Fig. 6.

Intra-MR ZK 200775 enhances approach-related motivation, but not mere hyperactivity. Data are means with SEM (N = 11). a Lever responses markedly increased when contingent presentations of VS were available and when 0.5 nmol ZK was noncontingently infused into the MR in the span of 90 min. b, c Data are combined between two repeated sessions: 1–2, 3–4, 5–6, and 7–8. b ZK administration significantly increased locomotor activity. *P<0.001, significantly greater than the values of sessions 1–2. c Lever presses of the ZK×VS condition (i.e., sessions 7–8) were compared with those of additive condition (ZK+VS; see text for detail). *P<0.005, significantly different from any other value