Brain Stimulation Reinforcement: Implications ofan Electrode Artifact

employed as described (3). 6. A similar result has been reported in rabbit superior cervical ganglion by H. Kobayashi and B. Libet, [J. Physiol. (London) 208, 353 (1970)]. In our experiments, membrane resistance was measured by using hyperpolarizing current pulses (-100 pA, 30 to 60 msec). Changes in input resistance as small as 10 percent were detectable. 7. D. Geduldig and D. Junge, J. Physiol. (London) 199, 347 (1968); M. Klein and E. R. Kandel, Proc. Natl. Acad. Sci. U.S.A. 75, 3512 (1978). 8. M. P. Blaustein, J. Pharmacol. Exp. Ther. 196, 80 (1976). 9. S. Minota and K. Koketsu, Jpn. J. Physiol. 27, 353 (1977). 10. K. Dunlap and G. D. Fishbach, Soc. Neurosci. Abstr. 4, 443 (1978). 11. C. Van Breemen, B. R. Farinas, R. Casteels, P. Gerba, F. Wuytack, R. Deth, Philos. Trans. R. Soc. London Ser. B 265, 57 (1973). 12. P. G. Kostyuk and D. A. Krishtal, J. Physiol. (London) 270, 569 (1978). 13. A. S. Marrazzi, J. Pharmacol. Exp. Ther. 65, 395 (1939); E. Bulbring, J. Physiol. (London) 103, 55 (1944). 14. D. D. Christ and S. Nishi, J. Physiol. (London) 213, 107 (1971); N. Dun and S. Nishi, ibid. 239, 155 (1974). 15. We thank P. J. Yarowsky for helpful discussions and L. Worth for assistance in preparing the manuscript. Supported by NIH gant NS-05820 and a Scottish Rite schizophrenia fellowship to J.P.H. who was on leave from the Department of Physiology and Biophysics, University of Miami School of Medicine when this research was perforned.