Fine morphology of the corticothalamic neurites of V1 revealed by the viral vector.

<p>StTTrG/FuG-B vector was injected into the thalamus and the retrogradely labeled cells were examined in V1 by immunoperoxidase or fluorescence detection. (A–E) Retrograde labeling of the corticothalamic cells with an injection involving the LGN. The break line in panel A indicates V1, which is magnified in panel C. As shown in panel B, we observed dense terminals in the LGN in this injection. (D and E) The section was counterstained with NeuN antibody (red) and Hoeschst nuclear staining (blue) to determine the exact lamina position for dendritic and axonal elaboration. (F–J) Retrograde labeling of the corticothalamic cells with an injection outside the LGN. In panel F, we observed the neurite staining in layer 5 that covers a large region. The break line in panel F indicates V1, which is magnified in panel H. Note the lack of labeling in layer 6 cells only within V1, which is considered to correspond to the lack of dense terminals in the LGN in panel G. (I and J) Same as panels D and E. (K–P) Magnified views of the corticothalamic processes shown in panels C and H. The lower case letters in each panel indicates the positions of the panels that enlarged the region of interest. Bar: 500 µm for A and F; 200 µm for B–E, G–J; 20 µm for K and L; 10 µm for M–P.