Light scattering in brain slices measured with a photon counting fiber optic system.
Light scattering in brain slices measured with a photon counting fiber optic system.
复制标题
使用光子计数光纤系统测量脑切片中的光散射。
DOI：
10.1016/s0165-0270(00)00251-x
复制
发表时间：
2000
影响因子：
3
通讯作者：
Tao,L
中科院分区：
文献类型：
--
作者：
Tao,L
来自神经组织的本征光信号（ios）的测量，通常具有反射型或透射型设置，已经越来越多地用于研究生理事件。然而，即使对于相同的事件，如扩张性压抑（SD）或渗透性挑战，不同的研究人员在类似的条件下使用类似的装置获得了相反极性的信号（增加或减少）。这种不一致的原因尚不清楚。本文认为，这种不一致可能是由与组织表面散射有关的伪影引起的。本文的主要目标是提出一种光子计数光纤（PCFO）系统，该系统设计用于排除表面伪影并主要测量组织内的光散射（LS）。渗透刺激下大鼠新皮层切片实验证实了PCFO数据的一致性：只要不诱发SD，高渗刺激总是使LS信号升高，低渗刺激则使LS信号降低。在强渗透刺激下（−100 mOsm），信号在刺激引起的SD开始时突然反转极性，并继续增加，直到刺激被消除。当SD被高[Mg2+]o阻断时，LS信号在−100 mOsm胁迫下仍呈下降趋势。用PCFO系统进行的光谱研究表明，组织散射光谱在650 ~ 470 nm的大部分可见范围内几乎是一个平坦函数，在500 nm处达到最大值，在450 nm处迅速下降。
Measurements of intrinsic optical signals (IOSs) from neural tissue, commonly with a reflection-type or transmittance-type set-up, have been used increasingly to study physiological events. Even for the same event, however, such as spreading depression (SD) or osmotic challenge, signals of opposite polarities (increase or decrease) have been obtained by different investigators using similar set-ups under similar conditions. The origin of the inconsistencies is still unknown. It is suggested here that the inconsistencies may be caused by artifacts associated with tissue surface scattering. The main goal of this paper was to present a photon counting fiber optic (PCFO) system designed to exclude surface artifacts and predominantly measure the light scattering (LS) within the tissue. Experiments on rat neocortical slices under osmotic challenges demonstrated the consistency of the PCFO data: hypertonic challenge always increased LS signal while hypotonic challenge decreased it, as long as the challenge did not induce SD. Under strong osmotic challenge (−100 mOsm), the signal suddenly reversed the polarity at the onset of SD induced by the challenge and continued to increase until the challenge was removed. When SD was blocked by high [Mg2+]o, the LS signal remained decreased during the −100 mOsm challenge. A spectroscopic study with the PCFO system showed that the spectrum of tissue scattering was almost a flat function in most of the visible range (650–470 nm) with a maximum at 500 nm and a rapid drop at 450 nm.