[Activation of reticulospinal neurons of the medulla oblongata by pyramidal fiber collaterals].

The responses of medullar reticulospinal neurons evoked by collaterals of pyramidal fibres were investigated in cats anesthetized with nembutal (40 mg/kg) or mixture of chloralose (45 mg/kg) and nembutal (15 mg/kg). Experiments were performed after preliminary electrolytic destruction of contralateral red nucleus and section of ipsilateral dorsolateral funiculus in C4. It was shown that pre- and postsynaptic effects evoked in neurons of gigantocellular nucleus by stimulation of cortex and DLF are mediated by collaterals of pyramidal fibres. Only excitatory responses were recorded from reticulospinal neurons after stimulation of DLF. The analysis of EPSPs had showed that they could be evoked by collaterals of both fast and slow pyramidal fibres.