A high-throughput mouse stop signal task (SST)

Abstract

The stop signal task (SST) has commonly been used to measure action cancellation (Logan, Cowan, & Davis, 1984; Humby, et al., 2013). Here we describe how a sorting system based on ID chips enabled the development of a less laborious stop signal task for mice. In this task, subjects are first trained to quickly respond after a go signal (go response). Once the go response is established, a stop signal is introduced to a proportion of trials. This stop signal is presented after the go signal but before the estimated time of completion for go response. The shorter the time interval that remains from presenting the stop signal to the time of completion, the more difficult it is to stop. Thus, by giving various stop signal delays (SSD), the subjects` ability for action cancellation is estimated. Several neurobiological disorders such as ADHD are associated with decreased action cancelation abilities. To better understand the nature of action cancelation and to develop potential treatment options requires analysing action cancelation in rodent models. However, existing tasks for mice and rats require long training periods and are labour intensive. In this study we used a sorting system based on an ID chip gating system to allow group housed mice to individually enter the operant chamber in a self-determined manner. Mice were gradually trained to perform a quick go response upon initiating trials by themselves through an initiation response. After the go response was established, a stop signal was introduced to 20% of the trials which initially coincided with trial initiation. Afterwards, delays (SSDs) were introduced between trial initiation and stop signal. It was observed that with increasing delay, stopping success decreased. The results suggest that our current automated task delivers hallmarks of SST while greatly decreasing experimenter labour and the time required for training.