Use of functional magnetic resonance imaging to identify cortical loci for lower limb movements and their efficacy for individuals after stroke.

BACKGROUND: Identification of cortical loci for lower limb movements for stroke rehabilitation is crucial for better rehabilitation outcomes via noninvasive brain stimulation by targeting the fine-grained cortical loci of the movements. However, identification of the cortical loci for lower limb movements using functional MRI (fMRI) is challenging due to head motion and difficulty in isolating different types of movement. Therefore, we developed a custom-made MR-compatible footplate and leg cushion to identify the cortical loci for lower limb movements and conducted multivariate analysis on the fMRI data. We evaluated the validity of the identified loci using both fMRI and behavioral data, obtained from healthy participants as well as individuals after stroke. METHODS: We recruited 33 healthy participants who performed four different lower limb movements (ankle dorsiflexion, ankle rotation, knee extension, and toe flexion) using our custom-built equipment while fMRI data were acquired. A subgroup of these participants (Dataset 1; n = 21) was used to identify the cortical loci associated with each lower limb movement in the paracentral lobule (PCL) using multivoxel pattern analysis and representational similarity analysis. The identified cortical loci were then evaluated using the remaining healthy participants (Dataset 2; n = 11), for whom the laterality index (LI) was calculated for each lower limb movement using the cortical loci identified for the left and right lower limbs. In addition, we acquired a dataset from 15 individuals with chronic stroke for regression analysis using the LI and the Fugl-Meyer Assessment (FMA) scale. RESULTS: The cortical loci associated with the lower limb movements were hierarchically organized in the medial wall of the PCL following the cortical homunculus. The LI was clearer using the identified cortical loci than using the PCL. The healthy participants (mean ± standard deviation: 0.12 ± 0.30; range: - 0.63 to 0.91) exhibited a higher contralateral LI than the individuals after stroke (0.07 ± 0.47; - 0.83 to 0.97). The corresponding LI scores for individuals after stroke showed a significant positive correlation with the FMA scale for paretic side movement in ankle dorsiflexion (R2 = 0.33, p = 0.025) and toe flexion (R2 = 0.37, p = 0.016). CONCLUSIONS: The cortical loci associated with lower limb movements in the PCL identified in healthy participants were validated using independent groups of healthy participants and individuals after stroke. Our findings suggest that these cortical loci may be beneficial for the neurorehabilitation of lower limb movement in individuals after stroke, such as in developing effective rehabilitation interventions guided by the LI scores obtained for neuronal activations calculated from the identified cortical loci across the paretic and non-paretic sides of the brain.

Localization of the central sulcus using the distinctive high signal intensity of the paracentral lobule on T1-weighted images.

PURPOSE: The central sulcus is an important landmark in the brain. This study aimed to investigate the distinctive signal of the paracentral lobule (PL) on T1-weighted images (T1WIs; the white PL sign) and evaluate its usefulness as a new method of identifying the central sulcus. METHODS: T1WIs of the brain of 96 participants (age, 58.9 ± 17.9 years; range, 8-87 years) scanned at 3-T MR system were retrospectively reviewed. First, we qualitatively analyzed the signal of the cortex of the PL by comparing it with that of the ipsilateral superior frontal gyrus on a 4-point grading score. Second, we compared the cortical signal intensity and gray/white-matter contrast between the PL and superior frontal gyrus. Third, we evaluated the usefulness of the PL signal for identifying the central sulcus. RESULTS: The PL cortex was either mildly hyperintense (grade 2) or definitely hyperintense (grade 3) in comparison with that of superior frontal cortex in all participants. The signal intensity of the PL cortex was significantly higher than that of the superior frontal cortex (p < 0.001), whereas the gray/white-matter contrast of the PL was weaker than that of the superior frontal gyrus (p < 0.001). The central sulci were identified with 94.3% accuracy (181/192) using the new method. CONCLUSION: The white PL sign may be helpful in identifying the central sulcus, and this approach can be recognized as a new method for identification of the central sulcus.

International Society for the Study of Women's Sexual Health (ISSWSH) Review of Epidemiology and Pathophysiology, and a Consensus Nomenclature and Process of Care for the Management of Persistent Genital Arousal Disorder/Genito-Pelvic Dysesthesia (PGAD/GPD).

BACKGROUND: Persistent genital arousal disorder (PGAD), a condition of unwanted, unremitting sensations of genital arousal, is associated with a significant, negative psychosocial impact that may include emotional lability, catastrophization, and suicidal ideation. Despite being first reported in 2001, PGAD remains poorly understood. AIM: To characterize this complex condition more accurately, review the epidemiology and pathophysiology, and provide new nomenclature and guidance for evidence-based management. METHODS: A panel of experts reviewed pertinent literature, discussed research and clinical experience, and used a modified Delphi method to reach consensus concerning nomenclature, etiology, and associated factors. Levels of evidence and grades of recommendation were assigned for diagnosis and treatment. OUTCOMES: The nomenclature of PGAD was broadened to include genito-pelvic dysesthesia (GPD), and a new biopsychosocial diagnostic and treatment algorithm for PGAD/GPD was developed. RESULTS: The panel recognized that the term PGAD does not fully characterize the constellation of GPD symptoms experienced by patients. Therefore, the more inclusive term PGAD/GPD was adopted, which maintains the primacy of the distressing arousal symptoms and acknowledges associated bothersome GPD. While there are diverse biopsychosocial contributors, there is a common underlying neurologic basis attributable to spontaneous intense activity of the genito-pelvic region represented in the somatosensory cortex and its projections. A process of care diagnostic and treatment strategy was developed to guide the clinician, whenever possible, by localizing the symptoms as originating in any of five regions: (i) end organ, (ii) pelvis/perineum, (iii) cauda equina, (iv) spinal cord, and (v) brain. Psychological treatment strategies were considered critical and should be performed in conjunction with medical strategies. Pharmaceutical interventions may be used based on their site and mechanism of action to reduce patients' symptoms and the associated bother and distress. CLINICAL IMPLICATIONS: The process of care for PGAD/GPD uses a personalized, biopsychosocial approach for diagnosis and treatment. STRENGTHS AND LIMITATIONS: Strengths and Limitations: Strengths include characterization of the condition by consensus, analysis, and recommendation of a new nomenclature and a rational basis for diagnosis and treatment. Future investigations into etiology and treatment outcomes are recommended. The main limitations are the dearth of knowledge concerning this condition and that the current literature consists primarily of case reports and expert opinion. CONCLUSION: We provide, for the first time, an expert consensus review of the epidemiology and pathophysiology and the development of a new nomenclature and rational algorithm for management of this extremely distressing sexual health condition that may be more prevalent than previously recognized. Goldstein I, Komisaruk BR, Pukall CF, et al. International Society for the Study of Women's Sexual Health (ISSWSH) Review of Epidemiology and Pathophysiology, and a Consensus Nomenclature and Process of Care for the Management of Persistent Genital Arousal Disorder/Genito-Pelvic Dysesthesia (PGAD/GPD). J Sex Med 2021;18:665-697.

Male Urogenital System Mapped Onto the Sensory Cortex: Functional Magnetic Resonance Imaging Evidence.

INTRODUCTION: The projection of the human male urogenital system onto the paracentral lobule has not previously been mapped comprehensively. AIM: To map specific urogenital structures onto the primary somatosensory cortex toward a better understanding of sexual response in men. METHODS: Using functional magnetic resonance imaging, we mapped primary somatosensory cortical responses to self-stimulation of the penis shaft, glans, testicles, scrotum, rectum, urethra, prostate, perineum, and nipple. We further compared neural response with erotic and prosaic touch of the penile shaft. MAIN OUTCOME MEASURE: We identified the primary mapping site of urogenital structures on the paracentral lobule and identified networks involved in perceiving touch as erotic. RESULTS: We mapped sites on the primary somatosensory cortex to which components of the urogenital structures project in men. Evidence is provided that penile cutaneous projection is different from deep penile projection. Similar to a prior report in women, we show that the nipple projects to the same somatosensory cortical region as the genitals. Evidence of differential representation of erotic and nonerotic genital self-stimulation is also provided, the former activating sensory networks other than the primary sensory cortex, indicating a role of "top-down" activity in erotic response. CLINICAL IMPLICATIONS: We map primary sites of projection of urogenital structures to the primary somatosensory cortex and differentiate cortical sites of erotic from nonerotic genital self-stimulation. STRENGTH & LIMITATIONS: To our knowledge, this is the first comprehensive mapping onto the primary somatosensory cortex of the projection of the components of the urogenital system in men and the difference in cortical activation in response to erotic vs nonerotic self-stimulation. The nipple was found to project to the same cortical region as the genitals. Evidence is provided that superficial and deep penile stimulation project differentially to the cortex, suggesting that sensory innervation of the penis is provided by more than the (pudendal) dorsal nerve. CONCLUSION: This study reconciles prior apparently conflicting findings and offers a comprehensive mapping of male genital components to the paracentral lobule. We provide evidence of differential projection of light touch vs pressure applied to the penile shaft, suggesting differential innervation of its superficial, vs deep structure. Similar to the response in women, we found nipple projection to genital areas of the paracentral lobule. We also provide evidence of differential representation of erotic and nonerotic genital self-stimulation, the former activating sensory networks other than the primary sensory cortex, indicating a role of top-down activity in erotic response. Allen K, Wise N, Frangos E, et al. Male Urogenital System Mapped Onto the Sensory Cortex: Functional Magnetic Resonance Imaging Evidence. J Sex Med 2020;17:603-613.

Identifying brain regions associated with the neuropathology of chronic low back pain: a resting-state amplitude of low-frequency fluctuation study.

BACKGROUND: Previous studies have found widespread pain processing alterations in the brain in chronic low back pain (cLBP) patients. We aimed to (1) identify brain regions showing altered amplitude of low-frequency fluctuations (ALFF) using MRI and use these regions to discriminate cLBP patients from healthy controls (HCs) and (2) identify brain regions that are sensitive to cLBP pain intensity changes. METHODS: We compared ALFF differences by MRI between cLBP subjects (90) and HCs (74), conducted a discriminative analysis to validate the results, and explored structural changes in key brain regions of cLBP. We also compared ALFF changes in cLBP patients after pain-exacerbating manoeuvres. RESULTS: ALFF was increased in the post-/precentral gyrus (PoG/PrG), paracentral lobule (PCL)/supplementary motor area (SMA), and anterior cingulate cortex (ACC), and grey matter volume was increased in the left ACC in cLBP patients. PCL/SMA ALFF reliably discriminated cLBP patients from HCs in an independent cohort. cLBP patients showed increased ALFF in the insula, amygdala, hippocampal/parahippocampal gyrus, and thalamus and decreased ALFF in the default mode network (DMN) when their spontaneous low back pain intensity increased after the pain-exacerbating manoeuvre. CONCLUSIONS: Brain low-frequency oscillations in the PCL, SMA, PoG, PrG, and ACC may be associated with the neuropathology of cLBP. Low-frequency oscillations in the insula, amygdala, hippocampal/parahippocampal gyrus, thalamus, and DMN are sensitive to manoeuvre-induced spontaneous back pain intensity changes.

Altered morphometric similarity networks in insomnia disorder.

Previous studies on structural covariance network (SCN) suggested that patients with insomnia disorder (ID) show abnormal structural connectivity, primarily affecting the somatomotor network (SMN) and default mode network (DMN). However, evaluating a single structural index in SCN can only reveal direct covariance relationship between two brain regions, failing to uncover synergistic changes in multiple structural features. To cover this research gap, the present study utilized novel morphometric similarity networks (MSN) to examine the morphometric similarity between cortical areas in terms of multiple sMRI parameters measured at each area. With seven T1-weighted imaging morphometric features from the Desikan-Killiany atlas, individual MSN was constructed for patients with ID (N = 87) and healthy control groups (HCs, N = 84). Two-sample t-test revealed differences in MSN between patients with ID and HCs. Correlation analyses examined associations between MSNs and sleep quality, insomnia symptom severity, and depressive symptoms severity in patients with ID. The right paracentral lobule (PCL) exhibited decreased morphometric similarity in patients with ID compared to HCs, mainly manifested by its de-differentiation (meaning loss of distinctiveness) with the SMN, DMN, and ventral attention network (VAN), as well as its decoupling with the visual network (VN). Greater PCL-based de-differentiation correlated with less severe insomnia and fewer depressive symptoms in the patients group. Additionally, patients with less depressive symptoms showed greater PCL de-differentiation from the SMN. As an important pilot step in revealing the underlying morphometric similarity alterations in insomnia disorder, the present study identified the right PCL as a hub region that is de-differentiated with other high-order networks. Our study also revealed that MSN has an important potential to capture clinical significance related to insomnia disorder.

Cerebral blood flow in the paracentral lobule is associated with poor subjective sleep quality among patients with a history of methadone maintenance treatment.

Introduction: Sleep disorders are prevalent and significant among individuals receiving methadone maintenance treatment (MMT), adversely affecting their quality of life and treatment adherence. While cerebral blood flow (CBF) plays a crucial role in the development of various diseases, its relationship with sleep disorders remains uncertain. This observational study focuses on possible correlations between CBF and poor subjective sleep quality in MMT patients. Methods: A total of 75 participants with a history of MMT were recruited and assessed using pseudo-continuous arterial spin labeling magnetic resonance imaging to determine CBF. A LAASO regression model was employed to identify the region of interest (ROI) most associated with sleep disturbance. The association between the CBF of the ROI and the Pittsburgh Sleep Quality Index (PSQI) was examined using regression analyses. Age, gender, BMI, history of hypertension, diabetes, hyperlipidemia, and methadone withdrawal were included as covariates. Results: Among MMT patients with poor subjective sleep quality, significantly higher CBF was observed in the right paracentral lobule (56.1057 ± 11.1624 ml/100 g/min, p = 0.044), right cerebelum_3 (56.6723 ± 15.3139 ml/100 g/min, p = 0.026), right caudate nucleus (48.9168 ± 6.9910 ml/100 g/min, p = 0.009), and left caudate nucleus (47.6207 ± 6.1374 ml/100 g/min, p = 0.006). Furthermore, a positive correlation was found between CBF in the right paracentral lobule and the total PSQI score (ß = 0.1135, p = 0.0323), with the association remaining significant even after adjustment for covariates (ß = 0.1276, p = 0.0405). Conclusion: MMT patients with poor subjective sleep quality exhibited significantly altered CBF in multiple brain regions. The association between increased CBF in the right paracentral lobule and subjective sleep quality in MMT patients could be crucial in understanding sleep disorders in individuals undergoing MMT. Clinical trial registration: https://www.chictr.org.cn/, identifier: ChiCTR2100051931.

Altered regional brain activity and functional connectivity patterns in major depressive disorder: A function of childhood trauma or diagnosis?

Childhood trauma (CT) is a non-specific risk factor for major depressive disorder (MDD). However, the neurobiological mechanisms of MDD with CT remain unclear. In the present study, we sought to determine the specific brain regions associated with CT and MDD etiology. Fractional amplitude of low-frequency fluctuation (fALFF) and functional connectivity (FC) analyses were performed to assess alterations of intrinsic brain activity in MDD with CT, MDD without CT, healthy controls with CT, and healthy controls without CT. Two-by-two factorial analyses were performed to examine the effects of the factors "MDD" and "CT" on fALFF and FC. Moderator analysis was used to explore whether the severity of depression moderated the relationship between CT and aberrant fALFF. We found that the etiological effects of MDD and CT exhibited negative impacts on brain dysfunction including altered fALFF in the left postcentral gyrus, left lingual gyrus, left paracentral lobule (PCL), and left cuneus. Decreased FC was observed in the following regions: (i) the left lingual gyrus seed and the left fusiform gyrus as well as the right calcarine cortex; (ii) the left PCL seed and the left supplementary motor area, left calcarine cortex, left precentral gyrus, and right cuneus; (iii) the left postcentral gyrus seed and left superior parietal lobule, right postcentral gyrus, and left precentral gyrus. Furthermore, the severity of depression acted as a moderator in the relationship between CT and aberrant fALFF in the left PCL. These data indicate that MDD patients with and without trauma exposure are clinically and neurobiologically distinct.

The Central Sulcus of the Insula: A Highly Reliable Radiographic Landmark for Identification of the Rolandic Sulcus.

BACKGROUND: Anatomic studies have suggested that the central insular sulcus (CIS) runs in line with the Rolandic sulcus (RS). The radiographic relationship between the RS and CIS has not been systematically studied. This study aims to evaluate the applicability of using the CIS as a radiologic landmark to identify the RS. METHODS: We retrospectively reviewed 100 consecutive normal magnetic resonance imaging (MRI) scans (200 hemispheres) performed at a single institution. MRI scans with any intracranial pathology or finding were excluded. Sagittal and axial fluid-attenuated inversion recovery sequences were used in this study. Two evaluators independently evaluated the relationship of the CIS and RS in all MRI scans. A predefined 3-step method was then used to identify the CIS, RS, and hand motor area in sagittal and axial images. RESULTS: The CIS was found to be correlated with the RS in 191 hemispheres (95.5%). In the remaining 9 hemispheres, the postcentral sulcus represented the most correlated sulcus with the CIS (7 hemispheres). The interrater agreement was 0.673 (P < 0.05), indicating a substantial agreement. The hand motor area was identified in the same section as the CIS in 175 hemispheres (87.5%). CONCLUSIONS: The CIS is a highly reliable radiographic landmark for the identification of the RS. The hand motor area can also be identified reliably using this method.

Morphology and Morphometry of Human Paracentral Lobule: An Anatomical Study with its Application in Neurosurgery.

BACKGROUND: The human paracentral lobule (PCL) is the medial continuation of the precentral and postcentral gyri. It has important functional area related to the lower limb and perineum. Its visible surface that corresponds to magnetic resonance imaging scout images varies in morphology, so it requires exact data. Studies related to such data are rare. With such a facile, we studied the morphology and morphometry of PCL. MATERIALS AND METHODS: Fifty formalin-fixed adult human brains dissected in the midsagittal plane were used in this study. First, the morphological types of PCL and its boundary were determined, followed by morphometry of its extrasulcal surface using digital vernier calipers. Measurements were done along the anteroposterior axis (length) and vertical axis (height). In addition to that, the extent of motor and sensory area into PCL was also measured. RESULTS: Three distinct morphological types of PCL were found: continuous (2%), partially segmented (91%), and completely segmented type (7%). In completely segmented type, a short transitional lobulolimbic gyrus was also found in three cases. The mean extrasulcal surface of the left PCL was significantly larger, both in males (left 10.67 cm2 vs. right 8.80 cm2) and in females (left 8.80 cm2 vs. right 6.99 cm2). Irrespective of gender and sidedness, motor area was significantly larger than the sensory area. CONCLUSION: Reported data will be useful in diagnosis and treatment of diseases affecting the human PCL. Variations in the distribution of sensorimotor cortex over PCL may help further assessment of hemispheric lateralization and the location of central sulcus as a reliable indicator of cytoarchitectonic borders.

Brain function state in different phases and its relationship with clinical symptoms of migraine: an fMRI study based on regional homogeneity (ReHo).

BACKGROUND: Using fMRI to analysis of brain function state in migraineurs at different phases, and combined with the clinical symptoms to explore the mechanisms and outcomes of migraine. METHODS: It's a case-control study. We analyzed the resting-state brain functional magnetic resonance imaging in 19 patients with episodes, 22 patients with interictal phase, and 22 healthy controls. The ReHo method was used for post-processing. All subjects were evaluated using the Montreal cognitive assessment (MoCA) scale, simple mental state examination (MMSE), Hamilton anxiety (HAMA) scale, and Hamilton depression (HAMD) scale. The subjects' clinical indicators (such as frequency of attack, course of disease, duration of each headache, and severity of headache) were correlated with the ReHo values of brain regions. This study was approved by the ethics committee of Yangtze River Shipping General Hospital. RESULTS: Compared with the interictal, patients in the episode group had lower activation in bilateral anterior cingulate cortex (ACC), with Montreal Neurological Institute (MNI) (-9, 42, 15); and had stronger activation in bilateral paracentral lobule (PCL), with MNI (-3, -24, 66). Compared with the control group, patients in interictal phase had lower activation in the bilateral cuneus and bilateral lingual gyrus, with MNI scores of (9, -84, 36) and (0, -72, 6), respectively. No significant difference in brain area was found between the episodes group and the control group. In the episodes group, a significant correlation was observed between attack frequency and ReHo value of the bilateral PCL (r=0.492; P=0.038). CONCLUSIONS: We need to observe the course of migraine as a whole. In the interictal period, the cuneus and lingual gyrus may affect the development of the disease. The ACC regulates different states of migraine by inducing anti-injury sensation regulation function. The paracentric lobule is not only associated with migraine attacks, but also with the frequency. This may have an effect on the outcome of subsequent migraines, as well as whether the condition becomes chronic, and the remodeling of the brain.

Connectivity of the frontal and anterior insular network: a cortico-cortical evoked potential study.

OBJECT The frontal and insular fiber network in humans remains largely unknown. This study investigated the connectivity of the frontal and anterior insular network in humans using cortico-cortical evoked potential (CCEP). METHODS This retrospective analysis included 18 patients with medically intractable focal epilepsy who underwent stereoelectroencephalography and CCEP. Alternating 1-Hz electrical stimuli were delivered to parts of the frontal lobe and anterior insula (prefrontal cortex [PFC], ventrolateral and dorsolateral premotor area [vPM and dPM, respectively], presupplementary motor area [pre-SMA], SMA, frontal operculum, and anterior insula). A total of 40-60 stimuli were averaged in each trial to obtain CCEP responses. The distribution of CCEP was evaluated by calculating the root mean square of CCEP responses. RESULTS Stimulation of the PFC elicited prominent CCEP responses in the medial PFC and PMs over the ipsilateral hemisphere. Stimulation of the vPM and dPM induced CCEP responses in the ipsilateral frontoparietal areas. Stimulation of the pre-SMA induced CCEP responses in the ipsilateral medial and lateral frontal areas and contralateral pre-SMA, whereas stimulation of the SMA induced CCEP responses in the bilateral frontoparietal areas. Stimulation of the frontal operculum induced CCEP responses in the ipsilateral insula and temporal operculum. CCEPs were observed in the ipsilateral medial, lateral frontal, and frontotemporal operculum in the anterior insular stimulation. Stimulation of the vPM and SMA led to the network in the dominant hemisphere being more developed. CONCLUSIONS Various regions within the frontal lobe and anterior insula were linked to specific ipsilateral and contralateral regions, which may reflect distinct functional roles.

The alteration of spontaneous low frequency oscillations caused by acute electromagnetic fields exposure.

OBJECTIVE: The motivation of this study is to evaluate the possible alteration of regional resting state brain activity induced by the acute radiofrequency electromagnetic field (RF-EMF) exposure (30min) of Long Term Evolution (LTE) signal. METHODS: We designed a controllable near-field LTE RF-EMF exposure environment. Eighteen subjects participated in a double-blind, crossover, randomized and counterbalanced experiment including two sessions (real and sham exposure). The radiation source was close to the right ear. Then the resting state fMRI signals of human brain were collected before and after the exposure in both sessions. We measured the amplitude of low frequency fluctuation (ALFF) and fractional ALFF (fALFF) to characterize the spontaneous brain activity. RESULTS: We found the decreased ALFF value around in left superior temporal gyrus, left middle temporal gyrus, right superior temporal gyrus, right medial frontal gyrus and right paracentral lobule after the real exposure. And the decreased fALFF value was also detected in right medial frontal gyrus and right paracentral lobule. CONCLUSIONS: The study provided the evidences that 30min LTE RF-EMF exposure modulated the spontaneous low frequency fluctuations in some brain regions. SIGNIFICANCE: With resting state fMRI, we found the alteration of spontaneous low frequency fluctuations induced by the acute LTE RF-EMF exposure.

A Case of Oligodendroglioma Attached to the Leptomeninges and Falx Cerebri

We have experienced a case of oligodendroglioma which was similar to a falx meningioma. The oligodendroglioma arose in the medial surface(paracentral lobule) of the right frontal lobe and firmly attached to the falx cerebri. The tumor was found in early life(16 year old) and it had no roentgenographic calcification. So histological confirmation was possible after the operation. We report this uncommon oligodendroglioma with a review of literatures.