Supplementary Figure 3: Detection of cell assemblies.
(a) Session example showing assembly spatial maps (of 12 cell assemblies) ordered from left to right across the entirety of the linear track. (b) Corresponding data showing the 57 CA1 place cells recorded during this session, each neurons weight in a given assembly is indicated by its deviation on the x-axis. Cells with a significant weight are color coded to the assembly to which they belong (from a). (c) Mean assembly strength during linear track exploration did not differ between genotypes (P = 0.83, Z = 0.22, two-sided Wilcoxon Rank-sum; CTR: N = 7 animals, n = 96 cell assemblies; SCN: N = 7 animals, n = 132 cell assemblies). (d) Cells classified as forming part of an assembly had significantly higher co-firing coefficients (r) with assembly partners, than cells which did not form part of any assembly (P = 3.32 × 10−23, Z = 9.92, two-sided Wilcoxon Rank-sum; n = 59 assembly cell pairs, n = 105 non-assembly cell pairs), relating to example session shown in a & b. (e) Place-field similarity was also significantly greater for assembly member pairs, compared with non-members (P = 1.62 × 10−16, Z = 8.25, two-sided Wilcoxon Rank-sum; n = 59 assembly cell pairs, n = 105 non-assembly cell pairs). (f) Across all subjects during SPW-Rs, cell pairs forming part of an assembly had consistently higher co-firing coefficients independent of genotype (CTRs, P = 1.28 × 10−52, Z = 15.3, two-sided Wilcoxon Rank-sum; SCN, P = 7.82 × 10−67, Z = 17.3, two-sided Wilcoxon Rank-sum; CTR: N = 7 animals; SCN: N = 7 animals), when compared to non-members. (g) Place field similarity was also significantly higher for cell-assembly members for both controls (P = 1.25 × 10−21, Z = 9.55, two-sided Wilcoxon Rank-sum, N = 7 animals) and mutants (P = 4.31 × 10−25, Z = 10.3, two-sided Wilcoxon Rank-sum, N = 7 animals). Cell-assembly members (P = 0.31, Z = 1.02, two-sided Wilcoxon Rank-sum; CTR: N = 7 animals; SCN: N = 7 animals) and non-members (P = 0.73, Z = 0.35, two-sided Wilcoxon Rank-sum; CTR: N = 7 animals; SCN: N = 7 animals) were not significantly different when compared across genotype. All boxplots represent the median (black line) and the 25th-75th percentiles, with whiskers extending to the most extreme data points, excluding outliers which are plotted as individual crosses. *P < 0.05.
