Locus coeruleus modulation of prefrontal dynamics during attentional switching in mice
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, United States
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States
- Neuroscience Graduate Program, University of California, Riverside, United States
Figures
Figure 1 with 1 supplement
Inhibiting locus coeruleus-norepinephrine (LC-NE) neurons or their terminals in the medial PFC (mPFC) impairs switching behavior.
(a) Task overview. (b) Example frames (top to bottom) showing when the mouse was in the waiting area, approaching the bowls, and digging. (c) Task performance (total number of trials to criterion) varied across stages: SD – simple discrimination, 12±1 trials; CD – compound discrimination, 7±1 trials; REV – intra-dimensional reversal, 20±1 trials; IDS – intra-dimensional shift, 10±1 trials; EDS – extra-dimensional shift, 17±1 trials. Repeated-measure ANOVA, F(4, 92)=47.8, p<0.001, n=24. Post hoc Tukey-Kramer tests: EDS vs. SD, p=0.003; EDS vs. CD, p<0.001; EDS vs. REV, p=0.20; EDS vs. IDS, p<0.001; SD vs. CD, p<0.001; SD vs. REV, p<0.001; SD vs. IDS, p=0.18; CD vs. REV, p<0.001; CD vs. IDS, p<0.001; REV vs. IDS, p<0.001. Note that in (c) statistical significance was only indicated when comparing EDS to other stages. (d) Schematic of DREADD inhibition in the LC and histological images showing DREADD(Gi) and TH (Tyrosine Hydroxylase) expression in the LC of a DBH-Cre mouse. (e) Task performance in the control (n=4, WT) and test (n=5) groups. Following systemic CNO injections, test group mice took more trials to complete extra-dimensional shift (EDS). Trials to reach performance criterion: control vs. test, 14±2 trials vs. 25±2 trials, p=0.007, t(7) = –3.8. (f) Histology showing terminal expression of mCherry in the mPFC. Scalebars: 100 µm. (g) Schematic of inhibiting LC terminals in the mPFC and histology displaying cannula placement in the mPFC. (h) Task performance in the control (n=7, WT) and test (n=8) groups. Following localized Clozapine N-oxide (CNO) injection, test group mice took more trials to complete EDS (Trials to reach criterion, control vs test: 16±1 trials vs. 24±2 trials, p=0.003, t(13) = –3.6).
-
Figure 1—source data 1
Data to generate c, e, h.
- https://cdn.elifesciences.org/articles/105911/elife-105911-fig1-data1-v1.zip
Figure 1—figure supplement 1
Mice learned to switch attention and LC inhibition impaired this process.
(a) Task performance in the control (n=4) and test (n=5) group of DBH-Cre mice expressing Gi-DREADD. Control group received saline injections and test group received Clozapine N-oxide (CNO) injections. Test group mice took more trials to complete extra-dimensional shift (EDS) (Trials to criterion: control vs. test, 17±2 trials vs. 25±2 trials, p=0.03, t(7) = –2.8). Test group is the same as in Figure 1b. (b) Task performance in the control (n=4, WT) and test (n=4, DBH-Cre mice expressing Gi DREADD) groups that received CNO injections and were subjected to mPFC miniscope imaging (same mice included in Figures 2—4). Test group mice took more trials to complete EDS (Trials to criterion: control vs. test, 14±2 trials vs. 20±1 trials, p=0.05, t(6) = –2.5). (c) Pooled behavior data (Figure 1e, h and (a, b)) to demonstrate the validity of set shifting from intra-dimensional shift (IDS) to EDS. Control group mice (n=19) took more trials to complete EDS (Trials to criterion: IDS vs. EDS, 11±1 trials vs. 15±1 trials, p=0.006, rank sum = 277). Test group mice (n=17) took more trials to complete EDS than the control group (Trials to criterion: control vs. test, 15±1 trials vs. 23±1 trials, p<0.001, rank sum = 217). (d) Pooled behavior data as in (c), but excluding three sessions (two control sessions and one test session), where task performance in IDS exceeded 95% (15 trials) of the naïve group shown in Figure 1c. Control group mice (n=17) took more trials to complete EDS (Trials to criterion: IDS vs. EDS, 11±1 trials vs. 15±1 trials, p=0.003, rank sum = 212). Test group mice (n=16) took more trials to complete EDS than the control group (Trials to criterion: control vs. test, 15±1 trials vs. 23±1 trials, p<0.001, rank sum = 178).
Figure 2 with 3 supplements
Locus coeruleus (LC) inhibition enhances medial PFC (mPFC) engagement and broadens tuning.
(a) Illustration of miniscope recording in the mPFC with DREADD inhibition in the LC. (b) Top: Histology showing lens implant and GCaMP6f expression in the mPFC (prelimbic). Bottom: Snapshot of miniscope recording during behavior. (c) Example time series of fluorescence signals. Over 50 ROIs were acquired from this session. (d) Left to right: Example traces of individual mPFC neurons responding to choice (left), trial history (middle), and switch (right) based on activity prior to choice (gray bars). (e) Example behavioral progression. Each dot represents a trial. We define the initial mixed correct and incorrect trials (rule-learning) and the last set of consecutive correct trials (rule-following) as two different states in switching behavior. (f) Bar plots showing the percentage of mPFC neurons responding to task-related variables in the control (black) and test (red) groups. Control vs. test, choice responsive: 10% (59/593) vs 17% (72/432), p=0.002, χ2=10.1; history responsive: 6% (34/593) vs 13% (55/432), p<0.001, χ2=15.4; switch responsive: 17% (102/593) vs 25% (106/432), p=0.004, χ2=8.3; overall fraction of responsive neurons: 27% (159/593) vs 40% (172/432), p<0.001, χ2=19.3; the fraction of mixed tuning neurons among all responsive neurons: 20% (31/159) vs 32% (55/172), p=0.01, χ2=6.7, Chi-squared test.
Figure 2—figure supplement 1
The effect of LC inhibition on calcium activity of mPFC neurons.
(a) Cumulative distribution of the frequency of calcium transients between control (black, n=593 neurons) and test groups (red, n=432 neurons). Control vs. test: 1.04±0.02 /min vs. 1.03±0.03 /min, p=0.83, rank sum = 30,000. (b) Cumulative distribution of transient duration between control (black) and test (red) groups. mPFC neurons in the test group mice exhibited slightly shorter transients. Control vs. test: 3.4±0.1 s vs. 3.2±0.1 s, p<0.001, rank sum = 32,000. (c) Cumulative distribution of transient amplitude between control (black) and test (red) groups. Control vs. test: 4.7±0.04 vs 4.8±0.06, p=0.21, rank sum = 30,000.
Figure 2—figure supplement 2
Mixed tuning in the mPFC.
For example, the first bar represents that 18% of trial-history responsive neurons also encode switch of attention (black bar), and that 21% of history responsive neurons also encode choice (red bar).
Figure 2—figure supplement 3
Dual-camera tracking of mouse behavior.
Schematic of the dual-camera setup (one overhead camera and one side-view camera) and three example frames captured during a digging event from the side-view camera. Independent behavioral analyses showed that the difference between digging onset estimated from the overhead camera and the side-view camera is 1.8±1.0 frames (signed value) or 5.2±0.6 frames (absolute value, 42 trials from two mice). Given the 20 Hz video rate, the time difference is on the order of 100 ms.
Figure 3 with 1 supplement
Locus coeruleus (LC) inhibition dampens medial PFC (mPFC) population dynamics during switching.
(a) Population vectors of mPFC activity representing early (light color) and late (dark color) states in control (black, left) and test (red, right) groups. Each line represents a population vector from a subset of neurons. (b) Projection of population vectors in (a) onto the first two PCs. (c) Left: Euclidean distance (mean ± SEM) between state vectors aligned to choice for control (black) and test (red) groups. Arrows indicate maximal fluctuations prior to choice (peak). Right: Comparison of Euclidean distance quantified prior to choice for control (black) and test (red) groups. Control vs. test, 12.9±0.08 vs 8.9±0.05, p<0.001, rank sum = 610, n=20. Sample size represents number of bootstraps. (d) Comparison of peak Euclidean distance quantified prior to choice for control (black) and test (red) groups. Control vs. test: 4.0±0.10 vs 2.1±0.06, p<0.001, rank sum = 610, n=20. (e) Comparison of vector similarities between the early and late states for control and test groups. Correlation coefficient, control vs. test: 0.15±0.04 vs 0.95±0.01, p<0.001, rank sum = 210, n=20. Black and red dots indicate group mean in (c–e).
-
Figure 3—source data 1
Data to generate c–e.
- https://cdn.elifesciences.org/articles/105911/elife-105911-fig3-data1-v1.zip
Figure 3—figure supplement 1
State vectors were more similar with LC inhibition.
(a) 2D projection of medial PFC (mPFC) population vectors in the control group during early (gray) and late (black) states. (b) 2D projection of mPFC population vectors in the test group during early (light red) and late (dark red) states.
Figure 4 with 1 supplement
Locus coeruleus (LC) inhibition impairs medial PFC (mPFC) encoding capacity of switching.
(a) Example behavioral state progression (solid curve: 0-early, 1-late) and hidden Markov model (HMM) predicted state progression (dashed curve) in a control session (black, left) and a test session (red, right). State prediction accuracy is 85% (control) and 71% (test). (b) Left: Cumulative distribution of the accuracy of predicting behavioral states in control (black) and test (red) groups. Sample size represents the total number of iterations that the model was tested (20 times per recording, four control mice, and four test mice). Control vs. test: 0.89±0.01 vs 0.75±0.02, p<0.001, rank sum = 7,828. Right: Cumulative distribution of the accuracy of predicting switch point in control (black) and test (red) groups. Control vs. test: –4±1 trials vs. –8±1 trials, p<0.001, rank sum = 7,398. (c) Example sequences of animals’ choices (solid, top) and generalized linear model (GLM) predicted choices (dashed, bottom) in a control session (black, left) and a test session (red, right). Prediction accuracy is 82% (control) and 60% (test). (d) Cumulative distribution of the accuracy of predicting trial-by-trial choices in control (black) and test (red) groups. Control vs. test: 0.75±0.01 vs 0.68±0.01, p<0.001, rank sum = 4,980.
-
Figure 4—source data 1
Data to generate b, d.
- https://cdn.elifesciences.org/articles/105911/elife-105911-fig4-data1-v1.zip
Figure 4—figure supplement 1
LC inhibition did not affect gross motor functions.
(a) Example movement trajectories during behavior for a control and a test mouse, respectively. (b–d) Distance traveled per trial, speed and response latency did not differ between test (n=4) and control (n=4) group mice. Distance traveled, control vs test: 133.8±20.8 cm vs. 130.9±16.2 cm, p=0.91, t=0.11; Locomotion speed, control vs test: 0.87±0.15 cm/s vs. 0.87±0.15 cm/s, p=0.99, t=–0.009; Reaction time (latency from trial start to digging), control vs test: 14.1±6.4 s vs. 10.6±1 s, p=0.56, t=0.61.
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Genetic reagent (Mus musculus) | DBH-Cre | MMRRC | 036778-UCD | |
| Strain, strain background (M. musculus) | C57BL/6 J | JAX | Strain #:000664 | |
| Recombinant DNA reagent | AAV8-hSyn-DIO-hM4D(Gi)-mCherry | Addgene | 44362-AAV8 | |
| Recombinant DNA reagent | AAV1-Syn-GCaMP6f-WPRE-SV40 | Addgene | 100837-AAV1 | |
| Antibody | Rabbit polyclonal anti-Tyrosine Hydroxylase | Thermo Fisher | OPA1-04050 | Primary 1:1000 |
| Antibody | Goat anti-rabbit polyclonal secondary | Thermo Fisher | A32731/A32740 | Secondary 1:500 |
| Software, algorithm | Matlab | MathWorks | RRID:SCR_001622 | |
| Other | Miniscope | Inscopix | nVista | |
| Chemical compound | Clozapine-N-oxide | Enzo Life Sciences | BML-NS105-0005 |
Additional files
-
Supplementary file 1
The fraction of specific groups of task-encoding neurons in individual mice from the control (n=4) and test (n=4) groups.
- https://cdn.elifesciences.org/articles/105911/elife-105911-supp1-v1.docx
-
MDAR checklist
- https://cdn.elifesciences.org/articles/105911/elife-105911-mdarchecklist1-v1.docx
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Locus coeruleus modulation of prefrontal dynamics during attentional switching in mice
eLife 14:RP105911.
https://doi.org/10.7554/eLife.105911.4
