2-Minute Neuroscience: Synaptic Transmission

Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics in 2 minutes or less. In this installment I will discuss synaptic transmission. Most communication between neurons occurs at a specialized structure called a synapse. A synapse is an area where two neurons come close enough to one another that they are able to pass chemical signals from one cell to another. The neurons are not actually connected, but are separated by a microscopically small space called the synaptic cleft. The cleft is less than 40 nm wide; by comparison a human hair is about 75,000 nanometers. The neuron where the signal is initiated is called the presynaptic neuron, while the neuron that receives the signal is called the postsynaptic neuron. In the presynaptic neuron, there are chemical signals called neurotransmitters that are packaged into small sacs called vesicles. Each vesicle can contain thousands of neurotransmitter molecules. When the presynaptic neuron is excited by an electrical signal called an action potential, this causes the vesicles to fuse with the presynaptic membrane and release their contents into the synaptic cleft. Once they are in the synaptic cleft, neurotransmitters interact with receptors on the postsynaptic membrane. They bind to these receptors and can cause an action to occur in the postsynaptic cell as a result. This action may involve increasing the likelihood that the postsynaptic cell will become activated and fire an action potential, or decreasing it. Eventually, the neurotransmitter molecules must be cleared from the synaptic cleft. Some of them will simply drift away in a process called diffusion. In some cases, the neurotransmitter is taken back up into the presynaptic neuron in a process called reuptake. Once back inside the presynaptic neuron, the neurotransmitter can be recycled and reused. In other cases, enzymes break down the neurotransmitter within the synaptic cleft. Then the component parts of the neurotransmitter can be sent back into the presynaptic neuron to make more neurotransmitter.

Channel: Neuroscientifically Challenged

Views: 1,130,671

Rating: 4.9263134 out of 5

Keywords: synapse, synapses, neuroscience, neuron, neurons, synaptic cleft, neurotransmitter, neurotransmitters, reuptake, action potential, action potentials, Neurotransmission

Id: WhowH0kb7n0

Length: 1min 51sec (111 seconds)

Published: Tue Jul 22 2014

Reddit Comments

[u/_learning_as_I_go_]

I now have an idea about how SSRI's work after this. Cheers)

[u/the_honest_liar]

Videos are the best for understanding concepts. I could not grasp nerve myelination until I watched a video. 5 years later I still remember even though I've never needed it since.

[u/fibonacci_theta]

I basically lived on Khan Academy when I was first studying neurobiology. Their videos on the topics are excellent, can really recommend.

[u/annoyedgrunt]

Went to a Young Earth Creationist baptist school for middle and high school, so I am always trying to play catch up with earth and life sciences. Commenting to watch this later :)

[u/bravo009]

Thank you for the contribution!

[u/kildoents]

These are awesome, thanks for sharing!

[u/Nemado]

Thank you very much for posting! I'm maintaining a link-library for our psychology department, and this will go right into it!

[u/[deleted]]

Scishow has a whole series about psychology and neuroscience if i'm not mistaking. They have a really attractive style of explaining!

[u/Demonicblanket]

Remind me! 1 day.