How the Brains of Anxious People Are Degraded – To Seek Out More Fear

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Take Aways:

  • [these] results provide a framework for conceptualizing the intrusive and distressing thoughts, worries, and memories that are a central feature of anxiety and mood disorders, including generalized anxiety, obsessive compulsive, posttraumatic stress, and major depressive disorders.
  • anxious individuals were less efficient at preventing threat-related distracters from gaining access to working memory
  • Dispositional anxiety was unrelated to the efficiency of filtering emotionally-neutral distracters
  • many of the maladaptive behaviors characteristic of anxiety, such as anticipatory apprehension, occur when threat is absent.
  • anxious individuals are less efficient at gating [filtering] threat’s access to working memory, a limited capacity workspace where information is actively retained, manipulated, and used to flexibly guide goal-directed behavior when it is no longer present in the external environment.

  • dispositionally anxious individuals allocate excessive working memory storage to threat, even when it is irrelevant to the task at hand
  • Ultimately, the unnecessary entry of threat into working memory may promote worry, intrusive thoughts, and other anxiety-related cognitions that disrupt on-going behavior.
  • the maladaptive cognitive-behavioral profile characteristic of anxious individuals reflects a failure to prevent (imagined) threat from gaining access to working memory
  • High levels of dispositional anxiety are associated with a similar pattern of dysregulated cognition.  Inefficient filtering of threat-related information from working memory potentially explains many of these features

The present study provides novel evidence that dispositional anxiety reflects a failure to adequately regulate the access of threat to working memory, the capacity-limited workspace that underlies adaptive, goal-directed behavior. These results set the stage for a more detailed understanding of the distressing thoughts and memories that afflict anxious individuals when threat is absent—a defining, but poorly understood feature of the internalizing spectrum of disorders. Future research aimed at clarifying the neural underpinnings of this regulatory deficit promises to enhance our understanding of the mechanisms that confer risk for the development of psychopathology.

Dispositional anxiety is a well-established risk factor for the development of psychiatric disorders along the internalizing spectrum, including anxiety and depression.  Importantly, many of the maladaptive behaviors characteristic of anxiety, such as anticipatory apprehension, occur when threat is absent.

……anxious individuals are less efficient at gating [filtering] threat’s access to working memory, a limited capacity workspace where information is actively retained, manipulated, and used to flexibly guide goal-directed behavior when it is no longer present in the external environment.

threat-related distracters were difficult to filter on average and that this difficulty was exaggerated among anxious individuals.  These results indicate that dispositionally anxious individuals allocate excessive working memory storage to threat, even when it is irrelevant to the task at hand.  More broadly, these results provide a novel framework for understanding the maladaptive thoughts and actions characteristic of internalizing disorders.

Anxiety disorders are debilitating, highly prevalent, and associated with substantial morbidity and mortality…High levels of dispositional anxiety and behavioral inhibition are a well-established risk factor for anxiety, depressive, and other psychiatric…alterations in core cognitive processes, such as executive control and working memory, are central to neurocognitive theories of anxiety.

Importantly, many of the maladaptive thoughts and actions characteristic of anxious individuals occur when threat-related cues are absent from the immediate external environment e.g.:

  • anticipatory apprehension
  • behavioral avoidance
  • intrusive thoughts.

This raises the possibility that dispositional anxiety reflects a broader regulatory deficit that encompasses problems governing threat’s access to working memory.

Working memory:  is the “blackboard of the mind”   a limited capacity workspace     where information is actively maintained, recalled, and manipulated   The internal representation of task sets and other kinds of goals in working memory plays a critical role in sustaining goal-directed attention, information processing (e.g., memory retrieval), and action in the face of competition with potential sources of distraction or interference

This framework suggests that the maladaptive cognitive-behavioral profile characteristic of anxious individuals reflects a failure to prevent (imagined) threat from gaining access to working memory.   Allowing [imaginary or real] threat-related distracters access to working memory would potentially allow them to bias the stream of information processing after they are no longer present in the external environment. Ultimately, the unnecessary entry of threat into working memory may promote worry, intrusive thoughts, and other anxiety-related cognitions that disrupt on-going behavior.

Difficulties controlling the processing of [real or imagined] threat are a central feature of dispositional anxiety and the anxiety disorders; anxious individuals frequently allow threat-related information to unduly control their thoughts and actions.

In particular, there is considerable evidence that anxious individuals are biased to allocate excess attention to threat-related cues when they are present in the immediate environment (e.g., words, faces), even when this comes at the expense of task-goals and on-going behavior.  This attentional bias to threat has been proposed to be a specific causal risk factor for the development and maintenance of anxious psychopathology.

dispositionally anxious individuals allocate unnecessary working memory storage to threat-related cues when they are irrelevant to the task at hand. This effect was not evident for emotionally-neutral distracters and could not be explained by individual differences in working memory capacity, the size of the task-relevant threat targets, or the efficiency of filtering emotionally-neutral distracters.

..dispositional anxiety is associated with a specific deficit in preventing threat-related distracters from gaining access to working memory. These results reinforce work emphasizing the importance of cognitive control deficits in anxiety and mood disorders.  More generally, our results provide a novel neurobiological framework for conceptualizing the neural mechanisms that underlie the intrusive thoughts and maladaptive actions characteristic of anxious individuals when threat is absent.

….anxiety is associated with inefficient [filtering] of threat-related distracters from working memory

Among anxious and behaviorally inhibited individuals, the amygdala is more reactive to potential threat.  The amygdala is poised to bias attention to threat via excitatory projections to the visual cortex.  Indeed:

  • functional connectivity between these two regions is increased when attending to threat cues
  • threat-induced recruitment of the amygdala precedes enhanced activation of visual cortex
  • Variation in amygdala activation also predicts the reorienting of attention to threat-related cues and the trial-by-trial detection of threat—an effect mediated by activation in the visual cortex

Collectively, these data suggest that difficulties regulating threat’s access to working memory could be a downstream consequence of anxious individuals’ bias to over-allocate covert and overt attention to threat.

A second possibility is that the unnecessary occupation of working memory by threat reflects problems monitoring the competition between targets and threat-distracters for attention.  Adjudication of this competition is thought to depend upon conflict-monitoring processes instantiated in the midcingulate cortex.  When conflict is detected in the MCC, it triggers prefrontal regulatory signals aimed at biasing competition to favor task-relevant cues over potential sources of distraction, such as the threat-distracters used in the present study. …it remains unclear whether anxious individuals are less efficient at monitoring threat-related conflicts…

From a translational perspective, our results provide a framework for conceptualizing the intrusive and distressing thoughts, worries, and memories that are a central feature of anxiety and mood disorders, including generalized anxiety, obsessive compulsive, posttraumatic stress, and major depressive disorders.  High levels of dispositional anxiety are associated with a similar pattern of dysregulated cognition.  Inefficient filtering of threat-related information from working memory potentially explains many of these features. That is, once it resides in working memory, threat-related information could continue to elicit distress and maladaptively bias attention and action after it is no longer present in the external environment.

Importantly, this framework also provides a potential mechanistic explanation for the intrusive, distressing memories that are a hallmark of both dispositional anxiety and many disorders on the internalizing spectrum.  In particular, it has become clear that items can enter working memory via either perceptual encoding, as with the threat-related distracters used in the present study, or retrieval from long-term memory.  From this perspective, working memory reflects the temporary activation of recently perceived items or the temporary re-activation of representations stored in long-term memory. This suggests that intrusive memories, such as those prominent in post-traumatic stress disorder, could result from problems preventing distressing long-term memories from gaining access to working memory.

On the basis of the present results and other data, we have proposed that the maladaptive profile of thoughts and behaviors exhibited by anxious individuals in the absence of overt threat could reflect a more fundamental deficit in controlling threat’s access to working memory.

Dispositional anxiety is an important risk factor for the development of anxiety, depressive, and other psychiatric disorders. The present study provides novel evidence that dispositional anxiety reflects a failure to adequately regulate the access of threat to working memory, the capacity-limited workspace that underlies adaptive, goal-directed behavior. These results set the stage for a more detailed understanding of the distressing thoughts and memories that afflict anxious individuals when threat is absent—a defining, but poorly understood feature of the internalizing spectrum of disorders. Future research aimed at clarifying the neural underpinnings of this regulatory deficit promises to enhance our understanding of the mechanisms that confer risk for the development of psychopathology.

Source:

Front Hum Neurosci. 2013; 7: 58. Published online 2013 Mar 4. 
Failure to filter: anxious individuals show inefficient gating of threat from working memory Daniel M. Stout, et al
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