Increase in Growth Cone Size Correlates with Decrease in Neurite Growth Rate

Figure 3

Neurite growth rates increase with decreasing growth cone size and time in culture. (a) A cultured bag cell neuron was imaged at 3 time points after plating (24 h, 48 h, and 72 h). At each time point, the displacement of growth cones over a 3 h time interval was used to calculate the growth rate. (b) Statistical comparison of P domain sizes at 24 h, 48 h, and 72 h after plating, respectively. Average P domain size ± SEM for 24 h is  μm², for 48 h is  μm², and for 72 h is  μm². (c) Statistical comparison of growth rates. Average growth rate ± SEM for 24 h is  μm/h, for 48 h is  μm/h, and for 72 h is  μm/h. (d) Plot of growth rate and P domain size for individual growth cones at different time points. Growth cones from different time points are shown in different color (red: 24 h, ; black: 48 h, ; green: 72 h, ). Spearman correlation coefficient and value are shown for data pooled from three time points. Inset shows the plot only for growth cones with P domain smaller than 100 μm². Plot is representative of two independent experiments. Box: 25th and 75th percentile plus median line; whisker: min and max. ; ; . Dunn’s test. Scale bar: 50 μm.

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