Joint Studies of Event-Related Brain Potentials and ^99mTc-Hexamethyl-propyleneamineoxime SPECT on Sensory-Guided Hand Tracking

Abstract

In humans, measurements of regional cerebral blood flow (rCBF) and electrophysiological recordings offer the possibility of directly studying the neuronal activity of brain structures and of establishing functional-anatomical relations in behavioral tasks. Current trends in topographical studies of brain functions include the use of scalp-recorded slow negative potential shifts (SPs), which occur time-locked to the performance of cognitive or motor tasks. The reason for this is the physiolgical significance of slow, surface-negative cortical potential shifts as an indicator of cortical activation. The spatial resolution of scalp-recorded SPs is limited, but sufficient, for instance, to separate the neuronal activity of localized cortical structures which are involved when preparing motor performance of different parts of the body (Boschert and Deecke 1986). In the present experiments, various tasks on sensory-guided hand tracking have been investigated. There were two points of interest: (1) Are there modality-specific effects on performance-related potential shifts? (2) What are the effects on SPs when changing variables of motor output by establishing conflicting response selection paradigms? These questions have been investigated by measuring both SPs and rCBF.