Haoyang Xing

Transcranial magnetic stimulation (TMS) combined with electroencephalography (EEG) enables millisecond-scale characterization of cortical responses, but direct multidimensional comparisons across stimulation protocols remain limited. In a randomized within-subject crossover study, 17 healthy adults received 10 Hz repetitive transcranial magnetic stimulation (rTMS), 1 Hz rTMS, and intermittent theta-burst stimulation (iTBS) over the left primary motor cortex in separate sessions. TMS-evoked potentials (TEPs), power spectral density (PSD), and EEG microstate dynamics were assessed before and immediately after stimulation. Following 10 Hz rTMS, group-level P30 amplitude increased from 0.17 to 0.89 μV, while N45 became less negative from −1.73 to −0.82 μV; PSD increased significantly across 15.5–45 Hz. In contrast, 1 Hz rTMS reduced P30 from 0.68 to 0.39 μV and increased P60 from 0.31 to 1.65 μV, with significant PSD reductions at 12.7–31.7 Hz and 32.2–45 Hz. iTBS reduced the magnitude of N45 from −2.76 to −1.93 μV and decreased P60 from 1.41 to 0.47 μV. These findings demonstrate protocol-specific multidimensional electrophysiological profiles across temporal and spectral measures. This framework facilitates systematic comparison across stimulation protocols and provides a basis for further investigation of TMS-induced cortical responses and individualized neuromodulation.

Background: For preoperative cervical assessment, both CT and MRI are often required for bony and soft‐tissue evaluation, yet CT entails radiation and MRI poorly depicts cortical bone. ZTE offers CT‐like contrast in one examination, but whether it correlates with CT for quantitative morphometry remains still uncertain. Purpose: To quantify ZTE‐CT agreement for cervical osseous morphometry and to compare ZTE with conventional MRI for depicting degenerative osseous features. Study Type: Prospective. Population: 38 consecutive surgical patients (21 men, mean age 54.3 ± 11.7 years). Field Strength/Sequence: 3.0 T MRI; sagittal T1 and T2; 3D ZTE; CT. Assessment: Nine categories of cervical morphometric parameters (80 measurements per patient) were assessed using standardized anatomical landmarks; the mean and minimum of all level‐specific values were derived per patient for each parameter. Two radiologists independently performed quantitative measurements; three radiologists independently assigned the degenerative osseous feature best depicted on ZTE relative to conventional MRI from four predefined categories. Statistical Tests: Intraclass correlation coefficients (ICC) and Bland–Altman analysis for quantitative measurements, and Fleiss' κ for qualitative comparison; post hoc exploratory analyses investigated unanticipated findings. A two‐sided p < 0.05 was considered statistically significant. Results: Interobserver agreement was excellent for all parameters (ICC > 0.98). For mean measurements, ZTE showed good‐to‐excellent agreement with CT for vertebral body height, disc height, and neuroforaminal dimensions (ICC 0.85–0.94). Minimum measurements showed moderate agreement overall; pedicle dimensions demonstrated low agreement with CT (ICC < 0.60), driven by overestimation of anatomically narrow pedicles. ZTE improved delineation of degenerative osseous features versus conventional MRI in 35 of 38 patients (92.1%; Fleiss' κ = 0.86). Data Conclusion: ZTE MRI shows strong agreement with CT for key cervical spine morphometric parameters and improves depiction of degenerative osseous changes compared with conventional MRI. However, CT may remain necessary when precise pedicle evaluation is required for surgical planning. Evidence Level: 1. Technical Efficacy: Stage 2.

Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) has emerged as a promising noninvasive approach for probing cortical reactivity and network dynamics with millisecond temporal resolution, with growing relevance for mechanistic and clinical neuroscience. However, despite rapid expansion of the field, TMS-EEG findings remain difficult to interpret because of substantial inter-individual variability and fragmentation across distinct analytical domains, including time-domain, spatially integrated, and time-frequency measures. These issues limit cross-study comparability and hinder clinical translation. In this review, we summarize the conceptual basis of TEPs, the physiological interpretation of canonical components (e.g., N15, P30), and commonly adopted analytical considerations. We further synthesize spatially integrated measures, including global and local mean field power (GMFP and LMFP), which quantify distributed cortical responses across multiple electrodes. Time-frequency indices, such as time-related spectral perturbation (TRSP) and inter-trial phase coherence (ITPC), are also reviewed to characterize TMS-induced oscillatory modulations. Drawing on the existing TMS-EEG literature in humans, we outline representative applications of these multidimensional metrics in neuropsychiatric and neurological conditions, including Alzheimer’s disease, depression, epilepsy, and stroke. Finally, we discuss key methodological and translational challenges, such as stimulation-related artifacts, inter-individual variability, state-dependency of baseline oscillatory activity, and limited standardization, and highlight how these issues complicate the interpretation of TMS-EEG findings across studies and individuals. Together, this review aims to provide a structured reference framework for integrating and interpreting multidimensional TMS-EEG measures, thereby supporting more consistent understanding of the literature and informing future efforts toward harmonization and clinical translation.

Background: While the left subgenual anterior cingulate cortex (sgACC) is a validated target for treating major depressive disorder (MDD) (e.g., with rTMS), the therapeutic relevance of the right sgACC is unknown. Given emerging evidence that treatment‐resistant depression (TRD) and non‐TRD (nTRD) may involve distinct neural circuits, a more precise, circuit‐based understanding is needed. This study, therefore, sought to determine the degree of sgACC functional lateralization and to elucidate TRD‐specific neural mechanisms, thereby informing the development of targeted neuromodulation therapies. Methods: Resting‐state fMRI (rs‐fMRI) data were acquired for 20 patients with TRD, 53 patients with nTRD, and 51 healthy controls (HCs). Analysis was performed to compare the static functional connectivity (sFC), dynamic functional connectivity (dFC), and effective connectivity via Granger causality analysis (GCA) of left and right sgACC between the three groups, followed by clinical correlation analyses. Results: Group analysis revealed significant sFC and dFC between left sgACC and temporal pole (TP), fusiform gyrus (FG), parahippocampal gyrus (PHG), and orbitofrontal cortex (OFC), and between right sgACC and cerebellum posterior lobule (CPL) and right dorsolateral prefrontal cortex (DLPFC.R). Furthermore, GCA showed increased effective connectivity between bilateral sgACC and left caudate (CAU.L), left thalamus (THA.L), right postcentral gyrus (PoCG.R), and DLPFC.L. Compared to the nTRD group the TRD group showed decreased sFC and dFC between sgACC and DLPFC and cerebellum, along with decreased effective connectivity between sgACC and CAU and DLPFC, indicating disrupted fronto‐limbic and cerebellar circuits in TRD. Conclusion: The distinct sgACC‐centered connectivity profiles of TRD and nTRD delineate a neurobiological continuum across MDD subtypes, pinpointing the sgACC, DLPFC, CAU, and cerebellum as key circuit targets for individualized neuromodulation in TRD.