Fig. 5.

Temporal evolution of the cortical sources of sigma activity. LORETA source estimation (squared magnitude of current source density [µA²/(mm⁴ Hz)] in the sigma band (12–16 Hz). Left: baseline, right: recovery sleep. Images represent average values of the two minutes before SO (-1 min), 4–6 min (5 min) and 8–10 min (9 min) after SO. The plane coordinates were chosen to best match the most active brain regions (−15, −40, 70 in MNI coordinates [mm]) (For interpretation of the references to color in this figure, the reader is referred to the web version of this article).