Yartsev et al. reply

Replying to C. Barry, D. Bush, J. O’Keefe & N. Burgess Nature 488, 10.1038/nature11276 (2012) Barry et al.1 propose that it is impossible to detect theta rhythmicity in bat grid cells because of their slow movement velocities and low firing rates; hence, they posit that our findings2 do not refute the oscillatory interference models of mammalian grid cells. To support this claim, they use a data set of rat grid cells of which only 58% were theta modulated, and constrained their analysis to periods of near immobility in the rat, a behavioural state in which theta is known to be absent3. Despite these biases, we argue that their own analysis showed that down-sampled rat cells were substantially more theta-modulated than real grid cells from bats, and we demonstrate further that the bat data have adequate statistical power to detect theta rhythmicity—if it was present in bat grid cells. Finally, Barry et al. focused solely on ‘first generation’ oscillatory interference models, ignoring our disproval of ‘second generation’ models. We thus uphold our original results and interpretation2.