The Action Potential: The electricity that makes us feel, think and move

There is an idea that seems almost mystical, yet is deeply biological:

Every cell in our body is electrically charged.

Every living cell maintains an electrical difference between its inside and outside. And millions of years ago, neurons learned to use that difference as a way of communicating.

Thanks to this, we can think, remember, feel, sing...

All of it begins with tiny electrical signals moving through the nervous system.

A neuron at rest is not switched off. It is waiting. Like a bow drawn back just before releasing the arrow.

Inside, it is more negatively charged than outside. This difference is called the resting membrane potential. It is usually around −70 millivolts. That might seem like a small number, but on the scale of a cell, it is enormous. It is the tension that allows the neuron to remain ready to respond.

And here is something I love: before a neurone can fire, it needs to mantain a delicate balance.

It is not asleep. It is regulated, holding energy, waiting for the right signal.

That balance depends on charged particles called ions: sodium, potassium, chloride and calcium.

These ions move in and out of the neuron through specific channels, like tiny doors in the cell membrane. And one of the most important mechanisms involved is the sodium-potassium pump. This pump works constantly to maintain the electrical difference between the inside and outside of the cell.

It is as if the neuron were taking care of its own internal climate.

And this connects beautifully with somatic work.

Because our nervous system needs balance too. We cannot live permanently activated. But neither can we live completely shut down. Health, often, is not about always being calm. It is about being able to move flexibly between activation and rest. Between tension and release. Between alertness and safety.

When a neuron receives enough stimulation, something quite extraordinary happens.

Its electrical charge changes incredibly quickly. The inside of the cell becomes less negative, moving closer to zero. And if it reaches a certain threshold — around −55 mV, known as the activation threshold — an all-or-nothing event is triggered: the action potential.

At that moment, voltage-gated sodium channels rapidly open, causing a sudden reversal of the electrical charge that allows the nerve impulse to travel along the axon.

The action potential is a brief, intense and precise electrical signal. It lasts only a few milliseconds.

But without it, there would be no thought, movement or sensation.

It is the neuron's electrical “yes”.

The moment it stops waiting and decides to act.

There is a fundamental rule here: the all-or-nothing principle.

If the stimulus does not reach the threshold, nothing happens. If it does, the neuron fires completely.

Not a little. Not halfway.

It fires.

If we think about it, many processes in life can feel similar. Sometimes we accumulate small internal signals for a long time. Tension. An unexpressed emotion. An intuition. Exhaustion. Discomfort. And eventually, the system crosses a threshold.

Then comes the reaction. We cry. We get angry. We freeze. We make a decision. We let go...

The body had been speaking for a long time, but perhaps we weren't listening.

After firing, the neuron needs to return to its resting state.

First it depolarises. Then it repolarises. And then it enters a refractory period.

The refractory period is a time during which the neuron cannot immediately fire again. It needs to recover. It needs to restore its balance.

And here there is a very human lesson: even a neuron needs a pause after being activated.

We are not designed to stay in response mode all the time. After an intense emotion, an argument, a stressful situation or a profound experience, the nervous system needs to reorganise itself.

It needs to integrate.

It needs to breathe.

It needs to find its centre again.

When the action potential reaches the end of the axon, the neuron has to pass the message on to another cell.

And this happens at the synapse.

The synapse is the space where neurons communicate. Sometimes transmission is electrical, fast and direct. But most of the time, it is chemical. The neuron releases neurotransmitters into a tiny space called the synaptic cleft. Those neurotransmitters cross the space and bind to receptors on the next neuron. Like a key fitting into a lock. And depending on the receptor, the message can activate or inhibit the neuron receiving it.

This is very important: A neurotransmitter is not good or bad in itself. Its effect depends on the receptor it binds to. The same messenger can produce different effects depending on the context. And this happens with our experiences too.

The same situation can evoke a sense of safety in one person and threat in another.

Silence can feel like peace or abandonment. A look can feel like intimacy or judgement.

The nervous system does not respond only to what happens.

It responds to the meaning that what happens has for it.

In the postsynaptic neuron, two main things can happen.

An excitatory signal can bring the neuron closer to firing, while an inhibitory signal can move it further away from firing.

Excitation and inhibition.

Activation and restraint.

Movement and containment.

The brain works because of this balance.

If everything were excitation, there would be chaos.

If everything were inhibition, there would be blockage.

Mental life needs both forces.

It needs impulse.

And it needs regulation.

Neurons do not make decisions based on a single isolated signal either.

They receive thousands of messages.

Some push them towards activation.

Others invite them to settle.

And the neuron integrates all of them.

It adds signals. Subtracts signals. Works out whether the moment has come to fire or not.

This is called neural integration.

And perhaps it is one of the most beautiful metaphors for the human nervous system.

Because we are integration too.

We are what we inherited.

What we lived.

What we felt.

What we remember.

What we suppressed.

What we expressed.

What the body learned to recognise as danger.

And what, little by little, it can learn to recognise as safety again.

This is where somatic healing begins to make a lot of sense.

When we work with breathing, slow movement, body awareness or the feeling of safety within the body, we are not doing something “magical”.

We are speaking to the nervous system in its own language.

The language of rhythm.

Of tension.

Of release.

Of inner perception.

Of regulation.

The body is not an object we have. The body is where our experience happens.

Science shows us that we are electricity, chemistry and organised matter.

But the experience of being alive goes beyond describing the mechanisms.

An emotion is not “just” neurotransmitters.

A thought is not “just” electricity.

A deep connection is not “just” synaptic activity.

All of that is true on a biological level, but the human experience has a depth that also needs the language of spirituality.

Neuroscience explains how the signal is transmitted. But each person has to discover what that signal means in their own life. In the end, every action potential is a tiny spark.

A spark travelling through the nervous system. A spark that can become movement, a word, desire, fear, intuition, memory, love... A decision that changes the course of a life.

The more we understand the mechanisms of the brain, the more mysterious the experience of being alive seems.

We are not energy in an abstract sense.

We are energy organised into biology.

And somehow, every time a neuron fires, life is saying to itself:

“I am here.”