Perceptual processing of tactile texture discrimination in the barrel cortex of behaving mice

When interacting with objects in the world the sensory system gathers information on the characteristics of stimuli from the environment. These inputs reach the perceptual system where they are identified, organized, integrated with prior knowledge and interpreted to establish a perceptual representation of the information in order to execute adequate behavior. However how and where cortex generate information that reflects the animals’ choice rather than the incoming stimuli is not fully understood.
To investigate cortical perceptual dynamics, we used wide-field imaging to record from the dorsal cortex as mice perform whisker-dependent texture discrimination task. The mice discriminated between sandpapers with noticeable grits. In each trial, one of two textures presented to the whisker pad and the mouse reported its decision by licking either a right or a left port based on surface texture. Once the animal reached high level of performance, a variety of intermediate textures were presented and the mice reported its subjective perception of the texture roughness.
The animals’ psychometric functions indicate mice discriminate surfaces roughness as well as extend this information over an arch of textures. Our findings show a significant difference in the barrel cortex neural activity based on the animal’s decision, rather than the stimulus itself. However, this modulation was markedly reduced in error trials. When an intermediate texture was presented at the animal’s threshold (where the animal reports at ~50%) the neural activity differs based on the mice decision (lick right vs. left), indicating the presence of neural-perceptual correlates. In addition, using supervised learning models and other machine learning algorithms we were able to predict the animals decision based on the neural response (notably in the animals perceptual threshold).
Together, these results suggest the dorsal cortex to be highly involved in forming perception and indicate the performance - neuronal response correlation.