Automated Training Systems in Real and Virtual Worlds for Tactile Discrimination Learning in Mice

Abstract

Somatic sensations are thought to be represented by the neural activity in the primary somatosensory cortex (S1), which can then be used for higher brain functions, such as decision-making, and memory. However, it is still unclear how neural activity represents these sensations and contributes to those functions. In a previous study, we showed that the intensity of limb stimulation in awake rodents could be coded by dendritic activity of layer 5 pyramidal neurons in S1⁽¹⁾. This implies that somatosensation of tactile stimuli can also be used as a primary mode of input for higher brain areas. To understand causal relationship between S1 activity and higher brain functions, we developed a new experimental system in which mice discriminated texture in a modified Y-maze. With this maze, mice were successfully trained to discriminate a specific tactile stimulus on the floor of the maze at an area just before the branch point. On the basis of these results, we designed a task in virtual world situations. This system also can present tactile stimulation while mice are running within the maze. Now, we are using this system for electrophysiological and optogenetic experiments, and trying to gain new knowledge in the field of neurobehavioral research.