Fig. 6

Cranial radiation impairs coupling between the prefrontal cortex (PFC) and ventral tegmental area (VTA). Local field potentials were recorded simultaneously from the PFC and VTA in free-moving animals during spontaneous alternating Y-maze tests before and after radiation treatments. (A) Significant distinctions were noted in the slow-frequency bands (Delta and Theta) of coherence between the PFC and VTA during one-arm-blocked and open-arms Y maze tests. (B and C) The robust coherence observed in slow-frequency bands of the PFC-VTA showed sustained depression at both day 3 (B) and day 28 (C) after irradiation (solid line: mean; shadow fills: SEM; n = 3 rats in each group). (D and E) Differing from the sham treatment (D), cranial radiation (E) substantially disrupted the functional coupling between the PFC and VTA, manifesting as an extended suppression in coherence between these two brain regions within (F) Delta bands (two-way ANOVA, F_{(2, 246)} = 45.01, P < 0.01; RT3D 0.14 ± 0.01 vs. sham3D 0.34 ± 0.01, P < 0.01; RT4W 0.05 ± 0.00 vs. sham4W 0.27 ± 0.01, P < 0.01, 3 rats in each group) and (G) Theta bands (two-way ANOVA F_{(2, 282)} = 22.68, P < 0.01; RT3D 0.13 ± 0.01 vs. sham3D 0.23 ± 0.01, P < 0.01; RT4W 0.05 ± 0.00 vs. sham4W 0.16 ± 0.00, P < 0.01, 3 rats in each group). **P < 0.01