A new ‘remarkable connection’ discovered between our heart and brain: ScienceAlert
In the few seconds it takes to read this sentence, your sense of time may expand and contract, and your perception of the world may change in ways you won’t notice.
These subtle effects on the brain are imperceptible—they pull an etheric pull from the heart beating far inside your chest—boosting motor function in short bursts, too, according to a new study.
Neuroscientist Isra Al of the Max Planck Institute for Human Cognitive and Brain Sciences in Germany has studied the effect of the heart on the brain for several years, building on decades-old research and recent studies using more powerful methods.
In 2020, Al and some of her colleagues found that our sense of external stimuli decreases each time the heart contracts in what is known as an asystole. This sensory acuity returns when the heart relaxes in relaxation. But with each contraction, our sensory perception diminishes.
How do our bodies and muscles respond in those silent moments when our senses are briefly dulled? Are we ready to act on the information we have just received or are we trapped in a lull?
Some research has indicated that reaction times are slow during a contraction and that it takes longer for us to gather tactile information because our sensory perception is momentarily muted. Other studies have found that rapid eye movements known as saccades They happen often As the heart contracts, motor movements are suggested Affected by the cardiac cycle.
A clear picture of this ebb and flow has eluded scientists until now. So Al and her fellow researchers set out to measure how the motor cortex, the part of the brain responsible for controlling voluntary motor movements, responds over the course of an entire cardiac cycle.
“Interestingly, this study reveals a remarkable relationship between the human heart and brain, revealing distinct time windows designed for action and cognition,” the researchers said in a statement.
The researchers fitted the participants with a few different machines to capture simultaneous recordings of brain, heart and hand muscle activity while they were sitting in a chair and when they completed a motor task that involved pressing a scale.
By analyzing data from 36 people, the researchers found that the nerve signals that control hand muscles spike during a contraction, which typically lasts three-tenths of a second. Hand muscle activity was also stronger for moments when participants happened to press the scale during systole, rather than relaxation.
“In general, we found that excitability in the sensorimotor cortex increases with contraction, and this increase is thus reflected in the strength of the motor output,” the researchers wrote.
Comparing these findings with previous findings, the researchers suggest that the increase in muscle activity during contraction complements the decrease in sensory perception such that there are distinct windows in the cardiac cycle where the brain is primed to process sensory information and then act on it.
“It is possible that distinct time windows exist across the cardiac cycle, leading to improved cognition or functioning,” the researchers concluded.
The study was published in PLoS Biology.