Dipole source analysis suggests selective modulation of the supplementary motor area contribution to the readiness potential

Abstract

The readiness potential preceding voluntary movement is modulated by the mode of movement selection, i.e. it has a higher ampli tude preceding freely selected than before prescribed movements (Praamstra, P., Stegeman, D,F., Horstink, M.W.I.M., Brunia, C.H.M. and Cools, A.R. Movement-related potentials preceding voluntary movement are modulated by the mode of movement selection. Exp. Brain Res., i 995, 103: 429-439). One cortical area that is likely to be involved in this modulation is the supplementary motor area (SMA). Recent attempts to elucidate the neural generators of the readiness potential using spatiotemporal dipole source analysis, how ever, failed to establish a significant SMA contribution to the readiness potential. This might be explained by a failure of the proposed analyses to discriminate between SMA and motor cortex contributions to the readiness potential. We applied a dipole source analysis approach that better separates these overlapping source activities* The resulting source model includes an SMA source generating pre movement activity consistent with evidence from intracranial recordings in humans. The SMA source accounts almost completely for the modulation of the readiness potential by different modes of movement selection. On the basis of these results, the relation between scalp-recorded movement-related activity, intracranially recorded potentials, and findings from functional imaging studies of voluntary movement, appears more transparent than suggested by previous dipole source analyses of premovement potentials.

Reset of human neocortical oscillations during a working memory task

“…Although we cannot rule out the latter possibility, the anatomical distribution of electrodes exhibiting preferential reset to probes (Fig. 5e) suggests that we are not analyzing purely movement-related activity, which has been localized to the central motor areas and premotor cortex (39). Rather, it is likely that memory comparison processes, which may operate in either serial or parallel fashion (40,21), cause preferential reset to probe items.…”

Automatic motor activation by mere instruction

“…This LRP is widely accepted as a measure of hand-specific response activation. First, its locus has been shown to lie in the motor cortex (Arezzo & Vaughan, 1975;Eimer, 1998;Gemba & Sasaki, 1990;Okada, Williamson, & Kaufman, 1982;Praamstra, Stegeman, Horstink, & Cools, 1996;Requin, 1985), suggesting that the LRP has strong ties with motor preparation and response activation. Second, the LRP is an extremely valid predictor of motor responses (Gratton et al, 1988).…”

Subliminal display of action words interferes with motor planning: A combined EEG and kinematic study

“…The RP, which is believed to arise from premotor and primary motor areas, is characterized by a slow negative going potential that starts approximately 1 second prior to movement onset, with maximum amplitudes at centrolateral recording sites (Ball et al, 1999;Cunnington et al, 2003;Deecke & Kornhuber, 1978;Deecke et al, 1987;Praamstra et al, 1996;Shibasaki et al, 1980). The RP is generally elicited prior to self-paced voluntary movements, but it has also been recorded in relation to stimulus-triggered movements (Castro et al, 2005;Kilner et al, 2004).…”