The ability ot observe both sensory neural activity and sensory performance simultaneously in a subject would be an important step in understanding how neural events lead to conscious sensory experience. The development of new multielectrode recording techniques in awake, behaving monkeys in this laboratory now permits simultaneous recordings of cerebral cortical somatosensory evoked potentials (SEPs), multiple unit activity (MUA) and psychophysical reports to the same somatosensory stimuli. A coherent interpretation of neural and behavioral event is made possible by employing the signal detection theoretical framework. Studies are proposed to determine whether MUA and SEPs at various sites in post-central gyrus are functionally related by correlating measures of their temporal, spatial, and quantitative characteristics. Whether these neural responses change as a function of psychophysical performance will also be determined. These experiments may permit tentative identification of cell populations involved in somatosensoty discriminations. Because of previously demonstrated similarities between monkey and man on this psychophysical test paradigm and in their neural-sensory structures, results of this work may be directly applicable to the question of the neural correlates of sensory experience in man.