In this verse –  Allah (swt) mentions the act of understanding/comprehension but ties this to the Heart whereby also mentioning the act of hearing and connecting that to the ears. Hearing and the ears makes a lot of sense but most would connect comprehension with the brain. But Allah (swt) never errs.

Dr. Armour, in 1991, discovered that the heart has a network of intrinsic cardiac neurons. Neurons areresponsible for sending and receiving neurotransmitters —chemicals that carry information between brain cells. Researchers found that the heart had nerve cells or neurons that were akin to the ones that made up the brain. In other words, the heart had its very own nervous system that could function independently of the brain! Many deemed this phenomenon as the “little brain” or “intrinsic cardiac nervous system.”

This “heart brain” is composed of approximately 40,000 neurons that seem to serve as a connection to the brain. The heart communicates with the brain in many methods: neurologically, biochemically, biophysically, and energetically. The Vagus nerve, which is 80% afferent, carries information from the heart and other internal organs to the brain. Signals from the “heart brain” redirect to the medulla, hypothalamus, thalamus, and amygdala and the cerebral cortex. For example  – research has demonstrated that pain perception is modulated by neural pathways and methods targeting the heart such as vagus nerve stimulation and heart-rhythm coherence feedback techniques.

More recent data (from 2022) has indicated the heart is in a constant two-way dialogue with the brain with the heart and cardiovascular system sending far more signals to the brain than the brain is sending to the heart!   Its circuitry enables it to learn, remember, and make functional decisions independent of the cranial brain. The heart is not just a pump –  it actually does function as a “little brain.” Allah (swt) never errs!