Scalp current density (SCD) mapping of cerebral activity during object and space selection in humans

Abstract In the present study we investigated neural selection mechanisms for object and space separately by recording Motor RTs and event-related potentials (ERPs) of the brain in humans with an relatively high-density electrode montage (i.e., 32 channels) mostly placed at the back of the scalp and . Reaction times (RTs) were about 100 ms faster in the location than the frequency selection task. Different morphologies characterized ERPs obtained in the two selection modes over the posterior regions of the scalp. ERPs for space selection were characterized by a prominent Pl peaking at about 140 msec, followed by a tiny N1 and a very early P300 component. Conversely, ERPs for object selection showed an early PN80 deflection followed by a prominent selection negativity (SN) and a delayed late positive component (LPC). The present findings support the view of two anatomically and functionally relatively distinct neural mechanisms for space and object selection. These mechanisms seem to be related to the activation of the “dorsal” and “ventral” streams of neural information processing.