Synapse: chemical vs electrical

[Suraj M]

electric transmission between 2 neurons is way faster than by chemical neurotransmitters...
then why are there so few electric transmission based synapses in our body??

 

[mark!]

Maybe neurotransmitters are like endocrinic hormones, or is there no ink at all?

 

[Ygggdrasil]

An important part of neurotransmission is the capability of neurons to modulate the strength of transmission between neurons. It may be the case that it is easier to modulate the strength of transmission for chemical synapses than direct electrical connection through gap junctions.

 

[Pythagorean]

Electrical synapse strength itself is tightly regulated by connectivity (density of electrical synapses) between cells. I assume one of the primary problems with electrical synapses is that they're passive and nonselective to any particular ion. They don't always excite or always inhibit; instead, they seek charge equilibrium between the two cells they connect. Further, they allow passage beyond ions, letting signaling molecules pass between cells. So all these together likely make it difficult to regulate whole brain coordination between cells compared to chemical synapses.

During early developmental, animals have a lot of gap junctions and as the brain becomes more stable, chemical synapses take over. This suggests to me that a brain with a lot of gap junctions is more susceptible to environment (with respect to how it develops and wires itself) and once the organism is developed, much of the processing has been internalized and automated and the more functionally idiosyncratic chemical synapses take over brain function.

Gap Junctions in Developing Thalamic and Neocortical Neuronal Networks
http://cercor.oxfordjournals.org/content/early/2013/07/10/cercor.bht175.full

 

[Andy Resnick]

electric transmission between 2 neurons is way faster than by chemical neurotransmitters...
then why are there so few electric transmission based synapses in our body??

You mean like a spark gap? That would be so bad for so many reasons...

 

[Suraj M]

You mean like a spark gap? That would be so bad for so many reasons...

considering the gap is 20nm wide.

 

[Suraj M]

okay thank you guys, for these replies.
A related question. My prof. was telling us that the slow speed of chemical transmission played an important role in the extinction of dinosaurs.
He also added that it took hours for a particular signal to be relayed from their tail to their tiny little brain. Is this true?

 

[Suraj M]

Maybe neurotransmitters are like endocrinic hormones, or is there no link at all?

Endocrine hormones would imply the involvement of blood.