Fig. 2: Evolution of late-delay M2 activity patterns carrying WM information.
From: Volatile working memory representations crystallize with practice
a, Imaging set-up and calcium activity of representative neurons across trials from one of the animals. Images of the other mice looked similar. Scale bars, 500 μm (left), 200 μm (left inset) and 100 μm (top and bottom right). ∆F/F, fluorescence signal change; SS, somatosensory. b, z-scored activity of four example neurons selectively responsive to specific odours, choices or delay epochs. c, Example neurons exhibiting mixed selectivity. In b and c, cells were sampled from at least 2 days after the animal achieved expert-level performance. d, The percentage of neurons exhibiting pure or mixed selective activity (n = 4 expert mice; first odour, P = 0.022; early delay, P = 0.035; late delay, P = 0.006; choice, P = 0.353). Statistical analysis was performed using paired t-tests. e, The accuracy of decoding the first odour (left and middle) or choice (right) using N% of the most selective neurons. n = 5 mice performing at expert level. f, The maximum decoding accuracy compared with shuffled data. g,h, The decoding accuracy of predicting the first odour and choice from the activity of M1 and M2 (g) and RSA and M2 (h) neurons separately and combined. The same number of neurons was used to ensure a fair comparison. i,j, Decoding accuracy comparison between correct and error trials in expert mice (i; n = 5), demonstrating significant predictive value during the late-delay epoch (P = 0.0001, paired t-test). The analysis in g–j is based on data from the last imaging day. For e, f and i, data are mean ± s.e.m. Details of the statistical analyses are provided in the Methods.
