SLOW BRAIN POTENTIALS IN A VISUAL-SPATIAL MEMORY TASK - TOPOGRAPHIC DISTRIBUTION AND INTER-LABORATORY CONSISTENCY

Slow brain electrical potentials (SPs) were investigated in a visual-s patialmemory task. Two issues were addressed: (1) the nature and topog raphic distribution of the potentials obtained under such conditions; and (2) the consistency of the SPs when recorded in six identically co nfigured laboratories. Fifteen young male subjects were studied at eac h laboratory (total n = 90). The paradigm entailed presentations of pa ired visual patterns (S1 and S2), to which subjects responded with a c hoice reaction time response indicating whether or not the two pattern s matched. A biphasic contingent negative variation (CNV) was produced which consisted of an early symmetric component with bilateral foci a t posterior temporal sites and a subsequent mid-parietal dominant wave later in the retention interval. Although the CNVs from all laborator ies were similar in waveform and in topographic distribution, there we re significant inter-laboratory differences in amplitude of the slow p otential components. The topographic distributions of the components a nd the possible role of sampling effects are discussed. (C) 1997 Elsev ier Science B.V.