<正> The thalamus and spinal cord are two importallt relays in mediating painsensation.To study further the roics of the cercbral cortex,brain stem andspinal cord in acupuncture analesia (AA),in the prescnt series of studiesstress was placed on two relays by means of investigating corticofugai modula-tion of the thalmus,corticofugal.regulation on brain stem descending inhi-bition via the ilmbic system,the rolc of Substance P(SP)in descending