EFFECT OF ETHANOL ON HIPPOCAMPAL-NEURONS DEPENDS ON THEIR BEHAVIORAL SPECIALIZATION

Acute effect of ethanol on hippocampal neurons was studied during food acquisition behaviour in seven rabbits. The rabbits were taught to acquire food from a feeder by pressing a pedal on the same side of the cage. The behaviourally specialized units (L units related to newly learned behaviour and M units related to behaviour formed before learning, e.g. certain movements) were comparable with the 'place' (projectional pyramidal and granular cells) and 'displace' (non-pyramidal interneurons) units of the current classification. The same direction of ethanol effects was found as for the limbic cortex; the number of certain kinds of L units decreased and that of M units increased but there was no significant change in the relative number of L and M units as a whole. The background frequency of L units decreased, but the frequency within activations increased. The results confirm our earlier findings on the most marked depressive effect of ethanol on L units and show that it is the behavioural specialization, not the morphological unit type, which is a major determinant of the ethanol influence.