Altered spontaneous brain activity patterns in patients with diabetic retinopathy using amplitude of low-frequency fluctuation

BACKGROUND Diabetes mellitus is a metabolic disorder characterized by prolonged elevation of blood glucose due to various causes.Currently,the relationship between diabetic retinopathy(DR)and altered connectivity of brain function is unclear.AIM To investigate the relationship between this brain activity and clinical manifestations and behaviors of DR patients by using the amplitude of low-frequency fluctuation(ALFF)technique.METHODS Twenty-four DR patients and 24 healthy controls(HCs)matched for age and gender were enrolled.We measured and recorded average ALFF values of DR patients and HCs and then classified them using receiver operating characteristic(ROC)curves.RESULTS ALFF values of both left and right posterior cerebellar lobe and right anterior cingulate gyrus were remarkably higher in the DR patients than in the HCs;however,DR patients had lower values in the bilateral calcarine area.ROC curve analysis of different brain regions demonstrated high accuracy in the area under the curve analysis.There was no significant relationship between mean ALFF values for different regions and clinical presentations in DR patients.Neuronal synchronization abnormalities in some brain regions of DR patients were associated with cognitive and visual disorders.CONCLUSION Abnormal spontaneous brain activity was observed in many areas of DR patients’brains,which may suggest a possible link between clinical manifestations and behaviors in DR patients.

Short-Term Visual Experience Leads to Potentiation of Spontaneous Activity in Mouse Superior Colliculus

Spontaneous activity in the brain maintains an internal structured pattern that reflects the external environment,which is essential for processing information and developing perception and cognition.An essential prerequisite of spontaneous activity for perception is the ability to reverberate external information,such as by potentiation.Yet its role in the processing of potentiation in mouse superior colliculus(SC)neurons is less studied.Here,we used electrophysiological recording,optogenetics,and drug infusion methods to investigate the mechanism of potentiation in SC neurons.We found that visual experience potentiated SC neurons several minutes later in different developmental stages,and the similarity between spontaneous and visually-evoked activity increased with age.Before eye-opening,activation of retinal ganglion cells that expressed ChR2 also induced the potentiation of spontaneous activity in the mouse SC.Potentiation was dependenton stimulus number and showed feature selectivity for direction and orientation.Optogenetic activation of parvalbumin neurons in the SC attenuated the potentiation induced by visual experience.Furthermore,potentiation in SC neurons was blocked by inhibiting the glutamate transporter GLT1.These results indicated that the potentiation induced by a visual stimulus might play a key role in shaping the internal representation of the environment,and serves as a carrier for short-term memory consolidation.

Altered spontaneous brain activity patterns in patients with hyperthyroidism exophthalmos using amplitude of low-frequency fluctuation:a resting-state fMRI study

AIM:To assess changed spontaneous brain activity in hyperthyroid exophthalmos(HE)patients by the amplitude of the low-frequency fluctuation(ALFF)method,and to analyze the correlation between brain activity and ALFF values in these patients.METHODS:Totally 18 HE and 18 hyperthyroid nonexophthalmos(HNE)patients were enrolled.The participants were tested by resting-state functional magnetic resonance imaging,and receiver operating characteristic(ROC)curves were generated to classify the ALFF values of the study population.Pearson’s correlation analysis was utilized to evaluate the relationship between the ALFF values obtained from different brain areas and clinical manifestations.RESULTS:Contrary to HNE patients,we observed lower ALFF values in the left calcarine fissure and surrounding cortex(LCFSC)in HE patients.In the ROC curve analysis of the LCFSC,the area under the curve reflected a high degree of accuracy.In addition,there was positive correlation between mean ALFF values of the LCFSC and the bestcorrected visual acuity of the affected eyes.CONCLUSION:The study displays abnormal brain activity in LCFSC in patients with HE,which might suggest pathological mechanism of visual impairment of HE patients.

The sensitivity of neurons with non-periodic activity to sympathetic stimulation in rat injured dorsal root ganglion

Objective The relationship between compressed dorsal root ganglion （DRG） neurons and firing pattern and sensitivity of neurons was studied in chronically the Hindmarsh-Rose （HR） neuronal model. Methods Spontane- ous activities from single fibers of chronically compressed DRG neurons in rats were recorded, and divided into periodic and non-periodic firing patterns. The sensitivity of the two kinds of firing pattern neuron to sympathetic stimulation （SS） was compared. Result It was found that 27.3% of periodic firing neurons and 93.2% of non-periodic firing neurons responded to SS respectively （ periodic vs non-periodic, P 〈 0.01 ）. The responses to SS with different stimulation time were greater non-periodic firing neurons than periodic firing neurons （P 〈 0.01 ）. The non-periodic firing neurons obviously responded to SS. After the firing pattern of these neurons transformed to periodic firing pattern, their responses to SS disappeared or decreased obviously. The HR neuronal model exhibited a significantly greater response to perturbation in non-periodic （chaotic） firing pattern than in periodic firing pattern. Conelusion The non-periodic firing neurons with deterministic chaos are more sensitive to external stimuli than the periodic firing neurons.

Translocation of telomerase reverse transcriptase coincided with ATP release in postnatal cochlear supporting cells

The spontaneous bursts of electrical activity in the developing auditory system are derived from the periodic release of adenosine triphosphate(ATP)by supporting cells in the Kölliker’s organ.However,the mechanisms responsible for initiating spontaneous ATP release have not been determined.Our previous study revealed that telomerase reverse transcriptase(TERT)is expressed in the basilar membrane during the first postnatal week.Its role in cochlear development remains unclear.In this study,we investigated the expression and role of TERT in postnatal cochlea supporting cells.Our results revealed that in postnatal cochlear Kölliker’s organ supporting cells,TERT shifts from the nucleus into the cytoplasm over time.We found that the TERT translocation tendency in postnatal cochlear supporting cells in vitro coincided with that observed in vivo.Further analysis showed that TERT in the cytoplasm was mainly located in mitochondria in the absence of oxidative stress or apoptosis,suggesting that TERT in mitochondria plays roles other than antioxidant or anti-apoptotic functions.We observed increased ATP synthesis,release and activation of purine signaling systems in supporting cells during the first 10 postnatal days.The phenomenon that TERT translocation coincided with changes in ATP synthesis,release and activation of the purine signaling system in postnatal cochlear supporting cells suggested that TERT may be involved in regulating ATP release and activation of the purine signaling system.Our study provides a new research direction for exploring the spontaneous electrical activity of the cochlea during the early postnatal period.

Brain mechanisms of mental processing:from evoked and spontaneous brain activities to enactive brain activity

Within the context of the computer metaphor,evoked brain activity acts as a primary carrier for the brain mechanisms of mental processing.However,many studies have found that evoked brain activity is not the major part of brain activity.Instead,spontaneous brain activity exhibits greater intensity and coevolves with evoked brain activity through continuous interaction.Spontaneous and evoked brain activities are similar but not identical.They are not separate parts,but always dynamically interact with each other.Therefore,the enactive cognition theory further states that the brain is characterized by unified and active patterns of activity.The brain adjusts its activity pattern by minimizing the error between expectation and stimulation,adapting to the ever-changing environment.Therefore,the dynamic regulation of brain activity in response to task situations is the core brain mechanism of mental processing.Beyond the evoked brain activity and spontaneous brain activity,the enactive brain activity provides a novel framework to completely describe brain activities during mental processing.It is necessary for upcoming researchers to introduce innovative indicators and paradigms for investigating enactive brain activity during mental processing.

Altered intrinsic functional connectivity of the primary visual cortex in youth patients with comitant exotropia: a resting state fMRI study

AIM： To evaluate the differences in the functional connectivity（FC） of the primary visual cortex（V1） between the youth comitant exotropia（CE） patients and health subjects using resting functional magnetic resonance imaging（f MRI） data.METHODS： Totally, 32 CEs（25 males and 7 females） and 32 healthy control subjects（HCs）（25 males and 7 females） were enrolled in the study and underwent the MRI scanning. Two-sample t-test was used to examine differences in FC maps between the CE patients and HCs. RESULTS： The CE patients showed significantly less FC between the left brodmann area（BA17） and left lingual gyrus/cerebellum posterior lobe, right middle occipital gyrus, left precentral gyrus/postcentral gyrus and right inferior parietal lobule/postcentral gyrus. Meanwhile, CE patients showed significantly less FC between right BA17 and right middle occipital gyrus（BA19, 37）.CONCLUSION： Our findings show that CE involves abnormal FC in primary visual cortex in many regions, which may underlie the pathologic mechanism of impaired fusion and stereoscopic vision in CEs.

Lower limb pain in sympathetic-sensory coupling

Previous studies have shown that sympathetic nerves are related to certain types of pain, and this phenomenon is referred to as sympathetic-sensory coupling. Chronic pain resulting from nerve injury can be exacerbated by sympathetic stimulation or relieved by sympathetic inhibition. In the present study, the correlation between pain and sympathetic nerves was analyzed in patients with severe pain in lower limbs, as we^l as in a chronically compressed dorsa~ root ganglion ~CCD） rat model （model of low back pain and sciatica）. Patients with severe pain in the lower limbs underwent chemical lumbar sympathectomy （CLS）, and the analgesic effects of CLS were compared with painkillers. Results demonstrated significantly relieved lower limb pain following CLS, and the analgesic effects of CLS were superior to those seen with painkillers. In the CCD rat model, dorsal root ganglion neuronal activity significantly increased as a result of electrical stimulation to the sympathetic nerves. These results suggest that sympathetic nerves are closely associated with pain and sympathetic-sensory coupling is likely in lower limb pain in both patients and rat models of CCD.

Altered brain network centrality in patients with retinal vein occlusion: a resting-state fMRI study

AIM:To explore the intrinsic brain activity variations in retinal vein occlusion(RVO)subjects by using the voxel-wise degree centrality(DC)technique.METHODS:Twenty-one subjects with RVO and twentyone healthy controls(HCs)were enlisted and underwent the resting-state functional magnetic resonance imaging(rs-f MRI)examination.The spontaneous cerebrum activity variations were inspected using the DC technology.The receiver operating characteristic(ROC)curve was implemented to distinguish the DC values of RVOs from HCs.The relationships between DC signal of definite regions of interest and the clinical characteristics in RVO group were evaluated by Pearson’s correlation analysis.RESULTS:RVOs showed notably higher DC signals in right superior parietal lobule,middle frontal gyrus and left precuneus,but decreased DC signals in left middle temporal gyrus and bilateral anterior cingulated(BAC)when comparing with HCs.The mean DC value of RVOs in the BAC were negatively correlated with the anxiety and depression scale.CONCLUSION:RVO is associated aberrant intrinsic brain activity patterns in several brain areas including painrelated as well as visual-related regions,which might assist to reveal the latent neural mechanisms.

The effects of inactivated SARS-CoV-2 vaccination and subsequent infection of pregnant mice on the behaviors of offspring

The mass inoculation of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines to induce herd immunity is one of the most effective measures we can deploy in the fight against coronavirus disease 2019(COVID-19).Pregnant women are prone to a higher risk of COVID-19,and maternal infection is a risk fac-tor for a range of neurological disorders leading to abnormal behavior in adulthood.However,there are limited clinical data to support whether vaccination or infection post-immunization in pregnant women can affect the behavioral cognition of fetuses in adulthood.In this study,human angiotensin-converting enzyme 2 pregnant mice(F0 generation)were immunized with CoronaVac and then infected with SARS-CoV-2.Subsequently,we analyzed the behavioral cognition of their adult offspring(F1 gen-eration)using the open-field test and Morris water maze test.The adult F1 generation did not exhibit any impairments in spontaneous locomotor activity or spatial refer-ence memory.

Spontaneous activation of hamster oocytes in vitro

Objectives To observe the time of spontaneous activation of hamster oocytes and to find out the early signs of hamster oocytes activation Methods First, 63 hamster oocytes including activated and non activated oocytes (group A) and 51 non activated oocytes (group B) were injected with human sperm and checked for fertilization after 16-18 hours Then, 20 hamster oocytes were cultured in vitro in medium with or without calcium and examined under light microscope every half an hour up to 9 hours Results Under light microscope, hamster oocytes activation were observed to undergo 4 stages: metaphase Ⅱ stage without meiotic spindle, appearance of meiotic spindle near the first polar body, protrusion of oolemma, and complete extrusion of second polar body with pronucleus formation After culture for 1 5 hours in vitro, 30% 40% of the oocytes demonstrated meiotic spindle; but after 9 hours, 50% showed complete activation Culture in medium without calcium showed a little delay in the process of activation The earliest sign of spontaneous activation in hamster oocytes was the appearance of meiotic spindle near the first polar body Although group A and B showed no difference, the damage rate was lower in group B (19 7%±16 6%) than in group A (35 9%±5 7%) ( P =0 08), whereas the fertilization rate (18 3%±10 9%) was higher in group B than in group A (14 2%±8 7%) ( P =0 135) Conclusions Hamster oocytes may be activated spontaneously early after their removal It is important to recognize the earliest sign of spontaneous activation and perform intracytoplasmic sperm injection (ICSI) before it happens

Ecotoxicological effects of waterborne PFOS exposure on swimming performance and energy expenditure in juvenile goldfish (Carassius auratus)

The potential risks of perfluorooctane sulfonate （PFOS） are of increasing ecological concern. Swimming performance is linked to the fitness and health of fish. However, the impacts of PFOS on swimming performance remain largely unknown. We investigated the ecotoxicological effects of acute exposure to PFOS on the swimming performance and energy expenditure of juvenile goldfish （Carassius auratus）. The fish were exposed to a range of PFOS concentrations （0, 0.5, 2, 8 and 32 mg/L） for 48 hr. The spontaneous swimming activity, fast-start swimming performance, critical swimming speed （Ucrit） and active metabolic rate （AMR） of the goldfish were examined after exposure to PFOS. PFOS exposure resulted in remarkable effects on spontaneous activity. Motion distance was reduced, and the proportion of motionless time increased with increasing concentrations of PFOS. However, no significant alterations in the fast-start performance-related kinematic parameters, such as latency time, maximum linear velocity, maximum linear acceleration or escape distance during the first 120 msec after stimulus, were observed after PFOS exposure. Unexpectedly, although PFOS exposure had marked influences on the swimming oxygen consumption rates and AMR of goldfish, the U crit of the goldfish was not significantly affected by PFOS. This may result in a noteworthy increase in the energetic cost of transport. The overall results indicate that, in contrast to spontaneous activity, underlying swimming capabilities are maintained in goldfish after short-term exposure to PFOS, but energy expenditure during the process of swimming is dramatically aggravated.

Evaluation of the anxiolytic effect of the methanol stem extracts of Cissus quadrangularis

Objective:To investigate the potentials of the stem of Cissus quadrangularis(C.quadrangularis)in the control of anxiety and related motor coordination effects in mice using experimental models.Methods:The methanol extract of the stem of C.quadrangularis was studied in mice using elevated plus maze,hole board,open field and stair case tests.Acute toxicity and phytochemical analysis were also carried out.Results:The methanol extract(100,200,300 and 400 mg/kg)exhibited significant anxiolytic effects,as evident by significant(P<0.05)increase in the number of crossings at 100,200 and 300 mg/kg dose and number of rearing at 200,300 and 400 mg/kg dose in open field behavior test.Time spent in the open arms and number of entrances in the open arms increased significantly(P<0.05,P<0.01)at the dose of 200 and 300 mg/kg in elevated plus maze test.Post hoc analysis showed that C.quadrangularis at the dose of 200 and 300 mg/kg significantly(P<0.05)increased the number of steps taken and number of head dips.Significant(P<0.05)reduction in time duration on the bar and number of rearing were observed at the dose of 200,300 and 400 mg/kg.The acute toxicity test revealed an oral LD_(50)above 5000 mg/kg,while phytochemical studies showed the presence of phytosterols,terpenoids,saponins,flavanoids,tannins,carbohydrates and aminoacids.Conclusions:The stem extracts of C.quadrangularis is anxiolytic in nature,which contribute to its use in traditional medicine as anxiolytic.