Aberrant intra and inter network resting state functional connectivity in thyrotoxicosis

Abstract

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. K E Y W O R D S functional connectivity, independent components, inter network, intra network, resting state network, thyrotoxicosis

Changed functional connectivity at rest in functional illiterates after extensive literacy training

“…Two lateralized FPNs with predominantly left (LFPN) and predominantly right (RFPN) brain areas involved can be distinguished. Both networks also comprise minor contributions from brain areas in the contralateral hemisphere (c.f [ 49 ]. ), as was also case in the current data set.…”

Brain functional connectivity in patients with hyperthyroidism after anti‐thyroid treatment

“…Before treatment, the right fronto-parietal network FC showed a positive correlation with the recognition of objects memory score (r = .449, p = .032). 14 After treatment with carbimazole and controlling for the effects of age, sex, and years of education, the right fronto-parietal network FC showed a better positive correlation with the recognition of objects memory score (r = .523, p = .031) (Figure 3). Thus, there might be an improvement in the right frontoparietal network FC in hyperthyroid patients after anti-thyroid treatment, as indicated by an increased value of the correlation coefficient.…”

“…The hyperthyroid patients showed significantly decreased temporal coherence compared to the healthy control group in the subregions of the sensorimotor network, fronto-temporal network, DMN, right fronto-parietal network, left fronto-parietal network, and salience network. 14 After anti-thyroid treatment, the FC of the patients was increased in the right fronto-parietal network subregions, superior parietal lobule, frontal pole, inferior and middle frontal gyrus (z-score = 4.5, p = .005) (Figure 2A), left fronto-parietal network subregion, superior parietal cortex (z-score = 4.1, p = .014) (Figure 2B), and DMN subregion, precuneous cortex (z-score = 4.26, p = .026) (Figure 2C). The brain regions showing increased connectivity in the corresponding networks in patients after anti-thyroid treatment are summarized in Table 2.…”

“…13 In our previous study, we found decreased FC in the subregions of the sensorimotor network, fronto-temporal network, DMN, right fronto-parietal network, left fronto-parietal network, and salience network in hyperthyroid patients compared to healthy controls. 14 Few studies have shown the effect of anti-thyroid treatment (i.e., methimazole) on the brain FC in hyperthyroid patients after one month 10,11 and 8 weeks. 13 In the present study, we aimed to investigate the effect of anti-thyroid treatment (i.e., carbimazole) on the brain FC in hyperthyroid patients after achieving euthyroid status, which is a continuation of our previous work.…”

“…13 In the present study, we aimed to investigate the effect of anti-thyroid treatment (i.e., carbimazole) on the brain FC in hyperthyroid patients after achieving euthyroid status, which is a continuation of our previous work. 14 We hypothesized that anti-thyroid treatment with carbimazole could improve the FC in the brain of these patients after achieving euthyroid status.…”