Figure 4.

The failure to perceive T2 is foreshadowed by early (80–140 ms) T1 processing in the ventral striatum, and conscious T2 target perception is associated with later (200–400 ms) ventral striatal activity. Shown are intracranial EEG data from the left (left figures) and right (right figures) ventral striatum. Time-frequency representations show oscillatory activity induced by T1 and T2 A, Short-interval T2-unseen B, short-interval T2-seen, and C, long-interval T2-seen trials. In trials in which T2 was not seen, T1 induced a strong increase in α and low β oscillatory activity (8–16) between 80 and 140 ms after T1 in the left ventral striatum. Moreover, in the left ventral striatum, when T2 was consciously perceived, an increase in θ oscillatory activity (4–8 Hz) was observed 215–400 ms after each target onset. However, when only T1 was seen, only the first increase in θ activity was present. Moreover, the second increase in θ activity is shifted in time with the presentation of T2 in long-interval trials, confirming that it is related to conscious perception of T2. Thus, only consciously perceived targets were signaled by θ oscillatory activity between 200 and 400 ms, in particular, in the left ventral striatum. Finally, conscious T2 perception was associated with a transient increase in β-band activity (15–30 Hz) in the right ventral striatum 210–260 ms after T2.