Table 1.

Axonal branching patterns of nigrostriatal cells at striatal and extrastriatal levels

Nigral sector, number of labeled axons (n), and cell type	Axonal branching: sites and degree1-a
	CPu			FStr	Extrastriatal structures
	M	S	SS
Dorsal tier (n = 19)
Type 1 (n = 12)	++/+++	−/+	−/+	−	−/+
Type 2 (n = 3)	++/+++	++/+++	−/+	−	+/++
Type 3 (n= 4)	−	−	−/+	++/+++	−/+
Ventral tier (n = 23)
Outside SNr (n = 12)	−/+	+	−/+	−	−/+
Within SNr (n = 7)	+	++/+++	−	−	+/++
Cell clusters (n= 4)
1	+++	−	+	−	++
2	+	−	+	−	+++
3	−	−	+	−	+++
4	−	+	−	−	+++

CPu, Caudate-putamen; FStr, fundus striati; M, striatal matrix compartment; S, striosome; SS, subcallosal streak.

^F1-aDegrees of axonal branching: −, none; +, weak; ++, moderate; +++, high.