Fig. 3: A prelimbic neuronal ensemble specifically encodes spontaneous pain behaviors.

a Experimental timeline and daily recording protocol for in vivo electrophysiology before and after CFA injection. b Stimuli-evoked responses of PL pyramidal neurons in different evoked modalities. Heatmap rows represented the Z score-transformed average PSTH for individual neurons, and columns represented time bins relative to stimulus onset. The right column of the heatmap indicated the subpopulations of neurons showing excitatory (red), inhibitory (blue) and neutral responses to spontaneous paw lifting behaviors, respectively. c Pattern comparisons of PL neuronal populations which showed significant responses between spontaneous paw lifting and locomotion (upper)/self-grooming (bottom) behaviors. Left: Venn diagrams of amounts of significantly responding neurons to the behaviors, and the overlay showing the synclastic responses. (i.e., positive or negative responses in both given modalities). Right: Distributions of hypergeometric probabilities for each comparisons showing whether two neuronal response patterns were similar or significantly different. A significant difference was observed between spontaneous paw lifting and other behaviors. d Pattern comparisons of the neuronal populations showing significant responses between spontaneous paw lifting and different evoked stimuli. Left: Matrix of amounts of responding neurons to the modality combinations among evoked stimuli and spontaneous paw lifting. Right: Hypergeometric probabilities indicated the significance of the neurons responding to the modality combinations. Stars and triangles represented significantly similar and different responsive patterns to the modality combination, respectively. Significantly different patterns were observed between spontaneous paw lifting and multiple evoked modalities (pin, 15-g hair, 2-g hair, laser and sound), but not between spontaneous paw lifting and any other evoked modality. e The population activities of all PL neurons significantly distinguished a majority of evoked behaviors except brush. Left: The confusion matrix of the prediction accuracies. Right: p values of the prediction performance. f The performance in predicting evoked behaviors using spontaneous pain-irrelevant PL neurons.