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  • Open Access

Multifunctional central pattern generator controlling walking and paw shaking

  • 1,
  • 2,
  • 2 and
  • 1Email author
BMC Neuroscience201415 (Suppl 1) :P181

https://doi.org/10.1186/1471-2202-15-S1-P181

  • Published:

Keywords

  • Central Pattern Generator
  • Oscillatory Regime
  • Walking Pattern
  • Hyperpolarized Membrane
  • Inhibitory Current
Central pattern generators (CPGs) are oscillatory neuronal networks controlling rhythmic motor tasks such as breathing and walking. A multifunctional CPG can produce multiple patterns, e.g. patterns with different periods [15]. Here, we investigate whether a pair of cat behaviors -- walking and paw shaking -- could be controlled by a single multifunctional CPG exhibiting multistability of oscillatory regimes. In experiments, both behaviors can be elicited in a spinalized cat, and there is evidence that the same circuitry is used for both rhythms [2, 3]. We present a parsimonious model of a half-center oscillator composed of two mutually inhibitory neurons. These cells contains two slowly inactivating inward currents, a persistent Na+ current (INaP) and a low voltage activated Ca++ current (ICaLVA). The dynamics of the multifunctional CPG is based on that the ICaLVA inactivates much slower than INaP and at the more hyperpolarized membrane potentials. Here, we demonstrate the co-existence of two rhythms (Figure 1). At first, the model demonstrates walking pattern. A switch from a slow, 1-2 Hz walking rhythm to fast, 7-10 Hz paw shake rhythm was elicited by a pulse of conductance of excitatory current delivered to extensor and flexor neurons. Then, a switch back to walking was triggered by a shorter pulse of conductance of inhibitory current delivered to the extensor neuron.
Figure 1
Figure 1

Two mutually inhibitory interneurons, IntE (Extensor Interneuron) and IntF (Flexor Interneuron) produce alternating bursting activity at approximately 1.6 Hz representing walking pattern. A switch to paw shaking is executed by a pulse of excitatory conductance delivered to both cells for 1 second. The paw shake rhythm is represented by a 9 Hz bursting regime. An inhibitory conductance activated for .1 second in IntF causes a large rebound burst and a fast transition back to the walking rhythm.

The CPG model was also incorporated into a neuromechanical model of a cat hindlimb in the AnimatLab environment [6]. The model provides a cellular mechanism of multifunctional CPG operation.

Declarations

Acknowledgments

The authors acknowledge support by the NSF PHY-0750456 to Gennady Cymbalyuk and by NIH P01 HD32571, R01 EB012855, and R01 NS048844 and by the Center for Human Movement Studies at GATech to Boris Prilutsky.

Authors’ Affiliations

(1)
Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302, USA
(2)
School of Applied Physiology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA

References

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