Skip to main content
  • Poster presentation
  • Open access
  • Published:

Paw-shake response and locomotion: can one CPG generate two different rhythmic behaviors?

Rhythmic limb movements like locomotion or paw-shake response are controlled by network of spinal circuits, known as central pattern generators (CPGs), as evidenced from locomotor-like and paw-shake like activity in limb peripheral nerves elicited in decerebrate or spinal animals with blocked neuromuscular transmission [4]. Unlike fictive locomotion and scratch, that are likely controlled by distinct CPGs [3], fictive paw-shake response has not been systematically investigated and it is not known whether it is controlled by a specialized CPG or by the CPG that also controls locomotion. In-vivo recordings of paw-shake motor patterns elicited by stimulation of paw skin afferents [7] have revealed high frequency hindlimb oscillations (~10 Hz) with atypical muscle synergies – reciprocal activation of anterior and posterior hindlimb muscles in each half of the paw-shake cycle; both anterior and posterior muscle groups include flexor and extensor muscles. We asked whether a paw-shake response with the atypical muscle synergies can be generated by a typical half-center locomotor CPG reciprocally activating flexor and extensor muscles.

Using software AnimatLab [2] we developed a 5-segment cat hindlimb model with 12 Hill-type muscle actuators controlled by (1) a half-center CPG activating flexor and extensor muscles (two-joint muscles received both flexion- and extension-related signals [5, 6]) and (2) proprioceptive input originated from the muscle spindle and Golgi tendon organ afferents. The CPG was modeled by two single-compartment spiking neurons in a half-center configuration. Other neurons (Ia-afferents, alpha-motor neurons, Ia-interneurons, and interneurons mediating autogenic and heterogenic reflex pathways) were modeled as non-spiking neurons (firing rate model based on work by [1]). Model parameters were adjusted such that computer simulations reproduced the recorded paw-shake mechanics and the anterior-posterior muscle activation patterns.

The obtained results demonstrated that a half-center locomotor CPG can produce movement mechanics and muscle activity patterns typical for paw-shake responses if (1) the locomotor CPG is capable to operate at frequencies 3 to10 times higher than during locomotion and (2) synaptic weights in spinal circuits can be modified during paw-shake response. We speculate that the two conditions can be realized by sensory input from paw skin afferents.


  1. Beer RD, San Diego: Intelligence as adaptive behavior: an experiment in computational neuroethology. 1990, Academic Press

    Google Scholar 

  2. Cofer D, Cymbalyuk G, Reid J, Zhu Y, Heitler WJ, Edwards DH: AnimatLab: a 3D graphics environment for neuromechanical simulations. J. Neurosci Methods. 2010, 187: 280-288. 10.1016/j.jneumeth.2010.01.005.

    Article  PubMed  Google Scholar 

  3. Frigon A, Gossard JP: Evidence for specialized rhythm-generating mechanisms in the adult mammalian spinal cord. J Neurosci. 2010, 30: 7061-7071. 10.1523/JNEUROSCI.0450-10.2010.

    Article  CAS  PubMed  Google Scholar 

  4. Pearson KG, Rossignol S: Fictive motor patterns in chronic spinal cats. J Neurophysiol. 1991, 66: 1874-1887.

    CAS  PubMed  Google Scholar 

  5. Perret C, Cabelguen JM: Main characteristics of the hindlimb locomotor cycle in the decorticate cat with special reference to bifunctional muscles. Brain Res. 1980, 187: 333-352. 10.1016/0006-8993(80)90207-3.

    Article  CAS  PubMed  Google Scholar 

  6. Prilutsky BI: Coordination of two- and one-joint muscles: functional consequences and implications for motor control. Motor Control. 2000, 4: 1-44.

    CAS  PubMed  Google Scholar 

  7. Smith JL, Hoy MG, Koshland GF, Phillips DM, Zernicke RF: Intralimb coordination of the paw-shake response: a novel mixed synergy. J Neurophysiol. 1985, 54: 1271-1281.

    CAS  PubMed  Google Scholar 

Download references


Supported by NIH grants: HD-032571, NS-048844, EB012855

Author information

Authors and Affiliations


Corresponding author

Correspondence to Alexander N Klishko.

Rights and permissions

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Klishko, A.N., Cofer, D., Cymbalyuk, G. et al. Paw-shake response and locomotion: can one CPG generate two different rhythmic behaviors?. BMC Neurosci 13 (Suppl 1), P70 (2012).

Download citation

  • Published:

  • DOI: