Hippocampal theta sweeps indicate goal direction during navigation

Successful spatial navigation requires rapid evaluation of potential future trajectories. Hippocampal 'theta sweeps', the sequential activation of place cells within individual theta cycles, exhibit predictive dynamics within the ideal timeframe for this role. However, whether these sequences reflect movement-related variables, perceptual targets or more cognitive goal-directed planning remains unresolved. Using data from the 'Honeycomb' maze, which dissociates head, movement and goal directions, we found that theta sweeps form vectors toward remembered goal locations independent of the rat's movement or heading directions. Stronger goal modulation preceded correct navigational choices, establishing the relevance of theta sweeps for spatial planning. A hierarchical continuous attractor network with goal-oriented directional inputs reproduced these findings and made several nontrivial predictions, which we confirmed empirically. Sequential activity during immobility-related sharp-wave ripples was also goal directed and, therefore, more aligned with theta sweeps than with previously experienced trajectories. Our findings identify hippocampal theta sweeps as neural substrates for online goal-directed planning.