Figure 10.

Left⁺ (X⁺) neuron increases firing during leftward movement and decreases firing during rightward movement. A, Detailed illustration of the correlation between firing rate and x-coordinates on a trial-by-trial basis. Neural activity and x-coordinates from 10 consecutive trials are shown. Each row represents a single trial. B, Neural and position data from a single trial are selected and compared. x-axis position changes during each movement are reflected in the firing rate of this neuron. The mouse moves to the right to consume sucrose. The activity of the neuron decreased during the rightward movement and then increased when the mouse moves left again to recover its initial starting position. C, Average firing rate changes and changes in different movement parameters. In this example, the y-component of the movement is much smaller. The plots on the right show velocity and acceleration data for the same movements. D, Using an egocentric reference frame, the direction of firing rate changes corresponds to the direction of movement. There was a positive correlation between neural activity and position change in a leftward direction (r = 0.99, p < 0.001). The correlation with the nonpreferred Cartesian axis is also shown. The diagram on the right shows the gradient of firing rate in relation to position coordinates.