Phase-coupling analysis

Spike phase-coupling to ongoing gamma (30–50 Hz) oscillations was analyzed separately for the two traversal directions. For every spike occurring, the corresponding instantaneous phase of the gamma oscillation was extracted from the Hilbert transform. Only neurons with ≥50 spikes in each traversal were included (WS: n = 204, NS: n = 21, FS-PV: n = 13). The strength of phase-coupling of single neurons to gamma oscillations were quantified using pairwise phase consistency (PPC)⁵⁵ (Figure 6A) and mean resultant length (MRL; pycircstat. resultant_vector_length) (Figure 6B). Significant gamma phase-coupling was based on Rayleigh test (p < 0.05, pycircstat.rayleigh).