- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Mouse optical imaging for understanding resting-state functional connectivity in human fMRI
摘要： Resting-state functional connectivity (FC), which measures the temporal correlation of spontaneous hemodynamic activity between distant brain areas, is a widely accepted method in functional magnetic resonance imaging (fMRI) to assess the connectome of healthy and diseased human brains. A common assumption underlying FC is that it reflects the temporal structure of large-scale neuronal activity that is converted into large-scale hemodynamic activity. However, direct observation of such relationship has been difficult. In this commentary, we describe our recent progress regarding this topic. Recently, transgenic mice that express a genetically encoded calcium indicator (GCaMP) in neocortical neurons are enabling the optical recording of neuronal activity in large-scale with high spatiotemporal resolution. Using these mice, we devised a method to simultaneously monitor neuronal and hemodynamic activity and addressed some key issues related to the neuronal basis of FC. We propose that many important questions about human resting-state fMRI can be answered using GCaMP expressing transgenic mice as a model system.
关键词： mouse,calcium imaging,functional connectivity,fMRI,resting-state
更新于2025-09-23 15:23:52
-
Perspective: Prospects of non-invasive sensing of the human brain with diffuse optical imaging
摘要： Since the initial demonstration of near-infrared spectroscopy (NIRS) for noninvasive measurements of brain perfusion and metabolism in the 1970s, and its application to functional brain studies (fNIRS) in the 1990s, the field of noninvasive optical studies of the brain has been continuously growing. Technological developments, data analysis advances, and novel areas of application keep advancing the field. In this article, we provide a view of the state of the field of cerebral NIRS, starting with a brief historical introduction and a description of the information content of the NIRS signal. We argue that NIRS and fNIRS studies should always report data of both oxy- and deoxyhemoglobin concentrations in brain tissue, as they complement each other to provide more complete functional and physiological information, and may help identify different types of confounds. One significant challenge is the assessment of absolute tissue properties, be them optical or physiological, so that relative measurements account for the vast majority of NIRS and fNIRS applications. However, even relative measurements of hemodynamics or metabolic changes face the major problem of a potential contamination from extracerebral tissue layers. Accounting for extracerebral contributions to fNIRS signals is one of the most critical barriers in the field. We present some of the approaches that were proposed to tackle this challenge in the study of cerebral hemodynamics and functional connectivity. Finally, we critically compare fNIRS and functional magnetic resonance imaging by relating their measurements in terms of signal and noise, and by commenting on their complementarity.
关键词： hemodynamics,functional connectivity,functional magnetic resonance imaging,human brain,near-infrared spectroscopy,diffuse optical imaging,non-invasive sensing,functional near-infrared spectroscopy
更新于2025-09-23 15:21:21
-
Effects of HD-tDCS on Resting-State Functional Connectivity in the Prefrontal Cortex: An fNIRS Study
摘要： Functional connectivity is linked to several degenerative brain diseases prevalent in our aging society. Electrical stimulation is used for the clinical treatment and rehabilitation of patients with many cognitive disorders. In this study, the effects of high-definition transcranial direct current stimulation (HD-tDCS) on resting-state brain networks in the human prefrontal cortex were investigated by using functional near-infrared spectroscopy (fNIRS). The intrahemispheric as well as interhemispheric connectivity changes induced by 1 mA HD-tDCS were examined in 15 healthy subjects. Pearson correlation coefficient-based correlation matrices were generated from filtered time series oxyhemoglobin (ΔHbO) signals and converted into binary matrices. Common graph theory metrics were computed to evaluate the network changes. Systematic interhemispheric, intrahemispheric, and intraregional connectivity analyses demonstrated that the stimulation positively affected the resting-state connectivity in the prefrontal cortex. The poststimulation connectivity was increased throughout the prefrontal region, while focal HD-tDCS effects induced an increased rate of connectivity in the stimulated hemisphere. The graph theory metrics clearly distinguished the prestimulation and poststimulation networks for a range of thresholds. The results of this study suggest that HD-tDCS can be used to increase functional connectivity in the prefrontal cortex. The increase in functional connectivity can be explored clinically for neurorehabilitation of patients with degenerative brain diseases.
关键词： HD-tDCS,neurorehabilitation,fNIRS,graph theory,functional connectivity,prefrontal cortex
更新于2025-09-23 15:21:01
-
Plasmon-induced light absorption in mid-infrared based on hexagonal-shape graphene
摘要： Background: The human striatum is a heterogeneous structure involved in diverse functional domains that related to distinct striatum subregions. Striatal dysfunction was thought to be a fundamental element in schizophrenia. However, the connectivity pattern of striatum solely based on functional or structural characteristics leads to inconsistent findings in healthy adult and also schizophrenia. This study aims to develop an integrated striatal model and reveal the altered functional connectivity pattern of the striatum in schizophrenia. Methods: Two data-driven approaches, task-dependent meta-analytic connectivity modeling (MACM) and task-independent resting-state functional connectivity (RSFC), were used for seven anatomical connectivity-based striatum subregions to provide an integrated striatal model. Then, RSFC analyses of seven striatal subregions were applied to 45 first-episode schizophrenia (FES) and 27 healthy controls to examine the difference, based on the integrated model, of functional connectivity pattern of striatal subregions. Results: MACM and RSFC results showed that striatum subregions were associated with discrete cortical regions and involved in distinct cognitive processes. Besides, RSFC results overlapped with MACM findings but showed broader distributions. Importantly, significantly reduced functional connectivity was identified between limbic subregion and thalamus, medial prefrontal cortex, anterior cingulate cortex, and insula and also between executive subregions and thalamus, supplementary motor area, and insula in FES. Conclusions: Combing functional and structural connectivity information, this study provides the integrated model of corticostriatal subcircuits and confirms the abnormal functional connectivity of limbic and executive striatum subregions with different networks and thalamus, supporting the important role of the corticostriatal-thalamic loop in the pathophysiology of schizophrenia.
关键词： resting-state functional connectivity,meta-analytic connectivity modeling (MACM),striatum,schizophrenia,corticostriatal circuits
更新于2025-09-12 10:27:22
-
Lesion Network Localization of Seizure Freedom following MR-guided? Laser Interstitial Thermal Ablation
摘要： treatment-resistant epilepsy is a common and debilitating neurological condition, for which neurosurgical cure is possible. Despite undergoing nearly identical ablation procedures however, individuals with treatment-resistant epilepsy frequently exhibit heterogeneous outcomes. We hypothesized that treatment response may be related to the brain regions to which MR-guided laser ablation volumes are functionally connected. to test this, we mapped the resting-state functional connectivity of surgical ablations that either resulted in seizure freedom (N =?11)?or?did?not?result in seizure freedom (N =?16)?in?over?1,000?normative?connectomes.?There?was?no?difference?seizure outcome with respect to the anatomical location of the ablations, and very little overlap between ablation?areas?was?identified?using?the?Dice?Index.?Ablations?that?did?not?result?in?seizure-freedom?were preferentially connected to a number of cortical and subcortical regions, as well as multiple canonical resting-state networks. in contrast, ablations that led to seizure-freedom were more functionally connected to prefrontal cortices. Here, we demonstrate that underlying normative neural circuitry may?in?part?explain?heterogenous?outcomes?following?ablation?procedures?in?different?brain?regions. These?findings?may?ultimately?inform?target?selection?for?ablative?epilepsy?surgery?based?on?normative intrinsic connectivity of the targeted volume.
关键词： resting-state functional connectivity,seizure freedom,treatment-resistant epilepsy,MR-guided laser ablation,prefrontal cortices
更新于2025-09-12 10:27:22
-
Intrinsic brain abnormalities in drug-naive patients with obsessive-compulsive disorder: a resting-state functional MRI study
摘要： Background: Using the resting-state functional magnetic resonance imaging (rs-fMRI) in a relatively large sample of drug-naive patients with obsessive-compulsive disorder (OCD), the current study aims to explore alterations in regional and network-level neural function and to determine the association between these alterations in intrinsic neural activity and symptom severity in OCD. Methods: A total of 68 drug-naive OCD patients and 68 healthy control subjects (HCS) were examined using rs-fMRI. Regional cerebral function was evaluated by measuring the fraction of amplitude of low-frequency fluctuation (fALFF). Regions with fALFF alterations were used as seeds in whole-brain functional connectivity (FC) analysis. Statistical analyses of fALFF and FC differences between OCD patients with HCS were performed voxel-by-voxel using a two-sample t-test in Statistical Parametric Mapping version 8 (SPM8). Whole brain correlation analyses were performed to identify the association between functional neural correlates and OCD symptom severity evaluated using Yale-Brown Obsessive Compulsive scale (Y-BOCS) and subscale scores. Results: Relative to HCS, OCD patients showed higher fALFF in the right putamen and right superior frontal gyrus (P < 0.05, corrected for AlphaSim); higher FC in the limbic-striatal circuit and lower FC in the fronto-temporal and fronto-striato-thalamic networks (P < 0.05, corrected for AlphaSim). FC in striato-thalamic junction was negatively correlated with the Y-BOCS total score (r = -0.493, P < 0.001). Conclusion: These findings of focal spontaneous hyperfunction confirmed the prevailing frontal-striatal model of OCD, and altered brain connectivity in large-scale resting-state networks indicated a connectivity-based pathophysiological process in OCD.
关键词： Obsessive-compulsive disorder,Functional connectivity,Resting-state fMRI,Drug-naive,Fractional amplitude of low-frequency fluctuation
更新于2025-09-10 09:29:36