<p>The standard <a href="https://en.wikipedia.org/wiki/Neuron" rel="nofollow noreferrer">textbook neuron</a> receives input at its dendritic tree, fires action potentials and has a single, long output axon to send the message off to distant locations. </p>

<p>However, non-spiking, anaxonic neurons are not a rarity; in various sensory systems there are <a href="http://webvision.med.utah.edu/book/part-v-phototransduction-in-rods-and-cones/bipolar-cell-pathways-in-the-vertebrate-retina/" rel="nofollow noreferrer">bipolar cells</a> present that lack a clearly defined axon and are non-spiking, such as the <a href="http://webvision.med.utah.edu/book/part-iii-retinal-circuits/roles-of-amacrine-cells/" rel="nofollow noreferrer">amacrine cells</a> and the <a href="http://neuronbank.org/wiki/index.php/Horizontal_cells" rel="nofollow noreferrer">horizontal cells</a> in the vertebrate retina (Fig. 1.) and the <a href="http://neurosciences.case.edu/faculty/strowbridge/OlfactoryBulb/bulb1.htm" rel="nofollow noreferrer">granule cells</a> in the mammalian olfactory bulb <a href="https://www.jstage.jst.go.jp/article/aohc1988/52/Supplement/52_Supplement_139/_pdf" rel="nofollow noreferrer">(Hisada, 1989)</a>. </p>

<p>Generally, non-spiking neurons work as analogue integrators. Where a spiking neuron can only transmit a spike, or no spike (binary signal), a non-spiking neuron can convey an infinitesimal number of membrane voltages instead. Hence, it is well suited to integrate the input from various other neurons. Amacrine cells and horizontal cells <a href="http://webvision.med.utah.edu/book/part-iii-retinal-circuits/roles-of-amacrine-cells/" rel="nofollow noreferrer">lack clearly defined axonic elements</a> and are thus non-spiking anaxonic neurons. Their dendrites, however, do form synapses with other neurons, generally on their dendrites too, forming <a href="http://hubel.med.harvard.edu/book/b12.htm" rel="nofollow noreferrer">dendro-dendritic connections</a>. <a href="http://hubel.med.harvard.edu/book/b12.htm" rel="nofollow noreferrer">The function of the bipolar cells in the vertebrate retina are unclear</a>.</p>

<p>There are other non-spiking anaxonic neurons identified. A notable example are the interneurons seen in the ganglia of the motor systems of various arthropods, including crayfish, locusts and cockroaches. Here, they are coupled to neurons that convey descending output to motoneurons, and they are thought to be involved in selecting the adequate information to be gated to the motoneurons <a href="http://www.ncbi.nlm.nih.gov/pubmed/7296293" rel="nofollow noreferrer">(Takahata <em>et al</em>., 1981)</a>, or to be necessary for generating oscillations in the system (<a href="http://jn.physiology.org/content/38/1/33.long" rel="nofollow noreferrer">Pearson &amp; Fourtner, 1975)</a>. But again, their exact functions are unclear. One reason why may be because they are local circuit neurons. In other words, they do not send their signals far off to distant locations because they lack clear axons. For example, the role of the retinal ganglion cells becomes readily apparent when you sever their long axons that are bundled in the optic nerve (one becomes blind in that eye).   </p>

<p><a href="https://i.sstatic.net/qSNns.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/qSNns.jpg" alt="retina"></a><br>
<sup>Fig. 1. Retinal circuitry showing the non-spiking, anaxonic horizontal and bipolar cells. Source: <a href="http://hubel.med.harvard.edu/book/b12.htm" rel="nofollow noreferrer">David Hubel's Eye, Brain, and Vision</a></sup></p>

<p><sub><strong>References</strong><br>
<strong>-</strong> <a href="https://www.jstage.jst.go.jp/article/aohc1988/52/Supplement/52_Supplement_139/_pdf" rel="nofollow noreferrer">Hisada, <em>Arch Histol Cytol</em> (1989); <strong>52</strong>(Suppl): 139-46</a><br>
<strong>-</strong> <a href="http://jn.physiology.org/content/38/1/33.long" rel="nofollow noreferrer">Pearson &amp; Fourtner, <em>J Neurophysiol</em> (1975); <strong>38</strong>(1): 33-52</a><br>
<strong>-</strong> <a href="http://www.ncbi.nlm.nih.gov/pubmed/7296293" rel="nofollow noreferrer">Takahata <em>et al</em>., <em>Brain Res</em>; <strong>226</strong>: 309-14</a></sub></p>

CC BY-SA 3.0
2016-05-31T21:17:09.853Z
Thanks for the answer; just to clarify: do they interact via gap junctions or do they implement special chemical synapses?
Silmathoron
CC BY-SA 3.0
2016-05-31T21:40:41.610Z
@Silmathoron - afaik via unconventional synapse-like structures using conventional neurotransmitters such as GABA
AliceD
CC BY-SA 3.0
2016-05-30T12:59:27.663Z
2016-05-30T18:08:07.400Z
2016-05-30T18:08:07.400Z
AliceD
<p>What is the purpose of <a href="https://en.wikipedia.org/wiki/Non-spiking_neuron" rel="nofollow">non-spiking neurons</a> and <a href="https://en.wikipedia.org/wiki/Anaxonic_neuron" rel="nofollow">anaxonic neurons</a> in neural tissue?</p>

CC BY-SA 3.0
2016-05-29T19:44:12.873Z
Do you mean in terms of what types of computation they enable?
Seanny123
<neuroscience><neurophysiology>
What is the purpose of non-spiking and anaxonic neurons?
David Parry
# What is the purpose of non-spiking and anaxonic neurons?

(Asked by: username_0 on 2016-05-24)

What is the purpose of [non-spiking neurons](https://en.wikipedia.org/wiki/Non-spiking_neuron) and [anaxonic neurons](https://en.wikipedia.org/wiki/Anaxonic_neuron) in neural tissue?

**Tags:** neuroscience, neurophysiology

> **Comments:**
> **username_1**: Do you mean in terms of what types of computation they enable?  

---

## 1 answers

### Answer by username_2 on 2016-05-30. Score: 2

The standard [textbook neuron](https://en.wikipedia.org/wiki/Neuron) receives input at its dendritic tree, fires action potentials and has a single, long output axon to send the message off to distant locations.

However, non-spiking, anaxonic neurons are not a rarity; in various sensory systems there are [bipolar cells](http://webvision.med.utah.edu/book/part-v-phototransduction-in-rods-and-cones/bipolar-cell-pathways-in-the-vertebrate-retina/) present that lack a clearly defined axon and are non-spiking, such as the [amacrine cells](http://webvision.med.utah.edu/book/part-iii-retinal-circuits/roles-of-amacrine-cells/) and the [horizontal cells](http://neuronbank.org/wiki/index.php/Horizontal_cells) in the vertebrate retina (Fig. 1.) and the [granule cells](http://neurosciences.case.edu/faculty/strowbridge/OlfactoryBulb/bulb1.htm) in the mammalian olfactory bulb [(Hisada, 1989)](https://www.jstage.jst.go.jp/article/aohc1988/52/Supplement/52_Supplement_139/_pdf).

Generally, non-spiking neurons work as analogue integrators. Where a spiking neuron can only transmit a spike, or no spike (binary signal), a non-spiking neuron can convey an infinitesimal number of membrane voltages instead. Hence, it is well suited to integrate the input from various other neurons. Amacrine cells and horizontal cells [lack clearly defined axonic elements](http://webvision.med.utah.edu/book/part-iii-retinal-circuits/roles-of-amacrine-cells/) and are thus non-spiking anaxonic neurons. Their dendrites, however, do form synapses with other neurons, generally on their dendrites too, forming [dendro-dendritic connections](http://hubel.med.harvard.edu/book/b12.htm). [The function of the bipolar cells in the vertebrate retina are unclear](http://hubel.med.harvard.edu/book/b12.htm).

There are other non-spiking anaxonic neurons identified. A notable example are the interneurons seen in the ganglia of the motor systems of various arthropods, including crayfish, locusts and cockroaches. Here, they are coupled to neurons that convey descending output to motoneurons, and they are thought to be involved in selecting the adequate information to be gated to the motoneurons [(Takahata *et al*., 1981)](http://www.ncbi.nlm.nih.gov/pubmed/7296293), or to be necessary for generating oscillations in the system ([Pearson & Fourtner, 1975)](http://jn.physiology.org/content/38/1/33.long). But again, their exact functions are unclear. One reason why may be because they are local circuit neurons. In other words, they do not send their signals far off to distant locations because they lack clear axons. For example, the role of the retinal ganglion cells becomes readily apparent when you sever their long axons that are bundled in the optic nerve (one becomes blind in that eye).

[![retina](https://i.sstatic.net/qSNns.jpg)](https://i.sstatic.net/qSNns.jpg)  
Fig. 1. Retinal circuitry showing the non-spiking, anaxonic horizontal and bipolar cells. Source: [David Hubel's Eye, Brain, and Vision](http://hubel.med.harvard.edu/book/b12.htm)

**References**  
**-** [Hisada, *Arch Histol Cytol* (1989); **52**(Suppl): 139-46](https://www.jstage.jst.go.jp/article/aohc1988/52/Supplement/52_Supplement_139/_pdf)  
**-** [Pearson & Fourtner, *J Neurophysiol* (1975); **38**(1): 33-52](http://jn.physiology.org/content/38/1/33.long)  
**-** [Takahata *et al*., *Brain Res*; **226**: 309-14](http://www.ncbi.nlm.nih.gov/pubmed/7296293)

> **Comments:**
> **username_3**: Thanks for the answer; just to clarify: do they interact via gap junctions or do they implement special chemical synapses?  
> **username_2**: @username_3 - afaik via unconventional synapse-like structures using conventional neurotransmitters such as GABA  

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