A parallel cholinergic brainstem pathway for enhancing locomotor drive

Nat Neurosci. 2010 Jun;13(6):731-8. doi: 10.1038/nn.2548. Epub 2010 May 16.

Abstract

The brainstem locomotor system is believed to be organized serially from the mesencephalic locomotor region (MLR) to reticulospinal neurons, which in turn project to locomotor neurons in the spinal cord. We identified brainstem muscarinoceptive neurons in lampreys (Petromyzon marinus) that received parallel inputs from the MLR and projected back to reticulospinal cells to amplify and extend the duration of locomotor output. These cells responded to muscarine with extended periods of excitation, received direct muscarinic excitation from the MLR and projected glutamatergic excitation to reticulospinal neurons. Targeted blockade of muscarine receptors over these neurons profoundly reduced MLR-induced excitation of reticulospinal neurons and markedly slowed MLR-evoked locomotion. The presence of these neurons forces us to rethink the organization of supraspinal locomotor control, to include a sustained feedforward loop that boosts locomotor output.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Brain Stem / anatomy & histology
  • Brain Stem / drug effects
  • Brain Stem / physiology*
  • Efferent Pathways / anatomy & histology
  • Efferent Pathways / drug effects
  • Efferent Pathways / physiology
  • Electric Stimulation
  • Excitatory Postsynaptic Potentials
  • Glutamic Acid / metabolism
  • In Vitro Techniques
  • Lampreys
  • Locomotion / drug effects
  • Locomotion / physiology*
  • Mesencephalon / anatomy & histology
  • Mesencephalon / drug effects
  • Mesencephalon / physiology
  • Neuronal Tract-Tracers
  • Neurons / drug effects
  • Neurons / physiology*
  • Patch-Clamp Techniques
  • Receptors, Muscarinic / metabolism*
  • Spinal Cord / anatomy & histology
  • Spinal Cord / drug effects
  • Spinal Cord / physiology
  • Swimming / physiology
  • Synapses / drug effects
  • Synapses / physiology
  • Time Factors

Substances

  • Neuronal Tract-Tracers
  • Receptors, Muscarinic
  • Glutamic Acid