25–0.45), the locomotor behaviors to which the cells were tuned switched

completely between tasks (mean correlation of self-motion maps was r = −0.03 for the open field versus hairpin maze, r = 0.38 for hairpin session A versus A′, D = 0.58, p < 0.001, K-S test; for acceleration maps, r = 0.09 for open field versus hairpin maze, r = 0.43 for hairpin A versus A′, selleck chemical D = 0.43, p < 0.001; Figure 7). Only half the cells that exceeded the 99th percentile of the shuffled distribution in the hairpin maze passed the same criterion in the open field, reinforcing the idea that PPC cells are modulated strongly by variables that distinguish the hairpin task from the open field. However, despite the indications above, it remains unclear from these analyses whether the change in tuning was

driven by differences in geometry or behavior. To determine whether PPC cells were sensitive primarily to changes in the spatial layout or to the differences in behavioral constraints between the two tasks, we recorded 100 single units in PPC of three additional rats (Figure S10) and trained them to perform a “virtual hairpin” task in which the animals ran stereotypic laps similar to the hairpin maze, but in the open field (Figure 8A see more and Movie S1; see also Derdikman et al., 2009). We then recorded from the animals as they performed the open field, virtual hairpin, and hairpin tasks. We compared self-motion and acceleration preferences of PPC cells in each of the tasks and found that the self-motion maps of the cells were significantly more matched between the virtual hairpin and

real hairpin maze (mean r value of 0.32) than between the virtual hairpin and open field (mean r value of 0.05; D = 0.55, p < 0.001, K-S and test, Figure 8B; mean r value of 0.26 for acceleration maps in the hairpin maze versus virtual hairpin, mean r of 0.13 for open field versus virtual hairpin, D = 0.37, p < 0.001). Although the maps were not perfectly matched between the virtual hairpin and hairpin maze (mean r value for self-motion maps from successive virtual hairpin sessions was 0.43, and 0.32 for virtual hairpin versus hairpin maze, D = 0.2, p < 0.05), the data nonetheless show that restructuring the animals’ behavior was a principal factor driving PPC cells to retune between the tasks. It is noteworthy that Derdikman et al. (2009) showed that grid cell maps did not change between the open field and virtual hairpin tasks, which further suggests that representations in PPC and MEC are expressed in parallel. Finally, we wished to test whether changing spatial inputs outside the task influenced self-motion tuning in PPC cells. To this end, we compared self-motion and acceleration maps from the PPC cells recorded in the two-room recording experiment outlined in Figure 6.