Thinking, reading, remembering: everything depends on synapses. These microscopic junctions orchestrate the activity of our 86 billion neurons.
The brain is made up of billions of neurons that communicate with each other. This communication takes place via synapses, specialized areas of contact where one neuron transmits a message to another.
There are two types of message:
An electrical signal, called an action potential, which is a brief variation in voltage travelling from the neuron to the synapse.
A chemical signal, produced when the neuron releases neurotransmitters, small molecules that cross the space between two neurons to activate the next one.
This mechanism enables the brain to process information, command movement, form memories or feel emotions.
Synapses ensure communication between neurons. When they function normally, the brain processes information fluidly: we think, we learn, we feel, we act.
But when these connections are too numerous, too weak, poorly organized or disappear prematurely, neuronal circuits lose their balance.
This can cause or aggravate many neurological and psychiatric diseases.
Today, we know that synaptic dysfunctions play a central role in pathologies such as Alzheimer's disease, autism, schizophrenia and epilepsy.
In Alzheimer's disease, synapses, the connections that enable neurons to communicate, begin to disappear silently, long before the neurons themselves die.
This early loss of connections slows down the transmission of information in the brain.
Little by little, circuits become less efficient, leading to memory problems, difficulties finding one's bearings, or finding one's words.
To better understand brain diseases, scientists are focusing on synapses.
These connections, invisible to the naked eye, play a central role in the formation of memories, brain development or the balance of thoughts.
Here are the two big questions guiding current research.How are synapses formed?
Duringthe first years of life, billions of synapses are formed in the brain. But the way they are set up has to be very precise: a mistake can disorganize the circuits.
Researchers are trying to understand which genetic and molecular signals guide this construction.
🔗 Medical challenge: to better understand developmental disorders such as autism or cognitive delays.Why are some synapses eliminated?
Thebrain sorts its connections. This is normal. But this sorting can become excessive. Microglia, an immune cell in the brain, plays a major role in this process.Scientists are seeking to understand when and how this sorting becomes pathological, particularly in adolescents and young adults.
🔗 Medical stakes: a better understanding of schizophrenia and certain forms of depression.
Slowing Alzheimer's without drugs: precision stimulation
What they've done:
Sinaptica Therapeutics has developed a targeted magnetic stimulation treatment called SinaptiStim®. It is tailored to each patient's individual MRI and EEG data. The idea is simple: to reactivate declining synaptic circuits, before it's too late.
What they observed:
In a Phase 2 clinical study (2024), patients treated with this non-invasive stimulation showed a significant slowdown in cognitive decline, with no major side effects.
Regrowing synapses: a pill that regenerates
What they did:
The Spinogenix company is developing an oral drug called SPG302, capable of promoting the formation of new synapses in the brain. This is not a treatment to slow down the disease, but to actively repair lost connections.
What they observed:
In animal models, SPG302 improved cognitive function. It is now in Phase 2 human clinical trials on patients with early-onset Alzheimer's disease.
🔹 Synapse = Therapeutic hopes
These advances are not experimental. They're in the clinic, tested in humans, sometimes ready to arrive in hospitals.They show that the synapse is no longer an unattainable target.It's becoming a therapeutic lever.And behind each protocol, there's a simple idea: reconnect what's going out, and give the brain a chance again.
