Connections in the Brain
When it comes to brain function, it is all about the connections. The brain comprises trillions of neurons interacting with one another. This cell network has to be able to connect and exchange information; otherwise, the whole body is affected as the brain is the center of command for everything we do. The nervous system is unique among the organ systems in animals because of the large number of interconnections between its synapses and the variety of neurons.
A neuron is an electrically excited cell, and that generates information and pass it on through electrochemical signaling. Neurons interact with each other through a small space known as a synapse, transmitting electrical signals from one neuron to the next. Chemicals function for the transmission of electrical impulses between neurons in the synapses. Neurons interact with each other in a predictable pattern that repeats itself from neuron to neuron.
Most neurons have a cell body, an axon, and dendrites. The collection of cells consists of both the nucleus and the cytoplasm. The axon outspreads from the cell body and often leads in many smaller subdivisions before ending up at the ends of the nerves. Dendrites spread from the cell body of the neuron and get communications from other neurons. Synapses are the points of connection to which one neuron interrelates with another. The dendrites are filled by synapses produced from the axon ends of other neurons.
In comparison to induction, proliferation, and migration that occurs internally during fetal development, the next stages of brain development are increasingly dependent on environmental interactions. After birth and beyond, behaviors such as listening to a voice, answering a toy, and even the reaction evoked by the room temperature lead to more neuronal connections.
The normal human brain has around eighty-six billion nerve cells and several other neuroglia that conserve and safeguard the neurons. Each neuron may be linked to up to the other ten thousand neurons, transmitting signals through as many as one thousand trillion synaptic connections to each other.
Unlike other body cells, many human brain neurons can only differentiate to create new cells, a phenomenon called neurogenesis, in the course of development of the fetus and for a few months after birth. These brain cells can enlarge until they are around eighteen years old, but they are built basically to last for life. Intriguingly, the hippocampus, a region necessary for memory processing and storage, is the only region of the brain where neurogenesis has been revealed to occur across existence.
The transfer of information within the brain, such as happens during memory extraction and recovery processes, is accomplished through a combination of chemicals and electricity. A standard neuron contains a single axon and a soma dendrite.
Because of metabolically mediated variations in sodium, potassium, chloride, and calcium ions in the cell, all with unlike charges, each neuron keeps a voltage gradient across its membrane. If the voltage changes substantially, an electrochemical pulse is created, which is known as an action potential. This electrical activity can be measured and shown as a brain wave or brain pulse called a waveform.
This pulsation moves progressively along the axon of the cell and is passed to a neighboring neuron through an intricate connection known as a synapse, which takes it through its soft dendrites. A synapse is an intricate membrane joint used to send information between cells, and therefore this communication is referred to as a synaptic connection. While synaptic links between axons and dendrites are the standard, other variations are also possible. An average neuron fires five-fifty times a second.
In this way, each particular neuron will make thousands of ties with other neurons, giving synapses well over 100 trillion to a normal brain. Functionally connected neurons interconnect to create neural networks. The neuronal relations are not fixed; however, they change over time. The more signals that are sent between two neurons, the stronger the connection develops. So the brain gradually re-wires its physical form with every new encounter and every recalled event or reality.
Neuron interactions, however, are not just electrical but electrochemical. Each axon end has thousands of membrane-bound pouches called vesicles, which consecutively contain thousands of molecules of neurotransmitters each. Neurotransmitters are chemical messengers that transmit, strengthen, and control neuronal and other cellular signals.
When triggered by an electrical pulse, several kinds of neurotransmitters are generated, crossing the cell membrane into the neuronal synaptic gap. These chemicals then join the receiving neuron to chemical receptors in the dendrites. In the course, they cause changes in the penetrability of the cell membrane to different ions, opening up distinct passages that allow loaded particles to overflow. It impacts the transmitting neuron’s probable charge, which then initiates a new electrical pulse inside the receiving neuron.
It takes no more than a 500th of a second to complete the process. In this manner, a message is transmitted in the brain as it travels from one neuron to the other, from an electrical impulse to a chemical impulse, and once again, into a continuous sequence of events that is the foundation of all brain action.
The electrochemical pulse produced by a specific brain chemical may be such as to promote release or prevent it from firing into the reception cell as well. Several neurotransmitters tend to act as either stimulating or receptor binding. Subtle variations in receptor activation processes allow the brain to respond to the various demands placed on it, including processing, consolidating, storing, and recalling memories.
Brain development is mainly a process of wiring, where neuronal connections are formed and refined. Neurons communicate with each other via connecting networks. Those links establish the electrical signal pathways. Connections that are used frequently get more robust and more complicated, but connections that are not used are eventually removed through the pruning process.
A process is known as synaptic pruning takes place during childhood, and especially during adolescence. While the brain keeps growing and advancing, the general sum of neurons and synapses are decreased by half, eliminating redundant neuronal organizations and letting them be substituted by more robust and effective structures that are more suitable to adult needs.
At birth, each baby has about one hundred billion neurons. The numbers of neuronal connections formed in a child’s brain are marvelous. A baby has fifty trillion synapses or connections at birth. The synapses increase more than twenty times within the first three months of life. The brain has one thousand trillion synapses in one year.