Figure 6.
Retinal Inputs Are Necessary for the Proper Integration of Newborn Neurons into Functionally Mature Sub-circuits
(A) Top: Representative raster plot of significant spontaneous Ca2+ transients, revealing episodes of synchronous activations at 4 dpe (8 dpf) in enucleated conditions. Middle: histogram of the raster. The red line indicates the threshold for significant population events. Bottom: representative traces of mature (top traces) and newborn neurons (bottom trace). Significant ΔF/F transients are highlighted in red.
(B) Average of the total dendritic length of newborn-labeled neurons in intact (solid box) and enucleated (dashed box) 4-dpe larvae. ns, non-significant. The error bars represent SEM.
(C) The relationship between the percentage of significant correlations among functionally mature neurons in enucleated (dashed line) and intact (solid line) larvae and the physical distance between the neurons. Note that the two curves are not significantly different.
(D) The same as (C), but for the correlations between newborn-labeled neurons and the rest of the tectal neurons. Note the significant difference between the two curves for short distances. The gray shaded area indicates the significant difference between the curves (p < 0.01; Mann-Whitney U test). Confidence intervals show the SEM.
(E) Two examples of the pairwise correlations between newborn-labeled and the rest of the tectal neurons at 4 dpe. Left: optical sections of the optic tectum with neurons color coded (color scale bar) according to their pairwise correlations with the newborn-labeled neuron (red). Right: the relationship between the percentage of significant correlations between the newborn-labeled neuron and the rest of the tectal neurons and the physical distance between them for the two examples on the left. Note the inability of the newborn-labeled neurons to incorporate into the tectal circuit in enucleated larvae. Neurons involving few pixels (less than five) or with unstable baselines (rapid changes generally indicating movement artifacts) were left unlabeled.