Figures and data in Cue-inhibited ventrolateral periaqueductal gray neurons signal fear output and threat probability in male rats

Figures
Tables
Additional files

4 figures, 1 table and 1 additional file

Figures

Figure 1

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Fear discrimination, histology, heat plot and waveform characteristics.

(A) Pavlovian fear discrimination consisted of three cues predicting unique foot shock probabilities: danger, p = 1.00 (red); uncertainty, p = 0.375 (purple); and safety, p = 0.00 (blue). (B) Microelectrode bundle placements for all rats (n = 6) and all neurons (n = 245) during recording sessions are represented by salmon bars. (C) Mean + individual (data points) suppression ratio for danger, uncertainty, and safety is shown for all recording sessions (n = 88). (D) Normalized firing rate in 1 s intervals is shown for each Flip (n = 45, top) and Sustain (n = 46, bottom) neuron for each trial type (danger, uncertainty and safety). Color scale for normalized firing rate is shown to the right; red indicates high firing and blue low firing. Cue onset and offset are indicated. Single-unit waveform properties of Flip (sea foam) and Sustain (periwinkle) neurons are shown: (E) baseline firing rate, (F) half the duration, and (G) amplitude ratio. ⁺95% bootstrap confidence interval for differential suppression ratio does not contain zero.

https://doi.org/10.7554/eLife.50054.002

Figure 2 with 1 supplement

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vlPAG neurons flip to excitation or sustain inhibition over cue presentation.

(A) Mean normalized firing to danger (red), uncertainty (purple) and safety (blue) is shown for the 2 s pre-cue period, 10 s cue period, and 2 s delay period for the Flip population (n = 45). Cue onset (On) and offset (Off) are indicated by vertical black lines. (B) Mean (bar) and individual (data points), normalized firing for Flip neurons during the first 5 s of cue presentation (Early, left) and the last 5 s of cue presentation (Late, right) is shown for each cue. (C) Mean normalized firing for the Sustain population (n = 45), shown as in A. (D) Mean and individual (data points), normalized firing for Sustain neurons, as in B. ⁺95% bootstrap confidence interval for differential firing does not contain zero. ^#95% bootstrap confidence interval for normalized firing does not contain zero.

https://doi.org/10.7554/eLife.50054.003

Figure 2—figure supplement 1

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Trial by trial firing for Flip and Sustain populations.

(A, left ) Normalized firing rate for the Flip population (n = 45) is shown across cue presentation for each of the six danger trials. Trials are color-coded from dark (first trial) to light (last trial) with ‘On’ indicating cue onset and ‘Off’ indicating cue offset. (A, center) Mean population firing rate for the first 5 s of cue presentation (early) is shown for each trial. Color scheme maintained from A, left. Mean population baseline firing rate (2 s prior to cue presentation) is shown for each trial (gray). (A, right) Firing for the last 5 s of cue presentation (late) shown as in A, center. Identical figures using unique color schemes were made for each trial type: (B) uncertainty shock, (C) uncertainty omission and (D) safety. An identical set of figures were made for the Sustain population (n = 46; **E–H**).

https://doi.org/10.7554/eLife.50054.004

Figure 3

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Sustain and Flip populations signal threat probability and fear output.

(A) Mean ± SEM beta coefficients are shown for each regressor (probability: pink, fear output: green), in 1 s intervals, for the Flip population (n = 46). (B) Beta coefficients during the first, 5 s of cue presentation (Early) for fear output and threat probability are plotted for all Flip neurons. Black dashed trendline, the square of Pearson’s correlation coefficient (R²) with associated p value, and sign test p value demonstrating regressor bias shown. Background shading indicates negative beta coefficients, color coded by regressor. (C) Beta coefficients during the last, 5 s of cue presentation (Late) for fear output and threat probability are plotted for all Flip neurons. (D) Mean ± SEM beta coefficients are shown for each regressor for the Sustain population (n = 46). All graph properties maintained from A. (E) Beta coefficients during Early cue presentation for fear output and threat probability are plotted for all Sustain neurons. All graph properties maintained from B. (F) Beta coefficients during Late cue presentation for fear output and threat probability are plotted for all Sustain neurons. ^#95% bootstrap confidence interval for beta coefficient does not contain zero.

https://doi.org/10.7554/eLife.50054.005

Figure 4

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Sustain and Flip populations probability tuning.

(A) Mean beta coefficient for probability is shown for early (light pink) or late (hot pink) cue presentation for each of nine uncertainty assignments for the Flip population (n = 45). The peak or trough of each curve is indicated by a single point with the corresponding uncertainty assignment highlighted in the same color on the x axis below. Black dashed line indicates the actual foot shock probability associated with uncertainty (p = 0.375). Green dashed line indicates the mean proportional distance of uncertainty between danger and safety (suppression ratio). The blue-to-red color bar at the top of the figure demonstrates that a leftward shift along the x-axis reflects an uncertainty assignment similar in quality to safety (p = 0.000) versus those that would be more similar to a danger cue on the far right (p = 1.000). (B) All graph properties maintained from A, but applied to the Sustain population.

https://doi.org/10.7554/eLife.50054.006

Tables

Key resources table

Reagent type (species) or resource	Designation	Source or Reference	Identifier	Additional information
Antibody	Anti-Tryptophan Hydroxylase (sheep polyclonal)	Sigma	Cat # T8575 RRID:AB_1080792	[1:1000] in 0.05M PBS
Antibody	Biotinylated Anti-Sheep (rabbit clonality unknown)	Vector Labs	Cat # PK-6106 RRID:AB_2336217	[1:200] in 0.05M PBS
Chemical Compound, Drug	Normal Rabbit Serum	Vector Labs	Cat # PK-6106 RRID:AB_2336825	1% in 0.05M PBS
Chemical Compound, Drug	Avidin	Vector Labs	Cat # PK-6106 RRID:AB_2336825	[1:200] in 0.05M PBS
Chemical Compound, Drug	Biotin	Vector Labs	Cat # PK-6106 RRID:AB_2336825	[1:200] in 0.05M PBS
Chemical Compound, Drug	NovaRED Perioxidase (HRP) Substrate Kit	Vector Labs	Cat # SK-4800 RRID: AB_2336845	18 drops (1), 12 drops (2), 12 drops (3) and 12 drops H₂O₂ solution in DI H₂O.
Chemical Compound, Drug	Triton	Sigma	Cat # T8787
Chemical Compound, Drug	Hydrogen Peroxide	Sigma	Cat # 216763
Chemical Compound, Drug	Paraformaldehyde	Sigma	Cat # P6148
Chemical Compound, Drug	Sucrose	Fisher Scientific	Cat # S5
Chemical Compound, Drug	Sodium Chloride	Fisher Scientific	Cat # S 640
Chemical Compound, Drug	Histoprep 100% Reagent Alcohol	Fisher Scientific	Cat # HC800
Chemical Compound, Drug	Histoprep 95% Reagent Alcohol	Fisher Scientific	Cat # HC1300
Chemical Compound, Drug	Histoclear II	Fisher Scientific	Cat # 5089990150
Chemical Compound, Drug	Omnimount	Fisher Scientific	Cat # 5089990146
Chemical Compound, Drug	10% Neutral Buffered Formalin	Fisher Scientific	Cat # 22899402
Chemical Compound, Drug	Potassium Phosphate Monobasic	Fisher Scientific	Cat # P285
Chemical Compound, Drug	Potassium Phosphate Dibasic	Fisher Scientific	Cat # P288
Software and Algorithms	MED PC-IV	Med Associates	RRID:SCR_012156
Software and Algorithms	OmniPlex	Plexon		Data Acquisition System
Software and Algorithms	Offline Sorter V6	Plexon	RRID:SCR_000012
Software and Algorithms	NeuroExplorer	Plexon	RRID:SCR_001818
Software and Algorithms	Matlab	Mathworks	RRID:SCR_001622
Software and Algorithms	Statistica	StatSoft	RRID:SCR_014213
Software and Algorithms	SPSS	IBM	RRID:SCR_002865
Software and Algorithms	Adobe Illustrator	Adobe	RRID:SCR_010279
Software and Algorithms	Adobe Photoshop	Adobe	RRID:SCR_014199
Other	Plexon standard commutator	Plexon	Cat # 50122
Other	Plexon head stage cable	Plexon	Cat # 91809–017	Metal Mesh Enclosed Cable
Other	Plexon head stage	Plexon	Cat # 40684–020
Other	Omnetics connector	Omnetics Corporation	Cat # A79042-001
Other	Green board - Moveable Array	San Francisco Circuits	Cat # PCB
Other	Stainless Steel ground wire	AM Systems	Cat # 791400
Other	Formvar Insulated Nichrome Wire	AM Systems	Cat # 761500
Other	Dustless Precision Pellets	Bio-Serv	Cat # F0021