NMDA-induced dendritic oscillations during a soma voltage clamp of chick spinal neurons

An investigation of dendritic membrane properties was performed by whole-ce ll patch measurements of the biophysical properties of intact chick spinal neurons that are involved in rhythmogenesis. A whole-cell voltage clamp of the somatic membrane was used to block NMDA-induced voltage oscillations fr om the cell body, thus partially isolating the intrinsic oscillatory proper ties of dendritic membranes from those of the soma. An experimental approac h was developed that takes into account the complexity of the dendritic tre e in an environment as normal as possible, without the need for cell isolat ion or slice preparations. A computational study of the experimentally dete rmined model showed that excitatory amino acid receptors on dendrites can d ynamically control the electrotonic length of the dendrites through the act ivation of negative slope conductances. These experiments demonstrate the p resence of NMDA receptors on the dendrites and that they induce intrinsic o scillations when the synaptic input from other cells is significantly reduc ed.