Description

The puzzle box was described by Deacon and colleagues in 2011 as a variant of the work of (Galsworthy et al., 2002, 2005).

Mice are placed in a brightly lit compartment and quickly develop preference for a smaller dark goal compartment due to light/dark motivation.

Mice are challenged with various interruptions of increasing difficulties and are tasked to adopt solutions to each new problem.

The arena consists of an acrylic white box divided by a removable barrier into two compartments: a brightly-lit start zone and a smaller covered goal zone. A narrow underpass is located under the barrier and multiple variants have been described as obstacles to be removed:

• Variant 1: Sawdust
• Variant 2: open
• Variant 3: plug (small cardboard piece)
• Variant 4: Weighted obstacle

Our Puzzle box is compatible with our tracking and analysis package ConductVision.

Documentation

Introduction

The puzzle box is a widely used behavioral task in neuroscience to assess problem-solving ability in rodents. It is a problem-solving paradigm in which subjects are required to escape the brightly-lit large chamber with increasing difficulty as trials progress (Ben Abdallah et al., 2011). The rodents’ cognitive abilities are influenced by several environmental and disease conditions such as schizophrenia. Thus with this paradigm, it is possible to assess the effect of environmental enrichment on the cognitive ability of rodents and to predict improvements in disease-related cognitive deficits after some therapeutic interventions (Hagan and Jones, 2005; Arguello et al., 2010). In contrast to other models like the 5-choice serial reaction time task and the attentional set-shifting task which are useful in determining cognitive ability/impairments, the puzzle box does not require long training sessions or much of the experimenter’s efforts.

The puzzle box has a brightly-lit large chamber and a smaller dark “goal box” separated by a sheet with a small undercut for rodents to pass under. It follows the principle of the Light-Dark box, i.e., it exploits the natural tendency of the rodents to explore their surroundings and avoid stress-inducing bright chamber to seek shelter in a darker and safer place.

The applicability of this paradigm to the assessment of the problem-solving ability of rodents and the cognitive deficits exhibited by mice models of schizophrenia have been determined (BenAbdallah et al., 2011).

The history of the puzzle box can be traced back to Edward Lee Thorndike and his dissertation on animal intelligence in 1898 (Chance, 1999). However, its application in neuroscience and pharmacology, especially in mice experiments are a result of recent improvements and modifications of similar paradigm like the burrowing task in rats and the Light-Dark box (Crinella and Yu, 1995; Galsworthy et al., 2002).

Apparatus and Equipment

The puzzle box is made from Plexiglas sheets. The larger chamber is brightly illuminated with a lamp, while the other smaller chamber is kept dark by the lid to cover the top and the black Plexiglas separating the two chambers. A timer could be used to record the time it takes the subject to move from the bright chamber to the dark goal box.

Observation of the Puzzle box can be done using tracking software such as ConductVision, Noldus Ethovision XT,and ANY-Maze. mounted above the apparatus. Live scoring is also possible.

Training Protocol

The purpose of the puzzle box test is to assess cognitive ability/impairment in rodents in control versus disease model/manipulated group, by assessing the time it will take them to explore and find their way through the obstruction on their path to the dark chamber.

Before the test, subjects are kept in the test room for acclimation for some days. During the test, the subject being tested is placed on the far end of the brightly-lit broad chamber facing the goal box and allowed to find its way to the dark goal box.  The time it takes for the animal to enter the goal box section is noted. This time is known as latency.

Mice are subjected to a total of nine trials within a three-day period with three trials for each day. During this period, barriers of increasing difficulties are placed in the small undercut of sheet demarcating the goal box from the bright chamber. The schematic below shows a plan for the task:

Each trial requires 3 minutes for less difficult activities and 4 minutes for the more difficult ones.

Evaluation of Disease-related Cognitive Impairment

The Puzzle Box can be used to examine the effects of disorders like schizophrenia that affect executive functioning. The rodents are subjected to several manipulations to induce schizophrenia. The time it takes for these subjects to solve obstruction puzzle serves as a measure of their cognitive ability (BenAbdallah et al., 2011).

Evaluation of the Effect of Environmental Enrichment

 This behavioral task is also used in assessing environmental enrichment on mice models. Environmental enrichment is known to significantly affect the behavior of animals as it reduces stress and improves performance in learning and memory tasks. For mice raised in enriched environments, it takes lesser time to solve obstruction puzzles than their counterparts raised in a standard laboratory environment (O’Connor et al., 2014).

Sample Data

The sample data is represented by plotting the relationship between the animal model of schizophrenia (hippocampus-lesioned mice) and control. The graph shows that schizophrenic rodent takes a longer time to execute tasks and enter the goal box.

Strengths & Limitations

• The puzzle box is a broadly used behavioral assay to assess cognitive ability in rodents.
• It is used to evaluate how disease conditions alter executive functioning and how environmental enrichment improves sensory motor activities and learning.
• The apparatus consists of a box demarcated into two parts. A larger brightly-lit part and a smaller dark goal box covered with a lid at its top.
• The assay is easily amenable and a proven preliminary assessment of cognitive function.

Summary and Key Points

The tube dominance task is a renowned protocol used to assess social hierarchy and social dominance in rodents.

Dalila Effect, proactive wooing, and urine marking behaviors correlate the test tube ranks.

The apparatus consists of a plexiglass tube, and a small plexiglass divider is placed in the center.

A significant modification of the apparatus is the automation of the equipment.

References

Arguello, P.A., Markx, S., Gogos, J.A., Karayiorgou, M. (2010). Development of Animal Models for Schizophrenia. Disease Models & Mechanisms 3, 22–26.

Ben Abdallah, N. M.et al. (2011). The Puzzle Box as a Simple and Efficient Behavioral Test for Exploring Impairments of General Cognition and Executive Functions in Mouse Models of Schizophrenia. Experimental Neurology 227, 42-52, doi: S0014-4886(10)00344-4 [pii] 10.1016/j.expneurol.2010.09.008.

Chance, P. (1999). Thorndike’s Puzzle Boxes and the Origins of the Experimental Analysis of Behavior.  Journal of the Experimental Analysis of Behavior 72(3): 433–440.

Crinella, F.M., Yu, J. (1995). Brain mechanisms in Problem Solving and Intelligence: A Replication and Extension. Intelligence 21, 225–246.

Galsworthy, M. J., Paya-Cano, J. L., Monleon, S., & Plomin, R. (2002). Evidence for general cognitive ability (g) in heterogeneous stock mice and an analysis of potential confounds. Genes, Brain and Behavior. 1, 88-95.

Hagan, J.J., Jones, D.N.C., (2005). Predicting Drug Efficacy for Cognitive Deficits in Schizophrenia. Schizophrenia Bulletin 31(4), 830–853.

O’Connor, A.M., Burton, T .J., Leamey, C.A., Sawatari, A. (2014). The Use of the Puzzle Box as a Means of Assessing the Efficacy of Environmental Enrichment. Journal of Visualized Experiments 94, e52225, doi: 10.3791/52225.