In sum, causal studies are needed to elucidate the nature of the association between heart rate, the HEP and the neural processing of incoming sensory stimuli. We hope these findings will help unravel these interactions and inspire further studies.

In within-subject analyses, we did not find evidence that heart rate affects sensorimotor processing. The HEP changed with heart rate but was not affected by attention orienting. Heart rate and cardiac phase at the time of stimulus onset did not predict reaction time.

Participants with faster heart rates showed stronger HEPs in the frontal lobe and participants with stronger HEP over the motor cortex responded slower. These suggest that the HEP and heart rate might interfere with neural processing. However, causal interactions remain to be established.

We examined three questions. One, if attention orienting changed the neural response to the heartbeat (heartbeat-evoked potential, HEP). Two, if the HEP changed with heart rate and, three, if heart rate and the HEP were associated with sensorimotor processing of an auditory suprathreshold stimulus.

Heart rate deceleration (bradycardia) is observed during states of focused attention, in response to a threat (fear response) or during attention orienting in expectation of an incoming stimulus (attentive anticipation). Yet the role of heart rate within these cognitive contexts remains unclear.

The modulation of the HEP by heart rate emerged as a marker of neuronal gain modulated by arousal and associated with mental effort, suggesting that the impact of heart rate fluctuations on the brain depends on cognitive state.

The heartbeat-evoked potential (HEP) was stronger for slower heart rates. Surprisingly, this effect was stronger during periods of high mental effort, was absent during rest, and was related to the amplitude of phasic pupil responses. #pupil #arousal #heart-brain