Beta power (Figures 5A–5C and 5E) exhibited complex multiphasic dynamics on swap trials (Figure 5F). It was suppressed initially after the saccade but later became enhanced, relative to power on no-swap trials (Figure 5F). On top of these overall dynamics, however, beta power on the swap conditions inverted: it became stronger for remembered locations shifting into the ipsilateral hemifield than for those shifting into the contralateral hemifield (Figures 5C and 5F). Thus, as for spiking, prefrontal LFP power signatures of WM laterality also exhibited the inversion predicted by the shifting trace model (Figure 3D). These results support the hypothesis that the memory trace is transferred from one cortical hemisphere to the other.
