Bioelectricity and Brain Development: Consciousness Before the First Neuron Fires

Language: en

Overview

The human brain is the most complex structure in the known universe — 86 billion neurons connected by approximately 100 trillion synapses, generating the electrical storms we experience as thought, emotion, and consciousness. The standard story of brain development begins with neural induction, continues through neurogenesis and migration, and culminates in synaptogenesis — the formation of synaptic connections that enable neural communication. In this story, the brain is electrically silent until neurons mature and begin firing action potentials. Consciousness begins when the neural circuits come online.

Michael Levin’s research at Tufts University has shattered this narrative. The embryonic brain is patterned by bioelectric signals — voltage gradients, ion flows, and gap-junctional communication — long before any neuron is born, let alone before any action potential fires. These pre-neural bioelectric patterns determine where the brain forms, how large it is, what structures it develops, and whether it develops at all. The embryonic brain is built by the same bioelectric intelligence that builds every other organ — an intelligence that uses electricity as information, that operates in non-neural cells, and that constitutes a form of cognition that precedes the nervous system.

This finding has profound implications for our understanding of consciousness. If the brain is built by a non-neural bioelectric intelligence, then consciousness-like information processing exists before there is any neural substrate to be conscious with. The brain does not create bioelectric intelligence. It inherits it. The brain is a specialization of a cognitive architecture that is as old as multicellular life itself.

Pre-Neural Bioelectric Patterning

The Brain Before Neurons

In vertebrate embryos, the central nervous system begins as the neural plate — a sheet of ectodermal cells on the dorsal surface of the embryo that is “induced” to become neural by signals from the underlying mesoderm (the classic Spemann-Mangold organizer). The neural plate folds to form the neural tube, which then differentiates into the brain and spinal cord. The first neurons are born (through neurogenesis) days to weeks after neural tube closure, depending on the species.

But long before neural induction, before the neural plate even forms, bioelectric patterns are already at work specifying where the brain will develop and what its properties will be. Levin and Dany Adams demonstrated this using voltage-sensitive fluorescent dyes in Xenopus embryos. They found that characteristic voltage patterns — specific regions of depolarization and hyperpolarization — appear on the dorsal ectoderm well before any morphological sign of neural induction. These voltage patterns predict the future position and extent of the brain.

In a 2016 paper in the Journal of Neuroscience, Vaibhav Bhatt and Levin showed that disrupting these early bioelectric patterns — by manipulating ion channels or gap junctions in pre-neural-plate-stage embryos — produced specific brain defects. Inhibiting particular potassium channels at a stage when no neural cells existed resulted in embryos with malformed brains, reduced brain size, or absent brain structures. The bioelectric signal was acting as a morphogenetic instruction for brain development, and it was operating hours to days before the first neural progenitor was specified.

The Bioelectric Face

One of the most visually striking demonstrations of pre-neural bioelectric patterning came from Adams and Levin’s study of craniofacial development. Using voltage-sensitive dyes, they photographed the “bioelectric face” of frog embryos — a pattern of voltage differences across the head region that prefigured the future facial structures. Areas of high and low voltage corresponded precisely to the locations of future eyes, nose, mouth, and brain.

This bioelectric face appeared long before the anatomical face. The voltage pattern was the blueprint. The cells then followed the blueprint, migrating, differentiating, and organizing according to the bioelectric coordinates. Disrupting the voltage pattern (by misexpressing ion channels) produced predictable craniofacial abnormalities — eyes in the wrong position, fused facial structures, or absent features — demonstrating that the bioelectric signal was instructive, not merely permissive.

The brain, in this view, does not develop autonomously through an intrinsic genetic program. It develops in response to bioelectric instructions provided by the surrounding tissue — a distributed computational process that uses voltage gradients as morphogenetic coordinates. The embryonic brain is being built by a non-neural intelligence that operates through the same bioelectric mechanisms found in every other tissue.

Serotonin as a Pre-Neural Signal

A particularly elegant aspect of Levin’s work on brain development involves serotonin (5-HT) — a neurotransmitter best known for its role in mood and cognition. Levin’s group discovered that serotonin functions as a morphogenetic signal long before the nervous system develops. In early frog embryos, serotonin is transported between cells through voltage-dependent transporters, and its distribution is shaped by the bioelectric gradient.

Disrupting serotonin signaling at early (pre-neural) stages — by blocking serotonin receptors or transporters — produced severe brain defects, including reductions in brain size and abnormalities in brain structure. Conversely, providing exogenous serotonin could rescue brain defects caused by other perturbations. The neurotransmitter was functioning not as a neural signal but as a morphogenetic molecule, carrying positional information through the bioelectric network.

This finding recontextualizes the role of neurotransmitters in biology. Serotonin, dopamine, acetylcholine, GABA, and glutamate — the canonical neurotransmitters — are all present in early embryos before any neurons exist. They are used as signaling molecules in a pre-neural communication system that predates the nervous system. When neurons eventually evolve, they co-opt these existing molecules for their specialized communication needs. The neurotransmitter system was not invented by the brain. It was inherited from a pre-neural bioelectric signaling system.

The Gap Junction Network in Brain Development

Electrical Coupling Before Synapses

Before the first chemical synapse forms, the developing brain is electrically connected through gap junctions. Neural progenitor cells in the ventricular zone are coupled by Cx43 and Cx26 gap junctions that allow ions, metabolites, and small signaling molecules to flow between cells. This gap-junctional coupling creates a bioelectric network in the developing brain that processes information before any neural circuit exists.

Elias and Bhatt demonstrated that gap junction coupling between neural progenitor cells influences their proliferation, migration, and differentiation. Disrupting gap junctions in the developing cortex (by knocking down Cx43 or Cx26) impairs neural progenitor migration, reduces cortical thickness, and produces disorganized cortical architecture. The gap junction network is not just a passive connection — it is an active information-processing system that guides brain construction.

Fushiki and colleagues at RIKEN showed that gap junction coupling between neurons in the developing Drosophila brain is essential for correct circuit formation. Without gap junctions, neurons make incorrect synaptic connections, producing behavioral deficits. The bioelectric template established by gap junctions guides the subsequent formation of chemical synapses — the bioelectric network scaffolds the neural network.

Spontaneous Activity and Self-Organization

Even after neurons are born but before sensory input reaches the brain, developing neural circuits display spontaneous electrical activity — waves of depolarization that propagate through the tissue without any external stimulus. These spontaneous waves, first described in the developing retina by Meister and colleagues (1991), are essential for the refinement of neural circuits. They calibrate the connections, test the circuits, and establish the functional architecture that will later process sensory information.

Remarkably, this spontaneous activity is shaped by the pre-existing bioelectric patterns of the tissue. The gap junction network that connected the neural progenitors continues to influence neural activity patterns as the circuits mature. The bioelectric template that guided brain construction continues to influence brain function — a continuity of bioelectric information processing from pre-neural development through to mature neural activity.

This continuity undermines the sharp distinction between “brain development” and “brain function” — between building the brain and running it. The same bioelectric mechanisms are involved in both. The brain is never electrically silent. It begins as a bioelectric pattern in non-neural cells, transitions through gap-junction-coupled progenitor networks, and matures into the synaptic networks that support cognition and consciousness. The bioelectric signal is continuous. The neural activity is the latest chapter.

Implications for Consciousness Research

Pre-Neural Cognition

If the developing brain is patterned by bioelectric signals that carry morphogenetic information, solve patterning problems, and make collective decisions — and if these processes occur in non-neural cells before the nervous system exists — then cognition-like information processing exists before neural cognition. This is Levin’s concept of “pre-neural intelligence” or “basal cognition.”

The developing embryo faces a computational challenge: from a single fertilized egg, build a brain with the correct structure, connectivity, and functional properties. This is an enormously complex problem — arguably more complex than anything the mature brain does. And it is solved not by neural circuits (which do not yet exist) but by the bioelectric network of embryonic cells communicating through gap junctions and ion channels.

Levin has asked a provocative question: if we are willing to call neural computation “intelligence” and attribute “consciousness” to the neural activity that emerges from it, why not extend the same concepts to the bioelectric computation that built the neural system in the first place? The pre-neural bioelectric system processes information, stores patterns, makes decisions, corrects errors, and pursues goals (the target brain anatomy). These are cognitive functions by any operational definition.

This does not mean that embryonic cells have subjective experience in the way that a mature brain does. But it does mean that the computational principles of cognition — information processing, pattern recognition, error correction, goal pursuit — are not unique to neural tissue. They are features of bioelectric networks in general, and the neural brain is a specialized, high-performance version of a computational architecture that is far older and far more distributed than the nervous system.

The Continuity of Consciousness

The standard view is that consciousness arises at some point during brain development — either at birth, during fetal maturation, or at some threshold of neural complexity. But if bioelectric information processing is continuous from the earliest embryonic stages through neural maturation, then there is no sharp onset of consciousness. There is a continuous gradient of information-processing complexity, from the bioelectric patterns of the blastula through the gap-junctional networks of neural progenitors through the synaptic circuits of the mature brain.

This gradient view is consistent with Tononi’s Integrated Information Theory (IIT), which holds that any system with integrated information has some degree of consciousness (Phi). The pre-neural embryo, with its gap-junction-coupled bioelectric network, has integrated information — and therefore, under IIT, has some degree of consciousness. This consciousness is minimal, undifferentiated, and without self-reflection. But it is not zero.

The yogic tradition describes consciousness as present at every level of creation, with different degrees of manifestation depending on the complexity of the vehicle. The Taittiriya Upanishad’s five koshas (sheaths) describe a hierarchy from gross matter (annamaya kosha) through vital energy (pranamaya kosha) through mind (manomaya kosha) through intellect (vijnanamaya kosha) to bliss (anandamaya kosha). The pre-neural bioelectric activity of the embryo corresponds to the pranamaya kosha — the energy body that mediates between physical matter and mental activity. It is consciousness at the level of vital energy, not yet refined into thought but already processing information and guiding form.

Brain Defects as Bioelectric Communication Failures

Levin’s work has shown that many congenital brain defects — microcephaly, holoprosencephaly, neural tube defects — can result from disruptions of bioelectric signaling rather than (or in addition to) genetic mutations. Nicotine, for instance, causes brain defects not just through direct neurotoxicity but through disruption of the bioelectric patterns that guide brain development. Levin’s group demonstrated that nicotine-induced craniofacial and brain defects in frog embryos could be rescued by artificially restoring the correct bioelectric pattern.

This has implications for understanding and preventing birth defects. Environmental exposures — alcohol, toxins, infections, medications — may cause brain defects partly by disrupting the bioelectric communication system of the developing embryo. If the bioelectric signal is the proximate cause of the defect (even when the ultimate cause is a chemical exposure), then bioelectric intervention could prevent the defect even in the presence of the exposure.

Folic acid supplementation to prevent neural tube defects may work partly through bioelectric mechanisms. Folate is required for the synthesis of S-adenosylmethionine (SAM), which methylates ion channel proteins and influences their function. Folate deficiency may disrupt the bioelectric gradients that guide neural tube closure. If this is correct, then understanding the bioelectric mechanism could lead to more targeted and effective preventive interventions.

The Evolutionary Perspective

The Brain Evolved From Bioelectric Networks

The evolutionary origin of the nervous system is one of the great questions in biology. The standard narrative is that neurons evolved from epithelial cells that developed specialized electrical signaling capabilities — voltage-gated ion channels and chemical synapses. But Levin’s work suggests a more nuanced picture: the bioelectric signaling system (ion channels, gap junctions, voltage-sensitive signaling molecules) was already in place in pre-neural organisms. Neurons evolved not by inventing electrical signaling but by refining and specializing an existing bioelectric communication system.

This is supported by comparative biology. Sponges — which lack neurons entirely — have genes for ion channels, gap-junction-like proteins (innexins), and neurotransmitter receptors. They use these molecules for intercellular communication and behavioral coordination. Plants — which diverged from animals over a billion years ago — use voltage-gated ion channels and electrical signaling for wound responses, tropisms, and long-distance communication (as demonstrated by Baluska, Mancuso, and colleagues).

The bioelectric signaling toolkit is older than neurons. It is even older than animals. It is a fundamental feature of life — a consequence of the fact that all cells maintain membrane potentials and that these potentials can carry information. The neuron is a specialist — a cell type optimized for fast, long-range, precisely targeted bioelectric signaling. But the general principle of bioelectric communication is universal.

From Bioelectric Network to Neural Network

The transition from bioelectric network (non-neural cells communicating through gap junctions and ion channels) to neural network (neurons communicating through synapses) was not a binary switch. It was a gradual refinement. The earliest “nervous systems” — the nerve nets of cnidarians (jellyfish, hydra) — are densely gap-junction-coupled, relying heavily on electrical synapses rather than chemical synapses. As nervous systems became more complex (in bilaterians, deuterostomes, and eventually vertebrates), chemical synapses became predominant for precise, directional signaling, while gap junctions were retained for synchronization, oscillation, and rapid signal propagation.

The mature brain uses both systems. Chemical synapses provide the computational specificity — the directional, modifiable, computationally flexible connections that enable learning, memory, and complex information processing. Electrical synapses (gap junctions between neurons) provide synchronization — the temporal coordination that generates oscillations, binds neural activity across areas, and produces the coherent electrical rhythms associated with consciousness.

The brain, in this view, is a hybrid system — part neural network (chemical synapses), part bioelectric network (gap junctions). The bioelectric component is the older, more fundamental layer. The neural component is the newer, more specialized layer. Consciousness arises from the interaction of both.

The Deeper Pattern

Intelligence Is Older Than the Brain

The deepest implication of Levin’s work on brain development is that intelligence — defined as the ability to process information, solve problems, and pursue goals — is not a product of the brain. It is a property of living systems at every scale, from individual cells through tissues and organs to whole organisms. The brain is the most sophisticated implementation of this intelligence, but it is not the origin.

This challenges the neurocentric worldview that dominates both science and culture — the assumption that the brain is the source of all intelligence and consciousness, and that everything else in the body (and in nature) is mechanistic, unconscious matter. Levin’s work suggests a different picture: intelligence is continuous from cells to brains, and the brain is a refinement of cellular intelligence, not a departure from it.

In the contemplative traditions, this continuity of consciousness is axiomatic. The Vedantic tradition holds that consciousness (Brahman/Atman) is the ground of all existence and manifests at every level — from atoms to organisms to the cosmos. The Buddhist tradition speaks of Buddha-nature inherent in all sentient beings. The shamanic traditions perceive consciousness in all living things — and in many things that Western science considers non-living.

Levin’s bioelectric research does not prove these traditions right in their specific metaphysical claims. But it does demonstrate something they have long asserted: that cognitive-like processes — information processing, goal pursuit, pattern maintenance — are not restricted to brains. They are features of living matter itself. The brain did not invent intelligence. It concentrated it.

The Recursive Nature of Consciousness Building Consciousness

There is a beautiful recursion in the fact that the brain — the organ of consciousness — is itself built by a form of consciousness (bioelectric intelligence). The pre-neural bioelectric system processes information and solves the patterning problem that produces the brain. The brain then processes information and solves the cognitive problems that produce mind and self-awareness. Mind and self-awareness then reflect on their own existence, seeking to understand consciousness itself.

This recursive structure — consciousness building the instruments of its own amplification — is consistent with the Vedantic concept of consciousness as primary. If consciousness is fundamental (rather than emergent), then it is not surprising that it operates at every level. The bioelectric intelligence of the embryo is consciousness working at the cellular level. The neural intelligence of the brain is consciousness working at the organismal level. Contemplative practice is consciousness working at the transcendent level. The same fundamental principle — awareness organizing matter and information — manifests at every scale.

Conclusion

The developing brain is patterned by bioelectric signals that operate before any neuron exists. Voltage gradients specify where the brain forms. Ion channels and gap junctions create a communication network that guides neural progenitor behavior. Neurotransmitters like serotonin function as morphogenetic signals long before they become neural signals. The brain is built by a non-neural bioelectric intelligence — a distributed computational system that uses the same electrical signaling mechanisms that the brain will later specialize for cognition and consciousness.

This finding transforms our understanding of both brain development and consciousness. The brain is not the origin of electrical intelligence. It is its greatest refinement. The bioelectric patterns that guide embryonic development are not merely physical processes — they are information-processing events, solving the most complex patterning problem in biology. If intelligence is information processing in pursuit of goals, then the embryonic bioelectric system is intelligent. If consciousness requires integrated information, then the gap-junction-coupled embryonic network has a form of consciousness.

The brain that reads these words was built by a bioelectric intelligence that predates it. The consciousness that comprehends this article was bootstrapped from a simpler consciousness that knew nothing of words but everything about how to build the organ that would one day use them. We are, at every level of our being, built by and from consciousness. The brain is not the beginning of the story. It is the middle.