In:
eLife, eLife Sciences Publications, Ltd, Vol. 6 ( 2017-02-14)
Abstract:
The nerve cells or neurons within an animal’s nervous system connect with one another like the wires in a complex circuit. Each neuron can send and receive signals and a major challenge in neuroscience is to understand how these circuits of neurons behave. To do this, researchers often use genetic tools and computer modeling to map the connections between the cells in a nervous system. However, it remains difficult to predict how an input signal will appear at the output after it passes through a network made of different types of neuron. Brains contain many networks of interconnected neurons. Some of these networks send signals with a rhythmic pattern and typically drive repetitive movements such as breathing and walking. The networks are called central pattern generators (or CPGs for short). They contain both excitatory and inhibitory neurons and can generate rhythmic activity without any additional input. Nevertheless CPGs are not rigid, but can flexibly control when and how fast the muscles are activated to suit the animal's needs. It is thought the circuits are flexible because of the way excitatory and inhibitory neurons interact, but it is not known how these interactions define the behavior of the circuit. Sternfeld et al. have now developed a new method to examine how the neurons that make up a circuit influence its activity. First, embryonic stem cells from mice were coaxed to develop into a number of subtypes of both excitatory and inhibitory neurons in the laboratory. These neurons were used to grow networks of neurons in a dish, named “circuitoids”. The precise combination of subtypes of neuron was deliberately varied between each circuitoid, and Sternfeld et al. then studied how the different circuitoids behaved. Several subtypes of excitatory neurons showed rhythmic bursts of activity, just like simple CPGs. Moreover, the ratio of excitatory to inhibitory neurons in the circuitoids was critical for establishing how fast and synchronized the bursts of activity were across the network. It is possible that the brain also uses this simple strategy of varying the ratio of excitatory to inhibitory neurons in circuits of neurons to generate complex, yet highly flexible, circuits with rhythmic activity. Further work will be needed to test this idea. Finally, other researchers will hopefully be able to use this new approach to construct circuitoids and learn more about how the brain generates and controls rhythmic activity. It might also be possible to one-day transplant similar circuitoids into people to repair injured or diseased parts of a nervous system, or use circuitoids that resemble specific neurological disorders to screen for new treatments.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.21540.001
DOI:
10.7554/eLife.21540.002
DOI:
10.7554/eLife.21540.003
DOI:
10.7554/eLife.21540.004
DOI:
10.7554/eLife.21540.005
DOI:
10.7554/eLife.21540.006
DOI:
10.7554/eLife.21540.007
DOI:
10.7554/eLife.21540.008
DOI:
10.7554/eLife.21540.009
DOI:
10.7554/eLife.21540.010
DOI:
10.7554/eLife.21540.011
DOI:
10.7554/eLife.21540.012
DOI:
10.7554/eLife.21540.013
DOI:
10.7554/eLife.21540.014
DOI:
10.7554/eLife.21540.015
DOI:
10.7554/eLife.21540.016
DOI:
10.7554/eLife.21540.017
DOI:
10.7554/eLife.21540.018
DOI:
10.7554/eLife.21540.019
DOI:
10.7554/eLife.21540.020
DOI:
10.7554/eLife.21540.021
DOI:
10.7554/eLife.21540.022
DOI:
10.7554/eLife.21540.023
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2017
detail.hit.zdb_id:
2687154-3