Table 2.

Regional morphometric analyses

	Wild-type	Igf1−/−	% change	p
Whole brain
Area (×104)	3.46  ± 0.10	2.62  ± 0.05	24⇓	<0.0001
Cerebellum
Area (×103)	3.84  ± 0.38	2.71  ± 0.15	30⇓	0.03
plp cell (/200 μm2)	25.50  ± 1.54	30.30  ± 1.07	19⇑	0.03
wm diam (μm)	108  ± 11	88  ± 12	19⇓	0.02
Purkinje cells/250 μm	12.6  ± 0.70	17.3  ± 0.6	37⇑	0.0005
Olfactory bulb
Area (×103)	3.18  ± 0.16	1.25  ± 0.23	60⇓	<0.0001
plp cells
epl (%)	3.84  ± 0.36	1.48  ± 0.30	62⇓	0.002
ml (%)	3.18  ± 0.91	0.91  ± 0.20	71⇓	0.005
mitral cells/250 μm	6.08  ± 0.78	6.15  ± 0.52	⇔	0.964
Anterior commissure
Area (×103)	0.074  ± 0.015	0.037  ± 0.015	51⇓	0.003
plp cell (/200 μm)
al	58.00  ± 4.60	59.20  ± 4.41	⇔	0.855
pl	40.80  ± 5.85	54.50  ± 4.99	34⇑	0.129

All morphometric analyses were done on anatomically matched parasagittal sections. Data are expressed as mean ± SEM withn = 4–6 for each observation. plp cells, PLP mRNA-positive cells, presumed to be oligodendrocytes. These cells were scored as a percentage of all cells in the indicated zones in each section. Counting them on an area basis was thought to be less accurate because the cell density of these regions is so low. However, their number was also significantly diminished when counted per 500 μm² (data not shown). Whole-brain, cerebellum, anterior commissure, and olfactory bulb areas were obtained using image analysis as explained in Materials and Methods and are given in pixels. The number of mitral and Purkinje cells were counted microscopically using an eyepiece reticule at 200×. epl, External plexiform layer; ml, mitral cell layer; wm, cerebellar white matter. The ⇓ symbol indicates a decrease. The ⇑ symbol indicates an increase. The ⇔ symbol indicates no change.