CONTROL OF NEURON POPULATION SIZE IN POLYPLOID ANURANS

对神经元精确发育调节的普遍解释 数字是神经元和突触后靶点的大小匹配， 这一过程涉及竞争和神经细胞死亡。 光肩星天牛 不同的倍性具有相同的身体大小，但神经元大小不同， number. 这些差异提供了一种方法来测试细胞死亡是否匹配 神经元数目到外周大小。 另一种可能性是， 神经元体积而不是神经元数量与外周尺寸相匹配， 也将受到考验。 腰椎运动和感觉神经元数量 (cell数量和神经元核大小）将被测量并与 肢体大小（表面积、体积和肌纤维数量）。 的 将对正常发育的二倍体、三倍体和 四倍体在细胞死亡之前、期间和之后的阶段，并显示 无论是神经元数量还是神经元总数 神经元体积和一些外围尺寸的测量。 此外，后肢 将处于早期发育阶段的芽移植到供体之间 和不同倍性的寄主。 测量发育的神经元数量 将显示四肢是否具有调节 细胞死亡以产生适当数量的神经元群体。 这 信息与理解相似性和差异性 在神经元群体中，大小由正常或异常发育引起。

The prevailing explanation for precise developmental regulation of neuron numbers is that neurons and postsynaptic targets are size matched by a process involving competition and neuronal cell death. Xeonpus laevis of different ploidy have the same body size, but differ in neuron size and number. These differences provide a way to test whether cell death matches neuron numbers to peripheral size. An alternate possibility, that total neuronal volume rather than neuron number is matched to peripheral size, will also be tested. Lumbar motor and sensory neuron population sizes (cell numbers and neuronal nuclear size) will be measured and compared with limb size (surface area, volume, and muscle fiber number). The measurements will be made for normally developing diploids, triploids and tetraploids at stages before, during, and after cell death, and show whether there is any correlation between either neuron number or total neuron volume and some measure of peripheral size. Additionally, hindlimb buds at an early developmental stage will be transplanted between donors and hosts of different ploidy. Measuring neuron populations that develop in the hosts will show whether limbs have intrinsic qualities that regulate cell death to produce neuron populations of appropriate numbers. This information is relevant to understanding how similarities and differences in neuron population size result from normal or abnormal development.