Documentation

The Walking Radial Arm Maze is a human-size adaptation of the conventional rodent Radial Arm Maze that is popularly used in the assessment of spatial learning and navigation in rodents. The maze is used in evaluating spatial processing and navigation abilities of humans based on the presence of different local and distal cues. Understanding the surroundings and effective navigation heavily rely on vision. Vision impairments make independent navigation difficult or impossible (for digital healthcare research tools visit Qolty). However, technological developments have resulted in the creation of Sensory Substitution Devices, which are being evaluated for their efficiency to allow independent navigation (see Virtual Stereo Sonic Task). While vision is an essential part of the equation, deficits in spatial cognition is another factor that greatly impacts navigation.

Neuropsychiatric disorders and neurodegenerative diseases can result in deficits in navigational abilities (Giuliani, & Schenk, 2015; Robaey, McKenzie, Schachar, Boivin, & Bohbot, 2016; Vlček, & Laczó, 2014). The Walking Radial Arm Maze can be used to investigate how characteristics of these diseases and disorders, such as spatial disorientation and disturbed eye movements, affect navigation, and the compensatory navigation strategies adopted by the participants. Unlike traditional Radial Arm Mazes that have walled choice arms, the Walking Radial Arm Maze is an unwalled-open arena with the choice arms laid out on a circular mat. This set-up allows distal environmental cues to aid with navigation. Additionally, different patterned floorings can be placed in the choice arms to add a level of complexity to the task while serving as local cues.

Other apparatuses also used in human behavioral assessments include the Finger Groove Maze, the Finger Maze Test, and the Human Vertical Maze. For virtual mazes, click here.

The Walking Radial Arm Maze is constructed using a 4 m diameter mat with 8 alleyway positions marked on it. The alleyways radiate from a central circular start area at an angle of 45° from each other. Each alley is 2 m long and 22 cm wide. Each arm can be equipped with a specific removable floor pattern. At the ends of each arm, reward holders having a capacity of 2 dl are present.

Depending on the investigation, proper illumination of the maze may be needed, or subjects may need to be blindfolded.

An automated tracking and recording system such as the Noldus EthoVison XT may be used to assist with the observations. Ancillary assessments and recordings, such as heart rate, may also be part of the investigations.

Prior to the experiments, provide a clear set of instructions. Ensure that the participants are not in the test area when reinforcing arms of the Walking Radial Arm Maze.

Following is a sample protocol for the Walking Radial Arm Maze task using patterned flooring.

Free Exploration Trial

Bait the cups of the reinforced patterns in the maze. Introduce the participant to the center of the maze and initiate the exploration trial. Allow the participant to explore the maze until all arms have been visited and the rewards collected.

Acquisition Trials

Following the exploration trial, begin acquisition trials. Place the rewards in the same reinforced arms as in the exploration trial. Introduce the participant to the center of the maze and instruct the participant to visit only the reinforced arms based on the free exploration trial. Perform 3 consecutive trials with an inter-trial interval of approximately 2 to 3 minutes.

Test Trials

Replace the patterned flooring and place identical single-color flooring in all arms. Bait the same arms with rewards as in the previous phases. Introduce the participant to the center of the maze and initiate the test trial.

Conflict Trials

Place the rewards in the same reinforced arms as in the exploration and acquisition trials. Rotate the entire set-up by 90 degrees. Introduce the participant to the center of the maze and instruct the participant to visit only the reinforced arms. Follow the trial by returning the setup to the original orientation and repeat the trial with all other conditions remaining the same (intermediate trial). Perform a third trial (permutation trial) by only changing the positions of the inserts while maintaining the positions of the rewards and other conditions.

Evaluation of spatial navigation performances of individuals with intellectual disabilities

9 participants with intellectual disability and 10 age and sex-matched controls were recruited for the investigation. The Walking Radial Arm was placed in an approximately 40 m² room with various distal cues (such as door and windows). Each alleyway of the maze had a distinct floor pattern. The pieces of chocolate were used as reinforcement for all trials, and for every trial, 4 arms were rewarded. The reward configuration was counterbalanced between participants. The participants were first allowed to explore the maze following which learning acquisition was assessed in two trials. The acquisition trials were followed by test trials wherein all local cues (patterned floorings) were removed. The rewards were maintained in the same arms throughout all trials. The intellectually disabled participants displayed a systematic approach to the first acquisition trial, where they were observed visiting adjacent arms. In comparison to the controls, in the second acquisition trial, the intellectually disabled participants were observed making slightly more entries into the non-reinforced arms. When tested without local cues, no prominent performance differences could be observed. (Bertholet et al., 2015)

The following observations can be recorded in the Walking Radial Arm Maze:

• The sequence of arm visit
• Time to complete the task
• Number of working memory errors (re-entries)
• Number of reference memory errors (entry into the non-reinforced arm)
• Foraging efficiency

Strengths

The Walking Radial Arm Maze is constructed using textile, making it easily moveable. Since the maze is unwalled, environmental cues can be used as-is without the need for any additional preparations. This design also makes it easy to test subjects that may need assistance while performing the task. The options of different removable alleyway patterns allow the creation of different visual cue combinations that are useful in the application of a range of learning and memory protocols. The maze can be used in combination with other equipment to observe different parameters, such as gaze direction simultaneously.

Limitations

Since the Walking Radial Arm Maze is an unwalled maze, distal cues may not be completely eliminated. Sensory and motor impairments can affect task performances. In blindfold requiring protocols, impairments in proprioception and movement decisions can impact performances. Performances may also be influenced by unintended cues such as auditory or visual cues and room traffic.

• The Walking Radial Arm Maze is constructed using a textile material and can be moved to different locations easily.
• The maze does not have walls, which may or may not be beneficial in terms of distal cues.
• The maze comes with a set of removable alleyway floorings to serve as local cues.
• The maze is suitable for the evaluation of individuals that may need some assistance while performing the task.

1. Bertholet, L., Escobar, M. T., Depré, M., Chavan, C. F., Giuliani, F., Gisquet-Verrier, P., … Schenk, F. (2015). Spatial radial maze procedures and setups to dissociate local and distal relational spatial frameworks in humans. Journal of Neuroscience Methods, 253, 126–141. doi:10.1016/j.jneumeth.2015.06.012
2. Robaey, P., McKenzie, S., Schachar, R., Boivin, M., & Bohbot, V. D. (2016). Stop and look! Evidence for a bias towards virtual navigation response strategies in children with ADHD symptoms. Behavioural Brain Research, 298, 48–54. doi:10.1016/j.bbr.2015.08.019
3. Vlček, K. & Laczó, J. (2014). Neural Correlates of Spatial Navigation Changes in Mild Cognitive Impairment and Alzheimer’s Disease. Frontiers in Behavioral Neuroscience, doi:10.3389/fnbeh.2014.00089
4. Giuliani, F., & Schenk, F. (2015). Vision, spatial cognition and intellectual disability. Research in Developmental Disabilities, 37, 202–208. doi:10.1016/j.ridd.2014.11.015