1. Previous experiments have shown that tones that were reinforced in this manner evoked a conditioned response and awakened the sleeping cat (D. Rodgers, N. Buendia, J. Gelber, andS. Yrarrazabal, in preparation).
2. N. Buendia, G. Sierra, M. Goode, andJ. P. Segundo, inNeurophysiological Basis of Mental Activity (Ed.R. Hernandez Peon), EEG clin. Neurophysiol., in press.
3. M. Granda andJ. T. Hammack, Science133, 1485 (1961).
4. M. Jouvet, Arch. Ital. Biol. sperim.100, 125 (1962).
5. E. V. Evarts, E. Bentol, B. Bihori, andP. R. Huttenlocher, Science135, 726 (1962).