Raw data for: Dynamic instability of dendrite tips generates the highly branched morphologies of sensory neurons

Calculation of branch angle: The angle of new branches was measured using the angle tool of ImageJ (zero angle defined as in the direction of the mother). The angle distribution graph was plotted using Prism. Calculation of branch rate: To determine branching events, time-lapse movies of duration 20-30 minutes were analyzed manually using ImageJ. A new protrusion of length >0.25 ?m was scored as a new branch. The total branching rate (min-1) was calculated by dividing the total number of branching events by the total time. The specific branching rate (?m-1min-1) was calculated as the total branching rate divided by the total branch length. The spatial distribution of all branching events was plotted using MATLAB with the soma at the origin (x=0,\ y=0). Analysis of the elongation of internal branches: To study the possible role that the elongation of internal branches in arbor growth, we imaged the same dorsal neurons (A3, A4, and A5) every 24 hrs. Larvae were mounted and imaged as described but without the use of anesthetics. Their movement was minimized by imaging at 4 °C for 2-5 mins. They were then returned to the apple-agar plate in the Darwin Chamber. The larvae were imaged using 20X and 40X objectives. For image analysis, the same neurons at 24 & 48 hr, and 48 & 96hr were segmented and aligned using ImageJ to identify conserved non-terminal internal branches in the proximal region. The fractional increases in branches and segment lengths were defined as" Fractional\ length\ change=\frac{Final\ length-Initial\ length}{Initial\ length}分支角度计算：新生分支的角度采用ImageJ的角度测量工具进行测定，零度定义为母枝的延伸方向。角度分布图采用Prism绘制。 分支速率计算：为确定分支事件，我们采用ImageJ手动分析时长为20~30分钟的延时成像影片。将长度大于0.25 μm的新生突起记为一个新的分支。总分支速率（单位：min⁻¹）通过分支事件总数除以总观测时长计算得到。单位长度分支速率（单位：μm⁻¹·min⁻¹）则通过总分支速率除以总分支长度计算得出。所有分支事件的空间分布采用MATLAB绘制，以神经元胞体作为坐标原点（x=0, y=0）。 内部分支伸长分析：为探究内部分支伸长在神经元树突生长中的潜在作用，我们每24小时对同一背侧神经元（A3、A4及A5）进行成像。幼虫的固定与成像按照前述方法进行，但不使用麻醉剂。通过在4℃下成像2至5分钟，最大限度减少幼虫的活动。随后将幼虫放回达尔文培养箱内的苹果琼脂平板上。成像过程采用20倍及40倍物镜。图像分析环节中，我们使用ImageJ对24小时与48小时、48小时与96小时采集的同一神经元进行分割与配准，以识别近端区域内的保守非末端内部分支。分支及节段长度的分数增长定义为：分数长度变化 = (最终长度 - 初始长度) / 初始长度