Automated 8 Arm Radial Maze

SKU 1901, 1902 Categories , ,
See more by: MazeEngineers

The 8 Arm Radial maze is an apparatus widely validated for spatial learning tasks. Using external cues outside of the maze, arms can be baited and the number of arm entries to collect all 8 rewards can be measured. Poor spatial working memory correlates well to increased return to arm choices and overall time to finish the task. The Maze Engineers automated 8 arm radial mazes create entirely automated environments to minimize anxiety and fear created by the human experimentor while collecting high volumes of data.

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Producer: MazeEngineers

Description

Specifications

Dimension

Mouse

Rat

Arm Width

5 cm

10 cm

Arm Length

35 cm

50 cm

Arm Height

10 cm

20 cm

The Automated Radial Arm Maze has 8 automated doors which can controlled with video tracking software such as ANY-Maze, EthoVision or BehaviorCloud or via sensors with 25 zones of detection.

Features

doors
Doors

Downward facing pneumatic doors

 

Quiet Operation

Updated, quiet, pneumatic movement

Conductor Software

Integrate to control with ANY-Maze, EthoVision, or BehaviorCloud

or

Use our stand-alone software and sensors

Strong Construction

Composed of aluminum and acrylic

Copper shielding for reduced electromagnetic interference is available

Customize!

Customize the dimensions and color of your maze.

Available in blue, white, grey, black, or clear

Modifications

cue lights
Goal Boxes

To fit at the end of each arm.

$250

Lickometers

Mouse or rat models

$1095

 

 

Pellet dispensers

Mouse or rat models

$1095


Cue Lights

Manual or automated

Ask for details

 

Lids

For particularly jumpy subjects

Ask for details

 

Y Maze Insert

To fit

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T Maze Insert

To fit

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Plus Maze Insert

To fit

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See our citation list

History

Origin

The Radial Arm Maze (RAM) is one of the most widely used behavioral tasks in neuroscience. It was originally designed by Olton and Samuelson in 1976 to understand spatial learning and memory in rodents. It was observed that rodents have a remarkable ability to remember spatial locations, especially when baited with food rewards, and this ability was adapted into a behavioral task. Radial Arm Maze was developed based on the fact that finding and retrieving food quickly and efficiently served as an essential survival strategy for rodents.

The hippocampus plays a vital role in the consolidation of short-term memory to long-term memory, spatial cognition, emotional behavior, learning and regulation of hypothalamic functions. The complex structure is one of the unique brain regions that see neurogenesis continue into adult life and is vulnerable to damage by a variety of stimuli. Studies have also shown the hippocampus to be affected in a variety of neurological and psychiatric disorders(Anand & Dhikav, 2012). Therefore, behavioral tasks, such as Radial Arm Maze, assist in gaining insight into hippocampal-dependent functions and effect of hippocampus changes.

The original design of Radial Arm Maze consisted of a 34 cm wide central platform with eight equal-length arms radiating out and was initially used to observe spatial learning and memory in rodents. Recent adaptations of the maze, however, no longer limit it to the assessment of spatial learning and memory and allow concurrent investigation of working and reference memory. RAM task requires the use of hippocampal-dependent spatial reference memory, and this ability to remember the location of visited arms can be affected by the administration of certain animal models. Variations of the maze have been used in research involving birds, insects, and even humans.

Recent Developments

The task apparatus has also seen various modifications over the years to include different cues (such as light cues), flexible arms (3D Radial Arm Maze), environments (Water model) and a variable number of arms, to list a few. The apparatus has also been adapted to be used with other subjects such as insects (Elizabeth et al., 2016), and humans (Mennenga et al., 2014). Finally, the Radial maze has been adapted for automated use to minimize human interaction (Layfield et al., 2020Quin et al., 2020).

An adapted human version of the Radial Arm Maze was used by Mennenga et al. to serve as a tool to connect human and rodent models of cognitive functioning. Their study evaluated human working memory and factors that contribute to the navigational ability of humans. The experiments showed that errors increased in a similar pattern as seen in a rodent model of RAM as the working memory demand increased.

The Radial Arm Maze has also seen adaptation as a computerized version wherein the subjects as tested in a virtual environment (Braun et al., 2012Lee et al., 2014).

Apparatus & Equipment

The Radial Arm Maze’s basic construction includes a central circular platform with the arms radiating outwards. The entrances of the arms usually have doors, that is either removable or guillotine styled, to limit access. The entire apparatus, in general, is transparent to allow the subject to visualize extra-maze cues, although opaque versions are also available. The apparatus is usually raised above the floor. The fully automated Radial Arm Maze detects the location of the animal within the maze, automates opening and closing of doors within the maze, and detects the presence of the food reward in the arm chambers.

The apparatus should be well lit from above to prevent shadows to ensure the proper utilization of Radial Arm Maze. Observation of the Radial Arm Maze task can be done using tracking software such as Noldus Ethovision XTor ANY-Maze, or Glia Science’s Video Tracking software mounted above the apparatus. Live scoring is also possible.

Training Protocol

The purpose of the Radial Arm Maze is to assess spatial memory and spatial learning in animals, in control vs. disease model/intervention group, by observing their ability to navigate the arms of the maze and remember which arms they have previously entered. Typically, animals are capable of learning and remembering the location of arms with food rewards using visual cues.

This test can provide information regarding hippocampal-dependent learning, specifically spatial memory. For example, the effects on memory abilities in animal models of aging (Shukitt et al., 2004) or cognition can be tested using the Radial Arm Maze. Learning and remembering are essential to survival strategy and tends to get impacted in subjects with impaired neuro-cognitive abilities. As the aptitude to remember decreases, the subject’s task errors increase, and the subject tends to make multiple re-entries into the arms.

Several protocols exist for Radial Arm Maze depending on the experimental aim, and the data researchers are looking to obtain. The most common protocol, used in the study of hippocampal lesions or degeneration and to determine the involvement of a specific gene or protein in spatial memory, uses a fully baited version of Radial Arm Maze wherein the subject is required to visit each arm only once per trial.

Pre-Training for the Fully-Baited Radial Arm Maze

Pre-training sessions can be done across several days prior to the experiment. Subjects are placed in small groups on the maze and allowed to explore the maze for 20 minutes freely. The maze floor is scattered with food rewards to encourage the subjects to explore. On the subsequent days, food rewards are only placed at the ends of the arms. For tasks involving automated Radial Arm Maze, the subjects are also familiarized with the movements and noise of opening and closing of the automated doors.

Evaluation of Spatial Learning and Memory Using the Radial Arm Maze

Training and testing processes begin with cleaning the apparatus to minimize olfactory cues and setting up of any visual cues within the test areas. Food rewards are placed in the chambers at the end of each arm. For tasks involving automated Radial Arm Maze, doors to each of the arms are closed. The subject is brought into the room and placed on the central platform and allowed an acclimate, if necessary.

For the fully-baited training procedure, subjects are tested over the course of 10 to 20 consecutive days. Each arm chamber consists of a food reward, and the subject is expected to learn to visit each arm only once per session. The session is terminated when the subject has visited all 8 arms and has eaten the reward after 16 arm visits are made (regardless of which arms) or after a maximum of 15 minutes. For the automated Radial Arm Maze task, the subject is placed on the central platform, and the doors are opened simultaneously to allow the subject to explore.

Subject’s reference memory can also be tested by baiting some of the arms while the remaining arms remain un-baited. The session is terminated when eight minutes have passed or until all baited arms are entered. A repeated entry into a baited arm is counted as a working memory error while any entry into an un-baited arm is recorded as a reference memory error.

Data Analysis

The data obtained from the Radial Arm Maze generally consists of following measures:

  • Number of total arm entries (the animal places all four paws in an arm)
  • Number of correct arm entries (the animal enters a novel arm not previously entered)
  • Number of error arm entries (the animal enters an arm previously entered or enters an un-baited arm)

The time between retrieving food rewards can also be recorded as a measure of activity and willingness to explore. As the animal learns that entering a new arm results in a food reward, the number of error arm entries is expected to decrease. These values can merely be graphed and compared to a sham control group and a disease model/intervention group.

In addition to counting entries, a memory score can also be calculated.

This score describes the memory performance on a scale from -1 to 1, with a score of 1 reflecting a perfect score of only entering novel arms (Richter et al., 2013). Memory scores are likely to improve over several tests.

Graphs allow easy visualization of comparisons of the effect on spatial memory and learning between different disease or treatment groups. Control groups are usually expected to show significant improvements in their correct arm entries and memory scores while subjects in disease models of neurodegenerative disorders, for example, should show a much slower learning curve with more error entries, even after several trials. Generally, animal cohorts of 20-30 animals are sufficient to obtain p-values of <0.05 using ANOVA, chi-squared test, and post-hoc tests (Dubreuil et al., 2003, Richter et al., 2013)

Traslational Research

Radial Arm Maze has also been adapted into a human model to act as a translational instrument in comparison of existing methodologies in rodent and human learning and memory research (Mennenga et al., 2014). The results of the research showed a significant correlation in error patterns seen in rodent-based models and the human-based model, as the working memory demand increased.

Genetic animal models employing delayed spatial win-shift task have shown high translational potential for the study of cognitive function (Richter et al., 2013). The model used two strains of rats: Congenitally helpless rats and rats resistant to helplessness, and tested them using Radial Arm Maze procedures used by Olton et al. and also with imposed temporal delay at some time within the sequence of arm visits. Congenitally helpless rats were shown to have impaired affective processing similar to depressed patients.

The Virtual Radial Arm Maze challenges the participant’s place learning skills, allowing assessment of their capacity to discriminate, remember and process the information as they explore the maze. The Radial Arm Maze can be easily adapted and modified to limit the use of certain strategies by the participants. Using inter-trial delays can also aid in the investigation of the memory capabilities of the participants. The absence of significant stressors and familiarization with the maze before testing allows for better observations of working and reference memory of the participants.

Strengths and Limitations

Radial Arm Maze was developed to allow place learning which was, in models before it, seen as a factor that needed to be controlled. By utilizing the subject’s place learning skills, researchers can assess the capacity of the subject to discriminate, remember and process information as it explores the maze (Olton et al., 1976).

In contrast to other mazes, Radial Arm Maze does not utilize aversive stimulus to test spatial learning as seen in Morris Water Maze that requires the animals to be submerged in water and swim in order to survive by searching for an escape platform (Hodges 1996). The Radial Arm Maze also allows the use of food rewards as task motivation, rather than using escape and survival reinforcers, which intrinsically places less stress on the animals (Hodges 1996). The absence of significant stressors and familiarization with the maze prior to testing allows for better observations of working and reference memory in the animals as they perform in the maze.

The RAM assists in repeated measures of detecting steady-state reference and working memory deficits, although this does require precise analysis (Hodges 1996). Additionally, RAM can be modified to limit the use of particular strategies by limiting route choices using doors to block off arms. Doors can also be used to create novel arms that can be revealed in the subsequent trials. Automation of the apparatus is also helpful in creating triggered delays (Dubreuil et al., 2003) to test how long the subject can remember spatial locations. The Radial Arm Maze can also be modified to complement the specific needs of the study/ experiment, such as using a water environment for a task trial (Shukitt et al., 2004). In many cases, the Radial Arm Maze is used in conjunction with other mazes to study disease models or transgenic animals and gain a fuller understanding of spatial learning and memory.

As with all mazes that measure aspects of learning and memory, it is important to remember that many different processes affect the behavior of the subject in the maze. Overtraining of the subject and the subject’s preferred behavioral response can impact the test results. It should also be kept in mind that the Radial Arm Maze requires more training and is more time-consuming than other mazes used for similar measures.

Summary

  • The Radial Arm Maze is extensively used to test spatial learning and memory.
  • RAM task asks animals to retrieve food rewards at the end of each of eight arms without visiting an arm more than once.
  • Different groups have adapted this maze in order to collect data regarding working or reference memory, and there are many modifications available, both regarding experimental protocol and data analysis.
  • Animals in control groups show rapid learning as they remember the location of the arms from which they have retrieved the food reward, while in comparison, animals with neurological lesions show a much slower learning curve with lower memory scores.

References

Layfield, D., Sidell, N., Abdullahi, A., Newman, E.L. (2020) Dorsal Hippocampus not always necessary in a radial arm maze delayed win-shift taskHippocampus 30(2):121-129.  PMID: 31453652.

Qian, Z.J., Ricci, A.J. (2020) Effects of cochlear hair cell ablation on spatial learning/memorySci Rep 10, 20687

Additional information

Weight 135 kg
Dimensions 166 × 66 × 91 cm
Size

Mouse, Rat

Color

Black, Blue, Clear, Grey, White

Software

Adapter software (For video tracking integration), Standalone (without video tracking integration)

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