By dividing the number of spines by the total dendritic length for each reconstructed neuron in sham animals, we were able to evaluate the overall spine density for each of the three types of striatal MSNs. Our data reveal that the D1/D2 MSNs have a 37% lower spine density (4.0 ± 0.2 spines/10 μm) than the D1 (6.4 ± 0.3 spines/10 μm, P < 0.0001) and the D2 (6.6 ± 0.2 spines/10 μm, P < 0.0001) MSNs (Fig. 5c). A Sholl analysis performed on all reconstructed neurons indicates that this lower spine density is maintained throughout the entire dendritic extent of the D1/D2 MSNs, the difference being statistically significant on a distance ranging between 45 and 105 μm from their parent cell bodies (Fig. 5d).
