[Info] The Amazing Neuron

[RobinN]

Neurons are specific, unique kinds of cells in our bodies that carry information through electrical and chemical signals. Neurons are a core component of our nervous system, which includes both the brain and the spinal cord.

The neuron hypothesis was a major influence on modern neuropsychology.

The neuron hypothesis has three key aspects:

Neurons are discrete, autonomous cells that interact but are not physically connected.
They send electrical signals that have a chemical basis.
They communicate with one another by using chemical signals.

Want to learn more about the amazing neuron? Read on…

Discovering the Neuron

Descartes described neurons as hollow filled tubes. However, when Anton van Leeuwenhoek examined nerves with a microscope, this is not what he found (Kolb, Whishaw, 2009).

As microscopes became more powerful, the neuron and its various parts became more visible. Eventually this led Theodor Schwann to suggest that cells are the basic structural units of the nervous system (neurons and glial cells).

An important development in the visualizing of cells was the introduction of staining, which permits us to differentiate among various parts of the nervous system. Anatomist Camillo Golgi used a silver-staining technique to become the first to visualize an entire neuron and all of its processes.
Electrical Activity and Behavior

Italian physicist Luigi Galvani found that wires used to electrically stimulate a frog’s nerve causes muscle contractions. Galvani got the idea that electrical stimulation may cause movement after observing that frog legs hanging from a metal wire twitched during an electrical storm.

Fritsch and Hitzig demonstrated that stimulating the cortex electrically produced movement. The technique of stimulating the cortex consisted of placing a thin uninsulated wire onto or into the cortex and sending a small electrical current through the uninsulated tip of the wire. Today researchers use transcranial magnetic stimulation (TMS) to induce electrical activity into the brain. This technique allows researchers to study how the brain produces behavior and which parts of the brain participate in specific actions.
Neurons as Basis of Learning

British psychologist Charles Scott Sherrington investigated how nerves connect to muscles. He suggested there is no continuous connection. He theorized that junctions connect neurons and that additional time is required to cross the junction. He referred to these junctions or gaps as synapses.

Otto Loewi found that chemicals carry messages across the synapse. Loewi’s discovery prompted a further discovery, that a synapse releases chemicals to influence the adjacent cell. Neuropsychologist Donald Hebb proposed a learning theory: individual cells, activated at the same time, form connecting synapses or strengthen existing ones and become a functional unit. He proposed that the new or strengthening units are the basis of memory.

Acceptance of the idea that the brain is plastic and is constantly changing at each of its billions of synapses revolutionizes our view of the brain from one that represents “self” by a static structure to one that represents self by dynamic, ongoing reorganization. (Kolb & Whishaw, 2009, p.23)

Neurons (more specifically neuronal communication) allow us to know what we know about the world; they allow us to sense, think and behave. In short, neurons allow us to function. In Part 1, we learned how neurons allow us to acquire, process and respond to information.

Neurons, their connections and their signaling mechanisms are responsible for learning and memory. Following the brain hypothesis, which stated that the brain is responsible for all behavior, the neuron hypothesis stated that the basic unit of brain structure and function is the nerve cell (neuron and glia cells). If we are to understand the brain and its complex activities it is important to understand neurons as a basic unit.

Neurons allow the body to communicate. In understanding the biological bases of behavior it is important to gain an understanding of neurons and neurotransmitters. The neuron is composed of three main parts: axon, cell body and dendrites.

What follows is a basic description of how neurons communicate (via electrical-chemical- electrical signaling).

The dendritic spine receives information from the synapse, where a neurotransmitter binds to a receptor on the dendrites’ membrane (axodendritic). The information then is sent to the neuron’s cell body where the information is processed. The axon,which carries impulses away from the cell body, carries information via electrical impulse to its end (terminal) where neurotransmitters (chemical substances) are released into the synapse,a tiny junction between neurons. They traverse to the other side and bind to receptors on another neuron’s dendrite. The electrical-chemical-electrical process is repeated.

Neurotransmitters are very important regarding neuronal communication. These chemical substances transmit messages from neuron to neuron at the synapse. They also transmit messages from neurons. Scientists have identified over 100 different types of neurotransmitters.

Proper functioning of neurotransmitters and neurotransmitter receptors are imperative for neuronal communication. The three different types of neurons — sensory, interneuron and motor — vary in structure and function.

In essence, you are your brain, and your brain is largely composed of neurons, so understanding these neurons is imperative to understanding yourself. Consider the plasticity of the brain and how forming and strengthening synapses shape who you are. As you engage in different activities, interact with people, see new places, recall, daydream, mentally rehearse, and engage in various other cognitive activities you strengthen existing synapses and also form new ones. This plasticity allows you to consistently modify who you are.

http://psychcentral.com/blog/archives/2011/10/08/the-amazing-neuron-facts-about-neurons-part-2/