Table 2.

Estimation of the number of synapses formed by a single VTA DA neuron in the ventral striatum of the rat

Number of DA neurons in the SNc (one hemisphere)	12,00029
Volume of striatum (mm3)	19.930
Volume of (dorsal) striatum per SNc DA neuron (mm3)	0.001658 (19.9/12,000)
Number of DA neurons in the VTA (one hemisphere)	20,00029
Volume of ventral striatum (mm3) (approximately one fifth of size of striatum)	∼ 4 (19.9/5)
Volume of ventral striatum per VTA DA neuron (mm3)	0.0002 (4/20,000)
Ratio of ventral versus dorsal striatum volume per DA neuron	0.121 (0.0002/0.001658)
Number of synapses formed by one DA neuron in the ventral striatum	12,351 to 29,644 (0.121 × 102,165a) to (0.121 × 245,103a)

^aEstimated number of synapses formed by one SNc DA neuron in the striatum in the rat (see Table 1).