Moreover, in both the AMD- and glaucoma-participant groups, the location of the grey matter density reduction corresponded with the approximate visual field defect projections in visual cortex.
A method for determination of centers of the defects projections on an arbitrary plane is developed.
Analysis of expression of the 165-kDa neurofilament protein revealed fusions of dorsal root ganglia and defects in projection of the spinal nerves (Fig. 5), which normally traverse only the rostral somite compartment.
The localized nature of the gland defects in pha-2 mutants, corresponding to the region where pha-2 results in muscle defects, strongly supports the hypothesis that the gland projection defects result from defects in the immediately surrounding musculature.
Although the M1 axon showed only 1% defects (ectopic projections in the metacorpus) in smp-1, these abnormalities were seen in 11% (n = 100) of the smp-1 smp-2 double mutants, suggesting that the two genes act redundantly (P < 0.05).
Histochemistry study provides evidence that there is an enlarged cell-free area in the internal capsule where presumably the abnormal thalamocortical pathway arises, which may explain the thalamocortical projection defect in Emx2 −/− mice (Lopez-Bendito et al., 2002).
Second, DiI tracing and PLAP labeling both show that corticothalamic fibers fail to target the dLGN, in Tbr1 knock out (Tbr1 −/−) mice, implying the defect of corticothalamic projections (Hevner et al., 2001).
It is possible that this disruption of glial architecture may partially contribute to the axon projection defects observed in Tsc1 mutants.
In contrast, S6k null mutations did not ameliorate the Tsc1 axon projection defects in the larval brain, and both the lamina plexus and medulla projections were highly disordered (Figure 6I, Table 1).
Indeed, ablation of protocadherin α and γ subclusters in mice causes defects in axonal projection of olfactory sensory neurons to the olfactory bulb [12] or drastic impairment in synaptic formation and extensive loss of interneurons in the spinal cord [5], [13].
