Mauthner Neuron

  • The Mauthner neuron, or the M-cell, is part of the vertebrate central nervous system. 
  • In the past, identifying the M-cell has led to discoveries in fields such as the molecular biology of neurons, behavior, and development. 
  • The First reticulospinal neuron appears at approximately 7.5 hours post fertilization.               
  • Most fish and amphibia have a pair of Mauthner cells, one on each side of the brainstem.                                       
  • The soma of each cell is about 100 μm in diameter.  There are two major dendrites, approximately 500 μm in length.  The axon extends along the spinal chord. 

 

http://www.iac-usnc.org/Methods/mauthner/diagram1-lgs.jpg

  • The Mauthner cells act as sensory integration centers.  They are modulated by a group of inhibitory interneurons. 

o     The M-cells inhibit these neurons?investigations of this process have led to a greater understanding of inhibitory synaptic transmission in the vertebrate central nervous system.

o     Reciprocal inhibition between the interneurons and the Mauthner neurons ensure that only one of the M-cells responds to sensory stimuli. 

o     When one M cell is activated, the other is inhibited.

  • The Mauthner neuron plays a role in the first stage of the C-start response

o     It triggers a predator avoidance response

o     It is the first neuron to respond to an abrupt sensory input and determines the initial direction of movement

o     Zebrafish respond to tail stimulation with C-start response.

  • Although the M-cell is not important in the recovery of the C-start response, it regenerates after a spinal chord injury at the spinomedullary level.**
  • Comparative studies of M-cells in fish have revealed that there is a large structural difference among fish species.
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Last Updated: 01/26/2006 HEC