Last Updated on August 24, 2023
1: Introduction and Background
Both visual discrimination (VD) and reversal learning (RL) in neurological studies are very important to study animals’ cognitive abilities.
- Reversal Learning:
Reversal learning requires an animal to learn to discriminate two different stimuli but reverse its responses to these stimuli every time it has reached a learning criterion. Thus, different from pure discrimination experiments, reversal learning experiments require the animal to respond to stimuli flexibly, and the reversal learning performance can be taken as an illustration of the animal’s cognitive abilities. (1)
- Visual Discrimination:
As for visual discrimination task, which is a task used extensively in the elucidation of cognitive impairment produced by lead, is a test in which the formerly correct stimulus becomes the incorrect one, and vice versa. (2)
2: Advantages of Touch Panel Operant System in Reversal Learning and Visual Discrimination
Our Touch panel operant training system has standard mazes that come with video tracking and automated data collection and analysis. It also contains several key features that make it a wise choice for rodent behavior, specifically mouse behavioral testing. The unique trapezoidal design creates a space for animals to focus more on the screen ahead during rodent behavior testing.
The Touch Panel operant training system contains infrared (IR) sensor technology, which locates at the top of the touchscreen, to improve the accuracy with which the system can detect touch responses from mice and rats. Unlike the touch screen technology that most of our smartphones and computer screens use, called projective capacitance, the infrared sensors inside the touch screen improve accuracy by eliminating the need for a minimum force required to generate a response. This means that even nose poke’s from mice will register a response.
In addition to improved sensitivity, our chamber was designed in a trapezoidal shape instead of a square, making it easier for the animal to focus on the screen ahead. Our touch panel chambers are compatible with in vivo electrophysiology and optogenetics techniques, as well as with miniature head-mounted microscopes.
The system also includes software that enables users to design and run their own tasks with video tracking capabilities for automated data collection.The chambers come with our Operant TaskStudio Software package, an extremely user-friendly software platform that enables customers to design and execute their own tasks or choose from a variety of pre-programmed tasks.
3: Example of Research
The team of Tatsuhiro Ayabe, Rena Ohya and Yasuhisa Ano used our touch panel-based operant system integrated with visual discrimination (VD) and reversal learning (RD) protocols.
During the VD task, vertical and horizontal stripes were shown on the screen as visual stimuli where vertical stripes were used as the correct response to half of the mice while horizontal stripes were used as the incorrect response to the other half of the mice (Figure 1). A trial started when the mouse touched the reward magazine. If the mouse was recorded poking at the vertical stripes (correct stimulus), it would be rewarded, and a 2-second inter-trial interval (ITI) would follow up. If the mouse poked at the horizontal stripes (incorrect stimulus), there would be no reward and a 5-second darkness would take place, followed up by a 5-second ITI. If the mouse touched the reward magazine again after each ITI, a new trial began. If the mouse failed to poke either stimulus in 30 seconds, the trial would be pruned. 60 minutes before the test session, the Iso-α-acids solution (1 mg/kg body weight) or distilled water (DW) would be administered through oval gavage. 30 minutes before the test session, scopolamine (0.8 mg/kg body weight) or saline would be intraperitoneally administered (Figure 2). Mice were expected to have a correct response rate that was above 80% (post-VD training) so that they would perform the VD test without drug treatments until that correct rate was achieved before they started performing the RD task.
After the treatment of scopolamine and iso-α-acid, both treated groups would perform the RD task. For the RD task, the visual stimuli were switched in the opposite order compared to the VD task, where horizontal stripes were used as the correct response and vertical stripes were used as the incorrect response. Only Iso-α-acids solution (1 mg/kg body weight) or distilled water (DW) would be administered through oval gavage 60 minutes before the test session for the RD task, and the scopolamine would not be administered to mice. DW and IAA solution was administered 17 times and scopolamine was treated 7 times in total during all experiment periods. The number of correct response changes was obtained by calculating the difference between the correct rate of each daily trial and the correct response rate of the first trial so that the efficiency of mice changing their previous memory conditions could be evaluated.
4. Applicable tasks for the Touch Panel Operant System
|Task:||Description:||Measures:||Useful for studying:|
|Visual Discrimination (VD)||Subject learns that one of two shapes is the correct stimulus that results in food/liquid reward.Correct response is then changed-reversal learning (RD).||
Neuropsychiatric disorders (Schizophrenia, Autism)
|Paired Associate Learning (PAL)||Subject must learn and remember which of 3 objects goes in which correct spatial location. Each trial involves 2 objects, 1 in the correct place and the other incorrect. Mice must choose the correct object for reward.||Hippocampal dysfunction||Neurodegenerative diseases (Alzheimers and Dementia)|
|Visuomotor Conditional Learning (VCL)||Stimulus-response task. Subject must learn that two stimuli go with two different locations. When a stimulus is presented, the subject must respond to the location associated with specific stimulus.||Motor dysfunction||Motor disorders (Parkinsons and Huntingtons disease)|
|5-Choice Serial Reaction Time (5CSRT)||Subjects must respond to brief visual stimuli presented in 1 of 5 locations. Stimulus disappears after a set interval which requires the subject to return the location by memory.||Attention span and impulsivity||Animal models of ADHD and Schizophrenia|
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(1): Bublitz, Alexander, et al. “Reversal of a Spatial Discrimination Task in the Common Octopus (Octopus Vulgaris).” Frontiers in Behavioral Neuroscience, vol. 15, 2021, https://doi.org/10.3389/fnbeh.2021.614523.
(2): Slikker, William, and Cheng Wang. “Chapter 31.” Handbook of Developmental Neurotoxicology, Academic Press, 1998, pp. 539–557. https://doi.org/10.1016/B978-0-12-648860-9.X5000-6
(3): Ayabe, T., Ohya, R., & Ano, Y. (2019). Hop-Derived Iso-α-Acids in Beer Improve Visual Discrimination and Reversal Learning in Mice as Assessed by a Touch Panel Operant System. Frontiers in Behavioral Neuroscience, 13, 67.