Article Figures & Data
Figures
- Fig. 1.
Schematic diagram of an E9–E10 zebra finch embryo, dorsal view. The shaded areas, approximately, show the dorsal hippocampal (H) and anterior telencephalon (AT) regions, which were dissected out and collected separately for transplantation. Op, Optic lobe; R, rostral; C, caudal.
- Fig. 2.
Hippocampal lesions are shown here with Nissl staining and anti-PA immunohistochemistry. The appearance of the hippocampal formation (HF) in the normal brain and the lesioned brain with Nissl staining is shown in Aand B, respectively. The arrowheads inB show the approximate boundaries of the lesion. The lesioned area was characterized by a loss of neuronal cell bodies, as shown with immunohistochemistry with anti-PA antibody: normal staining is shown in C, and the loss of PA-positive cells in the hippocampus is shown in D. This lesioned area is primarily located within the dorsolateral hippocampus and extends a little into the area parahippocampalis. The sections used for immunohistochemistry shown here were not directly adjacent to those used for Nissl staining. Scale bar: A–D, 128 μm.
- Fig. 3.
The typical location of some of the transplants. Three transplants (arrowheads) are shown growing partly within the ventricle underlying the Hf and partly within the Hf itself. The needle tract is visible on the right Hf above the transplant (Nissl staining). The arrowheads are placed on the side of the Hf. Scale bar, 112 μm.
- Fig. 4.
The typical histological characteristics of the H and AT transplants (T) located in the ventricles. These intraventricular transplants contained both unbeaded (A) and beaded fibers (B) as shown by immunohistochemistry with antibodies to a 200 kDa NFP and to SP, respectively (arrows show labeled fibers within the transplants). C, PA immunohistochemistry identified neurons within the transplants that had dendritic processes emanating from the cell bodies (large arrow). These neurons were similar in size and shape to those of the host brain (small arrow). D, Blood vessels and clusters of erythrocytes within blood vessels (arrowheads) were present in the transplants (Nissl staining). One blood vessel appeared to be forming a bridge between the graft and the host (large arrow), indicating that the transplants may have received host blood supply. These transplants were located in different parts of the ventricle; those shown in A and C were located in the lateral ventricle between the hippocampus and the hyperstriatum ventrale, and those shown in B andD were located in the ventral part of the ventricle. Scale bars: A, C, D, 37 μm; B, 28 μm.
- Fig. 5.
Performance of the birds on a one-trial associative memory task, as measured by the mean number of looks to find the baited compartment, before lesion in stage I (baseline performance) and after lesion in stage II. Performance at chance level = 4 looks; fewer looks indicate better performance.A, For the space task, the lesioned (L) birds were significantly worse compared with the prelesion performance and the control (C) and sham-lesioned (S) birds (*p < 0.05). The baseline performance (stage I) did not differ among groups. B, For the color task, the baseline color performance (stage I) of the L birds was significantly better than that of C and S birds, and the postlesion color performance (stage II) of the L birds was significantly worse than the C and S birds (*p < 0.05).
- Fig. 6.
The performance of the birds (mean number of looks) in each group before lesions (stage I), after lesions (stage II), and after transplantation (stage III). A, For the space task, the significant differences in the various groups among stages I, II, and III are shown in the graph (* p< 0.05, Tukey’s HSD for “within-bird” comparisons). The controls (C) and sham-lesioned (S) birds performed better than chance (of 4 looks) during all three stages. After lesioning (stage II), the lesioned (L) birds performed at or near chance level and significantly worse than their prelesion performance. After transplantation, only the birds with surviving H transplants (H–T) showed significant behavioral recovery, effectively reversing the lesion-induced deficit; compare stage I with II and stage II with III (*p < 0.05, HSD). The H transplanted birds without visible transplants (H–NT) did not show any significant differences among the three stages. The telencephalon transplanted birds with transplants (AT–T) or without visible transplants (AT–NT) only showed a significant effect of lesion but no improvement after transplantation.B, The mean number of looks on the color task for each group, among stages I, II, and III. Only the lesioned birds showed a significant performance impairment after lesioning (*p < 0.05, HSD).
