From cell to feeling: How the developing heart teaches the emotional brain to feel
Introduction
The development of the heart in the embryo is not merely an impressive architectural process; it is also a formative dialogue between biology and emotion, between structure and perception. What begins with microscopic cell movements and biochemical processes such as epithelial-to-mesenchymal transition (EMT) and the shaping of the extracellular matrix (ECM) ends in a beating, sensing organ — a heart that expresses itself rhythmically and informs the developing brain about safety, tension, rhythm, and connection. This process forms the foundation of the emotional memory that will later be governed by the limbic system.
EMT and ECM: The cellular origins of heart formation
During early embryogenesis, cells in the endocardium undergo a profound transformation known as epithelial-to-mesenchymal transition (EMT). Stable epithelial cells lose their polarity and adhesion and transform into migratory, multipotent mesenchymal cells. These cells contribute to the development of key heart structures such as the endocardial cushions, the heart valves, and the trabeculae — sponge-like muscular projections within the ventricles that are essential for early contraction and perfusion of the growing heart (Gitler et al., 2003; Liu et al., 2010).
This entire process is made possible and regulated by the extracellular matrix (ECM) — a dynamic, interactive network that:
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transports biochemical signals such as TGF-β, VEGF, and BMP;
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provides mechanical information via tension, stiffness, and resistance;
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and modulates bioelectrical properties through ion flow and electrical gradients in the cellular environment (Derrick & Noël, 2021).
The heart that emerge from this interaction are not simply anatomical outcomes, but the result of a rich interplay between cellular behavior, environmental cues, and rhythmic mechanics.
The formed heart as a sender of bio-information
Once the embryonic heart begins to beat, it becomes more than a pump: it becomes a transmitter of information. Every heartbeat generates a continuous stream of biomechanical, bioelectrical, and biochemical signals that spread via the ECM and fascia throughout the body — and especially toward the developing brain.
The brain receives these signals even before it can consciously interpret them. And yet, this is when a first bodily memory is formed — an implicit experience of rhythm, pressure, and safety.
- Biomechanical signals
Each heartbeat generates pressure waves that travel through the arterial system and reach the brain. These waves are transmitted not only through blood flow but also via mechanosensory pathways in the fascia and vascular walls, potentially contributing to the development of rhythmic brain activity (Sun et al., 2023).
A powerful example is the carotid fascia, the connective tissue layer surrounding the carotid artery, which is embedded along with the jugular vein and vagus nerve in the carotid sheath. This fascial structure functions not only as physical protection but also as a dynamic transmission system for mechanical signals. Each arterial pulse is registered as stretch, torsion, or vibration within the fascial network and can, through mechanotransduction, inform the forming nervous system about rhythm, intensity, and internal stability (Benetazzo et al., 2011). Thus, fascia acts as an intelligent sensory system that enables the brain to interpret bodily signals even before conscious perception arises.
- Bioelectrical signals
The electrical discharges associated with cardiac activity influence the electrophysiological tuning of the brainstem and thalamus — regions essential for generating basic rhythms such as breathing, arousal, sleep, and core emotional responses (Park & Blanke, 2019).
- Biochemical signals
The heart also produces signaling molecules, such as atrial natriuretic peptide (ANP), which travel via the bloodstream to reach limbic brain areas. These molecules play a role in stress regulation, homeostasis, and emotional calibration (Gutkowska & Jankowski, 2011).
Mechanical memory as an emotional blueprint
Each heartbeat, each stretch or pulse, moves through the fascia and informs the developing brain. These signals are repetitive, internal, and consistent — patterns the brain learns to recognize as “from within.” Over time, it learns to actively attenuate these signals (known as interoceptive attenuation) to distinguish internal noise from external stimuli (Park & Blanke, 2019).
Yet before this filtering occurs, these signals are deeply stored in what can be called a mechanical memory. From this, the brain learns:
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what safety feels like (regular rhythms);
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what threat feels like (sudden changes);
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what connection feels like (coherent patterns).
Emotions such as calm, tension, fear, and closeness thus acquire a bodily foundation — a blueprint of feeling formed through rhythm and motion, long before the development of language or conscious experience (Damasio, 1999; Seth, 2021).
The heart as a blueprint of emotional intelligence
What emerges is a body that feels before it thinks. The heart teaches the brain how to tune into itself, laying the groundwork for interoception — the ability to sense and interpret internal signals. This capacity is essential for:
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self-awareness;
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emotional regulation;
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social connection (Seth, 2021).
The heart — shaped by EMT and ECM — is not only an anatomical marvel but also a teacher of the brain, a rhythmic guide in the development of human emotional experience.
From embryonic motion to therapeutic touch: The role of osteopathy
This is where the connection with osteopathy becomes clear. Osteopaths approach the body as an interconnected system of moving fascia and rhythms. Disturbances in this system, whether physical or emotional, can affect sensory experience and regulation.
The osteopath “listens” with their hands to the body: where tension is held, where movement is restricted, where rhythm is lost. By gently releasing and re-aligning fascial structures — for example, around the carotid region — one can reconnect with the deeply stored mechanical memory of safety and coherence. This approach supports the self-regulatory capacity of both body and brain (Cerritelli et al., 2023).
Conclusion: Form becomes feeling
The journey from cell to rhythm, from heartbeat to sensation, shows that the heart is far more than a pump. It is a rhythmic messenger, a beating guide in the development of selfhood and emotion. Through EMT and ECM, it becomes a structure that sends not only blood, but also biomechanical, biochemical, and bioelectrical signals — messages that shape the brain long before conscious thought emerges.
What the heart teaches the brain is never forgotten. It lives on in how we experience tension, calm, connection, and safety. And in disciplines like osteopathy, we can reconnect with that original message — and remember what the heart already knew, even before we could feel it.
References
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Benetazzo, L., Bizzego, A., De Caro, R., Frigo, G., & Stecco, C. (2011). Histological study of the deep fasciae of the limbs. Journal of Bodywork and Movement Therapies, 15(4), 386–390. https://doi.org/10.1016/j.jbmt.2010.12.003
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Cerritelli, F., et al. (2023). Osteopathic Touch and Heart-Brain Interaction. Scientific Reports, 13, 4983.
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Damasio, A. (1999). The Feeling of What Happens: Body and Emotion in the Making of Consciousness. Harcourt.
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Derrick, C. J., & Noël, E. S. (2021). The ECM as a driver of heart development and repair. Development, 148(5), dev191320. https://journals.biologists.com/dev/article/148/5/dev191320
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Gitler, A. D., et al. (2003). EMT in cardiac development. Developmental Cell.
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Gutkowska, J., & Jankowski, M. (2011). Physiological role of natriuretic peptides in the central nervous system. Neuropeptides, 45(2), 105–112.
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Liu, J., et al. (2010). Control of cardiac trabeculation by Notch1 signaling in endocardial cells. Developmental Cell, 16(2), 233–244.
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Park, H. D., & Blanke, O. (2019). Heartbeat-evoked brain responses: A review. Trends in Neurosciences, 42(6), 442–454.
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Seth, A. (2021). Being You: A New Science of Consciousness. Faber & Faber.
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Sun, L. Y., et al. (2023). Mechanical signaling in cardiovascular tissue development. Life Science Alliance, 6(3), e202201785.
