The slow oscillation occurs earliest and most intensely in layer 5
Simultaneous extracellular multiple unit recordings from different layers in the cortex reveal that the slow oscillation occurs earliest in layer 5, followed by layer 6, and then by layers 2 and 3. Layers 5 and 6 exhibit significant spontaneous activity in between each of the "UP" states, and this activity decreases immediately following the cessation of the UP state. a) illustration of the electrode array. b) slow oscillation at a slow time scale. c) example of one up state expanded in time. d) alignment of the activity on the peak of activity in layer 5 reveals the slow oscillation to occur first and with the greatest intensity in layer 5.