Hexadirectional modulation (green line; 6-fold symmetry) appears within one theta cycle before choice. The effect is expressed as a t value obtained from a t test against zero across all neurons using beta estimates from the hexadirectional analysis. Control symmetries are represented with gray lines. The black horizontal line represents a cluster exceeding the 97.5th percentile of the length-corrected null distribution (n= 1,000 permutations; see STAR Methods—determining significance of the phase-aligned grid code analyses).
