The Decade of the Brain and Neurobiology

The 1990’s were known as the “Decade of the Brain.” As we all know, the brain is a very complex organ, and in the past 20 + years we have made huge strides in understanding parts that we never understood before.  George W. Bush declared the 1990’s the Decade of the Brain and his goal was to fund research so that we could understand the function of different parts of the brain in order to understand various disorders such as Alzheimer’s Disease, strokes, schizophrenia, bipolar disorder, depression, anxiety, autism spectrum disorders, and hundreds of other brain-based illnesses.  If you are interested in George W. Bush’s Presidential Proclamation, you can click here.

Today I want give you a basic introduction to neurobiology.  This is going to very basic so that everyone can understand; however, if I make something too difficult or confusing, please let me know.  Sometimes I have a gift of making things too confusing!  I’m going to start with a very basic part of the brain.  The brain is made up of 100,000,000,000 plus (yes that’s 100 billion) neurons which are present when are born.  There are many different types of neurons but like I said, I’m going to keep this basic.

The orange section on the left with the green oval is called the body of the nerve.  The technical name of the body is the soma.  The soma of the nerve is where the nucleus of the cell is (the green oval).  If you can’t remember back to high school biology class, the nucleus is the part of any cell that is responsible for replication of the cell, responsibility for powering the cell, and gives structure.

The orange fingers that are attached to the soma are called the dendrites. The dendrites are kind of like antennae.  They received signals from other neurons.

The yellow part of the drawing (the ones that look like hot dog buns), are called myelin sheaths (they insulate some nerves) and beneath them the axon runs down to more of those orange finger-like structures (dendrites).

So, the way an neuron works, a chemical called a neurotransmitter (serotonin, dopamine, adrenaline, etc) lands on little receptors on the dendrites.  Think of receptors and neurotransmitters like little locks and keys.  When a neurotransmitter (the little key) meets up with the receptor (the little lock), it opens the door so the neuron can send an electrical signal down through the axon, to the end.  Once this electrical signal reaches the end of the neuron, this causes the neuron to release its neurotransmitter.  The space between the two neurons is called, the synapse or synaptic cleft.  This is an important thing to remember because many medications affect the neurotransmitters while they are hanging out in the synapse.

Eventually, the neurotransmitters either diffuse away or they are taken back up into the neuron that released them. This process is called, reuptake.  We will talk more about this another time.

The neurotransmitter then attaches to the receptor and then starts the whole event over to the next neuron.  Keep in mind, a neuron fires 200 times per second! 

If you want to watch a video that explains a little more, this is a pretty good basic video.  It gives a little more information than I did, but if you’re a visual learner (like me), you might enjoy watching this:   2-Minute Neuroscience: Synaptic Transmission

So, here are the main points:

• You are born with 100,000, 000, 000 neurons in your brain. (Fearfully and wonderfully made!)
• The neuron is made up of the dendrites (the little fingers), the soma (the body/nucleus), and the axon.
• The dendrites receive a chemical signal from the previous neuron and that stimulates an electrical signal to travel down the axon of the nerve.
• The electrical signal gets to the end of the nerve and releases chemicals (neurotransmitters) into the synapse which is the space between the two neurons and the whole thing starts again in the next neuron.
• The unused neurotransmitter either diffuses or is taken back up into the sending neuron again.
• Lastly, this occurs 200 times per second.

So stay tuned for the next post because I’m going to talk about specific neurotransmitters …..