Figure 5. Attenuation of direct pathway functional connectivity after an asymptomatic partial dopaminergic lesion. a, Schematic representation of the position of all recorded MSNs in sham, asymptomatic, and symptomatic mice on a plate of Paxinos and Franklin mouse brain atlas (2001). Numbers of neurons recorded per experimental group were as follows: for dMSNs, n = 9 in sham, 12 in asymptomatic and n = 7 in symptomatic mice; for iMSNs, n = 11 in sham, 8 in asymptomatic, and 20 in symptomatic mice. b, Light microscopic images of coronal sections showing the position of the bipolar electrodes in a representative animal. c, d, Intensity–response curves to motor cortex stimulation for dMSNs (c) and iMSNs (d) recorded from sham (circles), asymptomatic (squares), and symptomatic (triangles) mice. For dMSNs, repeated-measures ANOVA significant interaction, p < 0.0001, followed by Bonferroni post hoc tests, *p < 0.05 asymptomatic versus sham, #p < 0.05 symptomatic versus asymptomatic. For iMSNs, repeated-measures ANOVA significant interaction, p = 0.03, followed by Bonferroni post hoc tests, *p < 0.05 symptomatic versus both sham and asymptomatic. e–g, Threshold (e), gain at 500 μA (f), and latency (g) differences across groups (two-way ANOVA, significant interactions followed by LSD post hoc tests, *p < 0.05 versus all other groups within cell type). Data are mean ± SEM.