The in vitro cortical slice preparation is a widely used tool for electrophysiological investigation of brain neurophysiology. However, slice quality can be highly variable despite attempts to standardise practice. The purpose of this study was to determine the extent to which this variability is due to sensitivity to aspects of the preparation methodology.

The study ultilised the no-magnesium seizure-like event (SLE) model and was in two parts. In the first, slice outcome was quantified following a standardised hypoxic-ischaemic insult applied to pre-prepared slices. The hypoxia-induced changes in SLE activity were used to characterise the effect of tissue damage on commonly measured electrophysiological variables. In the second, multivariate data associated with the slice preparation methodology was collected and related to tissue outcome, according to the same SLE characteristics.

Hypoxia-ischaemia damage was reflected most strongly in a reduction in SLE amplitude, inter-event frequency and intra-event high frequency activity. The number of active locations was also markedly reduced. In the second part of the study, between 21% and 47% of outcome variation was attributable to variability in the methodological parameters tested. Most important were slice position from the tissue block, depth of slice submersion during recording and the experience level of the experimenter. The latter showed a paradoxical relationship between inexperience, heightened SLE amplitude and reduced spatial viability.

While much of the variation in slice outcome remained unexplained, the factors shown to correlate with tissue viability will aid slice experimentalists in preparing tissue of optimal quality for electrophysiological investigation. In particular, using population event amplitude as the sole criterion of slice quality in the no-magnesium model is overly simplistic and must be viewed in the context of spatial activity.

在体外皮层切片准备对大脑的神经生理学电生理研究一种广泛使用的工具。然而，尽管尝试标准化实践，切片质量可能变化很大。本研究的目的是确定这种可变性在多大程度上是由于对制备方法方面的敏感性造成的。

该研究利用了无镁癫痫样事件 (SLE) 模型，分为两部分。首先，在对预先准备好的切片应用标准化的缺氧缺血性损伤后，对切片结果进行量化。缺氧引起的 SLE 活动变化用于表征组织损伤对常用电生理变量的影响。第二，根据相同的 SLE 特征，收集与切片制备方法相关的多变量数据并与组织结果相关。

缺氧缺血损伤最强烈地反映在 SLE 振幅、事件间频率和事件内高频活动的减少上。活动地点的数量也显着减少。在研究的第二部分，21% 到 47% 的结果变异可归因于测试方法参数的变异。最重要的是组织块的切片位置、记录过程中切片浸没的深度和实验者的经验水平。后者显示了缺乏经验、SLE 振幅增加和空间生存能力降低之间的矛盾关系。

虽然切片结果的大部分变化仍然无法解释，但显示与组织活力相关的因素将有助于切片实验者准备最佳质量的组织以进行电生理研究。特别是，在无镁模型中使用群体事件幅度作为切片质量的唯一标准过于简单化，必须在空间活动的背景下看待。