A Novel Method for Training Mice in Visuo-Tactile 3-D Object Discrimination and Recognition
- 1Department of Psychiatry, The First Affiliated Hospital of China Medical University, China
- 2Department of Neuroscience,, West Virginia University School of Medicine, United States
- 3Gladstone Institute of Neurological Disease, United States
- 4Department of Neuroscience, West Virginia University School of Medicine, United States
Perceiving, recognizing and remembering 3-dimensional (3-D) objects encountered in the environment has a very high survival value; unsurprisingly, this ability is shared among many animal species, including humans. The psychological, psychophysical and neural basis for object perception, discrimination, recognition and memory has been extensively studied in humans, monkeys, pigeons and rodents, but is still far from understood. Nearly all 3-D object recognition studies in the rodent used the “novel object recognition” paradigm, which relies on innate rather than learned behavior; however this procedure has several important limitations. Recently, investigators have begun to recognize the power of behavioral tasks learned through reinforcement training (operant conditioning) to reveal the sensorimotor and cognitive abilities of mice and to elucidate their underlying neural mechanisms. Here we describe a novel method for training and testing mice in visual and tactile object discrimination, recognition and memory, and use it to begin to examine the underlying sensory basis for these cognitive capacities. A custom-designed Y maze was used to train mice to associate one of two 3-D objects with a food reward. Out of 9 mice trained in two cohorts, 7 reached performance criterion in about 20-35 daily sessions of 20 trials each. The learned association was retained, or rapidly re-acquired, after a 6 week hiatus in training. When tested under low light conditions, individual animals differed in the degree to which they used tactile or visual cues to identify the objects. Switching to total darkness resulted only in a transient dip in performance, as did subsequent trimming of all large whiskers (macrovibrissae). Additional removal of the small whiskers (microvibrissae) did not degrade performance, but transiently increased the time spent inspecting the object. This novel method can be combined in future studies with the large arsenal of genetic tools available in the mouse, to elucidate the neural basis of object perception, recognition and memory.
Keywords: object discrimination, object recognition, operant conditioning, food restriction, mice (inbred B6), Tactile object recognition
Received: 23 Jul 2018;
Accepted: 24 Oct 2018.
Edited by:Xiao-Dong Wang, Zhejiang University, China
Reviewed by:Yan Yang, Institute of Biophysics (CAS), China
Gareth R. Barker, University of Bristol, United Kingdom
Copyright: © 2018 Hu, Urhie, Chang, Hostetler and Agmon. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Ariel Agmon, Department of Neuroscience, West Virginia University School of Medicine, Morgantown, United States, email@example.com