Ethograms predict visual fear conditioning status in rats
- Boston College Department of Psychology and Neuroscience, United States
Figures
Figure 1 with 1 supplement
Experimental design and suppression ratio results.
(A) Behavioral testing occurred in a dark, Med Associates chamber equipped with a food cup, port, and cue light on one wall (left). Cue light illumination provided a discrete visual cue in addition to generally illuminating the chamber. (B) Rats in each experiment were divided into paired (red; n = 16) and unpaired (gray; n = 16) conditions. Experiment 1 used foot shock intensities of 0.15 mA and 0.25 mA, while Experiment 2 used foot shock intensities of 0.35 mA and 0.50 mA. Behavior frames were captured every 200 ms, 5 s prior to and 2.5 s following cue light illumination. (C) Mean ± SEM suppression ratio for paired (red) and unpaired (gray) rats receiving 0.15 mA (diamond) or 0.25 mA (square) foot shock is shown for the 20 cue light illuminations (pre-exposure trials 1–8, conditioning trials 1–8, and extinction trials 1–4). (D) Formatting, other than foot shock intensity (0.35 mA, triangles; 0.50 mA, circles), is identical to (C). ^0.35 mA, independent samples t-test p<0.0025. *0.50 mA, independent samples t-test p<0.0025.
Figure 1—figure supplement 1
Conditioned suppression across sessions in female and male rats (Experiment 2).
(A) Mean ± SEM suppression ratios for paired (red) and unpaired (gray) female rats from Experiment 2 are shown for the two pre-exposure sessions (p1 and p2), two conditioning sessions (c1 and c2), and one extinction session (e1). (B) Mean ± SEM suppression ratios are shown for male rats from Experiment 2 with identical formatting. The significant group × sex × session interaction results from female paired and unpaired rats crossing over from pre-exposure to conditioning, plus paired and unpaired females showing greater differential suppression ratios during extinction. Despite this, both female and male paired rats acquired conditioned suppression to the visual cue.
Figure 2
Hand scoring inter-rater reliability.
(A) % identical observations for the comparison frames were calculated for each observer–observer pair. Brown to purple color indicates a higher % identical observations. The black bar on the scale shows the mean % identical observations across all observer–observer pairs. (B) % identical observations are broken down by the number of behaviors present during a trial, ranging from 4 to 8. Each point indicates a single observer–observer trial comparison. Large Xs indicate the mean % identical observations for all observer–observer comparisons for each number of behaviors. (C) A confusion matrix shows all observer–observer judgment pairs for the comparison trials. The y axis is observer 1 and x axis is observer 2. % behavior observations are plotted by row with black indicating 100%, white 0%, and shades of gray in between. The number of behavior observations is indicated for each in parentheses. Plus signs indicate behaviors for which fewer than 10 instances were observed.
Figure 3 with 3 supplements
Conditioning ethograms.
(A) Ethogram for paired rats shows % behavior (y axis) for each behavioral category in 200-ms intervals from 5 s prior to cue onset (time 0) to 2.5 s following cue offset (time 10). Paired rats had shock delivered at cue offset. Colors for each behavior category: freeze (light brown), stretch (orange), rear (mustard), light rear (yellow), scale (light green), light scale (green), jump (dark green), locomote (cyan), backpedal (sky blue), cup (purple), port (dark purple), and groom (magenta). (B) Ethogram for unpaired rats, details identical to paired rats. Unpaired rats did not receive shock at cue offset. Line graphs for the eight behaviors showing a significant group × time interaction are shown in panels (C–J). % behavior is shown for paired rats (P, red) and unpaired rats (U, gray). X axis same as in (A/B), y axis is scaled to best visualize behavior patterns. Colored bars at the top of each axis indicate 1 s time periods in which paired and unpaired % behavior differed (independent samples t-test, p<0.05). Red bars indicate greater behavior in paired rats, while gray bars indicate greater behavior in unpaired rats.
Figure 3—figure supplement 1
Conditioning ethograms by trial and intensity.
(A) Ethograms for paired rats receiving the 0.50 mA foot shock shows % behavior (y axis) for each behavioral category in 200-ms intervals from 5 s prior to cue onset to 2.5 s following cue offset. Colors for each behavior category: freeze (light brown), stretch (orange), rear (mustard), light rear (yellow), scale (light green), light scale (green), jump (dark green), locomote (cyan), backpedal (sky blue), cup (purple), port (dark purple), and groom (magenta). Column 1 shows trial 1, column 2 trial 2, etc. (B) Ethograms for unpaired rats receiving the 0.50 mA foot shock, details identical to paired rats. (C, D) Ethogram formatting is identical to (A) and (B) but for paired and unpaired rats receiving the 0.35 mA foot shock. Foot shock only followed cue light illumination offset for paired rats and is indicated with bolt symbol.
Figure 3—figure supplement 2
Conditioning ethograms by intensity.
(A) Ethogram for paired rats receiving the 0.50 mA foot shock shows % behavior (y axis) for each behavioral category in 200-ms intervals from 5 s prior to cue light onset to 2.5 s following cue light offset. Paired rats had shock delivered at cue light offset. Colors for each behavior category: freeze (light brown), stretch (orange), rear (mustard), light rear (yellow), scale (light green), light scale (green), jump (dark green), locomote (cyan), backpedal (sky blue), cup (purple), port (dark purple), and groom (magenta). (B) Ethogram for unpaired rats receiving the 0.50 mA foot shock, details identical to paired rats. Unpaired rats did not receive shock at cue light offset. (C, D) Ethogram formatting is identical to (A) and (B) but for paired and unpaired rats receiving the 0.35 mA foot shock.
Figure 3—figure supplement 3
Conditioning line graphs by sex.
Line graphs for the three behaviors showing a significant group × time × sex interaction are shown: rear (A, B), jump (C, D) and backpedal (E, F). Females are plotted in the left column and males in the right column. % behavior is plotted in 200-ms intervals from 5 s prior to cue onset to 2.5 s following cue offset. Paired rats (red) and unpaired rats (gray). Colored bars at the top of each axis indicate 1-s time periods in which paired and unpaired % behavior differed (independent samples t-test, p<0.05). Red bars indicate greater behavior in paired rats, while gray bars indicate greater behavior in unpaired rats.
Figure 4 with 3 supplements
Extinction ethograms.
(A) Ethogram for paired rats shows % behavior (y axis) for each behavioral category in 200-ms intervals from 5 s prior to cue onset (time 0) to 2.5 s following cue offset (time 10). No shock was delivered during this session. Colors for each behavior category: freeze (light brown), stretch (orange), rear (mustard), light rear (yellow), scale (light green), light scale (green), jump (dark green), locomote (cyan), backpedal (sky blue), cup (purple), port (dark purple), and groom (magenta). (B) Ethogram for unpaired rats, details identical to paired rats. Line graphs for the four behaviors showing a significant group × time interaction are shown in panels (C–F). % behavior is shown for paired rats (P, red) and unpaired rats (U, gray). Colored bars at the top of each axis indicate 1-s time periods in which paired and unpaired % behavior differed (independent samples t-test, p<0.05). Red bars indicate greater % behavior in paired rats, while gray bars indicate greater % behavior in unpaired rats. (G) Mean % differential freezing (paired – unpaired) is shown in 200-ms intervals from 5 s prior to cue onset to 2.5 s following cue offset. Areas above zero indicate times when paired behavior exceeded unpaired behavior (red). Areas below zero indicate times when unpaired behavior exceeded paired behavior (gray). (H) Mean % differential locomote, shown as in (G). Trial 1 locomote line graphs are shown for (I) rats receiving 0.50 mA foot shock and (J) rats receiving 0.35 mA foot shock. Note that the y axis maximum for (I) and (J) is twice as large as for (D).
Figure 4—figure supplement 1
Extinction ethograms by trial and intensity.
(A) Ethograms for paired rats receiving the 0.50 mA foot shock shows % behavior (y axis) for each behavioral category in 200-ms intervals from 5 s prior to cue onset to 2.5 s following cue offset. Colors for each behavior category: freeze (light brown), stretch (orange), rear (mustard), light rear (yellow), scale (light green), light scale (green), jump (dark green), locomote (cyan), backpedal (sky blue), cup (purple), port (dark purple), and groom (magenta). Column 1 shows trial 1, column 2 trial 2, etc. (B) Ethograms for unpaired rats receiving the 0.50 mA foot shock, details identical to paired rats. (C, D) Ethogram formatting is identical to (A) and (B) but for paired and unpaired rats receiving the 0.35 mA foot shock. No shocks were delivered during extinction testing.
Figure 4—figure supplement 2
Extinction ethograms by intensity.
(A) Ethogram for paired rats receiving the 0.50 mA foot shock shows % behavior (y axis) for each behavioral category in 200-ms intervals from 5 s prior to cue onset to 2.5 s following cue offset. Colors for each behavior category: freeze (light brown), stretch (orange), rear (mustard), light rear (yellow), scale (light green), light scale (green), jump (dark green), locomote (cyan), backpedal (sky blue), cup (purple), port (dark purple), and groom (magenta). (B) Ethogram for unpaired rats receiving the 0.50 mA foot shock, details identical to paired rats. (C, D) Ethogram formatting is identical to (A) and (B) but for paired and unpaired rats receiving the 0.35 mA foot shock.
Figure 4—figure supplement 3
Trial-by-trial differential behavior.
(A) % differential freezing (paired – unpaired) is shown for all rats in 200-ms intervals from 5 s prior to cue onset to 2.5 s following cue offset. Areas above zero indicate times when paired behavior exceeded unpaired behavior (red). Areas below zero indicate times when unpaired behavior exceeded paired behavior (gray). Column 1 shows trial 1, column 2 trial 2, etc. Differential behavior for (B) locomotion, (C) scale, and (D) light rear are shown. Formatting as in (A). Note the differences in scale for locomotion and light rear (±50%) vs. freeze and scale (±15%).
Figure 5
Linear discriminant analysis results.
Group classification accuracy (paired vs. unpaired) is shown for (A) all frames (baseline → post-cue light) comprising the ethogram data, (B) baseline, (C) cue light illumination, and (D) post-cue light illumination. Ethogram data were intact (Etho, black), shuffled by session (SS, light gray), or shuffled temporally (TS, dark gray). Each data point represents the accuracy of a single model. The dotted line indicates chance classification. Group classification accuracy for (E) cue light illumination is shown for separate, multibehavior categories (Immobile, light brown; Horizontal, cyan; Vertical, green; and Reward, purple). The dotted line indicates chance classification, while the solid line indicates mean classification accuracy for the total ethogram data during cue light illumination. Group classification accuracy for (F) post-cue light illumination is shown for separate, multibehavior categories (color as in B). The dotted line indicates chance classification, while the solid line indicates mean classification accuracy for the total ethogram data post-cue light illumination. *Significance of a one-sample t-test compared to 50% (chance). nsNonsignificance of an independent samples t-test comparing horizontal classification to total ethogram classification.
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Ethograms predict visual fear conditioning status in rats
eLife 14:e102782.
https://doi.org/10.7554/eLife.102782
