Brain Regions Research Articles

Regional heterogeneity of cerebral blood flow immediately after the onset of ventricular pacing in anesthetized rats.

Selective distribution of cerebral blood flow (CBF) to vital brain regions likely occurs during rapid severe hypotension caused by tachyarrhythmia, but has not yet been demonstrated. In this study, we aimed to test the hypothesis that CBF is differentially preserved between brain regions depending on the degree of hypotension. In anesthetized rats, CBF was measured in the motor cortex (MC), medial prefrontal cortex, amygdala, thalamus, dorsal hypothalamus, hippocampus, ventral tegmental area, dorsolateral periaqueductal gray (dlPAG), and parabrachial nucleus (PB) by using laser-Doppler flowmetry. Ventricular pacing was performed for 30 s at 550-800 beats/min. The cerebrovascular CO2 response time and reactivity were evaluated during 5% CO2 exposure. During 1-4 s of ventricular pacing, mean arterial pressure (MAP) rapidly decreased, with minor changes in central venous and intracranial pressures. CBF was relatively well maintained in brain regions other than the MC (Ps ≤ 0.012) when moderate hypotension occurred (-34 mmHg ≤ ΔMAP ≤ -15 mmHg), whereas severe hypotension (-54 mmHg ≤ ΔMAP ≤ -35 mmHg) induced selective CBF distribution to regions other than the MC, thalamus, and dlPAG. The cerebrovascular CO2 response time/reactivity was rapid or high in the thalamus, dlPAG, and PB, which almost completely differed from the brain regions in which CBF was relatively maintained during pacing-induced severe hypotension. These results suggest that regional heterogeneity of CBF arises depending on the degree of tachyarrhythmia-induced hypotension. Clarifying the mechanisms and functions of CBF maintenance would be beneficial to syncope and cerebral ischemia management in patients with arrhythmia.

Harsh parenting, amygdala functional connectivity changes across childhood, and behavioral problems.

Harsh parenting in early childhood is related to offspring's adverse behavioral outcomes. Due to the scarcity of longitudinal neuroimaging data, few studies have explored the neurobiological underpinnings of this association, focusing on within-person variability. This study examined the temporal associations among harsh parenting, later behavioral problems, and the developmental trajectories of amygdala volume and amygdala resting-state functional connectivity (RSFC) profiles, using longitudinal neuroimaging data. The study was embedded in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. T1-weighted (296 children, 642 scans) and resting-state functional scans (256 children, 509 scans) were collected at ages 4.5, 6, 7.5, and 10.5 years. Amygdala volume and RSFC between the amygdala and six brain regions that have leading roles in emotional regulation were extracted. Harsh parenting at 4.5 years and child behavioral problems at 10.5 years were assessed via parent-report questionnaires. Linear regression and linear mixed models were applied. Harsh parenting was associated with more severe externalizing problems in girls (β = 0.24, 95% CI 0.08-0.40) but not boys (pint = 0.07). In the overall sample, harsh parenting was associated with the developmental trajectories of amygdala-ACC, amygdala-OFC, and amygdala-DLPFC RSFC. In addition, the developmental trajectory of amygdala-ACC RSFC mediated the harsh parenting-externalizing problems association in girls (indirect effect = 0.06, 95% CI 0.01-0.14). Harsh parenting in early childhood was associated with amygdala neurocircuitry development and behavioral problems. The developmental trajectory of amygdala-ACC RSFC is a potential neural mechanism linking harsh parenting and externalizing problems in girls.

Neurocognitive correlates of cerebral mitochondrial function and energy metabolism using phosphorus magnetic resonance spectroscopy in older adults.

The goal of the current study was to learn about the role of cerebral mitochondrial function on cognition. Based on established cognitive neuroscience, clinical neuropsychology, and cognitive aging literature, we hypothesized mitochondrial function within a focal brain region would map onto cognitive behaviors linked to that brain region. To test this hypothesis, we used phosphorous (31P) magnetic resonance spectroscopy (MRS) to derive indirect markers of mitochondrial function and energy metabolism across two regions of the brain (bifrontal, left temporal). We administered cognitive tasks sensitive to frontal-executive or temporal-hippocampal systems to a sample of 70 cognitively unimpaired older adults with subjective memory complaints and a first-degree family history of Alzheimer's disease and predicted better executive function and recent memory performance would be related to greater frontal and temporal 31P MRS indirect markers, respectively. Results of separate hierarchical linear regressions indicated better recent memory scores were related to 31P MRS indirect markers of lower static energy and higher energy reserve within the left temporal voxel; these findings were associated with moderate effect sizes. Contrary to predictions, executive function performance was unrelated to 31P MRS indirect markers within the bilateral frontal voxel, which may reflect a combination of theoretical and/or methodological issues. Findings represent a snapshot of the relationship between cognition and 31P MRS indirect markers of mitochondrial function, providing potential avenues for future work investigating mitochondrial underpinnings of cognition. 31P MRS may provide a sensitive neuroimaging marker for differences in aspects of memory among persons at-risk for mild cognitive impairment or dementia.

Effects of robot-assisted hand function therapy on brain functional mechanisms: a synchronized study using fNIRS and sEMG

BackgroundRobot-assisted hand function therapy is pivotal in the rehabilitation of patients with stroke; however, its therapeutic mechanism remains elusive. Currently, research examining the impact of robot-assisted hand function therapy on brain function in patients with stroke is scarce, and there is a lack of studies investigating the correlation between muscle activity and alterations in brain function.ObjectiveThis study aimed to investigate the correlation between forearm muscle movement and brain functional activation by employing the synchronized use of functional near-infrared spectroscopy and surface electromyography methods. Moreover, it sought to compare neural activity patterns during different rehabilitation tasks and refine the mechanism of robot-assisted hand function therapy for post-stroke hand function impairments.MethodsStroke patients with hand dysfunction underwent three sessions of robot-assisted hand function therapy within 2 weeks to 3 months of onset. The fNIRS-sEMG synchronous technique was used to observe brain function and forearm muscle activation. Ten participants were randomly assigned to receive mirror, resistance, or passive rehabilitation training. During the intervention, cortical and muscle activation information was obtained using fNIRS and electromyographic signals. The primary outcomes included changes in oxyhemoglobin concentration and root mean square of surface electromyography.ResultsCompared to the resting state, the Oxy-Hb concentration in the brain regions involved in three rehabilitation tasks with robot-assisted hand function therapy significantly increased (p < 0.05). Mirror therapy significantly enhanced the prefrontal cortex and the superior frontal cortex activation levels. In contrast, resistance therapy significantly promoted the activation of the supplementary motor area and the premotor cortex. Passive rehabilitation tasks showed some activation in the target brain area premotor cortex region. Robot-assisted hand function therapy has shown that forearm muscle movement is closely related to oxygenated hemoglobin concentration activity in specific brain regions during different rehabilitation tasks.ConclusionThe simultaneous sEMG-fNIRS study found a significant correlation between muscle movement and brain activity after stroke, which provides an important basis for understanding the treatment mechanism of hand function impairment.

Olfactory and trigeminal routes of HSV-1 CNS infection with regional microglial heterogeneity.

Herpes simplex virus type 1 (HSV-1) primarily targets the oral and nasal epithelia before establishing latency in the trigeminal ganglion (TG) and other peripheral ganglia. HSV-1 can also infect and become latent in the central nervous system (CNS) independent of latency in the TGs. Recent studies suggest entry to the CNS via two distinct routes: the TG-brainstem connection and olfactory nerve; however, to date, there is no characterization of brain regions targeted during HSV-1 primary infection. Furthermore, the immune response by microglia may also contribute to the heterogeneity between different brain regions. However, the response to HSV-1 by microglia has not been characterized in a region-specific manner. This study investigated the time course of HSV-1 spread within the olfactory epithelium (OE) and CNS following intranasal inoculation and the corresponding macrophage/microglial response in a C57BL/6 mouse model. We found an apical to basal spread of HSV-1 within the OE and underlying tissue accompanied by an inflammatory response of macrophages. OE infection was followed by infection of a small subset of brain regions targeted by the TG in the brainstem and other cranial nerve nuclei, including the vagus and hypoglossal nerve. Furthermore, other brain regions were positive for HSV-1 antigens, such as the locus coeruleus (LC), raphe nucleus (RaN), and hypothalamus while sparing the hippocampus and cortex. Within each brain region, microglia activation also varied widely. These findings provide critical insights into the region-specific dissemination of HSV-1 within the CNS, elucidating potential mechanisms linking viral infection to neurological and neurodegenerative diseases.IMPORTANCEThis study shows how herpes simplex virus type 1 (HSV-1) spreads within the brain after infecting the nasal passages. Our data reveal the distinct pattern of HSV-1 through the brain during a non-encephalitic infection. Furthermore, microglial activation was also temporally and spatially specific, with some regions of the brain having sustained microglial activation even in the absence of viral antigens. Previous reports have identified specific brain regions found to be positive for HSV-1 infection; however, to date, there has not been a concise investigation of the anatomical spread of HSV-1 and the brain regions consistently vulnerable to viral entry and spread. Understanding these region-specific differences in infection and immune response is crucial because it links HSV-1 infection to potential triggers for neurological and neurodegenerative diseases.

Transcranial Focused Ultrasound Neuromodulation in Psychiatry: Main Characteristics, Current Evidence, and Future Directions

Non-invasive brain stimulation (NIBS) techniques are designed to precisely and selectively target specific brain regions, thus enabling focused modulation of neural activity. Among NIBS technologies, low-intensity transcranial focused ultrasound (tFUS) has emerged as a promising new modality. The application of tFUS can safely and non-invasively stimulate deep brain structures with millimetric precision, offering distinct advantages in terms of accessibility to non-cortical regions over other NIBS methods. However, to date, several tFUS aspects still need to be characterized; furthermore, there are only a handful of studies that have utilized tFUS in psychiatric populations. This narrative review provides an up-to-date overview of key aspects of this NIBS technique, including the main components of a tFUS system, the neuronavigational tools used to precisely target deep brain regions, the simulations utilized to optimize the stimulation parameters and delivery of tFUS, and the experimental protocols employed to evaluate the efficacy of tFUS in psychiatric disorders. The main findings from studies in psychiatric populations are presented and discussed, and future directions are highlighted.

A Relationship of Monoamine Oxidase-A with Serotonin in Violent Antisocial Behavior in Iraqi Prisoners

It is thought that the monoamine oxidase-A (MAOA) enzyme, which catalyzes key brain signaling chemicals like serotonin, noradrenaline, and dopamine, indirectly influences antisocial behavior by disrupting the neurotransmitter balance in brain regions and neural networks. This study aims to assess the MAOA enzyme level in serum and serotonin linked to antisocial behavior in cases in the prison of Baghdad City, Iraq. Blood samples were collected from (63) prisoners and (27) control groups, ages 18 years to 65 years, with a mean ± SD of 37.8 ± 8.8, all males, with different prison terms and different crimes for prisoners in the prison at Baghdad City, Iraq. MAOA and serotonin levels were measured in serum in prisoners and healthy men, and the results showed the serum levels of MAOA enzyme and serotonin were decreased in prisoners compared to the healthy (11.5 IU/ml vs. 19.5 IU/ml) and (79 IU/ml vs. 439 IU/ml), respectively, with the observed difference being significant (P < 0.001(. The results of the relationship between education and social violence were: illiterate 11.1%, primary school 27%, secondary 52.4%, and university 9.5%. The median serum level of MAOA and serotonin in the age group 18–39 years was (11.3 IU/ml, 68.3 ng/ml), respectively, and in the age group 40–65 years was (13 IU/ml, 139 ng/ml), respectively.

The causal relationship of DTI phenotypes and epilepsy: A two sample mendelian randomization study.

Clinical studies indicated a link between DTI imaging characteristics and epilepsy, but the causality of this connection had not been established. Therefore, we employed the Mendelian randomization analysis method to determine the causal relationship between DTI imaging characteristics and epilepsy. We used Mendelian randomization analysis to identify the causal relationship between brain structure and the risk of epilepsy. GWAS data of DTI phenotypes, focal epilepsy, and genetic generalized epilepsy (GGE) were utilized in the analysis. Our study found that DTI imaging phenotypes had a causal risk relationship with epilepsy. These phenotypes had a statistical impact on the risk of epilepsy seizures. There were differences in DTI phenotype causality between GGE and focal epilepsy, which were associated with the clinical phenotype differences of the two types of epilepsy. Our study demonstrated that the diagnosis of subtypes could be assisted by comparing the differences in DTI phenotypes of specific brain regions. This meant that by studying the changes in brain regions before the onset of epilepsy, we might be able to intervene in epilepsy at an earlier stage. Our study used Mendelian randomization to explore the causal relationship between brain structure, as seen in DTI imaging, and epilepsy. We found that specific DTI phenotypes are linked to an increased risk of epilepsy seizures, with notable differences between genetic generalized epilepsy and focal epilepsy. This suggested that analyzing DTI phenotypes could help in diagnosing and potentially intervening in epilepsy earlier by finding brain changes before seizures begin.

Behavioral and psychological symptoms and brain volumes in community-dwelling older persons from the Nakayama Study

The frequency of behavioral and psychological symptoms of dementia (BPSD) is high, and it is a challenge to elucidate its neural substrates underlying their development. In recent years, many findings have been reported on the relationship between BPSD and brain volume in dementia patients. However, the results are not fully conclusive. Furthermore, there have been few population-based studies. Therefore, the relationship between BPSD and brain volume was investigated as an exploratory study. Of the 927 older persons who participated in the fifth Nakayama study, 90 were included in this analysis, consisting of 52 patients with mild cognitive impairment and 38 patients with dementia, with head MRI and the Neuropsychiatric Inventory (NPI) data. Multiple regression analysis was used to examine the association between the total score of each BPSD score on the NPI and brain volume estimated by FreeSurfer. On multivariate adjustment, even after false discovery rate correction, insular cortical volumes decreased significantly as total scores for apathy/indifference increased (p value = 0.002, q-value = 0.01). Similarly, total brain volume decreased significantly as total scores for appetite and eating disturbance increased (p value = 0.03), and parietal, temporal, and hippocampal cortical volumes also decreased significantly as total scores for appetite and eating disturbance increased (all p and q values < 0.05). This study’s results suggest that apathy is negatively correlated with insular cortical volume, and that appetite and eating disturbance are also correlated with brain regions, including parietal, temporal, and hippocampal volume in a community-dwelling older population.

White matter integrity and motor function: a link between cerebral myelination and longitudinal changes in gait speed in aging.

Gait speed is a robust health biomarker in older adults, correlating with the risk of physical and cognitive impairments, including dementia. Myelination plays a crucial role in neurotransmission and consequently affects various functions, yet the connection between myelination and motor functions such as gait speed is not well understood. Understanding this link could offer insights into diagnosing and treating neurodegenerative diseases that impair mobility. This study analyzed 437 longitudinal observations from 138 cognitively unimpaired adults, aged 22 to 94years, to investigate the relationship between myelin content and changes in gait speed over an average of 6.42years. Myelin content was quantified using a novel multicomponent magnetic resonance relaxometry method, and both usual and rapid gait speeds (UGS, RGS) were measured following standard protocols. Adjusting for covariates, we found a significant fixed effect of myelin content on UGS and RGS. Longitudinally, lower myelin content was linked to a greater decline in UGS, particularly in brain regions associated with motor planning. These results suggest that changes in UGS may serve as a reliable marker of neurodegeneration, particularly in cognitively unimpaired adults. Interestingly, the relationship between myelin content and changes in RGS was only observed in a limited number of brain regions, although the reason for such local susceptibility remains unknown. These findings enhance our understanding of the critical role of myelination in gait performance in unimpaired adults and provide evidence of the interconnection between myelin content and motor functionimpairment.

Multimodal MRI changes associated with non-motor symptoms of rapid eye movement sleep behaviour disorder in Parkinson's disease patients.

Parkinson's disease (PD), a prevalent neurodegenerative disorder, assumes a more adverse prognosis when accompanied by rapid eye movement sleep disorder (RBD). Non-motor symptoms, particularly sleep and emotional disturbances, significantly impair patients' quality of life. This study aimed to investigate the neuroimaging underpinnings of PD-RBD using structural and functional magnetic resonance imaging (MRI) and to explore the associations between these imaging biomarkers and non-motor symptoms. Brain scans were acquired from 33 PD patients without and 21 with probable RBD (PD-pRBD). Comparative analyses were performed to evaluate structural and functional alterations between the two groups. Additionally, the correlations between neuroimaging metrics and clinical assessment scales were assessed. PD-pRBD patients demonstrated more pronounced grey matter atrophy, particularly in the putamen and insula. Functional MRI revealed decreased amplitude of low-frequency fluctuations (ALFF) in the bilateral posterior cingulate cortex and left precuneus of PD-pRBD patients. Furthermore, reduced functional connectivity (FC) was observed in specific regions of the whole brain and within the default mode network (DMN) in PD-pRBD. Notably, a negative correlation was found between mean ALFF values in the left posterior cingulate cortex of PD-pRBD patients and Hamilton Depression Rating Scale scores. PD-pRBD is characterized by more severe grey matter loss and functional MRI abnormalities compared to PD alone. Dysfunction of the posterior cingulate cortex is implicated in more pronounced affective impairments, providing novel insights into the complex pathophysiology of PD-RBD.

Nitric oxide donors rescue metabolic and mitochondrial dysfunction in obese Alzheimer’s model

Reduced nitric oxide (NO) bioavailability is a pathological link between obesity and Alzheimer’s disease (AD). Obesity-associated metabolic and mitochondrial bioenergetic dysfunction are key drivers of AD pathology. The hypothalamus is a critical brain region during the development of obesity and dysfunction is an area implicated in the development of AD. NO is an essential mediator of blood flow and mitochondrial bioenergetic function, but the role of NO in obesity-AD is not entirely clear. We investigated diet-induced obesity in female APPswe/PS1dE9 (APP) mouse model of AD, which we treated with two different NO donors (sodium nitrite or L-citrulline). After 26 weeks of a high-fat diet, female APP mice had higher adiposity, insulin resistance, and mitochondrial dysfunction (hypothalamus) than non-transgenic littermate (wild type) controls. Treatment with either sodium nitrite or L-citrulline did not reduce adiposity but improved whole-body energy expenditure, substrate oxidation, and insulin sensitivity. Notably, both NO donors restored hypothalamic mitochondrial respiration in APP mice. Our findings suggest that NO is an essential mediator of whole-body metabolism and hypothalamic mitochondrial function, which are severely impacted by the dual insults of obesity and AD pathology.

Association between focal amyloid deposition and cognitive impairment in individuals below the amyloid threshold

PurposeThis study aimed to investigate the characteristics of individuals with amyloid levels below the threshold. To achieve this, we differentiated between two groups: those with global amyloid negativity but focal deposition [G(–)F(+)] and those without focal deposition [G(–)F(–)].Materials and methodsA total of 2,677 participants were diagnosed with cognitive unimpairment (CU) or mild cognitive impairment (MCI). MRI-based regional centiloid (CL) values were used to establish threshold values for each brain region. After applying a cutoff of 20 rdcCL to identify amyloid positivity, participants who were globally amyloid-negative were grouped into three categories: those who showed focal amyloid uptake [G(–)F(+)], individuals without focal amyloid deposition but with relatively high CL(HC) levels comparable to those in the focal uptake group [G(–)F(–) HC)], and those with relatively low CL(LC) levels [G(–)F(–) LC]. We compared the neuropsychological test results and brain structural changes between these groups using ANCOVA.ResultsThe G(–)F(+) group demonstrated a lower cortical thickness (P &amp;lt; 0.001) than the G(–)F(–) HC group. In neuropsychological tests, the G(–)F(+) group exhibited lower the Seoul Verbal Learning Test delayed recall (SVLT-DR) and Mini Mental State Examination (MMSE), and showed progressed clinical status in the clinical dementia rating–sum of boxes (CDR-SOB) compared to the G(–)F(–) HC group (P &amp;lt; 0.001). The subsequent sensitivity analyses confirmed the persistence of these findings.ConclusionsIndividuals with focal amyloid deposition [G(–)F(+)] exhibited higher rates of cognitive impairment compared to patients with similar levels of amyloid, underscoring the importance of monitoring the progression of focal uptake, even when it remains below the amyloid threshold.

Posterior Basolateral Amygdala is a Critical Amygdaloid Area for Temporal Lobe Epilepsy.

The amygdaloid complex consists of multiple nuclei and is a key node in controlling temporal lobe epilepsy (TLE) in both human and animal model studies. However, the specific nucleus in the amygdaloid complex and the neural circuitry governing seizures remain unknown. Here, it is discovered that activation of glutamatergic neurons in the posterior basolateral amygdala (pBLA) induces severe seizures and even mortality. The pBLA glutamatergic neurons project collateral connections to multiple brain regions, including the insular cortex (IC), bed nucleus of the stria terminalis (BNST), and central amygdala (CeA). Stimulation of pBLA-targeted IC neurons triggers seizures, whereas ablation of IC neurons suppresses seizures induced by activating pBLA glutamatergic neurons. GABAergic neurons in the BNST and CeA establish feedback inhibition on pBLA glutamatergic neurons. Deleting GABAergic neurons in the BNST or CeA leads to sporadic seizures, highlighting their role in balancing pBLA activity. Furthermore, pBLA neurons receive glutamatergic inputs from the ventral hippocampal CA1 (vCA1). Ablation of pBLA glutamatergic neurons mitigates both acute and chronic seizures in the intrahippocampal kainic acid-induced mouse model of TLE. Together, these findings identify the pBLA as a pivotal nucleus in the amygdaloid complex for regulating epileptic seizures in TLE.

Delayed Recovery After Exercise-Induced Pain in People with Chronic Widespread Muscle Pain Related to Cortical Connectivity

Background/Objectives: There is a subset of patients with pain who become worse after exercise. To explore this, we examined the responses of people with chronic primary pain to a standardized high intensity exercise protocol used to induce delayed onset muscle soreness (DOMS). Methods: Ten participants with a diagnosis of chronic widespread muscle pain (CWMP) were matched by age and reported gender to ten participants without muscle pain (i.e., no pain (NP)). Participants completed a standardized DOMS protocol. Pain intensity in the arm at rest and with movement was assessed using daily electronic diaries. Peak pain, the timing of peak pain, and the time to recovery were compared between groups. Associations of pain variables with the functional connectivity of the sensorimotor (SMN), cerebellum, frontoparietal control (FPN), and default mode network (DMN) both within network nodes and the rest of the brain was assessed. Results: Significant differences in peak pain, the time to peak pain, and the time to recovery were noted between groups for both pain at rest and pain with movement after controlling for catastrophizing and pain resilience. Connectivity across the SMN, FPN, and DMN was associated with all pain-related variables. Significant group differences were identified between groups. Conclusions: A standardized muscle “injury” protocol resulted in more pain, a longer time to peak pain, and a longer time to resolve pain in the patient group compared to the NP group. These differences were associated with differences in connectivity across brain regions related to sensorimotor integration and appraisal. These findings provide preliminary evidence of the dysregulation of responses to muscle (micro)trauma in people with chronic pain.

Transcranial Magnetic Stimulation in Schizophrenia Patients

In schizophrenia, while antipsychotic medications are the primary treatment, auditory hallucinations may sometimes persist despite pharmacotherapy, and negative symptoms and cognitive impairments often show a limited response to these medications. Transcranial magnetic stimulation (TMS) has emerged as a promising adjunctive treatment, capable of modulating neuronal activity in targeted brain regions. Low-frequency repetitive TMS (rTMS) directed at the left temporoparietal cortex has demonstrated efficacy in reducing auditory hallucinations. In addressing negative symptoms, high-frequency rTMS applied to the dorsolateral prefrontal cortex has shown some effectiveness, though outcomes can vary. Innovative techniques, including theta burst stimulation and personalized approaches utilizing neuroimaging, are currently under investigation to further enhance the therapeutic potential of TMS. This review examines the application of TMS in the treatment of schizophrenia, emphasizing the necessity of ongoing research to refine and optimize its efficacy across diverse symptom domains.

Increased functional connectivity between brain regions involved in social cognition, emotion and affective-value in psychedelic states induced by N,N-Dimethyltryptamine (DMT)

The modulation of social cognition is suggested as a possible mechanism contributing to the potential clinical efficacy of psychedelics in disorders involving socio-emotional and reward processing deficits. Resting-state functional Magnetic Resonance Imaging (rs-fMRI) can be used to detect changes in brain connectivity during psychedelic-induced states. Thus, this pharmacoimaging study investigates the effects of N,N-Dimethyltryptamine (DMT) on functional connectivity in brain areas relevant to social cognition, using a within-subject design in eleven healthy experienced users. The study included both an active and a control condition, conducted at different time points. The active condition involved DMT inhalation, while the control condition did not. Seed-based connectivity was measured for the two core regions involved in theory of mind and emotional processing, respectively, the posterior supramarginal gyrus and the amygdala. DMT increased supramarginal gyrus connectivity with the precuneus, posterior cingulate gyrus, amygdala, and orbitofrontal cortex. Additionally, increased connectivity emerged between the amygdala and orbitofrontal cortex. These results demonstrate that DMT modulates brain connectivity in socio-emotional and affective-value circuits, advancing our understanding of the neural mechanisms underlying the psychedelic experience and its potential therapeutic action.

Heritability and genetic contribution analysis of structural-functional coupling in human brain

Abstract The flow of functional connectivity (FC) is thought to be supported by white matter structural connectivity (SC). While research on the correlations between SC and FC (SC-FC coupling) has progressed, the genetic implications of SC-FC coupling have not been thoroughly examined. Traditionally, SC-FC coupling investigations utilize predefined atlases. Here, we adopted an atlas-free SC-FC coupling built on the high-resolution white surface (the interface of white matter and gray matter) to uncover common genetic variations. Leveraging data from the Human Connectome Project, we demonstrated considerable heritability in areas within the early and intermediate visual cortex and across dorsal-attention, language, and somatomotor functional networks. We detected 334 genetic loci (spanning 234 cytogenetic bands) linked to SC-FC coupling (P &amp;lt; 1.26 × 10−11), notably in cingulo-opercular, somatomotor, and default mode networks. Using an external dataset from the Adolescent Brain Cognitive Development study, we confirmed 187 cytogenetic bands associated with SC-FC coupling across 22 brain regions (P &amp;lt; 1 × 10-5). Genetic correlation analyses revealed high genetic interrelatedness for SC-FC coupling in neighboring regions. Furthermore, it showed genetic correlations with a spectrum of complex traits, encompassing various neurological and psychiatric conditions. In essence, our study paves the way towards deciphering the genetic interplay between structural and functional connectivity of the brain.

Single-cell transcriptomic and proteomic analysis of Parkinson's disease brains.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder, and recent evidence suggests that pathogenesis may be in part mediated by inflammatory processes, the molecular and cellular architectures of which are largely unknown. To identify and characterize selectively vulnerable brain cell populations in PD, we performed single-nucleus transcriptomics and unbiased proteomics to profile the prefrontal cortex from postmortem human brains of six individuals with late-stage PD and six age-matched controls. Analysis of nearly 80,000 nuclei led to the identification of eight major brain cell types, including elevated brain-resident T cells in PD, each with distinct transcriptional changes in agreement with the known genetics of PD. By analyzing Lewy body pathology in the same postmortem brain tissues, we found that α-synuclein pathology was inversely correlated with chaperone expression in excitatory neurons. Examining cell-cell interactions, we found a selective abatement of neuron-astrocyte interactions and enhanced neuroinflammation. Proteomic analyses of the same brains identified synaptic proteins in the prefrontal cortex that were preferentially down-regulated in PD. By comparing this single-cell PD dataset with a published analysis of similar brain regions in Alzheimer's disease (AD), we found no common differentially expressed genes in neurons but identified many shared differentially expressed genes in glial cells, suggesting that the disease etiologies, especially in the context of neuronal vulnerability, in PD and AD are likely distinct.

Inhibition of an Alzheimer's disease-associated form of necroptosis rescues neuronal death in mouse models.

Necroptosis is a regulated form of cell death that has been observed in Alzheimer's disease (AD) along with the classical pathological hallmark lesions of amyloid plaques and Tau neurofibrillary tangles. To understand the neurodegenerative process in AD, we studied the role of necroptosis in mouse models and primary mouse neurons. Using immunohistochemistry, we demonstrated activated necroptosis-related proteins in transgenic mice developing Tau pathology and in primary neurons from amyloid precursor protein (APP)-Tau double transgenic mice treated with phosphorylated Tau seeds derived from a patient with AD but not in APP transgenic mice that only exhibited β-amyloid deposits. Necroptosis proteins in granulovacuolar degeneration (GVD) bodies were associated with neuronal loss in mouse brain regions also known to be vulnerable to GVD in the human AD brain. Necroptosis inhibitors lowered the percentage of neurons showing GVD and reduced neuronal loss, both in transgenic mice and in primary mouse neurons. This suggests that a GVD-associated form of necroptosis that we refer to as "GVD-necroptosis" may represent a delayed form of necroptosis in AD. We propose that inhibition of necroptosis could rescue this type of neuronal death in AD.