Neuroimaging predictors of treatment response in anxiety disorders.

Although several psychological and pharmacological treatment options are available for anxiety disorders, not all patients respond well to each option. Furthermore, given the relatively long duration of adequate treatment trials, finding a good treatment fit can take many months or longer. Thus, both clinicians and patients would benefit from the identification of objective pre-treatment measures that predict which patients will best respond to a given treatment. Recent studies have begun to use biological measures to help predict symptomatic change after treatment in anxiety disorders. In this review, we summarize studies that have used structural and functional neuroimaging measures to predict treatment response in obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), generalized anxiety disorder (GAD), and social anxiety disorder (SAD). We note the limitations of the current studies and offer suggestions for future research. Although the literature is currently small, we conclude that pre-treatment neuroimaging measures do appear to predict treatment response in anxiety disorders, and future research will be needed to determine the relative predictive power of neuroimaging measures as compared to clinical and demographic measures.

Diminished rostral anterior cingulate cortex activation during trauma-unrelated emotional interference in PTSD.

BACKGROUND: Previous research suggests that individuals with posttraumatic stress disorder (PTSD) preferentially attend to trauma-related emotional stimuli and have difficulty completing unrelated concurrent tasks. Compared to trauma-exposed control groups, individuals with PTSD also exhibit lower rostral anterior cingulate cortex (rACC) activation during tasks involving interference from trauma-related stimuli. However, it is not clear whether relatively diminished rACC activation in PTSD also occurs during interference tasks involving trauma-unrelated emotional stimuli. The present study employed functional magnetic resonance imaging (fMRI) and an interference task that involves emotional facial expressions and elicits rACC activation in healthy participants. FINDINGS: While performing a trauma-unrelated emotional interference task, participants with PTSD (n=17) showed less rACC activation than trauma-exposed non-PTSD (TENP; n=18) participants. In the PTSD group, rACC activation was negatively correlated with the severity of re-experiencing symptoms. The two groups did not significantly differ on behavioral measures (i.e., response times and error rates). CONCLUSIONS: These findings suggest that relatively diminished rACC activation in PTSD can be observed in interference tasks involving trauma-unrelated emotional stimuli, indicating a more general functional brain abnormality in this disorder. Future neuroimaging studies need not employ trauma-related stimuli in order to detect rACC abnormalities in PTSD.

An analysis of the determinants of the feeling of knowing.

Research has demonstrated that feeling-of-knowing (FOK) judgments are affected by the amount of accessible information related to an inaccessible target. Further, studies have demonstrated that, in some situations, FOK judgment magnitude is not only related to the amount (quantity) of accessed features, but also the correctness of those features (Thomas, Bulevich, & Dubois, 2011). The present study examined the conditions under which the correctness of features would influence FOK judgment magnitude. We hypothesized that accuracy of retrieved features would influence FOK judgments, but only in situations where semantically meaningful information was accessible. In three experiments, we manipulated accessibility of semantic information. In all experiments, the quantity, or amount of retrieved partial information had a greater impact on FOK judgments than the accuracy of that information. However, in situations where semantic information was accessible, accuracy of retrieved semantic features also influenced FOK judgment magnitude, and later recognition.

Context affects feeling-of-knowing accuracy in younger and older adults.

In feeling of knowing (FOK) studies, participants predict subsequent recognition memory performance on items that were initially encoded but that cannot presently be recalled. Research suggests that FOK judgment magnitude may be influenced by the total amount, or quantity, of contextual information retrieved related to the unrecalled target (e.g., Koriat, 1993). The present study examined the contribution of quality of that information to episodic FOK judgments. In addition, we tested whether the episodic FOK deficit demonstrated by older adults could be reduced by encouraging retrieval of contextual information relevant to the target. Three experiments demonstrated that quality of the retrieved partial information influenced FOK judgments in both older and younger adults; however, the manifestation of that influence was age dependent. The results also indicated that older adults required explicit retrieval of contextual information before making FOK judgments in order to make accurate FOK predictions. The results suggest that FOK accuracy may be partially determined by search processes triggered when participants are queried for contextual information.