In Logic Pro, do the following:
While a cell is not playing: Click the Track Activation button in the Divider column, or click the Restart button on the paused cell.
While cells are not playing: Click the Grid Stop button at the bottom of the Divider column to stop all cells, or stop multiple cells individually, then click the Track Activation button at the bottom of the Divider column, press Option and click the Restart button in the Divider column on any track, or click the Restart button on any of the paused cells.
When a scene is playing: Option-click the Scene trigger of the scene that is playing.
At the next quantize start point, any cells playing in the scene pause and the regions on the same tracks are audible.
Download the guides:
Logic Pro User Guide: PDF
Logic Pro Effects: PDF