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

As an important part of the cytoskeleton, microtubules play a crucial role in many cellular processes, such as cell division, intracellular transport, and maintaining cell morphology. The MAP1 family is an important family of microtubule-associated proteins, which includes three members: MAP1A, MAP1B, and MAP1S. These proteins are widely involved in the dynamic regulation of the cytoskeleton and play a key role in the development and function of the central nervous system, especially in the development and function of neurons. This study reviews the research progress of the MAP1 family, mainly focusing on the structure and function of MAP1 family members, and paying particular attention to their roles in neuronal development and regeneration, regulatory mechanisms, and neurodegenerative diseases.
Humans ; Animals ; Microtubule-Associated Proteins/classification* ; Neurons/cytology* ; Neurodegenerative Diseases/physiopathology* ; Microtubules/physiology* ; Cytoskeleton/physiology*

Repeated transcranial magnetic stimulation (rTMS) is one of the commonly used brain stimulation techniques. In order to investigate the effects of rTMS on the excitability of different types of neurons, this study is conducted to investigate the effects of rTMS on the cognitive function of mice and the excitability of hippocampal glutaminergic neurons and gamma-aminobutyric neurons from the perspective of electrophysiology. In this study, mice were randomly divided into glutaminergic control group, glutaminergic magnetic stimulation group, gamma-aminobutyric acid energy control group, and gamma-aminobutyric acid magnetic stimulation group. The four groups of mice were injected with adeno-associated virus to label two types of neurons and were implanted optical fiber. The stimulation groups received 14 days of stimulation and the control groups received 14 days of pseudo-stimulation. The fluorescence intensity of calcium ions in mice was recorded by optical fiber system. Behavioral experiments were conducted to explore the changes of cognitive function in mice. The patch-clamp system was used to detect the changes of neuronal action potential characteristics. The results showed that rTMS significantly improved the cognitive function of mice, increased the amplitude of calcium fluorescence of glutamergic neurons and gamma-aminobutyric neurons in the hippocampus, and enhanced the action potential related indexes of glutamergic neurons and gamma-aminobutyric neurons. The results suggest that rTMS can improve the cognitive ability of mice by enhancing the excitability of hippocampal glutaminergic neurons and gamma-aminobutyric neurons.
Animals ; Mice ; Hippocampus/cytology* ; Transcranial Magnetic Stimulation ; Neurons/physiology* ; Male ; Cognition/physiology* ; gamma-Aminobutyric Acid/metabolism* ; Action Potentials/physiology*

OBJECTIVES: The neurotoxicity of carbon monoxide (CO) to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning (DEACMP). Our previous study found that retinoic acid (RA) can suppress the neurotoxic effects of CO. This study further explores, in vivo and in vitro, the molecular mechanisms by which RA alleviates CO-induced central nervous system damage. METHODS: A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO, and a DEACMP animal model was established in adult Kunming mice. Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Annexin V/propidium iodide (PI) double staining. The transcriptional and protein expression of each gene was detected using real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting. Long noncoding RNA (lncRNA) SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes. In DEACMP mice, SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression. RESULTS: RA at 10 and 20 μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes, downregulation of SNHG15 and LINGO-1, and upregulation of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) (all P<0.05). Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity (all P<0.05). Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels (all P<0.05). Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP (all P<0.05). CONCLUSIONS RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes, thereby reducing central nervous system injury and exerting neuroprotective effects. LncRNA SNHG15 and LINGO-1 are key molecules mediating RA-induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway. These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.
Animals ; RNA, Long Noncoding/physiology* ; Brain-Derived Neurotrophic Factor/genetics* ; Carbon Monoxide Poisoning/complications* ; Mice ; Tretinoin/pharmacology* ; Nerve Tissue Proteins/metabolism* ; Membrane Proteins/metabolism* ; Apoptosis/drug effects* ; Hippocampus/cytology* ; Receptor, trkB/metabolism* ; Neurons/drug effects* ; Male ; Brain Diseases/etiology* ; Oligodendroglia/drug effects* ; Signal Transduction ; Cell Line

The thalamic reticular nucleus (TRN) plays a crucial role in regulating sensory encoding, even at the earliest stages of visual processing, as evidenced by numerous studies. Orientation selectivity, a vital neural response, is essential for detecting objects through edge perception. Here, we demonstrate that somatostatin (SOM)-expressing and parvalbumin (PV)-expressing neurons in the TRN project to the dorsal lateral geniculate nucleus and modulate orientation selectivity and the capacity for visual information processing in the primary visual cortex (V1). These findings show that SOM-positive and PV-positive neurons in the TRN are powerful modulators of visual information encoding in V1, revealing a novel role for this thalamic nucleus in influencing visual processing.
Animals ; Somatostatin/metabolism* ; Parvalbumins/metabolism* ; Neurons/physiology* ; Thalamic Nuclei/physiology* ; Visual Pathways/physiology* ; Mice ; Mice, Inbred C57BL ; Visual Perception/physiology* ; Male ; Mice, Transgenic ; Visual Cortex/physiology* ; Primary Visual Cortex/cytology*

Humans and animals have a fundamental ability to use experiences and environmental information to organize behavior. It often happens that humans and animals make decisions and prepare actions under uncertain situations. Uncertainty would significantly affect the state of animals' minds, but may not be reflected in behavior. How to "read animals' mind state" under different situations is a challenge. Here, we report that neuronal activity in the medial prefrontal cortex (mPFC) of rats can reflect the environmental uncertainty when the task situation changes from certain to uncertain. Rats were trained to perform behavioral tasks under certain and uncertain situations. Under certain situations, rats were required to simply repeat two nose-poking actions that each triggered short auditory tone feedback (single-task situation). Whereas under the uncertain situation, the feedback could randomly be either the previous tone or a short musical rhythm. No additional action was required upon the music feedback, and the same secondary nose-poking action was required upon the tone feedback (dual-task situation); therefore, the coming task was uncertain before action initiation. We recorded single-unit activity from the mPFC when the rats were performing the tasks. We found that in the dual task, when uncertainty was introduced, many mPFC neurons were actively engaged in dealing with the uncertainty before the task initiation, suggesting that the rats could be aware of the task situation change and encode the information in the mPFC before the action of task initiation.
Animals ; Prefrontal Cortex/cytology* ; Uncertainty ; Neurons/physiology* ; Male ; Rats ; Rats, Long-Evans ; Action Potentials/physiology* ; Acoustic Stimulation

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

Axon initial segment (AIS) is the most excitable subcellular domain of a neuron for action potential initiation. AISs of cortical projection neurons (PNs) receive GABAergic synaptic inputs primarily from chandelier cells (ChCs), which are believed to regulate action potential generation and modulate neuronal excitability. As individual ChCs often innervate hundreds of PNs, they may alter the activity of PN ensembles and even impact the entire neural network. During postnatal development or in response to changes in network activity, the AISs and axo-axonic synapses undergo dynamic structural and functional changes that underlie the wiring, refinement, and adaptation of cortical microcircuits. Here we briefly introduce the history of ChCs and review recent research advances employing modern genetic and molecular tools. Special attention will be attributed to the plasticity of the AIS and the ChC-PN connections, which play a pivotal role in shaping the dynamic network under both physiological and pathological conditions.
Animals ; Neuronal Plasticity/physiology* ; Cerebral Cortex/cytology* ; Axons/physiology* ; Nerve Net/physiology* ; Humans ; Synapses/physiology* ; GABAergic Neurons/physiology*

A deficit in spatial memory has been taken as an early predictor of Alzheimer's disease (AD) or mild cognitive impairment (MCI). The uncinate fasciculus (UF) is a long-range white-matter tract that connects the anterior temporal lobe with the orbitofrontal cortex (OFC) in primates. Previous studies have shown that the UF impairment associated with spatial memory deficits may be an important pathological change in aging and AD, but its exact role in spatial memory is not well understood. The pathway arising from the postrhinal cortex (POR) and projecting to the ventrolateral orbitofrontal cortex (vlOFC) performs most of the functions of the UF in rodents. Although the literature suggests an association between spatial memory and the regions connected by the POR-vlOFC pathway, the function of the pathway in spatial memory is relatively unknown. To further illuminate the function of the UF in spatial memory, we dissected the POR-vlOFC pathway in mice. We determined that the POR-vlOFC pathway is a glutamatergic structure, and that glutamatergic neurons in the POR regulate spatial memory retrieval. We also demonstrated that the POR-vlOFC pathway specifically transmits spatial information to participate in memory retrieval. These findings provide a deeper understanding of UF function and dysfunction related to disorders of memory, as in MCI and AD.
Animals ; Glutamic Acid ; physiology ; Male ; Mental Recall ; physiology ; Mice, Inbred C57BL ; Neural Pathways ; cytology ; physiology ; Neuroanatomical Tract-Tracing Techniques ; Neurons ; physiology ; Prefrontal Cortex ; cytology ; physiology ; Spatial Memory ; physiology ; Temporal Lobe ; cytology ; physiology

The complex spatial and temporal organization of neural activity in the brain is important for information-processing that guides behavior. Hence, revealing the real-time neural dynamics in freely-moving animals is fundamental to elucidating brain function. Miniature fluorescence microscopes have been developed to fulfil this requirement. With the help of GRadient INdex (GRIN) lenses that relay optical images from deep brain regions to the surface, investigators can visualize neural activity during behavioral tasks in freely-moving animals. However, the application of GRIN lenses to deep brain imaging is severely limited by their availability. Here, we describe a protocol for GRIN lens coating that ensures successful long-term intravital imaging with commercially-available GRIN lenses.
Animals ; Biocompatible Materials ; Brain ; physiology ; Hippocampus ; cytology ; Lenses ; Mice, Inbred C57BL ; Mice, Transgenic ; Microscopy, Fluorescence ; methods ; Neuroimaging ; instrumentation ; methods ; Neurons ; physiology