The Heartbeat-Evoked Potential in Young and Older Adults During Attention Orienting.

Cardiac cycle duration, or interbeat interval (IBI), is the period from one heartbeat to the next. IBI changes from cycle to cycle. Periods with longer IBI are associated with higher sensitivity to external sensory stimuli (exteroception). Warning cues induce a state of attentive anticipation characterized by an increase in IBI (anticipatory cardiac deceleration) and faster reaction times. Aging reduces the increase in IBI induced by warning cues and response speed. However, it is unclear which mechanism, if any, connects IBI with reaction time. The heartbeat-evoked potential (HEP) is a cortical response evoked by the heartbeat, modulated by attention and associated with sensitivity to external sensory stimuli. HEP might be affected by IBI and mediate the association between cardiac output and cortical processing. We investigated if the HEP was affected by warning cues as well as spontaneous fluctuations in IBI. To explore the impact of age-related changes in cardiac responses, we included young and older people (N = 33/29; 26/23 women; mean age 23/61 years). We analyzed the electroencephalograms and electrocardiograms simultaneously acquired during auditory cued simple reaction time and go/no-go tasks. The warning cue did not induce significant changes in the HEP. Yet, fluctuations in IBI (not locked with the warning cue) affected the HEP, and HEP amplitude was associated with average reaction time in the older group. However, on a trial-by-trial basis, reaction time was independent from IBI fluctuations. In conclusion, we found no evidence that the HEP mediates the effect of attention orienting on reaction time.