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Navigation through complex environments requires motor planning, motor preparation and the coordination between multiple sensory–motor modalities. For example, the stepping motion when we walk is coordinated with motion of the torso, arms, head and eyes. In rodents, movement of the animal through the environment is often coordinated with whisking. Here we trained head fixed mice – navigating a floating Airtrack plus maze – to overcome their directional preference and use cues indicating the direction of movement expected in each trial. Once cued, mice had to move backward out of a lane, then turn in the correct direction, and enter a new lane. In this simple paradigm, as mice begin to move backward, they position their whiskers asymmetrically: whiskers on one side of the face protract, and on the other side they retract. This asymmetry reflected the turn direction. Additionally, on each trial, mice move their eyes conjugately in the direction of the upcoming turn. Not only do they move their eyes, but saccadic eye movement is coordinated with the asymmetric positioning of the whiskers. Our analysis shows that the asymmetric positioning of the whiskers predicts the direction of turn that mice will make at an earlier stage than eye movement does. We conclude that, when mice move or plan to move in complex real-world environments, their motor plan and behavioral state can be read out in the movement of both their whiskers and eyes.Significance statementNatural behavior occurs in multiple sensory and motor dimensions. When we move through our environment we coordinate the movement of our body, head, eyes and limbs. Here we show that when mice navigate a maze, they move their whiskers and eyes; they position their whiskers asymmetrically, and use saccadic eye movements. The position of the eyes and whiskers predicts the direction mice will turn in. This work suggests that when mice move through their environment, they coordinate the visual-motor and somatosensory-motor systems.

A central function of the brain is to plan, predict, and imagine the effect of movement in a dynamically changing environment. Here we show that in mice head-fixed in a plus-maze, floating on air, and trained to pick lanes based on visual stimuli, the asymmetric movement, and position of whiskers on the two sides of the face signals whether the animal is moving, turning, expecting reward, or licking. We show that (1) whisking asymmetry is coordinated with behavioral state, and that behavioral state can be decoded and predicted based on asymmetry, (2) even in the absence of tactile input, whisker positioning and asymmetry nevertheless relate to behavioral state, and (3) movement of the nose correlates with asymmetry, indicating that facial expression of the mouse is itself correlated with behavioral state. These results indicate that the movement of whiskers, a behavior that is not instructed or necessary in the task, can inform an observer about what a mouse is doing in the maze. Thus, the position of these mobile tactile sensors reflects a behavioral and movement-preparation state of the mouse.SIGNIFICANCE STATEMENTBehavior is a sequence of movements, where each movement can be related to or can trigger a set of other actions. Here we show that, in mice, the movement of whiskers (tactile sensors used to extract information about texture and location of objects) is coordinated with and predicts the behavioral state of mice: that is, what mice are doing, where they are in space, and where they are in the sequence of behaviors.