Preoperative Prediction of Axillary Lymph Node Metastasis in Breast Cancer Using Mammography-Based Radiomics Method.

It is difficult to accurately assess axillary lymph nodes metastasis and the diagnosis of axillary lymph nodes in patients with breast cancer is invasive and has low-sensitivity preoperatively. This study aims to develop a mammography-based radiomics nomogram for the preoperative prediction of ALN metastasis in patients with breast cancer. This study enrolled 147 patients with clinicopathologically confirmed breast cancer and preoperative mammography. Features were extracted from each patient's mammography images. The least absolute shrinkage and selection operator regression method was used to select features and build a signature in the primary cohort. The performance of the signature was assessed using support vector machines. We developed a nomogram by incorporating the signature with the clinicopathologic risk factors. The nomogram performance was estimated by its calibration ability in the primary and validation cohorts. The signature was consisted of 10 selected ALN-status-related features. The AUC of the signature from the primary cohort was 0.895 (95% CI, 0.887-0.909) and 0.875 (95% CI, 0.698-0.891) for the validation cohort. The C-Index of the nomogram from the primary cohort was 0.779 (95% CI, 0.752-0.793) and 0.809 (95% CI, 0.794-0.833) for the validation cohort. Our nomogram is a reliable and non-invasive tool for preoperative prediction of ALN status and can be used to optimize current treatment strategy for breast cancer patients.

EEG Feature Analysis for Detecting the Fluctuation of Consciousness Level during Propofol Anesthesia.

Various EEG features have been proposed for differentiating the consciousness and unconsciousness states during general anesthesia. However, their performance for detecting the fluctuation of consciousness level remains unclear. In this work, we recorded 60-channels EEG data during propofol anesthesia, and extracted 110 EEG features that were shown to be sensitive to the change of consciousness level. Then, we used classification model to evaluate the performance of these features in distinguishing the response state fluctuating around the point of loss of behavioral responsiveness (LOBR) to external stimuli. We found that EEG features, including delta power, SynchFastSlow, and the topographical ratio of alpha power, were efficient in distinguishing the stable change in consciousness level with an accuracy of 95.8%, however, these features performed poorly in distinguishing the response state around the point of LOBR with an accuracy of 66.9%. Using EEG features selected specifically for detecting consciousness fluctuation, approximately 10% improvement in accuracy was obtained. Our results suggested that the EEG features that were sensitive to the stable change of consciousness level and fluctuation of consciousness level were largely different. EEG features including theta band power and functional connectivity are more relevant to the fluctuation of consciousness level.

Aberrant baseline brain activity in psychogenic erectile dysfunction patients: a resting state fMRI study.

Recent neuroimaging studies have elucidated many interesting and promising findings on sexuality regarding the neural underpinnings of both normal and abnormal sexual processes. Psychogenic erectile dysfunction (pED) consists of a major part of male sexual dysfunction in China, but the understanding of the central mechanism of pED is still in its infancy. It is commonly appreciated that pED is a functional disorder, which can be attributed predominantly or exclusively to psychological factors, such as anxiety, depression, loss of self-esteem, and psychosocial stresses. Most previous studies probed the central response in the brain of pED patients using sexual-related stimuli. However, little concern has been given to a more fundamental issue whether the baseline brain activity is altered in pED or not. With rs-fMRI data, the current study aimed to explain the central mechanism behind pED by investigating the alterations in baseline brain activity in patients with pED, as indexed by the amplitude of low-frequency (0.01-0.08 Hz) fluctuation (ALFF). After the psychological screening and urological examination procedure, 26 pED patients and 26 healthy matched controls were enrolled. Our results explicated significantly lower baseline brain activity in the right anterior insula and right orbitofrontal cortex for pED patients (multiple comparison corrected). Additionally, the voxel-wise correlation analysis showed that ALFF of the right anterior insula was correlated with the outcomes of erectile function (multiple comparison corrected). Our results implied there was impaired cognitive and motivational processing of sexual stimuli in pED patients. Our current findings may shed light on the neural pathology underlying pED. We hope that our study has provided a new angle looking into pED research by investigating resting state brain activity. Furthermore, we suggest that the current study may put forward a more subtle conception of insular influence on pED, which may help foster new specific, mechanistic insights.

Modulation on brain gray matter activity and white matter integrity by APOE ε4 risk gene in cognitively intact elderly: A multimodal neuroimaging study.

Apolipoprotein E (APOE) ε4 allele is the genetic risk factor with the most established evidence for sporadic Alzheimer's disease. Previous neuroimaging studies have demonstrated insufficiently consistent functional and structural changes among healthy APOE ε4 carriers when compared to non-carriers. Here, in a cognitively intact elderly group (a total of 110: 45 APOE ε4 carriers, 65 non-carriers), we aimed to investigate the potential role of APOE ε4 in the modulation of grey matter activity, white matter integrity, and brain morphology before the development of clinically significant symptoms and signs, by methods of: amplitude of low frequency fluctuations and regional homogeneity analysis based on resting state fMRI, and fiber tractography approach based on diffusion tensor imaging. Our results revealed that compared to non-carriers, APOE ε4 carriers showed: (1) an inconsistent pattern of activity change in the default mode network, including increased gray matter activity in anterior cingulate cortex and medial prefrontal cortex and decreased activity in precuneus; (2) lower mean diffusivity (MD) in fibers of corona radiata and corpus callosum, and lower axial diffusivity in genu of corpus callosum; and (3) significant positive correlation between the MD value of the right superior corona radiate and gross white matter volume; significant negative correlation between the MD value of the right superior corona radiate and Mini-Mental State Examination (MMSE) score. Our results suggested that APOE ε4 gene can modulate gray matter activity and white matter integrity in cognitive and memory related regions, even before any clinical or neuropsychic symtoms or signs of imminent disease.

Structural attributes of the temporal lobe predict face recognition ability in youth.

The face recognition ability varies across individuals. However, it remains elusive how brain anatomical structure is related to the face recognition ability in healthy subjects. In this study, we adopted voxel-based morphometry analysis and machine learning approach to investigate the neural basis of individual face recognition ability using anatomical magnetic resonance imaging. We demonstrated that the gray matter volume (GMV) of the right ventral anterior temporal lobe (vATL), an area sensitive to face identity, is significant positively correlated with the subject's face recognition ability which was measured by the Cambridge face memory test (CFMT) score. Furthermore, the predictive model established by the balanced cross-validation combined with linear regression method revealed that the right vATL GMV can predict subjects' face ability. However, the subjects' Cambridge face memory test scores cannot be predicted by the GMV of the face processing network core brain regions including the right occipital face area (OFA) and the right face fusion area (FFA). Our results suggest that the right vATL may play an important role in face recognition and might provide insight into the neural mechanisms underlying face recognition deficits in patients with pathophysiological conditions such as prosopagnosia.

Altered Functional Connectivity of Fusiform Gyrus in Subjects with Amnestic Mild Cognitive Impairment: A Resting-State fMRI Study.

Visual cognition such as face recognition requests a high degree of functional integration between distributed brain areas of a network. It has been reported that the fusiform gyrus (FG) is an important brain area involved in facial cognition; altered connectivity of FG to some other regions may lead to a deficit in visual cognition especially face recognition. However, whether functional connectivity between the FG and other brain areas changes remains unclear in the resting state in amnestic mild cognitive impairment (aMCI) subjects. Here, we employed a resting-state functional MRI (fMRI) to examine alterations in functional connectivity of left/right FG comparing aMCI patients with age-matched control subjects. Forty-eight aMCI and 38 control subjects from the Alzheimer's disease Neuroimaging Initiative were analyzed. We concentrated on the correlation between low frequency fMRI time courses in the FG and those in all other brain regions. Relative to the control group, we found some discrepant regions in the aMCI group which presented increased or decreased connectivity with the left/right FG including the left precuneus, left lingual gyrus, right thalamus, supramarginal gyrus, left supplementary motor area, left inferior temporal gyrus, and left parahippocampus. More importantly, we also obtained that both left and right FG have increased functional connections with the left middle occipital gyrus (MOG) and right anterior cingulate gyrus (ACC) in aMCI patients. That was not a coincidence and might imply that the MOG and ACC also play a critical role in visual cognition, especially face recognition. These findings in a large part supported our hypothesis and provided a new insight in understanding the important subtype of MCI.

Changes in thalamic connectivity in the early and late stages of amnestic mild cognitive impairment: a resting-state functional magnetic resonance study from ADNI.

We used resting-state functional magnetic resonance imaging (fMRI) to investigate changes in the thalamus functional connectivity in early and late stages of amnestic mild cognitive impairment. Data of 25 late stages of amnestic mild cognitive impairment (LMCI) patients, 30 early stages of amnestic mild cognitive impairment (EMCI) patients and 30 well-matched healthy controls (HC) were analyzed from the Alzheimer's disease Neuroimaging Initiative (ADNI). We focused on the correlation between low frequency fMRI signal fluctuations in the thalamus and those in all other brain regions. Compared to healthy controls, we found functional connectivity between the left/right thalamus and a set of brain areas was decreased in LMCI and/or EMCI including right fusiform gyrus (FG), left and right superior temporal gyrus, left medial frontal gyrus extending into supplementary motor area, right insula, left middle temporal gyrus (MTG) extending into middle occipital gyrus (MOG). We also observed increased functional connectivity between the left/right thalamus and several regions in LMCI and/or EMCI including left FG, right MOG, left and right precuneus, right MTG and left inferior temporal gyrus. In the direct comparison between the LMCI and EMCI groups, we obtained several brain regions showed thalamus-seeded functional connectivity differences such as the precentral gyrus, hippocampus, FG and MTG. Briefly, these brain regions mentioned above were mainly located in the thalamo-related networks including thalamo-hippocampus, thalamo-temporal, thalamo-visual, and thalamo-default mode network. The decreased functional connectivity of the thalamus might suggest reduced functional integrity of thalamo-related networks and increased functional connectivity indicated that aMCI patients could use additional brain resources to compensate for the loss of cognitive function. Our study provided a new sight to understand the two important states of aMCI and revealed resting-state fMRI is an appropriate method for exploring pathophysiological changes in aMCI.

Altered effective connectivity patterns of the default mode network in Alzheimer's disease: an fMRI study.

The aim of this work is to investigate the differences of effective connectivity of the default mode network (DMN) in Alzheimer's disease (AD) patients and normal controls (NC). The technique of independent component analysis (ICA) was applied to identify DMN components and multivariate Granger causality analysis (mGCA) was used to explore an effective connectivity pattern. We found that: (i) connections in AD were decreased than those in NC, in terms of intensity and quantity. Posterior cingulated cortex (PCC) exhibited significant activity in NC as it connected with most of the other regions within the DMN. Besides, the PCC was the convergence center which only received interactions from other regions; (ii) right inferior temporal cortex (rITC) in the NC exhibited stronger interactions with other regions within the DMN compared with AD patients; and (iii) interactions between medial prefrontal cortex (MPFC) and bilateral inferior parietal cortex (IPC) in the NC were weaker than those in AD patients. These findings may implicate a brain dysfunction in AD patients and reveal more pathophysiological characteristics of AD.

Prolonged hindlimb unloading leads to changes in electrophysiological properties of L5 dorsal root ganglion neurons in rats after 14 days.

INTRODUCTION: The purpose of this study was to evaluate the electrophysiological changes observed in dorsal root ganglion (DRG) neurons in a simulated weightlessness rat model and to assess the mechanisms involved in these changes. METHODS: The simulated weightlessness model was created by hindlimb unloading (HU). Whole-cell patch-clamp recordings, conduction velocity measurement, and ultrastructural observation were performed. RESULTS: In the HU rats, the action potentials had a longer duration and slower falling rate, but there was no significant effect on amplitude or rate of rise. HU also induced lowering of rheobase and of the threshold potential, making the cells more excitable. The conduction velocities in the proximal branches of ganglion cells were also decreased, and some degenerative changes in the myelin sheath were noted. CONCLUSIONS: This study provides evidence of plasticity of DRG neurons induced by HU. The changes observed might contribute to impaired motor performance in rats submitted to HU.

[Decreased neurotrophin-3 expression of intrafusal muscle fibers in rat soleus muscles under simulated weightlessness].

The present study aimed to study the changes of neurotrophin-3 (NT-3) expression of intrafusal muscle fibers in rat soleus muscles under simulated weightlessness. The tail-suspension (SUS) rat model was used to simulate weightlessness. Forty mature female Sprague-Dawley rats were randomly assigned to ambulatory control (CON), 3-day SUS, 7-day SUS, 14-day SUS and 21-day SUS groups. Immunohistochemistry ABC staining method and enzyme linked immunosorbent assay (ELISA) were used to detect the NT-3 expression of intrafusal muscle fibers in rat soleus muscles. The results from the immunohistochemistry staining technique showed that the extrafusal muscle fibers did not exhibit the NT-3-like immunoreactivity, and NT-3-like immunoreactivity was mainly expressed in nuclear bag 1 and nuclear bag 2 fibers of the muscle spindles. The ELISA results showed that the expression quantity of NT-3 in rat soleus muscles in control, 3-day SUS, 7-day SUS, 14-day SUS and 21-day SUS groups were (14.23±1.65), (14.11±1.53), (13.09±1.47), (12.45±1.51) and (9.85±1.52) pg/mg of tissue respectively. Compared to the control group, the expression quantity of NT-3 was significantly decreased after 14 days of SUS (P<0.05). After 21 days of SUS, the NT-3 expression was further reduced (P<0.01). These results suggest that simulated weightlessness induces an obvious decrease in the NT-3 expression level of intrafusal fibers in rat soleus muscles. Accompanying the simulated weightlessness extension, NT-3 expression in rat soleus muscle spindles is progressively decreased. These changes may contribute to the proprioceptive adaptations to microgravity.

[Influence of 100 Hz sinusoidal vibration on muscle spindle afferents of soleus muscles in suspended situation rat].

OBJECTIVE: To study influence of 100 Hz sinusoidal vibration on muscle spindle afferents discharges of rat soleus muscles in simulated-weightlessness situation. METHOD: The tail-suspended rat model was used to simulate weightlessness, and 100 Hz sinusoidal vibration was performed by a vibrator. Unit activity was recorded electrophysiologically from the centrally cut filaments of the spinal dorsal roots innervating muscle spindles of the rat soleus muscle; then observation on the changes in afferent discharges from muscle spindle in a rat soleus muscles were made after 7 d. RESULT: 1) Compared with control muscle spindle afferents discharges of rat soleus muscles decreased after 7 d tail-suspension (P<0.05). 2) Compared with suspension the afferent discharges from soleus muscle spindles increased after 7 d tail-suspension with 100 Hz sinusoidal vibration. CONCLUSION: Sinusoidal vibration (100 Hz; 300 micrometers) can selectively activate muscle spindles. Muscle spindle afferent input of the suspended rats increased after the application of 7 d 100 Hz sinusoidal vibration.