Laboratory of Experimental Functional Neurosurgery, Department of Neurosciences, K.U. Leuven, Provisorium I, Minderbroedersstraat 19 Bus 1033, 3000 Leuven, Belgium.
J Neurosci Methods. 2011 Jan 15;194(2):305-11. doi: 10.1016/j.jneumeth.2010.11.005. Epub 2010 Nov 16.
Contextual conditioning in rats is typically quantified using startle amplitude or freezing time. Our goal was to create a robust contextual conditioning protocol combining both startle amplitude and freezing time as measures of contextual anxiety. Comparison of 0.8 mA - 250 ms shocks with an established shock configuration (0.3 mA - 1 s) favoured the first parameters. Subsequently, we systematically investigated the effect of shock intensity (0.6 mA, 0.8 mA or 1.0 mA) and concurrently compared two different contextual conditioning procedures (shocks alone versus unpaired shock-tone presentations). In future experiments, this second type of contextual conditioning may form the optimal contrasting condition for a cued fear conditioning group, trained with explicit cue-shock pairings. The 0.8 mA shocks produced significant contextual freezing and startle potentiation, whereas the 0.6 mA and 1.0 mA shocks only led to a significant increase of freezing time. We found no major differences between the two types of conditioning, implying that these procedures might be equivalent. In conclusion, training with ten 0.8 mA - 250 ms shocks produced reliable contextual conditioning as measured with both startle amplitude and freezing time.
在大鼠中，情境条件作用通常使用起始振幅或冻结时间来定量。我们的目标是创建一个稳健的情境条件作用协议，将起始振幅和冻结时间结合起来作为情境焦虑的测量指标。与既定的电击配置（0.3 mA - 1 s）相比，对 0.8 mA - 250 ms 电击的比较更倾向于采用第一个参数。随后，我们系统地研究了电击强度（0.6 mA、0.8 mA 或 1.0 mA）的影响，并同时比较了两种不同的情境条件作用程序（单独电击与未配对的电击-音调呈现）。在未来的实验中，这种第二种情境条件作用可能会成为与明确的线索-电击配对训练的线索恐惧条件作用组的最佳对比条件。0.8 mA 的电击会导致显著的情境性冻结和起始增强，而 0.6 mA 和 1.0 mA 的电击仅导致冻结时间显著增加。我们没有发现两种条件作用之间的主要差异，这意味着这些程序可能是等效的。总之，用十个 0.8 mA - 250 ms 的电击进行训练可以产生可靠的情境条件作用，起始振幅和冻结时间都可以测量到。
