Figure 1. Dorsal periaqueductal gray (dPAG) single-unit recordings during risky foraging.

(A) Rats underwent pre-robot, robot, and post-robot sessions, successfully securing pellets in pre- and post-robot trials, and failing during robot trials due to robot interference. (B) Tetrode implantation in dPAG with a photomicrograph of the tip (arrowhead). (C) Outbound foraging time increased significantly in the robot session (Χ² = 64.00, p<0.0001, Friedman test; ps<0.05 for all comparisons, Dunn’s test, n = 42 recording days from 5 rats). ***p<0.001 compared to pre-robot and post-robot sessions. #p<0.05 compared to the pre-robot session. (D) The pellet success rate significantly decreased during robot session (Χ² = 84.00, p<0.0001, Friedman test; ps<0.0001 for all comparisons, Dunn’s test, n = 42 recording days from 5 rats). ***p<0.001 compared to pre-robot and post-robot sessions. (E) Cell-type proportions revealed that 23.4% cells responded to robot activation (robot cells). (F) Representative dPAG robot cell raster/event histograms aligned with robot activations. (G) Population activity of robot cells around the time of robot activation (t = 0) with 0.1 s and 1 s bins. Firing rates of the robot cells were higher during robot session (0–3 s blocks; Friedman test, all Χ²s > 6.952, all ps<0.05; Dunn’s test, all ps<0.05, n = 22 units). Shaded areas indicate SEM. **p<0.01 compared to pre-robot session. #, ##, and ### denote p<0.05, p<0.01, and p<0.001, respectively, compared to post-robot session. Panel (E) created with BioRender.com, and published using a CC BY-NC-ND license with permission.

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Figure 1E was created using BioRender, and is published under a CC BY-NC-ND 4.0. Further reproductions must adhere to the terms of this license.

Figure 1—figure supplement 1. Dorsal periaqueductal gray (dPAG) unit cell types.

(A) Representative multiple single units recorded in the dPAG. (B) A subset (35.1%) of dPAG neurons showed increased firing rates in response to the robot, food pellet, or both, with 66.7% responding exclusively to the robot. Units were categorized based on z-score responses: ‘robot cells’ for z > 3 during robot phase and z < 3 during pre-robot phase; ‘pellet cells’ for z > 3 during pre-robot phase and z < 3 during robot phase; and ‘BOTH cells’ for z > 3 in both phases. Raster plots display activity of robot, pellet, and BOTH cells across pre-robot, robot, and post-robot sessions. (C, D) Average (C) and maximum (D) firing rates of dPAG robot cells during pre-robot, robot, and post-robot sessions (average firing rate: Χ² = 7.636, p<0.05, Friedman test, p<0.05, Pre-robot vs. Robot, Dunn’s test, n = 22 units; maximum firing rate: Χ² = 12.29, p<0.01, Friedman test; p<0.05, Pre-robot vs. Robot, Dunn’s test, n = 22 units). (E) One neuron showed decreased firing rates (z –3) in response to the robot during the robot phase. (F) Top row: mean firing rate (± SEM; shaded areas) of robot cells and movement speed (± SEM; shaded areas) of animals across sessions (n = 22 units). Bottom row: correlation coefficients between firing rate and movement speed for the robot cell group during each session. * and ** denote p<0.05 and p<0.01, respectively.