2023-09-27 17:00:00
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The human brain is the organ that makes us unique. It is a small biological wonder capable of controlling the body’s actions and allowing us to relate to a changing environment. This enormous capacity for adaptation is possible thanks to the interconnection of some 80 billion neuronswhich move nerve impulses and communicate with each other to perform all types of tasks.
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From moving your fingers, to dancing, or letting your imagination fly, everything is orchestrated by chemical compounds and ions moving from one neuron to another. These movements, which occur in small gaps called neuronal synapses, allow information, actions, memories and feelings to form and reach the correct organ.
The jump from neuron to neuron creates different neuronal “pathways” depending on the type of action, the region of the brain, and even in which brain the study is being performed. All these variations are associated with the characteristics of each person, such as behavior, health, brain development and aging. Although our knowledge about neurological processes is becoming deeper, certain brain mechanisms are so complex and involve so many variables that they escape us. Therefore, there continues to be an aura of mystery that pushes us to ask ourselves everything from how consciousness is created to how the brain is organized during development.
How does a brain work?
A brain is a set of different cell types that fulfill very specific roles. The so-called glia cells, for example, have very diverse functions, such as covering the brain “wiring”, protecting against infections, or moving fluids from one place to another. But in this enormous cellular network, Neurons are those that receive and respond to internal and external stimuli. But a single neuron does not have much to do, it has to communicate with others so that complex functions can occur, and this occurs through neuronal synapses.
There are two types of synapses: electrical and chemical. At electrical synapses, ions flow directly between neurons through special junctions called gap junctions. This type of synapse is very fast and synchronized, but acts like a switch, i.e. does not allow much variation in the signal, practically only “on” or “off”. These connections occur mainly in the brain of invertebrates and in some areas of the human brain, such as the hippocampus.
In chemical synapses, neurons do not touch each other directly, but rather there is a space between them called the synaptic gap. When a neuron receives an electrical impulse, it releases vesicles that contain substances called neurotransmitters. Neurotransmitters travel through the synaptic space and bind to receptors on the membrane of the next neuron. This causes the receiving neuron to change its electrical potential and may or may not fire a new nerve impulse. This type of synapse is slower than electric, but allows a greater diversity of signals to transmit to the next neuron. This type of communication is what occurs in most regions of the human brain and is responsible for functions such as learning, memory or emotions.
That is to say, synapses are the language of the brainand the neurotransmitters are the words that neurons use to talk to each other. There are many types of neurotransmitters, such as dopamine, serotonin or acetylcholine, and each has a different effect on neuronal activity. Some are excitatory, that is, they increase the probability that the receiving neuron fires a nerve impulse; others are inhibitors, that is, they reduce it. So, Neurons can regulate their activity according to the needs of the body.
Why are brains different?
But not all brains behave exactly the same, and these variations occur in part due to each person’s genetics. Although in our DNA we all have the instructions to create a human person, There are small key differences that are what make us unique. And the same thing happens in the brain. There are genetic variants related to the thickness of the gray matter layer, the quantity and position of the “cerebral wrinkles” – called cerebral sulci and gyri – or the size and volume that the brain occupies in the skull.
To understand these aspects and other more complex ones, a study published in Nature genetics has employed brain images of 36,663 volunteers. In these images they have observed 180 key regions of the brain and compared them with the genetics of each person. The results show 4,349 variants in the genome that are related to different aspects of neurodevelopment. Among these characteristics is the thickness of the layer that covers the brain, its total surface area, the amount of gray matter and even the movement of fluid within the skull.
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Image of a diagnostic MRI of a brain.
Its about Largest study to date linking genetics to brain structure, and in it, neuroscientists have also been able to find other interesting aspects that will help understand certain neurological problems. In this research, they found that there are some genetic markers that affect both the expansion of the brain and the increase or decrease in the size of the skull, which is known as “cephalic disorder.”
From this study it is concluded that Genetics influences brain development. The findings can be used to understand how changes in brain shape and size can lead to neurological and psychiatric problems, and use this knowledge to create better treatments.
Genetics and the brain
These last few years have been a revolution in the field of genetics. Since it was published the most complete genome To date, the first sketches of the genome human and, recently, the first complete Y chromosome, researchers are discovering unknown genes and functions at all stages of human development. In the specific case of the study, the more than 4,000 genetic variants add to the map of an organ full of unknown regions.
Giving this thought a little spin, Neuroscientists are nothing more than brains trying to study themselves. Thus, while they navigate the complex folds of gray matter in search of the secrets whispered by the synapses, they illuminate the mysteries of the mind while putting together a puzzle of millions of pieces to try to understand themselves.
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