Editors' ChoiceNeuroscience

Getting to the Heart of Consciousness

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Science Translational Medicine  26 Mar 2014:
Vol. 6, Issue 229, pp. 229ec53
DOI: 10.1126/scitranslmed.3009017

The ancients saw the heart as both the physical and spiritual core of who we are. A new study by Park et al. gives some support to our ancestors’ intuitions by examining heartbeats as a reference point for synthesizing personal cognition with our own visual perceptions.

The authors began their study with the knowledge that certain parts of our brains oscillate their neural activity with the beating of the heart. This story becomes more interesting because these brain areas are not the brainstem structures we use for homeostatic regulation; rather, they are the higher-functioning neocortical areas implicated in distinctly human characteristics such as interoception and empathy. But, do these neural fluctuations simply correlate with heartbeats, or do they incorporate the cardiac cycle into perception and cognition?

Park et al. tackled this question by having human volunteers report whether or not they could perceive a transient, faint visual stimulus. The hit-and-miss rates of these reportings were found to be linked to the amplitude of the neural response to the subject’s preceding heartbeat. Using magnetoencephalography, the amplitude of activity in the ventral anterior cingulate cortex and right inferior parietal lobule was shown to be a strong predictor of the effect. The authors went on to rule out other physiologic factors, such as general cortical excitability, that could have accounted for the increased cognitive visual sensitivity.

The authors conclude with a suggestion that brain fluctuations synchronized with heartbeats may represent “a subjective frame” that integrates our sense of self into cognitive perceptions. Our scientist ancestors, from Aristotle to Galen to William Harvey, would likely be the first to agree.

H.-D. Park et al., Spontaneous fluctuations in neural responses to heartbeats predict visual detection. Nat. Neurosci. 10.1038/nn.3671 (2014). [Abstract]

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