Figure 4.
Normalized BOLD integral as a function of ISI in LGN and V1. At both ROIs, BOLD responses are significantly suppressed (i.e., below the reference line) at ISIs of < 1 second. When ISI gets longer, BOLD suppression at both ROIs gradually becomes smaller. Suppression in V1 BOLD activity completely disappears when ISI ≥ 1 second, whereas BOLD suppression in LGN sustains for even longer ISIs. V1 activity also shows a short period (~ 1 s) of facilitation (i.e., above the reference line) after ISI > 1 second.