. 2011 Mar 2;31(9):3384–3399. doi: 10.1523/JNEUROSCI.4899-10.2011

Table 2.

Quantification of structural parameters based on 3-D reconstructions of single retinocollicular arbors in WT and β2^−/− mice at multiple developmental stages

		P2		P4		P8/P9		P14/P15
Number of reconstructed arbors	WT	10		8		6		7
Number of reconstructed arbors	β2^−/−	6		8		7		6
Total length (μm)	WT	1690.82 ± 394.05	^**	4307.41 ± 585.95	^***	9127.77 ± 707.42	^#	12,593.99 ± 1475.64
								^*
	β2^−/−	1445.83 ± 362.03	^*	4167.13 ± 731.94		6939.13 ± 1541.13	^**	18,402.43 ± 2285.72
Number of branch points	WT	6.70 ± 2.52	^***	60.75 ± 8.03	^***	200.83 ± 15.10	^*	513.29 ± 83.62
				^†		^**
	β2^−/−	6.67 ± 2.81	^*	37.00 ± 9.08		69.71 ± 25.32	^**	411.50 ± 91.02
Average branch length (μm)	WT	355.40 ± 84.20	^**	73.14 ± 8.13	^*	46.21 ± 4.58	^*	27.98 ± 4.18
								^*
	β2^−/−	279.42 ± 61.94	^*	137.22 ± 30.27		198.50 ± 94.73		51.93 ± 7.43^‡
Arbor density	WT	0.15 ± 0.002	^***	0.19 ± 0.01	^***	0.31 ± 0.02	^**	0.44 ± 0.03
						^***		^***
	β2^−/−	0.15 ± 0.002	^**	0.18 ± 0.01		0.18 ± 0.01	^*	0.23 ± 0.01
Arbor area (μm²)	WT	15,852.12 ± 3733.34	^*	26,060.29 ± 2857.49		29,653.36 ± 2293.9^§		24,899.54 ± 2398.29^##
								^***
	β2^−/−	13,815.08 ± 3216.95	^*	32,376.74 ± 5051.2		51,424.19 ± 10203.94	^*	89,803.98 ± 9360.86
Rostrocaudal axis (μm)	WT	798.49 ± 85.50		732.42 ± 164.75		421.28 ± 132.18^‡‡		428.48 ± 79.90^††
						^***		^***
	β2^−/−	653.53 ± 106.11	^*	1005.67 ± 150.69		885.60 ± 70.69^§§		961.05 ± 139.96
Mediolateral axis (μm)	WT	185.36 ± 32.37		276.28 ± 55.52		304.60 ± 20.73	^*	230.24 ± 26.55
Mediolateral axis (μm)	β2^−/−	256.07 ± 43.60		322.79 ± 58.92		429.16 ± 130.39		392.91 ± 83.60

Mean ± SEM for all measurements for WT and β2^−/− retinocollicular arbors at different ages. Asterisks between columns and rows identify statistically significant differences:

*p < 0.05;

**p < 0.01;

***p < 0.001. For completion, all p values < 0.1 are reported. The following symbols indicate p values for age and genotype groups indicated:

^#p = 0.07 between P8/P9 and P14/P15 WT and ^##p = 0.07 between P2 and P14/P15 WT;

^†p = 0.07 between P4 WT and β2^−/− and ^††p < 0.01 between P2 and P14/P15 WT;

^‡p < 0.05 between P4 and P14/P15 β2^−/− and ^‡‡p < 0.05 between P2 and P8/P9 WT;

^§p < 0.05 between P2 and P8/P9 WT and ^§§p = 0.08 between P2 and P8/P9 β2^−/−.