Bolus isoproterenol infusions provide a reliable method for assessing interoceptive awareness

Abstract

Interoception, defined as the perception of internal body states, plays a central role in classic and contemporary theories of emotion. In particular, deviations from baseline body states have been hypothesized to be integral to the experience of emotion and feeling. Consequently, reliable measurement of interoception is critical to the testing of emotion theories. Heartbeat perception tasks have been considered the standard method for assessing interoceptive awareness, primarily due to their non-invasive nature and technical feasibility. However, these tasks are limited by the fact that above chance group performance rates on heartbeat detection (or the frequency of ‘good detectors’) are rarely higher than 40 percent, meaning that such tasks (as they are typically utilized) do not obtain a measure of interoceptive awareness in the majority of individuals. Here we describe a novel protocol for inducing and assessing a range of deviations in body states via bolus infusions of isoproterenol, a non-selective beta adrenergic agonist. Using a randomized, double-blinded, and placebo-controlled experimental design, we found that bolus isoproterenol infusions elicited rapid and transient increases in heart rate and concomitant ratings of heartbeat and breathing sensations, in a dose-dependent manner. Our protocol revealed changes in interoceptive awareness in all 15 participants tested, thus overcoming a major limitation of heartbeat detection tasks. These findings indicate that bolus isoproterenol infusions provide a reliable method for assessing interoceptive awareness, which sets a foundation for further investigation of the role of interoceptive sensations in the experience of emotion.

Altered interoceptive awareness in anorexia nervosa: Effects of meal anticipation, consumption and bodily arousal

“…The authors posited that the lack of differences may have been due to the high degree of task difficulty, task fatigue, and assessment of I Acc during resting states when heartbeat sensations are not typically reported. Such reports are consistent with our previous experience [22], which subsequently led us to develop [28] and utilize the current approach. We did find that meal ingestion significantly impacted I Acc , with lower accuracy following meal ingestion.…”

“…Instead, the AN group was significantly more likely to endorse interoceptive changes, across all conditions. A post hoc analysis did not find group differences in detection rates at high doses, which we have previously shown have a high probability of detection [28, 30]. Individuals with AN were more likely to incorrectly endorse interoceptive changes at low doses (with a low probability of detection) and during saline infusions.…”

“…To assess interoceptive accuracy (I Acc ), cross correlations for each dose were calculated from mean-centered dial ratings and mean-centered instantaneous heart rate changes occurring during each two-minute infusion interval (as in [28]) (see Supplement for additional cross correlation measure details.) (For interoceptive construct definitions see Supplement .…”

“…This method is less invasive than analogous investigations of IA (e.g., colorectal or esophageal balloon distension), and has been tested successfully in AN [27]. Isoproterenol produces reliable dose-dependent increases in heartbeat and breathing sensations [28]. Converging evidence suggests that awareness of these sensations requires brain regions involved in visceral perception, including the insula, cingulate and somatosensory cortices [29, 30].…”

Interoceptive awareness declines with age

“…Most of these sensory modalities have been classified as “exteroceptive” senses, as they relate to awareness and apprehension of stimuli that originate outside of the body, or as “proprioceptive”, as they relate to representation of the body in space. “Interoception” 1 corresponds essentially to sensations arising from within the body including the viscera (such as the feeling of the heartbeat, the breath and gastrointestinal sensations), to some extent the skin (for example, flushing of the skin and itching), as well as a host of chemical, endocrine and osmotic changes arising within the bloodstream (such as feelings related to thirst and hunger) (Cameron, 2001; Craig, 2002; Critchley, Wiens, Rotshtein, Ohman, & Dolan, 2004; Damasio, 2003; Khalsa, Rudrauf, Sandesara, Olshansky, & Tranel, In press; Mayer, Naliboff, & Craig, 2006; Pollatos, Herbert, Kaufmann, Auer, & Schandry, 2007; Vaitl, 1996). …”