Table 2. Morphological estimates of OHC to type II contacts.

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

Source	Method	Species / Age	Type of contact	# OHC synapses
Perkins and Morest 1975	Golgi Stain	Cats, 50 days 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 to auditory nerve	Mouse, 6–10 weeks	Branches	6 (range 3 to 10)
Brown, 1987a	HRP injection into basal turn spiral ganglion	Guinea pig, adult (250 to 500 grams)	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	~5–100^a
Jagger and Housley 2003	Biocytin, lucifer yellow in somata cochlear slice	Rat P7–10, 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Weisz et al 2009 and unpublished data	AlexaFluor 488 hydrazide fills	Rat, P5–P9 apical turn	Branches	14–30 (n=3)

– estimated from figure 5