Free Communications : D, Neurophysiology and Neuropharmacology 334 fast sleep ( fig. 3c and d) are more complicated than those during slow sleep; most elevations and depressions run parallel or diagonally to the abscissa, and those parallel to the ordinate are few or very short. They are rather similar to ' inhibition 3 ' (in fig. 2d ). It is difficult to predict correctly whether the forelimb EMG would appear or not, only from examining the pattern in the MP map of sensorimotor cortex,

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... ly during fast sleep. In the sleeping animal, data on subcortical MP may be helpful for correct prediction, because differences exist between MP maps with positive and negative EMG. However, these data are omitted from this report. References 1 Yoshii, N.; Miyamoto, K., and Hayase, S.: On the neural mechanism of decision making of lever-pressing. Med. J. Osaka Univ. 20: 97 (1969). 2 Yoshii, N.; Miyamoto, K., and Hayase, S.: On the inhibitory mechanism of the ' motor potential (MP) ' of lever-pressing in the dog. J. Physiol. Soc., Japan 33: 500 (1971). After the description of monoamine-containing nerve cells in the lower brain stem [4, 5] and subsequent delineation of ascending axons to the forebrain [15, 18] it has become possible to perform selective lesions Lidbrink Sleep-waking changes after Lesion of Ascending Noradrenaline 335 to these systems. It was then found that lesions in the lower brain stem,