<p>I guess the answer depends on what you mean with "connected more than once".</p>

<p>Initially, being connected is a strictly binary relation: either two neurons are connected or not. (The question may be: directly or not. Indirectly, each pair of neurons is connected, as I assume.)</p>

<p>If you consider "being connected more or less strongly" - which is not a binary relation anymore - you may consider the degree of connectedness as a natural number 1, 2, 3, ... and in this case, you might want to count synapses between two neurons. And surely, there can be more than one:</p>

<blockquote>
  <p>»<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4295841/" rel="nofollow noreferrer">An important experimentally observed feature [...] is the
  distribution of the number of synapses from one neuron to another,
  which has been measured in several cortical layers. All of these
  distributions are bimodal with one peak at zero and a second one at a
  small number (3–8) of synapses.«</a></p>
</blockquote>

<p>If you want to consider pathways between two neurons A and B - shortest sequences of connected neurons starting with A and ending with B - then the answer is "yes, of course" again:</p>

<blockquote>
  <p><a href="https://www.researchgate.net/post/What_is_the_average_number_of_synapses_between_any_two_neurons_in_the_brain" rel="nofollow noreferrer">»[Each neuron] is within two or three connections of all the others via myriad potential routes.«</a></p>
</blockquote>

CC BY-SA 4.0
2020-01-08T23:45:24.840Z
Thanks for the answer. I was curious about direct connections, i.e. can there be two synapses each connecting neuron A to neuron B.
danijar
CC BY-SA 4.0
2020-01-09T06:45:35.933Z
So 3-8 is an answer in several cortical layers.
Hans-Peter Stricker
CC BY-SA 4.0
2020-01-08T13:22:18.247Z
2020-01-08T13:36:07.367Z
2020-01-08T13:36:07.367Z
Hans-Peter Stricker
<p>Can two given neurons in the human brain can be directly connected more than once, either mutually or in the same or direction? Also, can the same neuron have transitive connections to itself (in order to amplify itself for example)?</p>

<neuroscience><neuroanatomy><neurophysiology>
Can two neurons in the brain be connected more than once?
danijar
# Can two neurons in the brain be connected more than once?

(Asked by: username_0 on 2016-01-18)

Can two given neurons in the human brain can be directly connected more than once, either mutually or in the same or direction? Also, can the same neuron have transitive connections to itself (in order to amplify itself for example)?

**Tags:** neuroscience, neuroanatomy, neurophysiology


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## 1 answers

### Answer by username_1 on 2020-01-08. Score: 4 | Accepted answer

I guess the answer depends on what you mean with "connected more than once".

Initially, being connected is a strictly binary relation: either two neurons are connected or not. (The question may be: directly or not. Indirectly, each pair of neurons is connected, as I assume.)

If you consider "being connected more or less strongly" - which is not a binary relation anymore - you may consider the degree of connectedness as a natural number 1, 2, 3, ... and in this case, you might want to count synapses between two neurons. And surely, there can be more than one:

> »[An important experimentally observed feature [...] is the
> distribution of the number of synapses from one neuron to another,
> which has been measured in several cortical layers. All of these
> distributions are bimodal with one peak at zero and a second one at a
> small number (3–8) of synapses.«](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4295841/)

If you want to consider pathways between two neurons A and B - shortest sequences of connected neurons starting with A and ending with B - then the answer is "yes, of course" again:

> [»[Each neuron] is within two or three connections of all the others via myriad potential routes.«](https://www.researchgate.net/post/What_is_the_average_number_of_synapses_between_any_two_neurons_in_the_brain)

> **Comments:**
> **username_0**: Thanks for the answer. I was curious about direct connections, i.e. can there be two synapses each connecting neuron A to neuron B.  
> **username_1**: So 3-8 is an answer in several cortical layers.  

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