RRC ID 5624
Author Satou C, Kimura Y, Kohashi T, Horikawa K, Takeda H, Oda Y, Higashijima S.
Title Functional role of a specialized class of spinal commissural inhibitory neurons during fast escapes in zebrafish.
Journal J. Neurosci.
Abstract In teleost fish, the Mauthner (M) cell, a large reticulospinal neuron in the brainstem, triggers escape behavior. Spinal commissural inhibitory interneurons that are electrotonically excited by the M-axon have been identified, but the behavioral roles of these neurons have not yet been addressed. Here, we studied these neurons, named CoLo (commissural local), in larval zebrafish using an enhancer-trap line in which the entire population of CoLos was visualized by green fluorescent protein. CoLos were present at one cell per hemi-segment. Electrophysiological recordings showed that an M-spike evoked a spike in CoLos via electrotonic transmission and that CoLos made monosynaptic inhibitory connections onto contralateral primary motoneurons, consistent with the results in adult goldfish. We further showed that CoLos were active only during escapes. We examined the behavioral roles of CoLos by investigating escape behaviors in CoLo-ablated larvae. The results showed that the escape behaviors evoked by sound/vibration stimuli were often impaired with a reduced initial bend of the body, indicating that CoLos play important roles in initiating escapes. We obtained several lines of evidence that strongly suggested that the impaired escapes occurred during bilateral activation of the M-cells: in normal larvae, CoLo-mediated inhibitory circuits enable animals to perform escapes even in these occasions by silencing the output of the slightly delayed firing of the second M-cell. This study illustrates (1) a clear example of the behavioral role of a specialized class of interneurons and (2) the capacity of the spinal circuits to filter descending commands and thereby produce the appropriate behavior.
Volume 29(21)
Pages 6780-93
Published 2009-5-27
DOI 10.1523/JNEUROSCI.0801-09.2009
PII 29/21/6780
PMID 19474306
MeSH Animals Animals, Genetically Modified Behavior, Animal Biotin / analogs & derivatives Biotin / metabolism Calcium / metabolism Dextrans / metabolism Electric Stimulation Escape Reaction / physiology* Gap Junctions / physiology Green Fluorescent Proteins / genetics Inhibitory Postsynaptic Potentials / physiology Interneurons / physiology* Larva Laser Therapy / methods Membrane Potentials / physiology Neural Inhibition / physiology* Neural Pathways / cytology Neural Pathways / physiology Patch-Clamp Techniques Rhodamines / metabolism Spinal Cord / cytology* Spinal Cord / physiology Swimming Zebrafish / physiology*
IF 6.074
Times Cited 56
WOS Category NEUROSCIENCES
Resource
Zebrafish Tol-056