Designed to bridge the gap between animal and human cognitive testing, rodent touchscreen technology enables researchers to assess functions like memory, attention, and learning with high precision. Dr. Kinga Sałaciak and Dr. Klaudia Lustyk demonstrate its applications, highlighting its value in CNS research and drug discovery.

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1.   Why use this method?

Touchscreens represent an innovative platform in rodent cognitive research, enabling direct translation of human cognitive tasks into animal studies. This modern approach ensures precise response recording, minimizes observer bias, and reduces human error, enhancing the accuracy and reproducibility of data. By using reward-based, non-aversive tasks, touchscreens reduce animal stress, leading to more natural behavior. Their versatility allows for multiple cognitive tests—like memory, attention, cognitive flexibility, and decision-making—within a single setup, supporting comprehensive, high-throughput studies. This technology is essential for advancing cognitive research, accelerating drug development, and fostering new neurological and psychiatric disorder treatments.

2.  What you’ll need

To set up a task to investigate one of the cognitive domains, cognitive flexibility, you will use a pairwise visual discrimination reversal test using a rodent touch screen. You will need the following items to carry out the task:

Equipment:

• Touchscreen operant chambers (from e.g. Campden Instruments, Med Associates) (Touchscreen Monitor, Walls, Food Dispenser, Reward Magazine, Speakers, Led Lights, Behavioral Monitoring Camera, Sensors- IR Beams, Masks)
• Soundproofing chambers with ventilation system
• Software (e.g., ABET II with the Whisker operating system is used for the first generation of Bussey-Saksida chambers, while ABET Cognition is utilized for the second generation)
• Computer (e.g., for Bussey-Saksida chambers: minimum- Microsoft Windows software 10, 2.5 GHz Core Processor, 8 GB of RAM, 100 GB Hard disk space)

Reagents:

• Rodents 
• Animal housing
• Rodent food pellets
• Cleaning materials
• Food rewards – sugar pellets (e.g., Dustless Precision Pellets^®, Bio-Serv), strawberry milk

3. Step-by-step instructions 

Pre-training Preparations:

• Food restriction

Touchscreen paradigms are food-motivated tasks, so dietary restriction is implemented before testing. By carefully adjusting daily food intake, animals are maintained at 85–90% of their free-feeding body weight throughout the task period (starting 3-7 days before training). Each week, their free-feeding weight is reassessed to account for natural, age-related weight gain, ensuring that animals remain healthy and appropriately motivated for the task.

• Reward Introduction

Three days before the training, animals should be placed in a cage and be introduced to the reward (sugar pellets or milkshake).

Training Stages

The training consists of several stages. After passing one stage, the rodent should move on to the next.

• Habituation

Habituation aims to acclimate rodents to the operant chamber environment and familiarize them with the reward delivered in the magazine. The criterion for successfully completing this stage is the consumption of all available rewards during the session.

Mice 2 stages – without reward 10min, with reward 20min

Rats 1 stage – with reward 30min

• Initial touch

Train animals to associate touchscreen interaction with reward

Mice – 100 trials, 30min

Rats – 60 trials, 60 min

• Must touch

Train animals that only touching the presented stimulus on the screen triggers a reward.

Mice – 100 trails, 30 min

Rats – 100 trials, 60 min

• Must initiate 

Train animals to actively start each trial by nose-poking into the magazine

Mice – 100 trails, 60 min 

Rats – 100 trails, 60 min

• Punish incorrect

Train animals to avoid incorrect responses by associating them with negative consequences (illumination in a hole chamber, no reward, and time out)

Mice – 100 trials, 60 min ≥70% correct

Rats – 100 trials, 60 min ≥80% correct 

Pairwise discrimination

In this stage, the rodent was required to choose the correct (rewarded) image from two options displayed on the screen, e.g., a mosaic and a windmill, neither of which had been used in previous stages. The mosaic served as the rewarded image and appeared in a pseudorandom left or right position to prevent side preference. Each trial began when the rodent placed its head in the magazine and then proceeded to make a selection by touching the screen. Upon a correct choice, a reward appeared in the illuminated magazine; once claimed, the light turned off, and an inter-trial interval followed. An incorrect choice resulted in an illumination of the entire chamber, followed by a pause. The subsequent trial started when the rodent returned to the magazine.

Mice – 100 trials, 60 min ≥80% correct

Rats – 100 trials, 60 min ≥80% correct

Testing – Reversal learning

The stimulus (image) that was previously associated with the reward should be avoided by the mouse, and an alternative image should be selected to receive the reward.

Assess the animals’ ability to adapt to changing reward rules by reversing learned stimulus-reward associations.

Mice – 100 trials, 60 min ≥80% correct

Rats – 100 trials, 60 min ≥80% correct

Parameters analyzed: 

• accuracy of response – how well rodents learn the subject
• number of trials to criterion – learning speed
• errors made – learning difficulties 
• perseverative errors – cognitive inflexibility
• correction trials – learn from a mistake

Correction Trials: To minimize the impact of random correct choices, a rodent would enter a correction trial following an incorrect selection. In a correction trial, the reward image’s arrangement remained the same as in the previous trial, allowing the rodent another opportunity to learn the correct choice. Correction trials did not count toward the total trial count and were excluded from calculations of percent correct.

• reaction time (time to touch reward and unrewarded stimulus) – decision-making speed 
• reward collection – motivation, motor function

4. Practical tips 

Before beginning the task, it is essential to secure approval for the animal study from the local research ethics authorities. To maintain animal welfare and ensure consistent data, it is also crucial to standardize the daily routine. This includes setting a fixed start time for the experiment each day and establishing consistent animal feeding times. Minimizing variability in experimenters is equally essential, as is counterbalancing testing times to reduce potential biases. By maintaining these routines, researchers can promote animal well-being and improve the reliability and reproducibility of the study outcomes.

Notably, different animal strains demonstrate varying performance levels in specific tests, as documented in the literature. Therefore, a thorough literature review is recommended to select the most appropriate animal strain before proceeding with a particular test.

5.  Critical appraisal & implications for future research 

The power of touchscreen testing lies in its ability to provide a highly precise, automated, and versatile method for assessing cognitive functions in animal research. Touchscreen tests offer several advantages:

• High translational value
• Sensitive detections
• Integration with advanced techniques (optogenetics, photometry)
• Automation and efficiency
• Reduce observer bias
• Detailed behavioral data

While touchscreen testing is a powerful tool in cognitive research, it has certain limitations to consider:

• Cost and setup requirements
• Strain and individual variability
• Limitations in complex behavior 
• Long training demands on animals
• Limited applicability 

However, touchscreen testing is a powerful tool in cognitive research, advancing our understanding of brain function and supporting the development of therapeutic interventions for cognitive disorders.

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