As Virginia Hughes noted in a recent piece for National Geographic’s Phenomena blog, the most common depiction of a synapse (that communicating junction between two neurons) is pretty simple:

External image

Signal molecules leave one neuron from that bulby thing, float across a gap, and are picked up by receptors on the other neuron. In this way, information is transmitted from cell to cell … and thinking is possible.

But thanks to a bunch of German scientists - we now have a much more complete and accurate picture. They’ve created the first scientifically accurate 3D model of a synaptic bouton (that bulby bit) complete with every protein and cytoskeletal element.

This effort has been made possible only by a collaboration of specialists in electron microscopy, super-resolution light microscopy (STED), mass spectrometry, and quantitative biochemistry.

says the press release. The model reveals a whole world of neuroscience waiting to be explored. Exciting stuff!

You can access the full video of their 3D model here.

Credit: Benjamin G. Wilhelm, Sunit Mandad, Sven Truckenbrodt, Katharina Kröhnert, Christina Schäfer, Burkhard Rammner, Seong Joo Koo, Gala A. Claßen, Michael Krauss, Volker Haucke, Henning Urlaub, Silvio O. Rizzoli


The emotional sensitivity gene

Serotonin is one of the major neurotransmitters (i.e. chemicals) in the brain. It’s very connected to our emotions and so it’s not a coincidence that a lot of the drugs that are used to treat depression and anxiety act on the serotonin system in the brain. This is clearly a very important chemical for determining the nature of our emotional lives.

The serotonin transporter gene regulates serotonin in the brain. People are born with variations of this gene. The long variation clears serotonin out of the neural synapse more efficiently. The short variation is less efficient, which lets the serotonin hang around a little bit longer in the synapse. 

The short variation was originally considered a risk gene — but it’s now being thought of as a sensitivity gene.

Learn more about how the gene impacts our emotional responses →

Incredible and rare micrograph of a synapse 

Neuron cell body (purple) with numerous synapses (blue) magnified 80,000x under a scanning electron microscope.

Everone talks about synapses even though some seem to use it to sound cool without actually knowing what it is. So for those persons (and everyone willing to become a bit more educated), here’s a simple explanation.

Information from one neuron flows to another neuron across a synapse. The synapse contains a small gap separating neurons. 

The synapse consists of:

a presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles,

a postsynaptic ending that contains receptor sites for neurotransmitters,

a synaptic cleft or space between the presynaptic and postsynaptic endings.

At the synaptic terminal (the presynaptic ending), an electrical impulse will trigger the migration of vesicles containing neurotransmitters toward the presynaptic membrane. The vesicle membrane will fuse with the presynaptic membrane releasing the neurotransmitters into the synaptic cleft. 

read more from Neurons Want Food 

One synapse, by itself, is more like a microprocessor–with both memory-storage and information-processing elements–than a mere on/off switch. In fact, one synapse may contain on the order of 1,000 molecular-scale switches. A single human brain has more switches than all the computers and routers and Internet connections on Earth.
—  Stephen Smith

Unutarnji pismonose / Internal letter-carriers
by ~strybor  [Croatia]


  • The cages are pre-synaptic vesicles,
  • freeing the bird-neurotransmitters, which,
  • when they position themselves on the branches - receptors,
    activate the trees which then
  • make their roots transfer more messages into the neuron’s body.

Scientists to simulate human brain inside a supercomputer

Scientists at its forerunner, the Switzerland-based Blue Brain Project, have been working since 2005 to feed a computer with vast quantities of data and algorithms produced from studying tiny slivers of rodent gray matter.

Last month they announced a significant advancement when they were able to use their simulator to accurately predict the location of synapses in the neocortex, effectively mapping out the complex electrical brain circuitry through which thoughts travel.

Henry Markram, the South African-born neuroscientist who heads the project, said the breakthrough would have taken “decades, if not centuries” to chart using a real neocortex. He said it was proof their concept, dubbed “brain in a box” by Nature magazine, would work.

Now the team are joining forces with other scientists to create the Human Brain Project. As its name suggests, they aim to scale up their model to recreate an entire human brain.

It is a step that will need both a huge increase in funding and access to computers so advanced that they have yet to be built.

If their current bid for €1 billion ($1.3 billion) of European Commission funding over the next 10 years is successful, Markram predicts that his computer neuroscientists are a decade away from producing a synthetic mind that could, in theory, talk and interact in the same way humans do.

The Neuromuscular Junction (NMJ) is a specialized synapse that serves to transmit electrical impulses (action potentials) from the motor neuron nerve terminal to the skeletal muscle. Basically, the NMJ allows for efficient and reliable communication between the motor neuron nerve and the muscles required for contraction and movement. The primary chemical messenger in this synapse, which consists of the presynaptic region (containing the nerve terminal), the synaptic cleft and the postsynaptic surface, is acetylcholine. These regions are defined by the differential localization of specific proteins, which underlie their distinct anatomical features and their physiological roles. 

Now it’s time to briefly sum up what goes on in the NMJ, as shown in the diagram above. 

1. The action potential (or electrical impulse signal) reaches the nerve terminal in the presynaptic region. The hallmark feature of the nerve terminal is that it contains the synaptic vesicles, along with the proteins that help vesicle function. These vesicles are aligned near their release site, called an active zone. 

2. When action potentials reach the nerve terminal they activate calcium channels, which open up and facilitate the influx of calcium into the presynaptic terminal, which in turn commences the process of vesicular release into the synaptic cleft. 

3. The increase in intracellular calcium concentration triggers the fusion of the synaptic vesicles with the nerve terminal membrane. The mechanism of synaptic vesicle fusion involves conformational changes in multiple docking proteins both on the vesicle and the nerve terminal’s plasma membrane. 

4. Once fused with the nerve terminal membrane, the vesicle releases its contents into the extracellular space, also known as the synaptic cleft. The chemical or neurotransmitters (in this case, acetylcholine) released then bind to their corresponding receptors on the postsynaptic surface (also known as the motor end plate in the NMJ). 

5 & 6. Acetylcholine binds to its receptors and opens ligand-gated Na+/K+ channels. These structures are designed to optimize cholinergic neurotransmission in order to produce an end plate potential (EPP). The EPP is simply the net synaptic depolarization caused by the release of acetylcholine triggered by the nerve action potential. The EPP is a function of the miniature endplate potential (MEPP) amplitude, which represents the depolarization of the postsynaptic membrane produced by the contents of a single vesicle, and quantal content (number of transmitter vesicles released by a nerve terminal action potential. The EPP serves to open the voltage-gated Na+ channels in the postsynaptic region, which in turn results in an action potential that triggers muscle fiber contraction. These changes in the postsynaptic region potential result in muscle stimulation and contraction.

7. Acetylcholinesterase degrades acetylcholine so that it (choline) can be re-uptaked and recycled to produce new acetylcholine molecules. It’s activity terminates synaptic transmission. 


Hughes, Benjamin W., et. al. 2006. Molecular architecture of the neuromuscular junction. Muscle & Nerve. 33(4): 445-461. DOI 10.1002/mus.20440

Motor Systems: Control of Movement and Behavior. 2008. Available at:


Tiny chip mimics brain, delivers supercomputer speed

Researchers Thursday unveiled a powerful new postage-stamp size chip delivering supercomputer performance using a process that mimics the human brain.

The so-called “neurosynaptic” chip is a breakthrough that opens a wide new range of computing possibilities from self-driving cars to artificial intelligence systems that can installed on a smartphone, the scientists say.

The researchers from IBM, Cornell Tech and collaborators from around the world said they took an entirely new approach in design compared with previous computer architecture, moving toward a system called “cognitive computing.”

“We have taken inspiration from the cerebral cortex to design this chip,” said IBM chief scientist for brain-inspired computing, Dharmendra Modha, referring to the command center of the brain.

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