一种对动物学习记忆能力突变筛查的新途

本文详细描述了一种全自动化的行为检测方案。在自然饲养环境/检测环境(24/7)中, 我们测量了小鼠针对两个给食器中获得食物的比例与它们在相应给食器停留时长的比例进行匹配的精确性与准确性。该方案是对传统条件性习得 (trials-to-acquisition) 行为测验设备的改进, 可以检测动物时间间隔能力的精确性与准确性, 对定时目标选择的相关概率的效果, 以及记忆一天中从不同给食器中获得食物次数的精确性与准确性。该压缩系统避免了在整个实验过程中对小鼠的持握操作, 可忽略实验者/技术员的实验操作时间, 而且可以递送小鼠置入实验环境后, 7~9个实验日中全部3组实验流程产生的大量结果。其中, 第一个实验流程为单个24小时周期内完成的时间匹配能力的筛查, 它对动物的时间、空间估计能力的记忆机制进行精确检测。因此, 该系统允许在有限的实验空间、较短的实验周期内, 对大量的实验小鼠进行有可能存在的学习记忆能力缺陷进行大规模筛查。此外, 该系统运行所依赖的软件可以在公共开放平台获得。     

Number and time in acquisition,extinction and recovery

We measured rate of acquisition, trials to extinction, cumulative responses in extinction, and the spontaneous recovery of anticipatory hopper poking in a Pavlovian protocol with mouse subjects. We varied by factors of 4 number of sessions, trials per session, intersession interval, and span of training (number of days over which training extended). We find that different variables affect each measure: Rate of acquisition [1/(trials to acquisition)] is faster when there are fewer trials per session. Terminal rate of responding is faster when there are more total training trials. Trials to extinction and amount of responding during extinction are unaffected by these variables. The number of training trials has no effect on recovery in a 4-trial probe session 21 days after extinction. However, recovery is greater when the span of training is greater, regardless of how many sessions there are within that span. Our results and those of others suggest that the numbers and durations and spacings of longer-duration “episodes” in a conditioning protocol (sessions and the spans in days of training and extinction) are important variables and that different variables affect different aspects of subjects' behavior. We discuss the theoretical and clinical implications of these and related findings and conclusions—for theories of conditioning and for neuroscience.     

Autoshaped head poking in the mouse: a quantitative analysis of the learning curve

In autoshaping experiments, we quantified the acquisition of anticipatory head poking in individual mice, using an algorithm that finds changes in the slope of a cumulative record. In most mice, upward changes in the amount of anticipatory poking per trial were abrupt, and tended to occur at session boundaries, suggesting that the session is as significant a unit of experience as the trial. There were large individual differences in the latency to the onset of vigorous responding. "Asymptotic" performance was unstable; large, bidirectional, and relatively enduring changes were common. Given the characteristics of the individual learning curves, it is unlikely that physiologically meaningful estimates of rate of learning can be extracted from group-average learning curves.     

IS MATCHING INNATE?

Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling. Matching was observed from the outset; it did not improve with training. When the numbers of pellets received were proportional to time invested, investment was unstable, swinging abruptly from sustained, almost complete investment in one hopper, to sustained, almost complete investment in the other-in the absence of appropriate local fluctuations in returns (pellets obtained per time invested). The abruptness of the swings strongly constrains possible models. We suggest that matching reflects an innate (unconditioned) program that matches the ratio of expected visit durations to the ratio between the current estimates of expected incomes. A model that processes the income stream looking for changes in the income and generates discontinuous income estimates when a change is detected is shown to account for salient features of the data.     

一种对动物学习记忆能力突变筛查的新途径

本文详细描述了一种全自动化的行为检测方案.在自然饲养环境/检测环境(24/7)中,我们测量了小鼠针对两个给食器中获得食物的比例与它们在相应给食器停留时长的比例进行匹配的精确性与准确性.该方案是对传统条件性习得(trials-to-acquisition)行为测验设备的改进,可以检测动物时间间隔能力的精确性与准确性,对定时目标选择的相关概率的效果,以及记忆一天中从不同给食器中获得食物次数的精确性与准确性.该压缩系统避免了在整个实验过程中对小鼠的持握操作,可忽略实验者/技术员的实验操作时间,而且可以递送小鼠置入实验环境后,7～9个实验日中全部3组实验流程产生的大量结果.其中,第一个实验流程为单个24小时周期内完成的时间匹配能力的筛查,它对动物的时间、空间估计能力的记忆机制进行精确检测.因此,该系统允许在有限的实验空间、较短的实验周期内,对大量的实验小鼠进行有可能存在的学习记忆能力缺陷进行大规模筛查.此外,该系统运行所依赖的软件可以在公共开放平台获得.