Exploring cerebral structural and functional abnormalities in a mouse model of post-traumatic headache induced by mild traumatic brain injury

Mild traumatic brain injury(mTBI)-induced post-traumatic headache(PTH)is a pressing public health concern and leading cause of disability worldwide.Although PTH is often accompanied by neurological disorders,the exact underlying mechanism remains largely unknown.Identifying potential biomarkers may prompt the diagnosis and development of effective treatments for mTBI-induced PTH.In this study,a mouse model of mTBI-induced PTH was established to investigate its effects on cerebral structure and function during short-term recovery.Results indicated that mice with mTBI-induced PTH exhibited balance deficits during the early post-injury stage.Metabolic kinetics revealed that variations in neurotransmitters were most prominent in the cerebellum,temporal lobe/cortex,and hippocampal regions during the early stages of PTH.Additionally,variations in brain functional activities and connectivity were further detected in the early stage of PTH,particularly in the cerebellum and temporal cortex,suggesting that these regions play central roles in the mechanism underlying PTH.Moreover,our results suggested that GABA and glutamate may serve as potential diagnostic or prognostic biomarkers for PTH.Future studies should explore the specific neural circuits involved in the regulation of PTH by the cerebellum and temporal cortex,with these two regions potentially utilized as targets for non-invasive stimulation in future clinical treatment.

Brain-wide activation involved in 15 mA transcranial alternating current stimulation in patients with first-episode major depressive disorder

Background Although 15 mA transcranial alternating current stimulation(tACS)has a therapeutic effect on depression,the activations of brain structures in humans accounting for this tACS configuration remain largely unknown.Aims To investigate which intracranial brain structures are engaged in the tACS at 77.5 Hz and 15 mA,delivered via the forehead and the mastoid electrodes in the human brain.Methods Actual human head models were built using the magnetic resonance imagings of eight outpatient volunteers with drug-naïve,first-episode major depressive disorder and then used to perform the electric field distributions with SimNIBS software.Results The electric field distributions of the sagittal,coronal and axial planes showed that the bilateral frontal lobes,bilateral temporal lobes,hippocampus,cingulate,hypothalamus,thalamus,amygdala,cerebellum and brainstem were visibly stimulated by the 15 mA tACS procedure.Conclusions Brain-wide activation,including the cortex,subcortical structures,cerebellum and brainstem,is involved in the 15 mA tACS intervention for first-episode major depressive disorder.Our results indicate that the simultaneous involvement of multiple brain regions is a possible mechanism for its effectiveness in reducing depressive symptoms.

Overexpression of Sirt6 ameliorates sleep deprivation induced-cognitive impairment by modulating glutamatergic neuron function

Sleep benefits the restoration of energy metabolism and thereby suppo rts neuronal plasticity and cognitive behaviors.Sirt6 is a NAD+-dependent protein deacetylase that has been recognized as an essential regulator of energy metabolism because it modulates various transcriptional regulators and metabolic enzymes.The aim of this study was to investigate the influence of Sirt6 on cerebral function after chronic sleep deprivation(CSD).We assigned C57BL/6J mice to control or two CSD groups and subjected them to AAV2/9-CMV-EGFP or AAV2/9-CMV-Sirt6-EGFP infection in the prelimbic cortex(PrL).We then assessed cerebral functional connectivity(FC) using resting-state functional MRI,neuron/astrocyte metabolism using a metabolic kinetics analysis;dendritic spine densities using sparse-labeling;and miniature excitato ry postsynaptic currents(mEPSCs) and action potential(AP) firing rates using whole-cell patchclamp recordings.In addition,we evaluated cognition via a comprehensive set of behavioral tests.Compared with controls,Sirt6 was significantly decreased(P<0.05) in the PrL after CSD,accompanied by cognitive deficits and decreased FC between the PrL and accumbens nucleus,piriform cortex,motor co rtex,somatosensory co rtex,olfactory tubercle,insular cortex,and cerebellum.Sirt6 ove rexpression reve rsed CSD-induced cognitive impairment and reduced FC.Our analysis of metabolic kinetics using [1-13C] glucose and [2-13C] acetate showed that CSD reduced neuronal Glu4and GABA2synthesis,which could be fully restored via forced Sirt6 expression.Furthermore,Sirt6 ove rexpression reversed CSD-induced decreases in AP firing rates as well as the frequency and amplitude of mEPSCs in PrL pyramidal neurons.These data indicate that Sirt6 can improve cognitive impairment after CSD by regulating the PrL-associated FC network,neuronal glucose metabolism,and glutamatergic neurotransmission.Thus,Sirt6 activation may have potential as a novel strategy for treating sleep disorder-related diseases.

Adolescent alcohol exposure changes RNA modifications in adult brain by mass spectrometry-based comprehensive profiling analysis

Alcohol consumption is one of the leading causes of death worldwide.Adolescence is a critical period of structural and functional maturation of the brain.Adolescent alcohol use can alter epigenetic modifications.However,little is known on the long-term effects of alcohol consumption during adolescence on RNA epigenetic modifications in brain.Herein,we systematically explored the long-term effects of alcohol exposure during adolescence on small RNA modifications in adult rat brain tissues by comprehensive liquid chromatography-electrospray ionization-tandem mass spectrometry(LC-ESI-MS/MS)analysis.We totally detected 26 modifications in small RNA of brain tissues.Notably,we observed most of these modifications were decreased in brain tissues.These results suggest that alcohol exposure during adolescence may impose a long-lasting impact on RNA modifications in brain tissues.This is the first report that alcohol use during adolescence can alter RNA modifications in adult brain.Collectively,this study suggests a long-term adverse effects of alcohol consumption on brain from RNA epigenetics angle by comprehensive mass spectrometry analysis.

Chronic sleep deprivation induces alterations in DNA and RNA modifications by liquid chromatography-mass spectrometry analysis

Sleep deprivation(SD)is a widespread issue that disrupts the lives of millions of people.These effects ini-tiate as changes within neurons,specifically at the DNA and RNA level,leading to disruptions in neuronal plasticity and the dysregulation of various cognitive functions,such as learning and memory.Nucleic acid epigenetic modifications that could regulate gene expression have been reported to play crucial roles in this process.However,there is a lack of comprehensive research on the correlation of SD with nucleic acid epigenetic modifications.In the current study,we aimed to systematically investigate the landscape of modifications in DNA as well as in small RNA molecules across multiple tissues,including the heart,liver,kidney,lung,hippocampus,and spleen,in response to chronic sleep deprivation(CSD).Using liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis,we characterized the dynamic changes in DNA and RNA modification profiles in different tissues of mice under CSD stress.Specifically,we ob-served a significant decrease in the level of 5-methylcytosine(5mC)and a significant increase in the level of 5-hydroxymethylcytosine(5hmC)in the kidney in CSD group.Regarding RNA modifications,we observed an overall increased trend for most of these significantly changed modifications across six tis-sues in CSD group.Our study sheds light on the significance of DNA and RNA modifications as crucial epigenetic markers in the context of CSD-induced stress.

Aberrant Hippocampal Development in Early‑onset Mental Disorders and Promising Interventions:Evidence from a Translational Study

Early-onset mental disorders are associated with disrupted neurodevelopmental processes during adolescence.The methylazoxymethanol acetate(MAM)animal model,in which disruption in neurodevelopmental processes is induced,mimics the abnormal neurodevelopment associated with early-onset mental disorders from an etiological perspective.We conducted longitudinal structural magnetic resonance imaging(MRI)scans during childhood,adolescence,and adulthood in MAM rats to identify specific brain regions and critical windows for intervention.Then,the effect of repetitive transcranial magnetic stimulation(rTMS)intervention on the target brain region during the critical window was investigated.In addition,the efficacy of this intervention paradigm was tested in a group of adolescent patients with early-onset mental disorders(diagnosed with major depressive disorder or bipolar disorder)to evaluate its clinical translational potential.The results demonstrated that,compared to the control group,the MAM rats exhibited significantly lower striatal volume from childhood to adulthood(all P<0.001).In contrast,the volume of the hippocampus did not show significant differences during childhood(P>0.05)but was significantly lower than the control group from adolescence to adulthood(both P<0.001).Subsequently,rTMS was applied to the occipital cortex,which is anatomically connected to the hippocampus,in the MAM models during adolescence.The MAM-rTMS group showed a significant increase in hippocampal volume compared to the MAM-sham group(P<0.01),while the volume of the striatum remained unchanged(P>0.05).In the clinical trial,adolescents with early-onset mental disorders showed a significant increase in hippocampal volume after rTMS treatment compared to baseline(P<0.01),and these volumetric changes were associated with improvement in depressive symptoms(r=−0.524,P=0.018).These findings highlight the potential of targeting aberrant hippocampal development during adolescence as a viable intervention for earlyonset mental disorders with neurodevelopmental etiology as well as the promise of rTMS as a therapeutic approach for mitigating aberrant neurodevelopmental processes and alleviating clinical symptoms.

Preoperative Acute Sleep Deprivation Causes Postoperative Pain Hypersensitivity and Abnormal Cerebral Function

Preoperative sleep loss can amplify post-operative mechanical hyperalgesia.However,the underlying mechanisms are still largely unknown.In the current study,rats were randomly allocated to a control group and an acute sleep deprivation(ASD)group which experienced 6 h ASD before surgery.Then the variations in cerebral function and activity were investigated with multi-modal techniques,such as nuclear magnetic resonance,functional magnetic resonance imaging,c-Fos immunofluorescence,and electrophysiology.The results indicated that ASD induced hyperalgesia,and the metabolic kinetics were remarkably decreased in the striatum and midbrain.The functional connectivity(FC)between the nucleus accumbens(NAc,a subregion of the ventral striatum)and the ventrolateral periaqueductal gray(vLPAG)was significantly reduced,and the c-Fos expression in the NAc and the vLPAG was suppressed.Furthermore,the electrophysiological recordings demonstrated that both the neuronal activity in the NAc and the vLPAG,and the coherence of the NAc-vLPAG were suppressed in both resting and task states.This study showed that neuronal activity in the NAc and the vLPAG were weakened and the FC between the NAc and the vLPAG was also suppressed in rats with ASD-induced hyperalgesia.This study highlights the importance of preoperative sleep management for surgical patients.