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. Author manuscript; available in PMC: 2013 Dec 1.
Published in final edited form as: J Neuropathol Exp Neurol. 2012 Dec;71(12):1047–1063. doi: 10.1097/NEN.0b013e318274a128

Figure 7.

Figure 7

Ectopic pyramidal neurons project to appropriate cortical and subcortical targets but have abnormal dendritic orientation. (A, B) In the somatosensory cortex of wild type (WT) Dag1+/+ and Dag1 conditional knockout (cKO) (Dag1−/−) brains, layer VI neurons with thalamic projections are retrogradely-labeled by DiI injections in the thalamic ventroposterior lateral nucleus (VPLN); however, ectopic layer VI neurons in superficial CP layers and heterotopic layer VI neurons (B, arrow) in Dag1 cKO brains also established thalamic connections despite severe dyslamination. (C, D) In Dag1+/+ and Dag1 cKO brains, neurons in all cortical plate (CP) layers with commissural projections are retrogradely labeled by DiI injections in the corpus callosum. In Dag1 cKO brains, many heterotopic neurons (D, arrow) also have commissural projections and are retrogradely labeled by DiI injections in the corpus callosum. (E, F) In Dag1+/+ brains and Dag1 cKO brains, layer V neurons with subcerebral projections (to the brainstem and spinal cord) are retrogradely labeled by DiI injections in the cerebral peduncles. Many ectopic layer V neurons in superficial CP layers and heterotopia (HT) (F, arrow) also have subcerebral projections. (G-I) layer V pyramidal neurons in Dag1+/+ brains have parallel, radially oriented apical dendrites ending in tufts in layer I (G). Heterotopic neurons in Dag1 cKO brains often have abnormally-oriented and tortuous apical dendrites, which occasionally are bent against the outer edge of the HT (H), or are inverted (I). Scale bars: A–F, 200 µm; G, I, 100 µm.