Figure 2.

Persistence of head-direction cell assemblies in the anterodorsal nucleus of the thalamus during waking and sleep. Waking. Simultaneously recorded head-direction cells with different direction preferences during exploration (right). Each line is a neuron, increasing firing rates are represented by hot colors. Neurons are ordered according to their preferred head-direction. Note sequential activity of head-direction neurons (from top to bottom). Bottom trace (white) is local field potential recording from the hippocampus. (Left) Head-direction cell assembly activity displayed on a ring. As the head points to different directions, the hill of spiking activity moves on the ring accordingly. REM, same arrangement as in waking. Note continued sequentially changing activity of the head-direction cells despite the absence of head or body movement. (Reprinted, with permission, from Peyrache et al. 2015.)