title: Disentangling interoception: insights from focal strokes affecting the perception of external and internal milieus.
abstract: Interoception is the moment-to-moment sensing of the physiological condition of the body. The multimodal sources of interoception can be classified into two different streams of afferents: an internal pathway of signals arising from core structures (i.e., heart, blood vessels, and bronchi) and an external pathway of body-mapped sensations (i.e., chemosensation and pain) arising from peripersonal space. This study examines differential processing along these streams within the insular cortex (IC) and their subcortical tracts connecting frontotemporal networks. Two rare patients presenting focal lesions of the IC (insular lesion, IL) or its subcortical tracts (subcortical lesion, SL) were tested. Internally generated interoceptive streams were assessed through a heartbeat detection (HBD) task, while those externally triggered were tapped via taste, smell, and pain recognition tasks. A differential pattern was observed. The IC patient showed impaired internal signal processing while the SL patient exhibited external perception deficits. Such selective deficits remained even when comparing each patient with a group of healthy controls and a group of brain-damaged patients. These outcomes suggest the existence of distinguishable interoceptive streams. Results are discussed in relation with neuroanatomical substrates, involving a fronto-insulo-temporal network for interoceptive and cognitive contextual integration.
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina ; UDP-INECO Foundation Core on Neuroscience, Diego Portales University Santiago, Chile ; National Scientific and Technical Research Council Buenos Aires, Argentina.
authors.forename: Blas
authors.initials: B
authors.lastname: Couto
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina.
authors.forename: Federico
authors.initials: F
authors.lastname: Adolfi
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina ; UDP-INECO Foundation Core on Neuroscience, Diego Portales University Santiago, Chile ; National Scientific and Technical Research Council Buenos Aires, Argentina.
authors.forename: Lucas
authors.initials: L
authors.lastname: Sedeño
authors.affiliation: Physics Department, University of Buenos Aires Buenos Aires, Argentina.
authors.forename: Alejo
authors.initials: A
authors.lastname: Salles
authors.affiliation: UDP-INECO Foundation Core on Neuroscience, Diego Portales University Santiago, Chile ; Medical Research Council-Cognition and Brain Sciences Unit Cambridge, UK.
authors.forename: Andrés
authors.initials: A
authors.lastname: Canales-Johnson
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina.
authors.forename: Pablo
authors.initials: P
authors.lastname: Alvarez-Abut
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina.
authors.forename: Indira
authors.initials: I
authors.lastname: Garcia-Cordero
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina.
authors.forename: Marcos
authors.initials: M
authors.lastname: Pietto
authors.affiliation: Department of Psychology, University of Cambridge Cambridge, UK.
authors.forename: Tristan
authors.initials: T
authors.lastname: Bekinschtein
authors.affiliation: Laboratory of Neuroscience, Universidad Torcuato Di Tella Buenos Aires, Argentina.
authors.forename: Mariano
authors.initials: M
authors.lastname: Sigman
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina ; National Scientific and Technical Research Council Buenos Aires, Argentina ; ARC Centre of Excellence in Cognition and its Disorders Sidney, NSW, Australia.
authors.forename: Facundo
authors.initials: F
authors.lastname: Manes
authors.affiliation: Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro University Buenos Aires, Argentina ; UDP-INECO Foundation Core on Neuroscience, Diego Portales University Santiago, Chile ; National Scientific and Technical Research Council Buenos Aires, Argentina ; ARC Centre of Excellence in Cognition and its Disorders Sidney, NSW, Australia ; Universidad Autónoma del Caribe Barranquilla, Colombia.
authors.forename: Agustin
authors.initials: A
authors.lastname: Ibanez
keywords: exteroception; interoception; interoceptive awareness; interoceptive sensitivity; lesion; peripersonal space; stroke