Neural Basis of Meal Related Interoceptive Dysfunction in Anorexia Nervosa
Condition: Anorexia Nervosa; Major Depressive Disorder; Generalized Anxiety Disorder; Panic Disorder; Brain Injury
MeSH terms: Brain Injuries; Anorexia; Depressive Disorder; Depressive Disorder, Major; Anxiety Disorders; Anorexia Nervosa; Panic Disorder
Study type: Interventional

Summary: 
      This study aims to identify the brain regions responsible for encoding cardiorespiratory
      'interoceptive' sensations and determine whether they are dysfunctional in individuals
      affected by eating disorders, anxiety, depression, or brain injury. By evaluating the same
      interoceptive sensations across different human illnesses, the investigators hope to provide
      convergent evidence resulting in identification of core underlying neural processes, and to
      discern relative contributions in each condition.
    

Detailed description: 
      The human brain has constant access to a multitude of complex signals, which it must simplify
      and organize in order to sustain the integrity of the organism. Many of these signals
      originate from outside of the body, such as lights, sounds, and smells, and much is known
      about how humans consciously perceive these 'exteroceptive' signals and how the human brain
      represents them. Comparatively little is known about how the human brain processes
      'interoceptive' signals originating from inside of the body, despite the fact that the brain
      has access to far more of them (for instance, intestinal tension, bladder distension, breath,
      heartbeat, body temperature, blood pressure, serum osmolality, inflammation, proprioception
      etc.).

      The current study study therefore aims to identify the brain regions responsible for encoding
      cardiorespiratory 'interoceptive' sensations and determine whether they are dysfunctional in
      individuals affected by eating disorders, anxiety, depression, or brain injury. Participants
      in this study will receive stimulation of the cardiorespiratory channel of the interoceptive
      system using bolus intravenous infusions of isoproterenol, a peripherally acting medication
      similar to adrenaline, and saline. Stimulation will occur during functional magnetic
      resonance imaging (fMRI) as well as outside of the fMRI scanner. After the scan participants
      will consume a meal. By evaluating the same interoceptive sensations across different human
      illnesses, the investigators hope to provide convergent evidence resulting in identification
      of core underlying neural processes, and to discern relative contributions in each condition.
    

Intervention name(s): Isoproterenol; Normal saline
Intervention type(s): Drug; Drug
Intervention description(s): Intravenous infusions of isoproterenol, delivered in a randomized double blinded order, in each participant from each group. Participants will rate the experience of heartbeat and breathing sensations as well as anxiety induced by the infusion.; Intravenous infusions of normal saline, delivered in a randomized double blinded order, in each participant from each group. Participants will rate the experience of heartbeat and breathing sensations as well as anxiety induced by the infusion.
Other intervention name(s): Isuprel; Saline
Intervention MeSH terms: Isoproterenol
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science
Keywords: heartbeat; respiration; interoception; anxiety; eating