Discharge patterns of reticular neurons subjected to direct electrical polarization.

Abstract

The relationship between firing rate and pattern was analyzed in neurons of the mesencephalic reticular formation of curarized rats using direct polarization through the recording extracellular micropipette to simulate wide range of firing rates. 40% of initially slow irregular cells change firing pattern when accelerated and 60% remains stable. 18% of initially fast regular cells change firing pattern when retarded and 82% remains stable. Since it is generally assumed that change in firing pattern can result only from change in overall synaptic drive it is suggested that in cases firing pattern is stable the polarizing current presumably influences the value of the transmembrane potential whereas clearcut changes in firing pattern accompanying shift in mean firing rate imply the change in synaptic inflow presumably due to enhanced or decreased excitability of some part of postsynaptic membrane.