CONTROL BY BRAIN STEM RETICULAR FORMATION OF SENSORY TRANSMISSION IN BURDACH NUCLEUS . ANALYSIS OF SINGLE UNITS

In cats anesthetized with Nembutal spontaneous and evoked activity of single units in the cuneate nucleus was extracellularly recorded and analyzed. CTR cells were activated by stimulation of contralateral medial lemniscus and ipsilateral forelimb nerves (RS, U, M). They might also be excited throughout bulbopontine reticular formation. The stimulation of bulbopontine reticular structures could reduce or abolish the activity evoked in CTR neurons by stimulation of peripheral nerve whereas it never modified the activity antidromically evoked in CTR neurons by lemniscal stimulation. The interneurons were activated by stimuli to the contralateral sensorimotor cortex, reticular structures and cutaneous nerves (RS, U, M). Most of them showed a convergence of different impulses on a single cell. From these results it can be deduced that the pontobulbar reticular formation has a presynaptic inhibitory effect on afferent transmission to cuneate neurons, presumably by interneurons located in the nucleus itself. © 1969.