Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Ingardena 6, 30-060 Krakow, Poland.
J Neurosci Methods. 2010 Jan 15;185(2):199-203. doi: 10.1016/j.jneumeth.2009.09.022. Epub 2009 Sep 26.
Stereotaxy is commonly used to implant microelectrodes or microprobes in specific structures of the brain in vivo. In this technique, the positions of the brain nuclei are determined as the distance from a defined reference point on the skull. Thus, it is crucial to correctly locate the reference point. On the rodent skull cap, the principal stereotaxic reference point is called the bregma and is defined as the midpoint of the curve of best fit along the coronal suture. Rough determination of the position of the bregma often results in error. In our experiments we developed and tested an alternative method of locating the bregma point on the skull of mature Wistar rats. In this method, a digital picture of the exposed skull cap is analyzed by a computer. The curve is mathematically fitted to the outline of the coronal suture, and the brain midline is delineated based on the temporal ridges of the skull. The crossing of these two lines is defined as the bregma. Systematic, experimental testing of this new method revealed that, in many cases, the position of the bregma point as located by two different methods (old, rough method and the new one) varied by as much as hundreds of microns. The error in stereotaxic positioning of the microprobe in the brain was significantly decreased when the bregma was determined using the new approach. These results confirm that the new method of locating the stereotaxic reference point improves the precision of in vivo electrode implantation.
立体定位术常用于将微电极或微探针植入活体大脑的特定结构中。在该技术中，脑核的位置是通过从颅骨上的定义参考点测量距离来确定的。因此，正确定位参考点至关重要。在啮齿动物颅骨盖上，主要的立体定向参考点称为前囟门，定义为冠状缝上最佳拟合曲线的中点。前囟门位置的粗略确定常常导致误差。在我们的实验中，我们开发并测试了一种在成熟 Wistar 大鼠颅骨上定位前囟门的替代方法。在该方法中，通过计算机分析暴露的颅骨盖的数字图像。该曲线通过数学拟合到冠状缝的轮廓，并根据颅骨的颞嵴描绘脑中线。这两条线的交点被定义为前囟门。对这种新方法的系统实验测试表明，在许多情况下，通过两种不同方法（旧的、粗略的方法和新的方法）定位的前囟门位置差异可达数百微米。当使用新方法确定前囟门时，脑内微探针的立体定位定位误差显著降低。这些结果证实，定位立体定向参考点的新方法提高了活体电极植入的精度。
