Figure 1.
Localization of the electrode-tips of all animals.
The plus symbols indicate endpoints of electrodes placed in the NAcc core, closed circles indicate endpoints of electrodes placed in the lateral shell, and open circles indicate endpoints of electrodes placed in the medial shell. Animals with electrodes placed outside the target area were not included in the analysis (adapted from; [33]).
Figure 2.
Effect of DBS on the consumption of food.
The graph represents mean food intake in grams (+SEM) (y-axis). Intensity of stimulation is depicted on the x-axis. Stimulation of the core (top graph) or lShell (middle) did not affect food intake. Stimulation of the mShell (bottom) at the highest intensity (100 µA) significantly increased food intake. Stimulation at lower intensities did not affect food consumption in any target area.
Figure 3.
Effect of DBS on operant responding for sucrose.
The graph represents the mean number of obtained rewards (+SEM) as a percentage of those obtained during sham stimulation (y-axis). Stimulation areas are depicted on the x-axis. Stimulation of the NAcc (core, lShell or mShell) did not significantly affect responding for sucrose (top) but there was a strong trend towards a significant increase in lShell stimulated animals. Responding under a progressive ratio schedule for sucrose (bottom) was not affected by DBS of the core or mShell. Stimulation of the lShell at the highest intensity (100 µA) significantly decreased responding. Stimulation at lower intensities did not affect performance in either task, in any target area.
Table 1.
Average number of lever presses per condition.
Figure 4.
Effect of DBS on sucrose preference.
The graph represents mean preference ratio's (±SEM) for all target groups (core, lshell, mshell) (y-axis). Stimulation-intensities are depicted on the x-axis. Base-line preference was significantly different from chance-levels (50% indicated by dotted-line), but was not affected by stimulation, for any group.
Figure 5.
Effect of DBS on sucrose/water intake.
The graph represents the mean intake of water and sucrose (1%) in grams (+SEM) (y-axis). Stimulation-intensities are depicted on the x-axis. Stimulation of the NAcc core (top), lShell (middle) or mShell (bottom) did not affect intake of either water or sucrose solution.