Method for testing sustained attention in touchscreen operant chambers in rats

Abstract

Background Sustained attention, the ability to detect rare and unpredictable events, is central to cognitive performance. This construct can be tested in rodents using a Sustained Attention Task (SAT), where rats are trained to detect an unpredictably occurring signal (a brief light presentation) from non-signal events. The traditional version of this task utilizes an operant chamber with a central panel light for the signal and two retractable response levers. Adaptation of SAT to the increasingly popular touchscreen operant chambers, which do not have levers or fixed lights, could enhance the versatility of the task. New method Here we developed a touchscreen version of SAT where the light signal is presented in the center of the touchscreen, followed by a tone to indicate the beginning of the response period. Rats indicate their choice during this period by touching their nose to one of two touchscreen response areas. The remaining parameters were kept similar to the traditional version Results Rats acquired touchscreen SAT at a similar rate to the traditional version. As with the traditional version, shorter stimulus durations on the signaled trials reduced accuracy and the presence of a distractor (a flashing houselight) disrupted performance on the touchscreen version. Comparison to existing method Collectively, these data suggest that the touchscreen version is comparable to the traditional version of the SAT, and is an equally valid way of measuring sustained attention. Conclusions Many researchers with touchscreen chambers could easily implement our modifications in order to study sustained attention.

Touchscreen Sustained Attention Task (SAT) for Rats

“…A failure to make any response during the response window counts as an omission. To expand the availability of SAT, we recently modified the task for touchscreen operant chambers, in which one wall is a touchscreen that can both display visual stimuli and record nose-poke responses 19 . Touchscreen chambers are becoming popular because of their versatility to run a variety of tasks (e.g., paired associate learning, reversal learning, etc.)…”

“…Similar to other touchscreen procedures 20,21,22 , our adaptation of SAT requires the use of an opaque plastic touchscreen cover, called a mask, with holes cut into it. A central, circular hole allows for the presentation of a signal by presenting a white stimulus on the screen behind it, and two square response areas, one designated for hits and one for CRs, allow the rat to make touch responses 19 . In the traditional chambers, the 4-s response window is typically indicated with the presentation of the levers, but a previous study demonstrated that a tone can also be used to signal the response window 23 .…”

“…The present protocol details how to run touchscreen SAT in the laboratory. The training schedules have been slightly altered from our previous report of the task 19 to optimize acquisition time in female rats, which, unlike males, had difficulty advancing through the previous schedules…”

“…In the current study, we tested attention in the Sprague-Dawley rat strain. This strain was chosen based on our previous work investigating behavior in male and female Sprague-Dawley rats 18,19,36,37 . Other strains, including Fischer/Brown Norway hybrid rats, Wistar, and Long-Evans rats, have been tested with the original version of SAT 10,32,38 .…”

“…Another important aspect of our study design is that we compared SAT performance between the sexes. While both sexes have been assessed using traditional SAT 10,11 , many touchscreen tasks of attention were developed utilizing only male rodents or did not compare the performance of males and females 8,19,41 . We found that touchscreen SAT acquisition and criteria performance were similar in males and females, suggesting that, much like with traditional SAT, touchscreen SAT is an equally valid test of attention in both sexes.…”