Fig. 6: Miniscope calcium imaging of mPFC→dmStr projection neurons during T-maze DNMTP task.

a Left: Schematic of the virus injection and miniscope mounting for cellular resolution imaging of mPFC→dmStr projection neurons. Right: Confocal images of GCaMP6f expression in left PrL indicating GRIN lens insertion into an implanted cannula. b Representative field of view for miniscope imaging (single time frame of pre-processed data). c Trial-related cellular activity traces of 7 example neurons for one correct trial. Left: output signal in arbitrary units, right: corresponding deconvolved estimated spike rate. Dashed lines, purple, orange and cyan bars indicate different task periods. d Example cells identified as being significantly more active in either encoding (left), maintenance (middle), or retrieval (right) period. Six example correct trials are plotted for each neuron. e Relative significance of single-cell activity during the 10 trial phases. High values indicate significantly elevated activity of a given cell in a particular trial phase, compared to the rest of the phases. The heatmap shows all cells for one example mouse. Only correct trials were analyzed and cells sorted according to the Left Sample trials. f Fraction of cells preferentially active in encoding (E), maintenance (M), and retrieval (R) period (E: 0.22 ± 0.05 M: 0.56 ± 0.05, R: 0.22 ± 0.06, mean ± s.e.m.; ***p = 3.97 × 10⁻¹² for E vs M, ***p = 4.01 × 10⁻¹² for E vs M, binomial test, p-values composed over mice using Fisher’s method with Bonferroni correction; n = 6 mice). g Mean activity levels of neurons preferentially active in encoding (E), maintenance (M), and retrieval (R) period (E: 0.18 ± 0.011 M: 0.123 ± 0.004, R: 0.176 ± 0.01, mean ± s.e.m.). Mean spike rate for a given period was calculated in arb. units for each trial and averaged for each neuron across all correct trials (***p = 6.29 × 10⁻⁶ for E vs M, ***p = 2.83 × 10⁻⁵ for M vs R, p = 0.81 for E vs R, two-sided Wilcoxon signed rank test, Bonferroni corrected, n = 6 mice). Box-whiskers plot shows minimum-maximum range and 25th and 75th percentiles. White circles represent means. h Matrix plot showing the fraction of neurons significantly active in pairs of task phases (left) or periods (right) (n = 6 mice). Values on the diagonal represent fraction of neurons significantly active in each respective phase or period. Note the overlap of neuronal fractions that show significant activity in encoding and retrieval periods as well as in corresponding phases during these periods. Source data are provided as a Source Data file.