Anxiety as a Gut Feeling: Understanding Interoception

Marcus Paulus presented the April 2011 Warren Neuroscience Frontiers in Neuroscience Lecture.  The presentation was titled: Interoception and Anxiety.

Interoception is the summation of a variety of bodily perceptions that make up the integrated sense of our own physiological state.  Perceptions included in interoception include: pain, temperature, tickle, sensual touch, stomach discomfort to due acidity, air hunger and muscle tension.  Here are my notes from Dr. Paulus' presentation and his research manuscript on this topic area.

• Anxiety proneness is a trait that can be measured and is associated with high risk of later development of an anxiety disorder
• Anxiety proneness linked to increased activation of the dorsal amygdala and the anterior insula in brain fMRI tasks such as the Emotion Face Assessment task of Hariri
• Patients with anxiety also show insular hyperactivation in anticipation of negative cues
• Benzodiazepines like Valium reduce activation of the insula as well as the amygdala in response to angry faces

• There is growing awareness the brain insular cortex plays a key role in interoception--receiving signals from the body and integrating these signals with emotional response and regulation (see a previous post summarizing the function of the insula and possible roles in clinical neuroscience disorders)
• The insula also connects to a central pathway important in anxiety involving the anterior cingulate cortex and the dorsolateral prefrontal cortex--these areas provide input to the insula for planning and acting in the face of

• Key properties of the interoception include the signals from internal organs including the lungs, heart, gastrointestinal tract and genitourinary systems
• Many of these signals provide awareness of body and help promote homeostasis
• These signals also are involved in our sense of self and the passing of time

• A new area of understanding is the important role of personal beliefs in emotional processing--personal beliefs may modulate interoception and the perception of emotional cues
• A belief that a situation or cue is more dangerous than it really is, i.e. I will embarrass myself at the party, can modulate how emotion is processed, and can amplify a anxious response to the situation

Future research in the area of interoception and anxiety will target:

• Genetic influences on interoception
• How cognitive interventions may influence dysfunctional beliefs related to anxiety
• How interoception may help with more biological classification of types of anxiety
• Can people be trained to up or down regulate the insular cortex to reduce anxiety?
• How treatments for anxiety effect the elements of interoception

Brain Tutor iPad Screenshot of Insular Cortex in Green Courtesy of Author

Paulus MP, & Stein MB (2010). Interoception in anxiety and depression. Brain structure & function, 214 (5-6), 451-63 PMID: 20490545

The Brain Insula: Function and Disease

Nature Reviews Neuroscience is a scientific journal dedicated to neuroscience topics that recently celebrated it’s ten year anniversary.  To commemorate the accomplishment, the most highly cited articles from each of the last 10 years was identified.  This method provides a good proxy for the most important publication each year.  The 2009 most cited article was Dr. A.D. Craig’s article entitled: “How do you feel—now? The anterior insula and human awareness”.

Dr. Craig’s article highlights the converging fields of knowledge about the brain cortex region known as the insula.  This region lays hidden inside the brain in close proximity to the anterior cingulate gyrus (ACC).  The ACC is receiving increased attention as an important area for emotional processing.   The insula and the ACC have significant numbers of connections supporting a role for their mutual role in a variety of brain functions. 

The insula has been long identified as a sensory region for the gut and body.  New anatomical and imaging research has identified significant expanded domains related to the insular cortex including:

• Interoception (sensing state of gut, heart, pain etc)
• Body movement
• Self-recognition
• Vocalizationand music
• Emotional awareness
• Risk, uncertainty and anticipation
• Visual and auditory awareness of movement
• Time perception
• Attention
• Perceptual decision-making
• Cognitive control and performance monitoring

Dr. Craig provides a summary of the research supporting the expanded role of the insula in each of  these additional domains.  He notes that the expanding role of the insula is supportive of the James-Lang theory of emotion.  The James-Lang theory of emotion denotes a theory developed independently by William James and Carl Lange in the 19^th century.  Their theory states that emotions follow rather than precede the autonomic nervous system changes to environmental stimuli.  So instead of the sequence 1.) see bear, 2.) experience fear, 3.) heart races, the James-Lang theory states the correct sequence is 1.) see bear, 2.) heart races, 3.) experience fear.   The James-Lang theory. 

The evolving research on insular cortex function also supports the somatic marker hypothesis of Antonio Damasio from the University of Iowa.  Damasio proposes that decision making is influenced by somatic/emotional processes that can guide or bias our behaviors.  These somatic/emotional processes are thought to be stored in the ventromedial prefrontal cortex regions.

There are going to be significant discoveries related to a variety of clinical neuroscience disorders that are likely to involve the insular cortex.  There is already evidence of it playing a key role in such diverse disorders as:

• Autism
• ADHD
• Addictions including nicotine dependence
• Anorexia nervosa
• Major depression
• Pain disorders
• Alzheimer’s disease (in nonfluent primary progressive aphasia)

 I highly recommend both the 10 year anniversary manuscript as well as the 2009 summary of research on the insula.  They are both packed with data and commentary that I found quite revealing and intriquing.

Photo of iPad snap shot of Brain Tutor app with insular cortex in blue courtesy of Yates Photography.

Craig AD (2009). How do you feel--now? The anterior insula and human awareness. Nature reviews. Neuroscience, 10 (1), 59-70 PMID: 19096369


Luo L, Rodriguez E, Jerbi K, Lachaux JP, Martinerie J, Corbetta M, Shulman GL, Piomelli D, Turrigiano GG, Nelson SB, Joëls M, de Kloet ER, Holsboer F, Amodio DM, Frith CD, Block ML, Zecca L, Hong JS, Dantzer R, Kelley KW, & Bud Craig AD (2010). Ten years of Nature Reviews Neuroscience: insights from the highly cited. Nature reviews. Neuroscience, 11 (10), 718-26 PMID: 20852655