Table 2.

Morphological estimates of OHC to type II contacts^a

Source	Method	Species/Age	Type of contact	Number of OHC synapses
Perkins and Morest, 1975	Golgi stain	Cats, 50 d to 4 months Rats, P0–P22	Swellings and branches	Typically 10–20, up to 60
Ginzberg and Morest, 1983	Golgi stain	Cats, newborn to one month	Branches	“Many” P3 kitten examples: apical fiber 14, basal fiber 37
Berglund and Ryugo, 1987	HRP injection into auditory nerve	Mouse, 6–10 weeks	Branches	6 (range 3–10)
Brown, 1987a	HRP injection into basal turn spiral ganglion	Guinea pig, adult (250–500 g)	Branches	Row 1: 8 (range 5–12) Row 2: 16 (range 12–21) Row 3: 20 (range 14–28)
Simmons and Liberman, 1988a	HRP injection into auditory nerve	Cat, adult	Swellings and branches	∼5–100b
Jagger and Housley, 2003	Biocytin, lucifer yellow in somata in cochlear slice	Rat P7–P10, apical turn (one basal)	Branches	6–16 OHC in rows 1 and 2 apex (n = 7) 9 OHC row 3 basal turn (n = 1)
Weisz et al., 2009 and unpublished data	AlexaFluor 488 hydrazide fills	Rat, P5–P9 apical turn	Branches	14–30 (n = 3)

^aA literature survey provides estimates of OHC synaptic inputs to type II cochlear afferents based on measurements of branches or dendritic swellings contacting OHCs.

^bEstimated from Figure 5.