Figure 6. Oxytocin reinstates fictive locomotor oscillations, despite subthreshold concentrations of neurochemicals.

Alternating oscillations of a stable FL, evoked by the addition of 3 μM NMDA and 10 μM 5HT (A), slow down once the concentration of neurochemicals is finely titrated down to 1.7 μM NMDA and 5 μM 5HT (B). A further decrease in NMDA (1.5 μM) + 5HT (4 μM) suppresses locomotor-like discharges, which are finally replaced by a tonic activity (C). By adding oxytocin (1 nM) to subthreshold concentrations of NMDA and 5HT, no FL oscillations reappear (D). By augmenting the neuropeptide to 100 nM, locomotor-like oscillations are restored (E). Further increase in oxytocin (1 μM) does not affect periodicity of the reinstated pattern nor its cycle amplitude (F).