The brain is a complex and fascinating organ that allows us to experience the world around us in ways that are both subtle and profound. At the heart of the brain's functioning are synapses, tiny connections between neurons that allow them to communicate with one another. In this article, we will explore what synapses are, how they work, and what we still have to learn about them.
Synapses are essential for creating thoughts, emotions, personality, memories, and everything else that makes up our daily experience. When an action potential reaches the end of a neuron, it triggers the release of neurotransmitters, which are stored at the neuron terminal. These neurotransmitters are then released into the synaptic cleft, the space between the two neurons, and are picked up by the postsynaptic neuron's receptors.
The process is similar to a warehouse, where items are stored in preparation for when they are needed. When an order is placed, the items are packaged correctly and dispatched to the right location. Similarly, neurotransmitters are stored ahead of time in preparation for when an action potential requires them. Once an order has been placed, the neurotransmitters are packaged into small vesicles, which carry them to the axon's membrane and into the synaptic cleft. There, they are picked up by the postsynaptic neuron's receptors, which are proteins with a specific shape that ensures only specific neurotransmitters can activate the neuron.
Once enough neurotransmitters have bound with their respective receptors, an action potential is generated in the postsynaptic neuron, and the process repeats itself. However, the fate of the neurotransmitters after they have done their job depends on their type and size. Some of them degrade quickly after their single use, while others are cleared from the synaptic cleft by glial cells. Finally, some neurotransmitters are returned to the presynaptic neuron for repackaging and reuse.
One question that still remains is the plasticity of synapses. Plasticity refers to the capacity of neurons to learn, which means that if a specific synapse is no longer being used, the brain will create a new, more useful connection with another neuron. This process can occur when we learn new habits and skills, and old and used ones die out. The brain has a remarkable capacity for this, and it is why the expression "if you don't use it, you lose it" is so apt.
While we have a good understanding of the synaptic mechanism, there is still much to learn about how synapses work. We do not yet fully understand how neurons are capable of seemingly choosing which synapses to maintain and which to eliminate. This is an area of ongoing research, and new discoveries are being made all the time.
In conclusion, synapses are critical to our brain's functioning and allow us to experience the world around us. We have a good understanding of how they work, but there is still much to learn about their plasticity and other aspects of their functioning. As we continue to explore the brain and its workings, we can look forward to new insights and discoveries that will deepen our understanding of this remarkable organ.