Neuroplasticity in an Extended Amygdala Network as a Target Mechanism for Attention Bias Modification Outcome
Condition: Anxiety
Study type: Interventional

Summary: 
      Anxiety disorders are one of the most common psychological disorders. Underlying anxiety is
      an increased attentional bias to threat, which has been identified as a causal contributor in
      the development of anxiety. Given this causal relationship, attention bias modification was
      introduced as a treatment option where anxiety is reduced by training individuals to direct
      their attention away from threat and thereby decreasing anxiety. Over a decade of research
      using this approach, called attention bias modification (ABM), suggests that overall the
      approach is effective in reducing anxiety. Although ABM appears to be a very promising
      treatment option for anxiety, there are several factors limiting the effectiveness of ABM.
      These include the recognition of individual-level needs and a known underlying mechanism of
      action by which ABM is effective. Neuroimaging evidence suggests that attentional bias to
      visual threat is associated with a network of brain regions including the amygdala, anterior
      cingulate cortex, and visual cortex. In human participants, experience-dependent
      neuroplasticity is visible in voxel-based morphometry based measures of gray matter volume
      following training. Recently, voxel-based morphometry measures of gray matter volume have
      been linked to dendritic spine density-a known cellular mechanism for learning-related
      neuroplasticity. Thus, voxel-based morphometry measures are ideally suited to measure
      learning-related neuroplasticity following attention bias modification. In this proposal
      participants' level of attentional bias, anxiety, and gray matter volume will be measured
      before and after completing six weeks of attention bias modification training (N = 50) or
      attention control training (N= 50). The proposal aims to (1) establish that pre-treatment
      bias predicts variability in gray matter volume in the extended amygdala and anterior
      cingulate cortex, (2) assess the extent to which reduced extended amygdala and anterior
      cingulate cortex gray matter volume following ABM underlies reductions in attentional bias
      and anxiety, and (3) Establish pre-treatment bias as a predictor of successful ABM as
      measured by reduced bias, reduced anxiety, and reduced gray matter volume in the extended
      amygdala and anterior cingulate cortex. Consistent with the objectives of the AREA grant and
      NIMH's focus on identifying and validating new targets for treatment development that
      underlie disease mechanisms, the current proposal plans to involve students at a rural
      primarily undergraduate university in a research project aimed at establishing
      neuroplasticity in the extended amygdala and anterior cingulate cortex as a target mechanism
      for ABM training outcome, which could be used to objectively track training-related outcomes
      in anxiety treatment.
    


Intervention name(s): Attention Bias Modification; Attention Control
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Attention bias modification (ABM) sessions will consist of a modified dot-probe task that only contains incongruent trials (i.e., target-dot - neutral stimulus 100% pairing).; Attention control (AC) sessions, will consist of a standard dot-probe task (i.e., target-dot - neutral/threat stimulus 50% pairing). Thus, for AC participants, bias should remain the same, while ABM participants should show a reduced bias to threat.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Attentional Bias to Threat