Discussion
extinction and cognitive models, PTSD, non-affective
REMISSION, RECRUITMENT, CORTEX
It is notable that across the paradigms employed in this study, the two affective paradigms involved associations between improvement of PTSD symptoms after treatment and changes in neural activity. In contrast, the non-affective paradigm involving response inhibition was not implicated in any associations between symptom and neural changes. This latter finding accords with one previous study that also found no association between PTSD remission and neural activation during a Go-NoGo paradigm [The finding that improvement after treatment was associated with decreased left hippocampal activation and connectivity when viewing affective faces accords with the role that the hippocampus plays in context processing. PTSD models have emphasized that the hippocampus is implicated in extinction memory because it enables differentiation between contexts and in this way can influence fear generalization [The association between response and increased activation in the anterior insula as well as reduced activation in the posterior right insula during emotional processing can be understood in the context of the functional role of this region. The posterior insula encodes somatosensory information, which is integrated with affective information in the middle insula which projects to the anterior insula, in which limbic and sensory information is used for other cognitive processes [The observation that response was associated with decreased recruitment of the left dlPFC during reappraisal was contrary to our hypothesis and previous meta-analytical finding that prefrontal cortex activation is increased following treatment [We note several limitations in this study. First, the sample size available in our analysis was modest and further study is required with larger samples. Although we commenced with 37 PTSD participants, a significant number would not participate in a second scanning session, and future studies need to initially oversample in recruitment to ensure adequate sample size is maintained at the subsequent scanning session. Second, although we included a comparison healthy control group, our design lacked a wait-listed PTSD group that did not receive TF-psychotherapy. Even with our control group we did not observe differences in change in neural measures with treatment in PTSD. This could possibly be due to the limited sample size available. We conducted exploratory analyses after splitting PTSD responders and non-responders relative to controls at each time and observe differences in hippocampal and posterior insula activation at pre and post-treatment (supplementary section: Supplementary Figs. SIn summary, this study demonstrates differential associations between affective and non-affective neural processing with level of remission of PTSD symptoms after TF-psychotherapy. This pattern of findings converges with the goals of TF-psychotherapy that enhances more effective and efficient mastery of affective states, which converges with extinction and cognitive models of PTSD that emotional processing as a central change mechanism of successful treatment.