To better understand the temporal dynamics of interhemispheric WM transfer, we compared the latencies of all studied neural signals (Figure S5). The earliest signals after the saccade instruction included beta synchrony within the sender hemisphere and between hemispheres, consistent with the idea that it may be involved in establishing a communication channel for interhemispheric transfer. Beta signals then exhibited a bilateral decrease around the time the receiver hemisphere begins to convey information about the WM trace, consistent with the idea that suppressing beta may disinhibit cortex and allow WMs to be expressed (Lundqvist et al., 2016). Finally, WM information decreased in the sender hemisphere about 120 ms after the rise in the receiver. Interhemispheric transfer in this task thus involves a ‘‘soft handoff,’’ in which information overlaps in time in both hemispheres before being cleared out of the sending hemisphere. This is similar to what has been found for tracking moving objects across the midline (Drew et al., 2014).
