Phasic nicotinic potentiation of frog retinotectal transmission enhances intrinsic activity of tectum column.

It is well established that cholinergic modulation of functioning of neuronal networks is common in the central nervous system at all scales from neuronal columns to large nuclei. It is involved in various attentional, cognitive and behavioral performances. We have recently demonstrated that a frog retinotectal transmission exhibits after-burst (phasic) potentiation caused by activation of presynaptic nicotinic receptors. We show in the present study that the phasic potentiation of the retinotectal transmission enhances activity of the tectum column by increasing dendritic L-type calcium current, and excitation of recurrent pear-shaped neurons of the column. This enhancement lasts for tens of seconds and may provide the mechanism of animal alertness.