The purpose of this study was to investigate the anxiety-like behaviors, circadian rhythms and sleep, and to elucidate the possible underlying mechanisms of the abnormal sleep behavior in Shank3 gene knockout (Shank3-KO) mice. The anxiety-like behaviors were detected by elevated plus-maze (EPM) test, open field test (OFT) and tail suspension test (TST). The circadian rhythms were detected by running wheel test. The electroencephalogram (EEG)/electromyogram (EMG) recordings were performed synchronically by polysomnograph. The distribution of SHANK3 in anterior cingulate cortex (ACC), paraventricular thalamus (PVT), nucleus accumbens (NAc), basolateral amygdala (BLA) and hippocampal CA2 region in wild type (WT) mice was detected by immunofluorescence assay. The protein expression of c-Fos in PVT, ACC and NAc was also detected by immunofluorescence assay during light cycle. The colocalization of c-Fos and vesicular glutamate transporter 2 (Vglut2, a marker for glutamatergic neurons) in the PVT was detected by immunofluorescence double labeling experiment. The results of EPM test showed that, compared with the WT mice, the Shank3-KO mice showed less time in open arms and less number of open arm entries. The results of OFT showed that the Shank3-KO mice showed less time in central area and less number of central area entries. The immobility time of Shank3-KO mice was increased in the TST. The results of running wheel rhythm test showed that the phase shift time of Shank3-KO mice in the continuous dark period was increased. The results of EEG/EMG recording showed that, compared with the WT mice, the duration of wakefulness in Shank3-KO mice was increased and the duration of non-rapid eye movement (NREM) sleep was decreased during light phase; The bout number of wakefulness was increased, the bout number of NREM sleep was decreased, NREM-wake transitions were increased, and wake-NREM transitions were decreased during light phase. SHANK3 was expressed in ACC, PVT, NAc and BLA in the WT mice. The expression of c-Fos in the PVT of Shank3-KO mice was up-regulated 2 h after entering the light phase, and majority of c-Fos was co-localized with Vglut2. These results suggest that the anxiety level of Shank3-KO mice is increased, the regulation of the internal rhythms is decreased, and the bout number of wakefulness is increased during light phase. The glutamatergic neurons in PVT may be involved in the regulation of abnormal sleep behavior in Shank3-KO mice during the light phase.
Animals ; Mice, Knockout ; Mice ; Neurons/metabolism* ; Nerve Tissue Proteins/physiology* ; Male ; Midline Thalamic Nuclei/cytology* ; Circadian Rhythm/physiology* ; Sleep/physiology* ; Anxiety/physiopathology* ; Proto-Oncogene Proteins c-fos/metabolism* ; Vesicular Glutamate Transport Protein 2/metabolism* ; Mice, Inbred C57BL ; Microfilament Proteins

OBJECTIVE: To determine whether the glutamatergic neurons in the paraventricular nucleus of the thalamus (PVT) is involved in the change of consciousness induced by propofol through a combination of behavioral and electroencephalography (EEG) recordings. METHODS: Healthy male VGluT2-IRES-Cre mice aged 8-12 weeks were used in this experiment. (1) The glutamatergic neurons in the PVT was selectively damaged, and its effect on propofol anesthesia induction and recovery times as well as the energy of EEG in different frequency bands were observed. (2) Optogenetics was utilized to selectively activate or inhibit glutamatergic neurons in the PVT to assess their influence on anesthesia induction and recovery times under propofol as well as the energy of EEG in different frequency bands. RESULTS: (1) Selective ablation of glutamatergic neurons in the PVT significantly delayed recovery from propofol anesthesia with statistical difference as compared with the control group (s: 409.43±117.49 vs. 273.71±51.52, P < 0.05), but had no significant effect on anesthesia induction time. During the recovery phase of propofol, selective ablation of glutamatergic neurons in the PVT exhibited higher α-wave (1-4 Hz) power and reduced β-wave (12-15 Hz) power as compared with the control group. (2) Optogenetic activation of glutamatergic neurons in the PVT significantly prolonged anesthesia induction time under propofol (s: 161.67±29.09 vs. 119.33±18.98, P < 0.05) while significantly shortening the recovery time from propofol anesthesia (s: 208.67±57.19 vs. 288.83±34.52, P < 0.05). During the induction phase of propofol, activation of glutamatergic neurons in PVT reduced α-wave and α-wave (8-12 Hz) power, while during the recovery phase, α-wave power significantly increased as compared with the control group. (3) Optogenetic inhibition of glutamatergic neurons in the PVT delayed recovery from propofol anesthesia (s: 403.50±129.06 vs. 252.83±45.31, P < 0.05), but had no significant effect on induction time. During both the induction phase and recovery phase of propofol, the optogenetic inhibition of glutamatergic neurons in the PVT exhibited increased α-wave power. CONCLUSION Glutamatergic neurons in the PVT are involved in the regulation of propofol anesthesia recovery process.
Animals ; Propofol/pharmacology* ; Mice ; Neurons/physiology* ; Male ; Electroencephalography ; Wakefulness ; Midline Thalamic Nuclei ; Optogenetics

At present, the problem of drug addiction treatment mainly lies in the high relapse rate of drug addicts. Addictive drugs will bring users a strong sense of euphoria and promote drug seeking. Once the drug is withdrawn, there will be withdrawal symptoms such as strong negative emotions and uncomfortable physical reactions. The recurrence of context-induced withdrawal memory is an important reason for drug relapse. Our previous study has shown increased c-Fos expression in prelimbic cortex (PrL) neurons projecting to paraventricular nucleus of the thalamus (PVT) (PrL^-PVT) during conditioned context-induced retrieval of morphine withdrawal memory. However, whether PrL^-PVT neurons are involved in withdrawal memory retrieval and the underlying molecular mechanisms remain unknown. In this study, we used conditioned place aversion (CPA) model combined with in vivo calcium signal recording, chemogenetics and nucleus drug injection methods to investigate the role and molecular mechanism of PrL^-PVT neurons in retrieval of morphine withdrawal memory. The results showed that the calcium signals of PrL^-PVT neurons were significantly enhanced by withdrawal-related context; Inhibition of PrL^-PVT neurons blocked the conditioned context-induced morphine withdrawal memory retrieval; Activation of PrL^-PVT neurons caused animals to escape from the context; After the inhibition of NMDA receptors in the PrL, withdrawal-related context failed to increase c-Fos and Arc expressions in PrL^-PVT neurons. The above results suggest that NMDA receptors in PrL^-PVT neurons are associated with retrieval of morphine withdrawal memory. This study is of great significance for further understanding the neural circuit mechanism of withdrawal memory retrieval as well as the intervention and prevention of drug relapse.
Animals ; Substance Withdrawal Syndrome/physiopathology* ; Morphine/adverse effects* ; Neurons/physiology* ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Male ; Rats ; Paraventricular Hypothalamic Nucleus/metabolism* ; Memory ; Rats, Sprague-Dawley ; Morphine Dependence/physiopathology* ; Midline Thalamic Nuclei/physiology* ; Neural Pathways/metabolism*

The orbitofrontal cortex (ORB), a region crucial for stimulus-reward association, decision-making, and flexible behaviors, extensively connects with other brain areas. However, brain-wide inputs to projection-defined ORB neurons and the distribution of inhibitory neurons postsynaptic to neurons in specific ORB subregions remain poorly characterized. Here we mapped the inputs of five types of projection-specific ORB neurons and ORB outputs to two types of inhibitory neurons. We found that different projection-defined ORB neurons received inputs from similar cortical and thalamic regions, albeit with quantitative variations, particularly in somatomotor areas and medial groups of the dorsal thalamus. By counting parvalbumin (PV) or somatostatin (SST) interneurons innervated by neurons in specific ORB subregions, we found a higher fraction of PV neurons in sensory cortices and a higher fraction of SST neurons in subcortical regions targeted by medial ORB neurons. These results provide insights into understanding and investigating the function of specific ORB neurons.
Animals ; Neurons/physiology* ; Mice ; Prefrontal Cortex/cytology* ; Parvalbumins/metabolism* ; Brain Mapping/methods* ; Neural Pathways/physiology* ; Somatostatin/metabolism* ; Male ; Interneurons/physiology* ; Mice, Inbred C57BL ; Thalamus/physiology* ; Mice, Transgenic

Sleep deprivation has been shown to exacerbate pain sensitivity and may contribute to the onset of chronic pain, yet the precise neural mechanisms underlying this association remain elusive. In our study, we explored the contribution of cholinergic neurons within the medial habenula (MHb) to hyperalgesia induced by sleep deprivation in rats. Our findings indicate that the activity of MHb cholinergic neurons diminishes during sleep deprivation and that chemogenetic stimulation of these neurons can mitigate the results. Interestingly, we did not find a direct response of MHb cholinergic neurons to pain stimulation. Further investigation identified the interpeduncular nucleus (IPN) and the paraventricular nucleus of the thalamus (PVT) as key players in the pro-nociceptive effect of sleep deprivation. Stimulating the pathways connecting the MHb to the IPN and PVT alleviated the hyperalgesia. These results underscore the important role of MHb cholinergic neurons in modulating pain sensitivity linked to sleep deprivation, highlighting potential neural targets for mitigating sleep deprivation-induced hyperalgesia.
Animals ; Habenula/physiology* ; Sleep Deprivation/physiopathology* ; Cholinergic Neurons/physiology* ; Male ; Hyperalgesia/physiopathology* ; Rats, Sprague-Dawley ; Rats ; Interpeduncular Nucleus/physiology* ; Pain Threshold/physiology* ; Midline Thalamic Nuclei/physiology* ; Neural Pathways/physiopathology*

General anesthesia plays a significant role in modern medicine. However, the precise mechanism of general anesthesia remains unclear, posing a key scientific challenge in anesthesiology. Advances in neuroscience techniques have enabled targeted manipulation of specific neural circuits and the capture of brain-wide neural activity at high resolution. These advances hold promise for elucidating the intricate mechanisms of action of general anesthetics. This review aims to summarize our current understanding of the role of cortical and subcortical nuclei in modulating general anesthesia, providing new evidence of cortico-cortical and thalamocortical networks in relation to anesthesia and consciousness. These insights contribute to a comprehensive understanding of the neural network mechanisms underlying general anesthesia.
Humans ; Anesthesia, General ; Animals ; Nerve Net/physiology* ; Cerebral Cortex/drug effects* ; Neural Pathways/drug effects* ; Thalamus/drug effects* ; Consciousness/drug effects*

The incidence rate of anxiety and depression is significantly higher in patients with inflammatory bowel diseases (IBD) than in the general population. The mechanisms underlying dextran sulfate sodium (DSS)-induced depressive-like behaviors are still unclear. We clarified that IBD mice induced by repeated administration of DSS presented depressive-like behaviors. The paraventricular thalamic nucleus (PVT) was regarded as the activated brain region by the number of c-fos-labeled neurons. RNA-sequencing analysis showed that lipocalin 2 (Lcn2) was upregulated in the PVT of mice with DSS-induced depressive behaviors. Upregulating Lcn2 from neuronal activity induced dendritic spine loss and the secreted protein induced chemokine expression and subsequently contributed to microglial activation leading to blood-brain barrier permeability. Moreover, Lcn2 silencing in the PVT alleviated the DSS-induced depressive-like behaviors. The present study demonstrated that elevated Lcn2 in the PVT is a critical factor for DSS-induced depressive behaviors.
Mice ; Humans ; Animals ; Lipocalin-2/genetics* ; Midline Thalamic Nuclei ; Brain ; Inflammatory Bowel Diseases ; Proto-Oncogene Proteins c-fos ; Mice, Inbred C57BL

Auditory Cortex ; Depression/drug therapy* ; Thalamus

This study aims to explore the auditory response characteristics of the thalamic reticular nucleus (TRN) in awake mice during auditory information processing, so as to deepen the understanding of TRN and explore its role in the auditory system. By in vivo electrophysiological single cell attached recording of TRN neurons in 18 SPF C57BL/6J mice, we observed the responses of 314 recorded neurons to two kinds of auditory stimuli, noise and tone, applied to mice. The results showed that TRN received projections from layer six of the primary auditory cortex (A1). Among 314 TRN neurons, 56.05% responded silently, 21.02% responded only to noise and 22.93% responded to both noise and tone. The neurons with noise response can be divided into three patterns according to their response time: onset, sustain and long-lasting, accounting for 73.19%, 14.49% and 12.32%, respectively. The response threshold of the sustain pattern neurons was lower than those of the other two types. Under noise stimulation, compared with A1 layer six, TRN neurons showed unstable auditory response (P < 0.001), higher spontaneous firing rate (P < 0.001), and longer response latency (P < 0.001). Under tone stimulation, TRN's response continuity was poor, and the frequency tuning was greatly different from that of A1 layer six (P < 0.001), but their sensitivity to tone was similar (P > 0.05), and TRN's tone response threshold was much higher than that of A1 layer six (P < 0.001). The above results demonstrate that TRN mainly undertakes the task of information transmission in the auditory system. The noise response of TRN is more extensive than the tone response. Generally, TRN prefers high-intensity acoustic stimulation.
Rats ; Mice ; Animals ; Wakefulness ; Auditory Pathways/physiology* ; Rats, Wistar ; Mice, Inbred C57BL ; Thalamus/physiology*

The thalamocortical (TC) circuit is closely associated with pain processing. The hyperpolarization-activated cyclic nucleotide-gated (HCN) 2 channel is predominantly expressed in the ventral posterolateral thalamus (VPL) that has been shown to mediate neuropathic pain. However, the role of VPL HCN2 in modulating TC circuit activity is largely unknown. Here, by using optogenetics, neuronal tracing, electrophysiological recordings, and virus knockdown strategies, we showed that the activation of VPL TC neurons potentiates excitatory synaptic transmission to the hindlimb region of the primary somatosensory cortex (S1HL) as well as mechanical hypersensitivity following spared nerve injury (SNI)-induced neuropathic pain in mice. Either pharmacological blockade or virus knockdown of HCN2 (shRNA-Hcn2) in the VPL was sufficient to alleviate SNI-induced hyperalgesia. Moreover, shRNA-Hcn2 decreased the excitability of TC neurons and synaptic transmission of the VPL-S1HL circuit. Together, our studies provide a novel mechanism by which HCN2 enhances the excitability of the TC circuit to facilitate neuropathic pain.
Animals ; Mice ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels/genetics* ; Neuralgia ; RNA, Small Interfering ; Thalamus/metabolism* ; Up-Regulation