Fig. 5.

Acute cocaine abruptly decreased CBFv in somatosensory cortex of chronically cocaine-exposed rats. Dynamic CBFv maps in the somatosensory cortex of control rats with 2-week (red curve) and 4-week (blue curve) saline-treatment (a0–a5), and cocaine treated rats treated for 2 weeks (b0–b5) or 4 weeks (c0–c5) in response to saline ($0.1\mathrm{cc}/100\mathrm{g}$, i.v.) or acute cocaine ($1\mathrm{mg}/\mathrm{kg}$, i.v.). The first column presents the laser speckle contrast images taken at ${\lambda }_3=830\mathrm{nm}$, reflecting the CBFv changes in this area. (a6, b6, c6) Time courses of CBF changes in response to saline or cocaine among all groups, indicating an abrupt and transient CBFv decrease after acute cocaine in chronically exposed cocaine rats and this decrease was more dramatic and longer-lasting in the 4-week than the 2-week cocaine rats. *significant differences between saline- and cocaine-treated groups ($n=3$, $m=9$, $*p<0.05$).