Dynamic neurocognitive changes in interoception after heart transplant

Abstract

<jats:title>Abstract</jats:title> <jats:p>Heart-brain integration dynamics are critical for interoception (i.e., the sensing of body-signals). In this unprecedented longitudinal study, we assessed neurocognitive markers of interoception in patients who underwent orthotopic heart transplants and matched healthy controls. Patients were assessed longitudinally before surgery (T1), a few months later (T2), and a year after (T3). We assessed behavioral (heartbeat detection) and electrophysiological (heartbeat evoked potential) markers of interoception. Heartbeat detection task revealed that pre-surgery (T1) interoception was similar between patients and controls. However, patients were outperformed by controls after heart transplant (T2), but no such differences were observed in the follow-up analysis (T3). Neurophysiologically, although heartbeat evoked potential analyses revealed no differences between groups before the surgery (T1), reduced amplitudes of this event-related potential were found for the patients in the two post-transplant stages (T2, T3). All these significant effects persisted after covariation with different cardiologic measures. In sum, this study brings new insights into the adaptive properties of brain-heart pathways.</jats:p>

The effects of vibrotactile masking on heartbeat detection: Evidence that somatosensory mechanoreceptors transduce heartbeat sensations

“…Although the ability to detect heartbeat sensations is the most common basis for inferring individual differences in interoceptive sensitivity or accuracy, there is no direct evidence that performance on tests of heartbeat detection is dependent on the interoceptive afferent system. There is, however, a body of research involving case studies and experiments on cardiac and neurological patients which suggests that the somatosensory system is implicated in the processing of heartbeat sensations (Barksy et al, 1998;Brener & Ring, 1995;Khalsa, Rudrauf, Sandesara, et al, 2009;Salamone et al 2020). Indeed, the available experimental evidence supports the emerging consensus that cardioception is based on afferent information from the somatosensory system, the interoceptive system, and possibly the exteroceptive system too (Brener, 1977;Cameron, 2001;Craig, 2003;Hassanpour et al, 2016;Khalsa et al, 2008;Khalsa, Rudrauf, Sandesara, et al, 2009;Rudrauf et al, 2009).…”

“…These results have recently received support from a study by Salamone et al (2020) of transplant patients whose capacities to detect heartbeat sensations were assessed prior to and following heart transplantation using a novel measure of heartbeat detection (Couto et al, 2014). The accuracy of heartbeat detection had fallen significantly when participants were retested 4 months after heart transplantation but had recovered partially when tested one year following the surgery.…”

“…However, based on the observation that the participants’ intact somatosensory pathways did not compensate fully for the loss in cardioception following vagotomy, Salamone et al. (2020) inferred that the interoceptive pathway is primary.…”

“…This variation in cardioception was attributed to the loss of interoceptive function that resulted from the transplantrelated vagotomy but, in agreement with several others (e.g., Cameron, 2001;Craig, 2003;Pollatos et al, 2007), Salamone and colleagues concluded that both the interoceptive and somatosensory pathways contribute to cardioception. However, based on the observation that the participants' intact somatosensory pathways did not compensate fully for the loss in cardioception following vagotomy, Salamone et al (2020) inferred that the interoceptive pathway is primary.…”

“…Using the masking paradigm, we examined if heartbeat sensations are detected through the Pacinian channel, non-Pacinian channel, neither of these channels, or both channels (Gescheider et al, 2002(Gescheider et al, , 2004. Masking stimuli were presented to the sternum (breastbone) on the grounds that heartbeat sensations are reported to be located in the chest more than any other site (e.g., Brener & Kluvitse, 1988;Khalsa, Rudrauf, Sandesara, et al, 2009;Ring & Brener, 1992;Salamone et al, 2020).…”