Statistical analysis of 40 neurones of the midbrain reticular formation in hungry rabbits has shown that in the animals with food motivation, 50% of the neurones has a specific activity pattern--domination on the interval histogram of interspike intervals within the ranges of 2-10 ms and 100-200 ms characteristic of the hungry animal's status. Microiontophoresis of noradrenaline exerts a specific action on reticular formation neurones, manifesting in the increased number of neurones that react to the application by the enhanced "bundle-formation", i. e. by domination on the histograms of the intervals in the ranges of 2-10 ms and 100-200 ms. Acetylcholine action may cause an analogous distribution of the intervals between neuronal spikes in the hungry animals, although in a less number of neurones but with a more remarkable difference in the peak magnitudes within the ranges of 5-10 and 100-200 ms. Microiontophoretic application of serotonin to reticular formation neurones was found to produce no such an effect.