Functional Organization of the Brain Stem Reticular Formation and Sensory Input

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Science  30 Nov 1962:
Vol. 138, Issue 3544, pp. 973-975
DOI: 10.1126/science.138.3544.973


Injections of 20 µg of adrenaline, dissolved in 10, µl of Tyrode solution, directly into the brain stem reticular formation, are followed by a transient increase in the amplitude of the cortical-evoked response obtained from single-shock stimulation of the optic chiasma, while injections of the same amount of acetylcholine produce a transient decrease. Furthermore, injections of procaine in the medial region of the rostral pontine reticular formation are followed by a long-lasting increase in the amplitude of these evoked responses, while the same injections at mesencephalic levels produce a marked decrease. These findings are interpreted in terms of the presence, in the reticular formation, of two antagonistic ascending systems: one adrenergic, the other cholinergic, whose tonic activity originates in the mesencephalic tegmentum in one case and in the caudal regions of the brain stem in the other.