title: Staggered multi-site low-frequency electrostimulation effectively induces locomotor patterns in the isolated rat spinal cord.
abstract: METHODS
  Experimental animal study.
  
  
  OBJECTIVE
  Epidural stimulation has been used to activate locomotor patterns after spinal injury and typically employs synchronous trains of high-frequency stimuli delivered directly to the dorsal cord, thereby recruiting multiple afferent nerve roots. Here we investigate how spinal locomotor networks integrate multi-site afferent input and address whether frequency coding is more important than amplitude to activate locomotor patterns.
  
  
  METHODS
  Italy and Belgium.
  
  
  METHODS
  To investigate the importance of input intensity and frequency in eliciting locomotor activity, we used isolated neonatal rat spinal cords to record episodes of fictive locomotion (FL) induced by electrical stimulation of single and multiple dorsal roots (DRs), employing different stimulating protocols.
  
  
  RESULTS
  FL was efficiently induced through staggered delivery (delays 0.5 to 2 s) of low-frequency pulse trains (0.33 and 0.67 Hz) to three DRs at intensities sufficient to activate ventral root reflexes. Delivery of the same trains to a single DR or synchronously to multiple DRs remained ineffective. Multi-site staggered trains were more efficient than randomized pulse delivery. Weak trains simultaneously delivered to DRs failed to elicit FL. Locomotor rhythm resetting occurred with single pulses applied to various distant DRs.
  
  
  CONCLUSIONS
  Electrical stimulation recruited spinal networks that generate locomotor programs when pulses were delivered to multiple sites at low frequency. This finding might help devising new protocols to optimize the increasingly more common use of epidural implantable arrays to treat spinal dysfunctions.
authors.affiliation: Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy.|SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), Udine, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Dose
authors.affiliation: Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Deumens
authors.affiliation: Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Forget
authors.affiliation: Neuroscience Department, International School for Advanced Studies (SISSA), Trieste, Italy.|SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), Udine, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Taccola
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D063226:Central Pattern Generators / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods*; D066298:In Vitro Techniques; D008124:Locomotion / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology*; D051381:Rats; D013116:Spinal Cord / Q000502:physiology*