Fig. 3

Area density of SNCA transcripts in neurons in the substantia nigra and amygdala. A, B Box and whisker plots of the total cell body SNCA transcripts area density in the substantia nigra (SN, A) and amygdala (B). SNCA transcript area density in neurons without disease-associated α-synuclein (α-syn) immunoreactivity (IR) in the SN (n = 117) and amygdala (n = 305) are similar to neurons with punctate disease-associated α-syn IR in the SN (n = 18) and amygdala (n = 37). However, SNCA transcript area density in neurons with irregular-shaped compact inclusions (n = 14), and those with brainstem-type Lewy bodies (bLB, n = 17) in the SN show a gradual decrease (A). The SNCA transcript area density in neurons containing cortical LB (cLB, n = 176) also shows a decrease compared to neurons without disease-associated α-syn IR and with disease-associated punctate α-syn IR (B). C, D Distribution of SNCA area density in neurons in the SN (C) and amygdala (D). Distribution curves of SNCA area density gradually deviate to a lower value during the maturation process of LBs. X-axis represents the area density expressed as the percentage and y-axis demonstrates the number of cells (Note that y-axis scales are different from C and D). While the nuclear SNCA transcript area density shows no differences (E), a significant decrease in cytoplasmic SNCA transcript area density is evident during LB maturation process in the SN (F). A significant decrease in SNCA transcript area density is also observed in the cytoplasmic area without compact inclusions and LB (G). The upper and lower whiskers indicate the 95th percentile and 5th percentile, respectively. The top and bottom of the box indicate the first and third quartiles, respectively. The middle line splitting the box indicates the median. The small circles in the plots indicate outliers. For statistics, Kruskal–Wallis test and Dunn’s post hoc analysis with Bonferroni correction are used. Statistically significant findings where p < 0.05, p < 0.01, and p < 0.001 are indicated as *, **, and *** respectively