Table 1.

Interoceptive dimensions.

Interoceptive Component	Definition	Method of Assessment	Neural correlates	Findings in OCD
Attention	Observation of internal body sensations	Focusing task:Attend to sensations in specific organ (e.g., Simmons et al. (60); Farb et al. (61)	Right dorsal middle anterior insula (60), posterior insula (61)	N/A
Detection	Presence/absence of conscious report	Example:Subjects judge whether external tones occur simultaneous to pulse/heartbeat (e.g., Khalsa et al. (62)	Anterior insula (63)	N/A
Magnitude	Intensity of body sensations	Example: Dial ratings of internal sensation intensity [e.g. Khalsa et al. (64)]	N/A	N/A
Discrimination	Localization of sensation to a specific system, and differentiation from other sensations	Organ specific ratings, heartbeat discrimination task [e.g., Aziz et al. (65); Khalsa et al. (64)]	Anterior cingulate (65)	N/A
Interoceptive accuracy (IAcc)	Objective accuracy of interoceptive states	Examples:Heartbeat detection Task: Comparison of subjective heartbeat count to actual heartbeats measured with EEG [e.g., Schandry et al. (66)]	Subcortical: Insula and right dorsal anterior insula in particular, midbrain, ventral striatumCortical anterior cingulate, orbitofronal somatosensory (41, 63, 67–69)	•Decreased IAcc:° Heartbeat counting task (32)° Muscle tension task (35) •Increased IAcc (70)
Interoceptive Awareness (IA)	Meta-cognitive awareness of interoceptive accuracy	Agreement between objective and subjective report: Subjective confidence ratings during heartbeat detection task compared to IAcc [e.g., Garfinkel et al. (71)]	N/A	N/A
Interoceptive Sensibility (IS)	Subjective assessment of how internal body signals are appraised, regulated, and impact behavior	Self-report, for example:MAIA (72), BPQ (73) BAQ (74) Confidence ratings	Anterior-mid insula, cingulate cortex, orbitofrontal cortex, somatosensory and sensorimotor regions (75–78)	•Compared to healthy controls, OCD demonstrated higher noticing, distracting, worrying, emotional awareness, listening but lower trusting on MAIA •Higher noticing related to responsibility/harm,symmetry/ordering symptoms •Higher distracting related to unacceptable/taboo thoughts (34)
Emotional Evaluation of Interoceptive Signals (IE)	Emotional appraisal of internal bodily signals	MAIA Not Worrying Subscale (72), ASI Physical Subscale (79)	Posterior, dorsal, and anterior insula, dorsal anterior cingulate (75)	•OCD appraises internal physical sensations more negatively than controls (34, 80) •Negative appraisal of internal sensations correlated with responsibility/harm, contamination/washing, symmetry/ordering, certainty/doubting (34, 81, 82)

ASI, Anxiety Sensitivity Index; BPQ, Body Perception Questionnaire; BAQ, Body Awareness Questionnaire; EEG, electroencephalogram; MAIA, Multidimensional Assessment of Interoceptive Awareness; OCD, obsessive-compulsive disorder.