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Shiromani PJ, Vidal-Ortiz A. Most dynorphin neurons in the zona incerta-perifornical area are active in waking relative to non-rapid-eye movement and rapid-eye movement sleep. Sleep 2024; 47:zsae065. [PMID: 38447008 DOI: 10.1093/sleep/zsae065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/26/2024] [Indexed: 03/08/2024] Open
Abstract
Dynorphin is an endogenous opiate localized in many brain regions and spinal cord, but the activity of dynorphin neurons during sleep is unknown. Dynorphin is an inhibitory neuropeptide that is coreleased with orexin, an excitatory neuropeptide. We used microendoscopy to test the hypothesis that, like orexin, the dynorphin neurons are wake-active. Dynorphin-cre mice (n = 3) were administered rAAV8-Ef1a-Con/Foff 2.0-GCaMP6M into the zona incerta-perifornical area, implanted with a GRIN lens (gradient reflective index), and electrodes to the skull that recorded sleep. One month later, a miniscope imaged calcium fluorescence in dynorphin neurons during multiple bouts of wake, non-rapid-eye movement (NREM), and rapid-eye movement (REM) sleep. Unbiased data analysis identified changes in calcium fluorescence in 64 dynorphin neurons. Most of the dynorphin neurons (72%) had the highest fluorescence during bouts of active and quiet waking compared to NREM or REM sleep; a subset (20%) were REM-max. Our results are consistent with the emerging evidence that the activity of orexin neurons can be classified as wake-max or REM-max. Since the two neuropeptides are coexpressed and coreleased, we suggest that dynorphin-cre-driven calcium sensors could increase understanding of the role of this endogenous opiate in pain and sleep.
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Affiliation(s)
- Priyattam J Shiromani
- Laboratory of Sleep Medicine and Chronobiology, Research Service, Ralph H. Johnson Veterans Healthcare System Charleston, SC, USA
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Aurelio Vidal-Ortiz
- Laboratory of Sleep Medicine and Chronobiology, Research Service, Ralph H. Johnson Veterans Healthcare System Charleston, SC, USA
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Vidal-Ortiz A, Blanco-Centurion C, Shiromani PJ. Unilateral optogenetic stimulation of Lhx6 neurons in the zona incerta increases REM sleep. Sleep 2024; 47:zsad217. [PMID: 37599437 DOI: 10.1093/sleep/zsad217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/08/2023] [Indexed: 08/22/2023] Open
Abstract
To determine how a waking brain falls asleep researchers have monitored and manipulated activity of neurons and glia in various brain regions. While imaging Gamma-Aminobutyric Acid (GABA) neurons in the zona incerta (ZI) we found a subgroup that anticipates onset of NREM sleep (Blanco-Centurion C, Luo S, Vidal-Ortiz A, Swank C, Shiromani PJ. Activity of a subset of vesicular GABA-transporter neurons in the ventral ZI anticipates sleep onset. Sleep. 2021;44(6):zsaa268. doi:10.1093/sleep/zsaa268.). To differentiate the GABA subtype we now image and optogenetically manipulate the ZI neurons containing the transcription factor, Lhx6. In the first study, Lhx6-cre mice (n = 5; female = 4) were given rAAV-DJ-EF1a-DIO-GCaMP6M into the ZI (isofluorane anesthesia), a GRIN lens implanted, and 21days later sleep and fluorescence in individual Lhx6 neurons were recorded for 4 hours. Calcium fluorescence was detected in 132 neurons. 45.5% of the Lhx6 neurons were REM-max; 30.3% were wake-max; 11.4% were wake + REM max; 9% were NREM-max; and 3.8% had no change. The NREM-max group of neurons fluoresced 30 seconds ahead of sleep onset. The second study tested the effects of unilateral optogenetic stimulation of the ZI Lhx6 neurons (n = 14 mice) (AAV5-Syn-FLEX-rc[ChrimsonR-tdTomato]. Stimulation at 1 and 5 Hz (1 minute on- 4 minutes off) significantly increased percent REM sleep during the 4 hours stimulation period (last half of day cycle). The typical experimental approach is to stimulate neurons in both hemispheres, but here we found that low-frequency stimulation of ZI Lhx6 neurons in one hemisphere is sufficient to shift states of consciousness. Detailed mapping combined with mechanistic testing is necessary to identify local nodes that can shift the brain between wake-sleep states.
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Affiliation(s)
- Aurelio Vidal-Ortiz
- Laboratory of Sleep Medicine and Chronobiology, Ralph H. Johnson Veterans Healthcare System, Charleston, SC, USA
| | - Carlos Blanco-Centurion
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Priyattam J Shiromani
- Laboratory of Sleep Medicine and Chronobiology, Ralph H. Johnson Veterans Healthcare System, Charleston, SC, USA
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
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Blanco-Centurion C, Vidal-Ortiz A, Sato T, Shiromani PJ. Activity of GABA neurons in the zona incerta and ventral lateral periaqueductal grey is biased towards sleep. Sleep 2023; 46:6902001. [PMID: 36516419 DOI: 10.1093/sleep/zsac306] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/31/2022] [Indexed: 12/15/2022] Open
Abstract
STUDY OBJECTIVES As in various brain regions the activity of gamma-aminobutyric acid (GABA) neurons is largely unknown, we measured in vivo changes in calcium fluorescence in GABA neurons in the zona incerta (ZI) and the ventral lateral periaqueductal grey (vlPAG), two areas that have been implicated in regulating sleep. METHODS vGAT-Cre mice were implanted with sleep electrodes, microinjected with rAAV-DIO-GCaMP6 into the ZI (n = 6) or vlPAG (n = 5) (isoflurane anesthesia) and a GRIN (Gradient-Index) lens inserted atop the injection site. Twenty-one days later, fluorescence in individual vGAT neurons was recorded over multiple REM cycles. Regions of interest corresponding to individual vGAT somata were automatically extracted with PCA-ICA analysis. RESULTS In the ZI, 372 neurons were identified. Previously, we had recorded the activity of 310 vGAT neurons in the ZI and we combined the published dataset with the new dataset to create a comprehensive dataset of ZI vGAT neurons (total neurons = 682; mice = 11). In the vlPAG, 169 neurons (mice = 5) were identified. In both regions, most neurons were maximally active in REM sleep (R-Max; ZI = 51.0%, vlPAG = 60.9%). The second most abundant group was W-Max (ZI = 23.9%, vlPAG = 25.4%). In the ZI, but not in vlPAG, there were neurons that were NREMS-Max (11.7%). vlPAG had REMS-Off neurons (8.3%). In both areas, there were two minor classes: wake/REMS-Max and state indifferent. In the ZI, the NREMS-Max neurons fluoresced 30 s ahead of sleep onset. CONCLUSIONS These descriptive data show that the activity of GABA neurons is biased in favor of sleep in two brain regions implicated in sleep.
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Affiliation(s)
| | - Aurelio Vidal-Ortiz
- Laboratory of Sleep Medicine and Chronobiology, Ralph H. Johnson Veterans Healthcare System, Charleston, SC, USA
| | - Takashi Sato
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - Priyattam J Shiromani
- Department of Psychiatry and Behavioral Sciences, Charleston, SC, USA
- Laboratory of Sleep Medicine and Chronobiology, Ralph H. Johnson Veterans Healthcare System, Charleston, SC, USA
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Blanco-Centurion C, Vidal-Ortiz A, Shiromani P. 0126 Zona incerta Lhx6 neurons are most active during NREM and REM sleep and after prolonged waking. Sleep 2022. [DOI: 10.1093/sleep/zsac079.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction
Emerging data shows that GABA neurons in the zona incerta (ZI) play a prominent role in regulating sleep. Transfer of the orexin gene into ZI neurons blocks cataplexy in narcoleptic orexin-knockout mice (Liu et al., JNeurosci, 2011) and vGAT GABA neurons in the ZI anticipate onset of NREM (Blanco-Centurion et al., SLEEP, 2021). To identify the subtype of GABA neurons regulating sleep, we examined the activity of Lhx6 neurons. This study tests the hypothesis that Lhx6 neurons show peak calcium fluorescence during sleep, and that the fluorescence is further increased after prolonged waking.
Methods
In Lhx6-cre mice (mice=4; all females; 4-5 mo), rAAV-DIO-GCaMP6s was delivered stereotaxically to the ZI (isofluorane anesthesia) and a GRIN lens, along with EEG and EMG electrodes were implanted. 21d later a miniscope (INSCOPIX) was attached, and after 3d of adaptation, sleep and fluorescence in individual Lhx6 neurons were recorded for 4h (baseline). On another day, the mice were kept awake for 6h (gentle handling; 9a-3p) and fluorescence in Lhx6 neurons was recorded for 2h during recovery sleep. The imaged data from the two recording periods (baseline and recovery sleep) was combined into a single data file and the change in fluorescence was determined against the mean image frame (F0). Previously, we and others found that the GCamP calcium fluorescence is a direct measure of action potentials and serves as a marker of activity.
Results
97 neurons were automatically extracted (PCA-ICA analysis; blinded without knowledge of sleep state). In 66 neurons (68%) the average fluorescence was significantly higher during REM, NREM or both, compared to waking (Mixed Model ANOVA; SPSS25; P<0.01). In this population the fluorescence was significantly higher during recovery sleep compared to baseline (P<0.001) indicating increased activity of the sleep-active neurons during recovery sleep. With ensuing sleep, the increase in fluorescence gradually returned to baseline levels, attesting to the fluorescence as a marker of homeostatic sleep pressure. In 14 neurons (14%), fluorescence was highest in waking as compared to the other states during baseline, and in these neurons, fluorescence did not increase after sleep loss. Interestingly, six neurons (6%) were most active in waking and NREM but silent in REM (REM-off).
Conclusion
This is the first study to measure fluorescence in individual neurons after sleep loss. We find that the fluorescence in two-thirds of ZI Lhx6 neurons is tightly linked to sleep, and that the average fluorescence is further increased after prolonged waking. Microendoscopy is superior to indirect measures such as c-FOS or photometry in gauging sleep pressure in individual neurons.
Support (If Any)
VA BX000798, 1K6BX004216.
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Blanco-Centurion C, Luo S, Vidal-Ortiz A, Swank C, Shiromani PJ. Activity of a subset of vesicular GABA-transporter neurons in the ventral zona incerta anticipates sleep onset. Sleep 2021; 44:6017820. [PMID: 33270105 DOI: 10.1093/sleep/zsaa268] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/01/2020] [Indexed: 01/03/2023] Open
Abstract
STUDY OBJECTIVES Sleep and wake are opposing behavioral states controlled by the activity of specific neurons that need to be located and mapped. To better understand how a waking brain falls asleep it is necessary to identify activity of individual phenotype-specific neurons, especially neurons that anticipate sleep onset. In freely behaving mice, we used microendoscopy to monitor calcium (Ca2+) fluorescence in individual hypothalamic neurons expressing the vesicular GABA transporter (vGAT), a validated marker of GABA neurons. METHODS vGAT-Cre mice (male = 3; female = 2) transfected with rAAV-FLEX-GCaMP6M in the lateral hypothalamus were imaged 30 days later during multiple episodes of waking (W), non-rapid-eye movement sleep (NREMS) or REMS (REMS). RESULTS 372 vGAT neurons were recorded in the zona incerta. 23.9% of the vGAT neurons showed maximal fluorescence during wake (classified as wake-max), 4% were NREM-max, 56.2% REM-max, 5.9% wake/REM max, while 9.9% were state-indifferent. In the NREM-max group, Ca2+ fluorescence began to increase before onset of NREM sleep, remained high throughout NREM sleep, and declined in REM sleep. CONCLUSIONS We found that 60.2% of the vGAT GABA neurons in the zona incerta had activity that was biased towards sleep (NREM and REMS). A subset of vGAT neurons (NREM-max) became active in advance of sleep onset and may induce sleep by inhibiting the activity of the arousal neurons. Abnormal activation of the NREM-max neurons may drive sleep attacks and hypersomnia.
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Affiliation(s)
- Carlos Blanco-Centurion
- Laboratory of Sleep Medicine and Chronobiology, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC
| | - SiWei Luo
- Laboratory of Sleep Medicine and Chronobiology, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC
| | | | - Colby Swank
- Laboratory of Sleep Medicine and Chronobiology, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC
| | - Priyattam J Shiromani
- Laboratory of Sleep Medicine and Chronobiology, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC.,Ralph H. Johnson VA Medical Center, Charleston, SC
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Abstract
It was in the influenza pandemic of 1918 that von Economo identified specific brain regions regulating sleep and wake. Since then researchers have used a variety of tools to determine how the brain shifts between states of consciousness. In every enterprise new tools have validated existing data, corrected errors and made new discoveries to advance science. The brain is a challenge but new tools can disentangle the brain network. We summarize the newest tool, a miniature microscope, that provides unprecedented view of activity of glia and neurons in freely behaving mice. With this tool we have observed that the activity of a majority of GABA and MCH neurons in the lateral hypothalamus is heavily biased toward sleep. We suggest that miniscope data identifies activity at the cellular level in normal versus diseased brains, and also in response to specific hypnotics. Shifts in activity in small networks across the brain will help identify point of criticality that switches the brain from wake to sleep.
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Affiliation(s)
- Priyattam J Shiromani
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States.,Department of Psychiatry and Biobehavioral Science, Medical University of South Carolina, Charleston, SC, United States
| | - Carlos Blanco-Centurion
- Department of Psychiatry and Biobehavioral Science, Medical University of South Carolina, Charleston, SC, United States
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Sun Y, Blanco-Centurion C, Bendell E, Vidal-Ortiz A, Luo S, Liu M. Correction: Activity dynamics of amygdala GABAergic neurons during cataplexy of narcolepsy. eLife 2019; 8:52397. [PMID: 31583999 PMCID: PMC6777978 DOI: 10.7554/elife.52397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Sun Y, Blanco-Centurion C, Bendell E, Vidal-Ortiz A, Luo S, Liu M. Activity dynamics of amygdala GABAergic neurons during cataplexy of narcolepsy. eLife 2019; 8:48311. [PMID: 31411561 PMCID: PMC6703899 DOI: 10.7554/elife.48311] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/11/2019] [Indexed: 12/26/2022] Open
Abstract
Recent studies showed activation of the GABAergic neurons in the central nucleus of the amygdala (CeA) triggered cataplexy of sleep disorder narcolepsy. However, there is still no direct evidence on CeA GABAergic neurons’ real-time dynamic during cataplexy. We used a deep brain calcium imaging tool to image the intrinsic calcium transient as a marker of neuronal activity changes in the narcoleptic VGAT-Cre mice by expressing the calcium sensor GCaMP6 into genetically defined CeA GABAergic neurons. Two distinct GABAergic neuronal groups involved in cataplexy were identified: spontaneous cataplexy-ON and predator odor-induced cataplexy-ON neurons. Majority in the latter group were inactive during regular sleep/wake cycles but were specifically activated by predator odor and continued their intense activities into succeeding cataplexy bouts. Furthermore, we found that CeA GABAergic neurons became highly synchronized during predator odor-induced cataplexy. We suggest that the abnormal activation and synchronization of CeA GABAergic neurons may trigger emotion-induced cataplexy.
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Affiliation(s)
- Ying Sun
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, United States
| | - Carlos Blanco-Centurion
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, United States
| | - Emmaline Bendell
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, United States
| | - Aurelio Vidal-Ortiz
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, United States
| | - Siwei Luo
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, United States
| | - Meng Liu
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, United States
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Sun Y, Blanco-Centurion C, Vidal-Ortiz A, Luo S, Zou B, Shiromani P, Liu M. 0003 Deep-brain Imaging Identifies Cataplexy-on Neurons In The Amygdala. Sleep 2019. [DOI: 10.1093/sleep/zsz067.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ying Sun
- Medical University of South Carolina, Charleston, SC, USA
| | | | | | - Siwei Luo
- Medical University of South Carolina, Charleston, SC, USA
| | - Bingyu Zou
- Medical University of South Carolina, Charleston, SC, USA
| | - priyattam Shiromani
- Medical University of South Carolina, Charleston, SC, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Meng Liu
- Medical University of South Carolina, Charleston, SC, USA
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