Figure 2. PAWS and B-SOiD automated pain assessment platforms detect defensive coping behaviors associated with pain sensation during inflammation.

(Ai) A behavioral response to a somatosensory stimulus at baseline. (Aii) Post-carrageenan injection mice guard the paw in the air for extended time. (i,ii) Green lines show paw trajectory pattern across entire behavior, and mouse image shows single frame with paw at its apex. (B) PAWS software measures reflexive (i.e. height, paw displacement along the y axis, etc.) and affective behavioral features (i.e. shaking, guarding, distance traveled by the paw, etc.). The apex t* or first peak of the behavioral response separates reflexive and affective behavioral features (as described in the methods from Jones et al., 2020). Here, the y axis is a univariate projection of the paw displacement across both x and y dimensions, in centimeters. This graph thus captures paw movements in both x and y directions over time, following dynamic brush stimulation at baseline, for 1 mouse. Further details on the computation methods used to generate this graph can be found in Jones et al., 2020. (C,D) Affective features such as paw guarding and paw shaking are upregulated in response to dynamic brush and light pinprick comparing baseline to 4- and 24-hours post-carrageenan injection. (E,F) Paw guarding was found upregulated at 10-days after MIA knee injection, consistent with the paw being a potential secondary site of hypersensitivity. (G) Low-dimensional projection of feature clusters as identified after UMAP/HDBSCAN. 5 colors were then assigned to the 11 identified sub-clusters to indicate their post-hoc behavioral group assignment. Stacked bar plots of the percent of time spent doing each behavior (rest, paw lift, angled guard, flat guard, hovering) in response to dynamic brush (H) and (I) light pinprick at baseline, 4-hours, and 24-hours time points post-carrageenan injection. Responses are color-coded by the identified action type as in panel (G). Examples of the angled paw guard identified by B-SOiD, which may be indicative of the activation of different subsets of sensory neurons (mechanoreceptors by brush, inducing (J) angled guard, nociceptors by pinprick, inducing (K) flat guard). N=10 mice per group; * p < 0.05, ** p < 0.01: Kruskal-Wallis test followed by Dunn’s multiple comparisons were performed to determine statistical significance between the responses of mice to each stimuli across time independently.