Cognitive Deficit-Related Interhemispheric Asynchrony within the Medial Hub of the Default Mode Network Aids in Classifying the Hyperthyroid Patients

Brain-thyroid crosstalk: 18F-FDG-PET/MRI evidence in patients with follicular thyroid adenomas

OBJECTIVE

The hypothalamic-pituitary-thyroid axis has been well-known. However, whether follicular thyroid adenoma (FTA) could affect brain glucose metabolism is still unknown. Therefore, we explored the brain glucose metabolic characteristics of FTA with Fluorodeoxyglucose F18 positron emission tomography/magnetic resonance imaging.

METHODS

Totally 30 FTA patients without clinical symptoms (FTA group), and 60 age- and sex-matched healthy controls (HC group) were included and randomly divided into cohort A and B in 2:1 ratio. Cohort A was analyzed with scaled sub-profile model/principal component analysis (SSM/PCA) for pattern identification. Cohort B was calculated the individual scores to validate expression of the pattern. Then we calculated the metabolic connectivity based on characteristics of the pattern to investigate the underlying mechanism. Finally, we constructed metabolic brain networks and analyzed the topological properties to further explore the brain metabolic model.

RESULTS

In SSM/PCA, FTA group showed an almost global, left-right symmetrical pattern. In metabolic connectivity, FTA group showed increased metabolic connectivity in brain regions of the sensorimotor network, ventral default mode network (DMN), posterior salient network, right executive control network (ECN), visuospatial network and language network when compared to HC group, and showed decreased connectivity in dorsal DMN and left ECN. In topological properties of brain network, FTA group showed an increased betweenness centrality (BC) in left rolandic operculum, a decreased BC in superior temporal gyrus, increased BC and Degree in right precentral gyrus, increased D in right parahippocampal gyrus and left hippocampus, and decreased D and efficiency in right orbital part of middle frontal gyrus (FDR correction for multiple comparisons, P < 0.05).

CONCLUSION

Although FTA patients are not yet symptomatic, their brain metabolic characteristics include extensive brain alterations, disrupted internal connectivity, not only involving brain regions associated with endocrine activity, but also brain networks and regions associated with motor, emotion and cognition.

Altered Functional Connectivity of the Multisensory Vestibular Cortex in Patients with Chronic Unilateral Vestibulopathy

Background: Chronic unilateral vestibulopathy (CUVP) is a common chronic vestibular syndrome; the mechanisms of central vestibular compensation in CUVP are rarely studied. Methods: This study analyzed the data of 18 patients with CUVP and 18 healthy controls (HCs) and used seed-based functional connectivity (FC) and voxel-mirrored homotopic connectivity (VMHC) analyses to explore the FC alterations. Results: Compared with HCs, patients with CUVP showed decreased FC between the left dorsolateral superior frontal gyrus and the right hippocampus; the left middle frontal gyrus and the right posterior cingulate gyrus, the right hippocampus, the right parahippocampal gyrus. There is also a reduction in FC between the left and right insula. There was enhanced FC between the left supplementary motor area (SMA) and the bilateral superior occipital gyrus, the left hippocampus and the left posterior cingulate gyrus, as well as a the left middle temporal gyrus (p = 0.03). Additionally,VMHC was decreased between the bilateral medial superior frontal gyrus, the bilateral precentral gyrus, and the bilateral postcentral gyrus (p = 0.001). The zVMHC values in the bilateral superior frontal gyrus and the precentral gyrus were both negatively corrected with the Dizziness Handicap Inventory (DHI) score.well as Conclusions: Altered FC in regions of bilateral multisensory vestibular cortex existed in patients with CUVP. Decreased FC and VMHC in the bilateral multisensory vestibular cortex may affect vestibular information integration, thus affecting self-motion perception, spatial orientation, and postural control.

Brain functional connectivity in hyperthyroid patients: systematic review

INTRODUCTION

Functional connectivity (FC) is the correlation between brain regions' activities, studied through neuroimaging techniques like fMRI. It helps researchers understand brain function, organization, and dysfunction. Hyperthyroidism, characterized by high serum levels of free thyroxin and suppressed thyroid stimulating hormone, can lead to mood disturbance, cognitive impairment, and psychiatric symptoms. Excessive thyroid hormone exposure can enhance neuronal death and decrease brain volume, affecting memory, attention, emotion, vision, and motor planning.

METHODS

We conducted thorough searches across Google Scholar, PubMed, Hinari, and Science Direct to locate pertinent articles containing original data investigating FC measures in individuals diagnosed with hyperthyroidism.

RESULTS

The systematic review identified 762 articles, excluding duplicates and non-matching titles and abstracts. Four full-text articles were included in this review. In conclusion, a strong bilateral hippocampal connection in hyperthyroid individuals suggests a possible neurobiological influence on brain networks that may affect cognitive and emotional processing.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42024516216.

The decreased connectivity in middle temporal gyrus can be used as a potential neuroimaging biomarker for left temporal lobe epilepsy

OBJECTIVE

We aimed to explore voxel-mirrored homotopic connectivity (VMHC) abnormalities between the two brain hemispheres in left temporal lobe epilepsy (lTLE) patients and to determine whether these alterations could be leveraged to guide lTLE diagnosis.

MATERIALS AND METHODS

Fifty-eight lTLE patients and sixty healthy controls (HCs) matched in age, sex, and education level were recruited to receive resting state functional magnetic resonance imaging (rs-fMRI) scan. Then VHMC analyses of bilateral brain regions were conducted based on the results of these rs-fMRI scans. The resultant imaging data were further analyzed using support vector machine (SVM) methods.

RESULTS

Compared to HCs, patients with lTLE exhibited decreased VMHC values in the bilateral middle temporal gyrus (MTG) and middle cingulum gyrus (MCG), while no brain regions in these patients exhibited increased VMHC values. SVM analyses revealed the diagnostic accuracy of reduced bilateral MTG VMHC values to be 75.42% (89/118) when differentiating between lTLE patients and HCs, with respective sensitivity and specificity values of 74.14% (43/58) and 76.67% (46/60).

CONCLUSION

Patients with lTLE exhibit abnormal VMHC values corresponding to the impairment of functional coordination between homotopic regions of the brain. These altered MTG VMHC values may also offer value as a robust neuroimaging biomarker that can guide lTLE patient diagnosis.

Aberrant intra and inter network resting state functional connectivity in thyrotoxicosis

Thyroid hormones epigenetically play an important role in the regularisation of neural networks and in neural differentiation during brain development. The present study aimed to explore the intra and inter network resting state functional connectivity changes underlying the neurobehavioural symptoms in thyrotoxicosis. To understand the pathophysiological changes, we investigated the correlation between functional connectivity and clinical and behavioural measures. Twenty-eight freshly diagnosed thyrotoxicosis patients suffering with symptoms such as palpitation, loss of weight, trembling and heat intolerance from days to weeks and 28 healthy controls were recruited for the study. Thyrotoxicosis patients showed significantly decreased functional connectivity in sensorimotor network, fronto-temporal network, default mode network, right fronto-parietal network, left fronto-parietal network and salience network. Inter network functional connectivity was significantly reduced between the basal ganglia network and sensorimotor network and increased between the salience network and fronto-temporal network in thyrotoxicosis. Cognitive functions such as visual retention, recognition of objects, mental balance and performance on neuropsychological tests (ie, the Bender Gestalt test, Nahar-Benson test and Mini Mental State Examination) also showed significant decline in thyrotoxicosis patients. The altered intrinsic resting state functional connectivity might underlie these cognitive deficits. The increased functional connectivity between the salience network and fronto-temporal network suggests the recruitment of additional neuronal circuitry needed to compensate for the neuropathology in the primary neural network in thyrotoxicosis.