and attentional control and cognitive flexibility (prefrontal cortex and hippocampus) in fostering positive outcomes following trauma. There is also emerging evidence for a role of neural circuitry subserving interoceptive awareness (in particular, the anterior insula cortex) in resilience. Further, we discuss several ongoing issues in neuroimaging study design and analysis that will need to be addressed in order to enable us to harness insight from such studies to improve treatments for – or, ideally, guard against the development of – debilitating post-traumatic stress syndromes.

Neuroimaging correlates and predictors of response to repeated-dose intravenous ketamine in PTSD: preliminary evidence

“…This finding is consistent with a body of evidence from previous imaging studies of PTSD and other trauma-exposed groups: specifically, that individuals with PTSD may exhibit hypoactive prefrontal and hyperactive amygdala responses to trauma cues and trauma-unrelated emotional stimuli [13][14][15][16][17]; that differences in prefrontal-amygdala function are implicated in and predictive of resilient outcomes following trauma exposure [62][63][64]; and that increases in vmPFC-amygdala resting functional connectivity are observed during trials of the current gold standard treatment for PTSD, prolonged exposure therapy [59,65]. Exploratory follow-up analysis via dynamic causal modelling indicated that whilst responders in both drug conditions showed decreased excitatory influence from the amygdala to the vmPFC in response to emotional faces (perhaps representing a common anxiolytic effect of treatment), greater top-down vmPFC inhibition of the amygdala during emotional face viewing was only related to PTSD symptom reduction under ketamine (Fig.…”

Neuroimaging correlates and predictors of response to repeated-dose intravenous ketamine in PTSD: preliminary evidence

“…Increased emotion-related vmPFC-amygdala coherence was the strongest correlate of symptom change across all subjects -with evidence of a stronger effect in individuals who received ketamine, and some specificity to reduction in cardinal PTSD symptoms (i.e., over and above concomitant decreases in depressive symptoms; Figure S3, Figure 2, Figure S4). This finding is consistent with a body of evidence from previous imaging studies of PTSD and other trauma-exposed groups: specifically, that individuals with PTSD may exhibit hypoactive prefrontal and hyperactive amygdala responses to trauma cues and trauma-unrelated emotional stimuli [13][14][15][16][17]; that differences in prefrontal-amygdala function are implicated in and predictive of resilient outcomes following trauma exposure [62][63][64]; and that increases in vmPFC-amygdala resting functional connectivity are observed during trials of the current gold standard treatment for PTSD, prolonged exposure therapy [59,65]. Exploratory follow-up analysis via dynamic causal modelling indicated that whilst responders in both drug conditions showed decreased excitatory influence from the amygdala to the vmPFC in response to emotional faces (perhaps representing a common anxiolytic effect of treatment), greater top-down vmPFC inhibition of the amygdala during emotional face viewing was only related to PTSD symptom reduction under ketamine (Figure 3).…”

Resilience-driven neural synchrony during naturalistic movie watching

“…For instance, individuals with higher resilience tend to report more positive emotional experiences 9 , demonstrate quicker disengagement from emotional stimuli 10 , and employ adaptive emotional regulation strategies more effectively 11 . Accumulating evidence from imaging studies has suggested that these inter-individual differences in resilience may arise from functional variations in brain regions involved in salience detection, emotion regulation, and cognitive control 12,13 . The activity in key regions like the prefrontal cortex, amygdala, and insula, which play crucial roles in emotional processing and salience detection, has consistently been identified as neural markers of resilience 14,15 .…”