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.

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 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