Fig. 2: Object-vector cells respond to two-dimensional objects.

a Experimental design with four different trials: mice foraged in an environment with either an object absent (‘Empty Box’) or present (‘2D’, ’50%’, ‘3D’). In the three object trials, we varied the amount of the object’s volume exposed to the animal. In the 2D trial, the visible part of the object was a flat 2D surface, with the rest completely embedded into the wall. In the middle trial, the object was partially embedded into the wall so that 50% of its volume was exposed. In the 3D trial, the full volume of the object was exposed. The reference trial, used to find the cell’s vector coordinates, is shown on the left. This was the original ‘Object’ trial used to identify the cell as an OV cell (Fig. 1a, middle). b Colour-coded rate maps from example OV cell that responded as strongly to 2D surfaces as to 3D objects. Rate maps show colour-coded firing rate in Hz as a function of the animal’s position. The white square marks the object location. The dotted circle marks the ROI in which we expected the cell to fire based on its vector coordinates. The vector coordinates of the cell were found by applying the algorithm from Supplementary Fig. 3 to the ‘Reference trial’ on the left. This trial is also what we used as a template for computing the OV score. Peak firing rate (Hz) is indicated below each map. Scale bar, 40 cm. c Box-and-whisker plots of normalised firing rates (Hz) of object-vector cells (n = 30) as a function of object dimensionality. Firing rates were normalised to the maximum data point across all eight data points observed for each cell (4 experimental conditions × inside/outside ROI) so that the maximum rate is 1. The middle line (in red) on each box indicates the median, while the bottom and top lines (in blue) indicate the lower and upper quartiles, respectively. Whiskers show the range of data in each condition. Red crosses show outliers that lie more than 1.5 times outside the interquartile range. The firing rate was measured either inside (left) or outside the ROI (right). d Box-and-whisker plot of object-vector scores (ranging from −1 to 1) as a function of object dimensionality. The object-vector score is equivalent to the Pearson correlation between pairs of object-centred rate maps (see 'Method' for details). Here, the reference rate map is from the ‘Object’ trial originally used to identify the cell.