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Balanced Inhibition and Excitation Drive Spike Activity in Spinal Half-Centers
Rune W. Berg,1Aidas Alaburda,2Jørn Hounsgaard1*
Many limb movements are composed of alternating flexions andextensions. However, the underlying spinal network mechanismsremain poorly defined. Here, we show that the intensity of synapticexcitation and inhibition in limb motoneurons varies in phaserather than out of phase during rhythmic scratchlike networkactivity in the turtle. Inhibition and excitation peak withthe total neuron conductance during the depolarizing waves ofscratch episodes. Furthermore, spike activity is driven by depolarizingsynaptic transients rather than pacemaker properties. Thesefindings show that balanced excitation and inhibition and irregularfiring are fundamental motifs in certain spinal network functions.
1 Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen DK 2200 Copenhagen N, Denmark. 2 Department of Biochemistry and Biophysics, Faculty of Natural Sciences, Vilnius University, Ciurlionio 21/27, 03101 Vilnius, Lithuania.
* To whom correspondence should be addressed. E-mail: j.hounsgaard{at}mfi.ku.dk
GABAA Receptor-Mediated Signaling Alters the Structure of Spontaneous Activity in the Developing Retina.
C.-T. Wang, A. G. Blankenship, A. Anishchenko, J. Elstrott, M. Fikhman, S. Nakanishi, and M. B. Feller (2007)
J. Neurosci.
27, 9130-9140
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