Four Macaca nemestrina monkeys were trained to pull a manipulandum to escape electrocutaneous stimulation (ES) applied to either leg. The intensities of stimulation which the monkeys chose to escape were those that humans identify as painful. The duration of escape trials was inversely related to stimulus intensity, and the force of escape responses was directly related to ES intensity. Reflexi...

A procedure is reported in which radiofrequency lesions were stereotactically placed in the central cord region at the cervicomedullary junction to interrupt selectively the extralemniscal system. Physiological recognition of the target site was based upon the homuncular organization of the dorsal funiculi, which is analysed. Only subjective (segmentally unrelated) analgesia was achieved, usual...