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1.
Medicine (Baltimore) ; 99(16): e19835, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32312005

RESUMO

RATIONALE: Pusher syndrome is a disorder of postural control. It is associated with unilateral lesions on central vestibular system. In the current study, we attempted to identify and investigate neural connectivity of the parieto-insular vestibular cortex in a patient with pusher syndrome, using diffusion tensor imaging. PATIENT CONCERNS: A 60-year-old male patient had left hemiplegia due to an infarction on right premotor cortex, primary motor cortex, corona radiata and temporal and occipital lobe. The patient had severe motor weakness in left upper and lower limb, left side neglect and significant pusher syndrome. DIAGNOSIS: Patient was diagnosed with left hemiplegia due to an infarction in the right middle cerebral artery territory at the neurology department of a university hospital. INTERVENTIONS: One patient and 5 control subjects of similar age participated. Diffusion tensor imaging data were acquired at 4-month and 12-month after the initial injury. OUTCOMES: Fractional anisotropy, mean diffusivity, and tract volume (TV) were measured. TV values in both affected and unaffected hemispheres of the patient were significantly decreased at 4-month compared to those of control subjects. In the unaffected hemisphere of the patient, TV value showed significant increase at 12-month compared to that at 4-month. Although the TV value at 12-month of the affected hemisphere was out of reference range, TV was considerably increased compared to that at 4-month. Mean values for fractional anisotropy or mean diffusivity in 2 hemispheres did not show significant difference compared to those of control subjects regardless of month. LESSONS: Restoration of an injured projection pathway between the vestibular nuclei and parieto-insular vestibular cortex with recovery of pusher syndrome was found in a patient with stroke.


Assuntos
Imagem de Tensor de Difusão/métodos , Hemiplegia/diagnóstico , Sistema Nervoso/diagnóstico por imagem , Equilíbrio Postural/fisiologia , Anisotropia , Infarto Encefálico , Córtex Cerebral/fisiopatologia , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Hemiplegia/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/patologia , Córtex Motor/diagnóstico por imagem , Córtex Motor/patologia , Sistema Nervoso/fisiopatologia , Lobo Occipital/diagnóstico por imagem , Lobo Occipital/patologia , Lobo Parietal/fisiopatologia , Córtex Somatossensorial/fisiopatologia , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
2.
PLoS One ; 15(2): e0228541, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32069294

RESUMO

Switching between tasks requires individuals to inhibit mental representations of the previous task demands and to activate representations of the new task demands. The inhibition of the executed task remains active for a while so that when the inhibited task set must be re-activated shortly after, the need to overcome residual task set inhibition leads to behavioral costs. In a sham-controlled balanced-order within-subjects experimental design we investigated whether applying right anodal/left cathodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal or parietal cortex modulated the ability to overcome persistent task inhibition during task switching. Results showed that right anodal/left cathodal tDCS over the parietal cortex improves performance selectively when switching back to a recently inhibited task that requires previous inhibition to be overcome. Right Anodal/left cathodal tDCS over the prefrontal cortex improves performance during task switching in general, either when re-engaging in a inhibited task or when engaging in a non-inhibited task. Results suggest a different contribution of prefrontal and parietal regions to task switching, with parietal cortex being selectively involved in overcoming persistent task inhibition and prefrontal cortex being more generally involved in the control of task set during task switching.


Assuntos
Lobo Frontal/fisiologia , Inibição Psicológica , Lobo Parietal/fisiologia , Tempo de Reação/fisiologia , Análise e Desempenho de Tarefas , Estimulação Transcraniana por Corrente Contínua/métodos , Adaptação Fisiológica/fisiologia , Adulto , Eletrodos , Feminino , Lateralidade Funcional/fisiologia , Neuroimagem Funcional , Humanos , Masculino , Projetos de Pesquisa , Adulto Jovem
3.
Br J Radiol ; 93(1108): 20190887, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31904268

RESUMO

OBJECTIVE: In spite of the well-known importance of thalamus in hemifacial spasm (HFS), the thalamic resting-state networks in HFS is still rarely mentioned. This study aimed to investigate resting-state functional connectivity (FC) of the thalamus in HFS patients and examine its association with clinical measures. METHODS: 25 HFS patients and 28 matched healthy controls underwent functional MRI at rest. Using the left and right thalamus as seed regions respectively, we compared the thalamic resting-state networks between patient and control groups using two independent sample t-test. RESULTS: Compared with controls, HFS patients exhibited strengthened bilateral thalamus-seeded FC with the parietal cortex. Enhanced FC between right thalamus and left somatosensory association cortex was linked to worse motor disturbance, and the increased right thalamus-right supramarginal gyrus connection were correlated with improvement of affective symptoms. CONCLUSION: Our findings indicate that the right thalamus-left somatosensory association cortex hyperconnectivity may represent the underlying neuroplasticity related to sensorimotor dysfunction. In addition, the upregulated FC between the right thalamus and right supramarginal gyrus in HFS, is part of the thalamo-default mode network pathway involved in emotional adaptation. ADVANCES IN KNOWLEDGE: This study provides new insights on the integrative role of thalamo-parietal connectivity, which participates in differential neural circuitry as a mechanism underlying motor and emotional functions in HFS patients.


Assuntos
Espasmo Hemifacial/fisiopatologia , Imagem por Ressonância Magnética , Lobo Parietal/fisiopatologia , Descanso , Tálamo/fisiopatologia , Estudos de Casos e Controles , Estudos Transversais , Feminino , Espasmo Hemifacial/diagnóstico por imagem , Espasmo Hemifacial/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Índice de Gravidade de Doença , Tálamo/diagnóstico por imagem
4.
Psychiatry Res Neuroimaging ; 296: 111028, 2020 02 29.
Artigo em Inglês | MEDLINE | ID: mdl-31911320

RESUMO

Affective instability (i.e., large and frequent shifts in negative emotions) is a key emotion dysregulation symptom in emotional distress disorders and can be reliably and validly assessed using ambulatory assessment. However, no study has examined whether affective instability is associated with brain function and structure. Using multimodal neuroimaging and ambulatory assessment, we examined associations between functional activation and cortical structure with ambulatory-assessed affective instability in emotional distress disorders (n = 27). Increased daily life-affective instability was associated with decreased neural activation on an emotion regulation task in a left inferior parietal region consistently associated with emotion regulation. Daily-life affective instability was also associated with hypogyria in this same left inferior parietal region, with hypogyria extending into additional posterior parietal regions. This study found evidence that daily-life affective instability was associated with both functionstructure of the posterior parietal cortex, a key attentional control region involved in emotion regulation.


Assuntos
Emoções/fisiologia , Lobo Parietal/patologia , Lobo Parietal/fisiopatologia , Angústia Psicológica , Atenção/fisiologia , Humanos , Imagem por Ressonância Magnética , Neuroimagem
5.
Behav Brain Sci ; 42: e301, 2020 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-31896360

RESUMO

The ventral lateral parietal cortex (VLPC) shows robust activation during episodic retrieval, and is involved in content representation, as well as in the evaluation of memory traces. This suggests that the VLPC has a crucial contribution to the quality of recollection and the subjective experience of remembering, and situates it at the intersection of the core and attribution systems.


Assuntos
Memória Episódica , Mapeamento Encefálico , Humanos , Transtornos da Memória , Rememoração Mental , Lobo Parietal
6.
PLoS One ; 15(1): e0216185, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31929531

RESUMO

The ability to interpret transcranial magnetic stimulation (TMS)-evoked electroencephalography (EEG) potentials (TEPs) is limited by artifacts, such as auditory evoked responses produced by discharge of the TMS coil. TEPs generated from direct cortical stimulation should vary in their topographical activity pattern according to stimulation site and differ from responses to sham stimulation. Responses that do not show these effects are likely to be artifactual. In 20 healthy volunteers, we delivered active and sham TMS to the right prefrontal, left primary motor, and left posterior parietal cortex and compared the waveform similarity of TEPs between stimulation sites and active and sham TMS using a cosine similarity-based analysis method. We identified epochs after the stimulus when the spatial pattern of TMS-evoked activation showed greater than random similarity between stimulation sites and sham vs. active TMS, indicating the presence of a dominant artifact. To do this, we binarized the derivatives of the TEPs recorded from 30 EEG channels and calculated cosine similarity between conditions at each time point with millisecond resolution. Only TEP components occurring before approximately 80 ms differed across stimulation sites and between active and sham, indicating site and condition-specific responses. We therefore conclude that, in the absence of noise masking or other measures to decrease neural artifact, TEP components before about 80 ms can be safely interpreted as stimulation location-specific responses to TMS, but components beyond this latency should be interpreted with caution due to high similarity in their topographical activity pattern.


Assuntos
Potenciais Evocados Auditivos/fisiologia , Córtex Motor/fisiologia , Lobo Parietal/fisiologia , Estimulação Magnética Transcraniana , Adulto , Mapeamento Encefálico , Eletroencefalografia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Adulto Jovem
8.
Neurology ; 94(6): e594-e606, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-31996450

RESUMO

OBJECTIVE: To combine MRI-based cortical morphometry and diffusion white matter tractography to describe the anatomical correlates of repetition deficits in patients with primary progressive aphasia (PPA). METHODS: The traditional anatomical model of language identifies a network for word repetition that includes Wernicke and Broca regions directly connected via the arcuate fasciculus. Recent tractography findings of an indirect pathway between Wernicke and Broca regions suggest a critical role of the inferior parietal lobe for repetition. To test whether repetition deficits are associated with damage to the direct or indirect pathway between both regions, tractography analysis was performed in 30 patients with PPA (64.27 ± 8.51 years) and 22 healthy controls. Cortical volume measurements were also extracted from 8 perisylvian language areas connected by the direct and indirect pathways. RESULTS: Compared to healthy controls, patients with PPA presented with reduced performance in repetition tasks and increased damage to most of the perisylvian cortical regions and their connections through the indirect pathway. Repetition deficits were prominent in patients with cortical atrophy of the temporo-parietal region with volumetric reductions of the indirect pathway. CONCLUSIONS: The results suggest that in PPA, deficits in repetition are due to damage to the temporo-parietal cortex and its connections to Wernicke and Broca regions. We therefore propose a revised language model that also includes an indirect pathway for repetition, which has important clinical implications for the functional mapping and treatment of neurologic patients.


Assuntos
Afasia Primária Progressiva/diagnóstico por imagem , Área de Broca/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem , Área de Wernicke/diagnóstico por imagem , Idoso , Afasia Primária Progressiva/fisiopatologia , Área de Broca/fisiopatologia , Estudos de Casos e Controles , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Imagem de Tensor de Difusão , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Tamanho do Órgão , Lobo Parietal/fisiopatologia , Área de Wernicke/fisiopatologia , Substância Branca/diagnóstico por imagem
9.
Nat Commun ; 11(1): 471, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31980655

RESUMO

Astrocytes may function as mediators of the impact of noradrenaline on neuronal function. Activation of glial α1-adrenergic receptors triggers rapid astrocytic Ca2+ elevation and facilitates synaptic plasticity, while activation of ß-adrenergic receptors elevates cAMP levels and modulates memory consolidation. However, the dynamics of these processes in behaving mice remain unexplored, as do the interactions between the distinct second messenger pathways. Here we simultaneously monitored astrocytic Ca2+ and cAMP and demonstrate that astrocytic second messengers are regulated in a temporally distinct manner. In behaving mice, we found that while an abrupt facial air puff triggered transient increases in noradrenaline release and large cytosolic astrocytic Ca2+ elevations, cAMP changes were not detectable. By contrast, repeated aversive stimuli that lead to prolonged periods of vigilance were accompanied by robust noradrenergic axonal activity and gradual sustained cAMP increases. Our findings suggest distinct astrocytic signaling pathways can integrate noradrenergic activity during vigilance states to mediate distinct functions supporting memory.


Assuntos
Nível de Alerta/fisiologia , Astrócitos/fisiologia , Norepinefrina/fisiologia , Sistemas do Segundo Mensageiro/fisiologia , Animais , Sinalização do Cálcio/fisiologia , Condicionamento Clássico/fisiologia , AMP Cíclico/metabolismo , Medo/fisiologia , Corantes Fluorescentes , Locus Cerúleo/citologia , Locus Cerúleo/fisiologia , Memória/fisiologia , Camundongos , Plasticidade Neuronal/fisiologia , Lobo Parietal/citologia , Lobo Parietal/fisiologia , Receptores Adrenérgicos/fisiologia
10.
World Neurosurg ; 135: 253-258, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31887463

RESUMO

BACKGROUND: Generally, enlargement of arachnoid cysts (ACs) has been found mostly in cases occurring during early childhood. Therefore, progressively enlarged ACs found to be symptomatic in elderly patients are extremely rare, and the mechanisms have remained unexplored. CASE DESCRIPTION: Our first patient was a 72-year-old woman with memory disturbance, who had presented with a large cyst beneath the right temporal convexity 9 years previously. The annual follow-up magnetic resonance imaging (MRI) studies had revealed that the cyst had progressively enlarged. In addition, her memory disturbance had become advanced. Endoscopic cyst fenestration was performed between the cyst and lateral ventricle, resulting in a reduction of her symptoms. Our second patient was a 79-year-old woman with unsteadiness, who had presented with a large cyst under the right parietal convexity 6 years previously. The annual follow-up MRI studies had shown that the cyst had gradually enlarged. She subsequently developed left hemiparesis. Because the pyramidal tract was located between the cyst and ventricle, a cyst-ventricle shunt was placed to allow the cystic fluid into the lateral ventricle, with complete resolution of her symptoms. In both cases, MRI showed obliteration of the subdural spaces around the cysts. Endoscopic observations revealed that the arachnoid membrane was lined under the surrounding brain, leading to the diagnosis of an AC. CONCLUSION: The establishment of stable communication between a cyst and the normal cerebrospinal fluid space is important to treat symptomatic ACs characterized by progressive enlargement, even in elderly patients. The 1-way entry of the cerebrospinal fluid into the cyst and the closure of the surrounding subdural space might result in AC enlargement internally.


Assuntos
Cistos Aracnóideos/cirurgia , Ventrículos Cerebrais/cirurgia , Drenagem/métodos , Neuroendoscopia/métodos , Idoso , Cistos Aracnóideos/complicações , Cistos Aracnóideos/diagnóstico por imagem , Progressão da Doença , Feminino , Humanos , Imagem por Ressonância Magnética , Transtornos da Memória/etiologia , Procedimentos Neurocirúrgicos , Paresia/etiologia , Lobo Parietal , Lobo Temporal
11.
World Neurosurg ; 135: e447-e451, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31843723

RESUMO

BACKGROUND: Slit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal for small ventricles. At this center, routine use of electromagnetic (EM) stereotactic guidance (Stealth, Medtronic, Dublin, Ireland) has enabled a parietooccipital (P-O) burr hole approach to the frontal horns. We compare shunt placement and revisions required for patients with slit ventricles who had shunts inserted via a P-O approach versus frontal shunt. METHODS: We studied a retrospective cohort of patients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012 and 2018. Slitlike ventricles were defined as the widest point of the lateral ventricle <3 mm. Outcome measures included placement accuracy and survival using the Kaplan-Meier curve. Optimal final catheter tip location was considered to be the frontal horn of the ipsilateral lateral ventricle. RESULTS: Eighty-two patients (77 female, 5 male) aged 34.9 ± 10.8 years (mean ± standard deviation) had ventricular shunts inserted for idiopathic intracranial hypertension (n = 63), chiari/syrinx (n = 8), congenital (n = 10), and pseudomeningocele (n = 1). Of those identified, 35 had primary P-O shunts and 46 had frontal shunts. Overall, 94% of cases had the catheter tip sitting in the frontal horn. The P-O approach was just as accurate as the frontal approach. Eight P-O shunts and 9 frontal shunts required revision over a 60-month period. There was no significant different in shunt survival between the 2 approaches (P = 0.37). CONCLUSIONS: EM-guided placement has enabled the P-O approach to be as safe and with equivalent survival to frontal approach. The accuracy of shunt placement between the 2 approaches was similar.


Assuntos
Craniotomia/métodos , Derivação Ventriculoperitoneal/métodos , Adulto , Ventrículos Cerebrais/cirurgia , Feminino , Lobo Frontal/cirurgia , Humanos , Masculino , Lobo Occipital/cirurgia , Lobo Parietal/cirurgia , Resultado do Tratamento , Retroversão Uterina
12.
Biol Lett ; 15(12): 20190666, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31847744

RESUMO

The approximate number system (ANS), which supports the rapid estimation of quantity, emerges early in human development and is widespread across species. Neural evidence from both human and non-human primates suggests the parietal cortex as a primary locus of numerical estimation, but it is unclear whether the numerical competencies observed across non-primate species are subserved by similar neural mechanisms. Moreover, because studies with non-human animals typically involve extensive training, little is known about the spontaneous numerical capacities of non-human animals. To address these questions, we examined the neural underpinnings of number perception using awake canine functional magnetic resonance imaging. Dogs passively viewed dot arrays that varied in ratio and, critically, received no task-relevant training or exposure prior to testing. We found evidence of ratio-dependent activation, which is a key feature of the ANS, in canine parietotemporal cortex in the majority of dogs tested. This finding is suggestive of a neural mechanism for quantity perception that has been conserved across mammalian evolution.


Assuntos
Córtex Cerebral , Lobo Parietal , Animais , Cães , Humanos , Imagem por Ressonância Magnética
13.
BMC Neurol ; 19(1): 326, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842821

RESUMO

BACKGROUND: Mild Cognitive Impairment (MCI) carries a high risk of progression to Alzheimer's disease (AD) dementia. Previous clinical trials testing whether cholinesterase inhibitors can slow the rate of progression from MCI to AD dementia have yielded disappointing results. However, recent studies of the effects of repetitive transcranial magnetic stimulation (rTMS) in AD have demonstrated improvements in cognitive function. Because few rTMS trials have been conducted in MCI, we designed a trial to test the short-term efficacy of rTMS in MCI. Yet, in both MCI and AD, we know little about what site of stimulation would be ideal for improving cognitive function. Therefore, two cortical sites will be investigated in this trial: (1) the dorsolateral prefrontal cortex (DLPFC), which has been well studied for treatment of major depressive disorder; and (2) the lateral parietal cortex (LPC), a novel site with connectivity to AD-relevant limbic regions. METHODS/DESIGN: In this single-site trial, we plan to enroll 99 participants with single or multi-domain amnestic MCI. We will randomize participants to one of three groups: (1) Active DLPFC rTMS; (2) Active LPC rTMS; and (3) Sham rTMS (evenly split between DLPFC and LPC locations). After completing 20 bilateral rTMS treatment sessions, participants will be followed for 6 months to test short-term efficacy and track durability of effects. The primary efficacy measure is the California Verbal Learning Test-II (CVLT-II), assessed 1 week after intervention. Secondary analyses will examine effects of rTMS on other cognitive measures, symptoms of depression, and brain function with respect to the site of stimulation. Finally, selected biomarkers will be analyzed to explore predictors of response and mechanisms of action. DISCUSSION: The primary aim of this trial is to test the short-term efficacy of rTMS in MCI. Additionally, the project will provide information on the durability of cognitive effects and potentially distinct effects of stimulating DLPFC versus LPC regions. Future efforts would be directed toward better understanding therapeutic mechanisms and optimizing rTMS for treatment of MCI. Ultimately, if rTMS can be utilized to slow the rate of progression to AD dementia, this will be a significant advancement in the field. TRIAL REGISTRATION: Clinical Trials NCT03331796. Registered 6 November 2017, https://clinicaltrials.gov/ct2/show/NCT03331796. All items from the World Health Organization Trial Registration Data Set are listed in Appendix A. PROTOCOL VERSION: This report is based on version 1, approved by the DSMB on 30 November, 2017 and amended on 14 August, 2018 and 19 September, 2019.


Assuntos
Disfunção Cognitiva/terapia , Lobo Parietal , Córtex Pré-Frontal , Projetos de Pesquisa , Estimulação Magnética Transcraniana/métodos , Idoso , Feminino , Humanos , Masculino
14.
J Headache Pain ; 20(1): 103, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31711415

RESUMO

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) manifests principally as a suite of cognitive impairments, particularly in the executive domain. Executive functioning requires the dynamic coordination of neural activity over large-scale networks. It remains unclear whether changes in resting-state brain functional network connectivity and regional homogeneities (ReHos) underly the mechanisms of executive dysfunction evident in CADASIL patients. METHODS: In this study, 22 CADASIL patients and 44 matched healthy controls underwent resting-state functional magnetic resonance imaging (fMRI). Independent component analysis (ICA) was used to measure functional brain network connectivity, and ReHos were calculated to evaluate local brain activities. We used seed-based functional connectivity (FC) analyses to determine whether dysfunctional areas (as defined by ReHos) exhibited abnormal FC with other brain areas. Relationships among the mean intra-network connectivity z-scores of dysfunctional areas within functional networks, and cognitive scores were evaluated using Pearson correlation analyses. RESULTS: Compared to the controls, CADASIL patients exhibited decreased intra-network connectivity within the bilateral lingual gyrus (LG) and the right cuneus (CU) (thus within the visual network [VIN)], and within the right precuneus (Pcu), inferior frontal gyrus (IFG), and precentral gyrus (thus within the frontal network [FRN]). Compared to the controls, patients also exhibited significantly lower ReHos in the right precuneus and cuneus (Pcu/CU), visual association cortex, calcarine gyri, posterior cingulate, limbic lobe, and weaker FC between the right Pcu/CU and the bilateral parahippocampal gyrus (PHG), and between the right Pcu/CU and the right postcentral gyrus. Notably, the mean connectivity z-scores of the bilateral LG and the right CU within the VIN were positively associated with compromised attention, calculation and delayed recall as revealed by tests of the various cognitive domains explored by the Mini-Mental State Examination. CONCLUSIONS: The decreases in intra-network connectivity within the VIN and FRN and reduced local brain activity in the posterior parietal area suggest that patients with CADASIL may exhibit dysfunctional visuomotor behaviors (a hallmark of executive function), and that all visual information processing, visuomotor planning, and movement execution may be affected.


Assuntos
Encéfalo/diagnóstico por imagem , CADASIL/diagnóstico por imagem , Disfunção Cognitiva/fisiopatologia , Função Executiva , Adulto , Encéfalo/fisiopatologia , CADASIL/fisiopatologia , CADASIL/psicologia , Estudos de Casos e Controles , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiopatologia , Cognição , Disfunção Cognitiva/psicologia , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Neuroimagem Funcional , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/fisiopatologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiopatologia , Descanso , Córtex Visual/diagnóstico por imagem , Córtex Visual/fisiopatologia
15.
J Headache Pain ; 20(1): 104, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31711434

RESUMO

BACKGROUND: Functional connectivity (FC) has been used to investigate the pathophysiology of migraine. Accumulating evidence is pointing toward malfunctioning of brainstem structures, i.e., the red nucleus (RN) and substantia nigra (SN), as an important factor in migraine without aura (MwoA). We aimed to identify atypical FC between the RN and SN and other brain areas in patients with MwoA and to explore the association between RN and SN connectivity changes and performance on neuropsychological tests in these patients. METHODS: Resting-state functional magnetic resonance imaging (fMRI) data were obtained from 30 patients with MwoA and 22 age-, sex-, and years of education-matched healthy controls (HC). The FC of the brainstem structures was analyzed using a standard seed-based whole-brain correlation method. The results of the brainstem structure FC were assessed for correlations with other clinical features. RESULTS: Patients with MwoA exhibited reduced left RN-based FC with the left middle frontal gyrus, reduced right RN-based FC with the ipsilateral superior parietal lobe, and increased FC with the ipsilateral cerebellum. Additionally, patients with MwoA demonstrated significantly decreased right SN-based FC with the right postcentral gyrus, left parietal lobule, and left superior frontal gyrus. Hypo-connectivity between the right SN and right postcentral gyrus was negatively correlated with disease duration (r = - 0.506, P = 0.004). Additionally, increased connectivity of the right RN to the ipsilateral cerebellar lobes was positively correlated with the Headache Impact Test-6 scores (r = 0.437, P = 0.016). CONCLUSIONS: The present study suggested that patients with MwoA have disruption in their RN and SN resting-state networks, which are associated with specific clinical characteristics. The changes focus on the regions associated with cognitive evaluation, multisensory integration, and modulation of perception and pain, which may be associated with migraine production, feedback, and development. Taken together, these results may improve our understanding of the neuropathological mechanism of migraine.


Assuntos
Enxaqueca sem Aura/diagnóstico por imagem , Núcleo Rubro/diagnóstico por imagem , Substância Negra/diagnóstico por imagem , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Tronco Encefálico/diagnóstico por imagem , Tronco Encefálico/fisiopatologia , Estudos de Casos e Controles , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Enxaqueca sem Aura/fisiopatologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Dor/diagnóstico por imagem , Dor/fisiopatologia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiopatologia , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiopatologia , Núcleo Rubro/fisiopatologia , Substância Negra/fisiopatologia
16.
Nat Neurosci ; 22(11): 1903-1912, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31591557

RESUMO

Parietal cortex RNA-sequencing (RNA-seq) data were generated from individuals with and without Alzheimer disease (AD; ncontrol = 13; nAD = 83) from the Knight Alzheimer Disease Research Center (Knight ADRC). Using this and an independent (Mount Sinai Brain Bank (MSBB)) AD RNA-seq dataset, cortical circular RNA (circRNA) expression was quantified in the context of AD. Significant associations were identified between circRNA expression and AD diagnosis, clinical dementia severity and neuropathological severity. It was demonstrated that most circRNA-AD associations are independent of changes in cognate linear messenger RNA expression or estimated brain cell-type proportions. Evidence was provided for circRNA expression changes occurring early in presymptomatic AD and in autosomal dominant AD. It was also observed that AD-associated circRNAs co-expressed with known AD genes. Finally, potential microRNA-binding sites were identified in AD-associated circRNAs for miRNAs predicted to target AD genes. Together, these results highlight the importance of analyzing non-linear RNAs and support future studies exploring the potential roles of circRNAs in AD pathogenesis.


Assuntos
Doença de Alzheimer/metabolismo , Atlas como Assunto , Perfilação da Expressão Gênica , Lobo Parietal/metabolismo , /biossíntese , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/patologia , Estudos de Casos e Controles , Humanos , MicroRNAs/metabolismo , RNA Mensageiro/biossíntese , Análise de Sequência de RNA , Índice de Gravidade de Doença
17.
Elife ; 82019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31612855

RESUMO

Prior expectations of movement instructions can promote preliminary action planning and influence choices. We investigated how action priors affect action-goal encoding in premotor and parietal cortices and if they bias subsequent free choice. Monkeys planned reaches according to visual cues that indicated relative probabilities of two possible goals. On instructed trials, the reach goal was determined by a secondary cue respecting these probabilities. On rarely interspersed free-choice trials without instruction, both goals offered equal reward. Action priors induced graded free-choice biases and graded frontoparietal motor-goal activity, complementarily in two subclasses of neurons. Down-regulating neurons co-encoded both possible goals and decreased opposite-to-preferred responses with decreasing prior, possibly supporting a process of choice by elimination. Up-regulating neurons showed increased preferred-direction responses with increasing prior, likely supporting a process of computing net likelihood. Action-selection signals emerged earliest in down-regulating neurons of premotor cortex, arguing for an initiation of selection in the frontal lobe.


Assuntos
Antecipação Psicológica , Comportamento de Escolha/fisiologia , Tomada de Decisões/fisiologia , Macaca mulatta/fisiologia , Córtex Motor/fisiologia , Lobo Parietal/fisiologia , Potenciais de Ação/fisiologia , Animais , Sinais (Psicologia) , Eletrodos Implantados , Funções Verossimilhança , Macaca mulatta/anatomia & histologia , Macaca mulatta/psicologia , Córtex Motor/anatomia & histologia , Neurônios Motores/citologia , Neurônios Motores/fisiologia , Movimento/fisiologia , Lobo Parietal/anatomia & histologia , Reconhecimento Visual de Modelos/fisiologia , Desempenho Psicomotor , Recompensa , Técnicas Estereotáxicas
18.
Behav Neurol ; 2019: 1410425, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31565094

RESUMO

Previous studies have shown that the neural mechanisms underlying visual spatial attention rely on top-down control information from the frontal and parietal cortexes, which ultimately amplifies sensory processing of stimulus occurred at the attended location relative to those at unattended location. However, the modulations of effective brain networks in response to stimulus at attended and unattended location are not yet clear. In present study, we collected event-related potentials (ERPs) from 15 subjects during a visual spatial attention task, and a partial directed coherence (PDC) method was used to construct alpha-band effective brain networks of two conditions (targets at attended and nontargets at unattended location). Flow gain mapping, effective connectivity pattern, and graph measures including clustering coefficient (C), characteristic path length (L), global efficiency (E global), and local efficiency (E local) were compared between two conditions. Flow gain mapping showed that the frontal region seemed to serve as the main source of information transmission in response to targets at attended location while the parietal region served as the main source in nontarget condition. Effective connectivity pattern indicated that in response to targets, there existed obvious top-down connections from the frontal, temporal, and parietal cortexes to the visual cortex compared with in response to nontargets. Graph theory analysis was used to quantify the topographical properties of the brain networks, and results revealed that in response to targets, the brain networks were characterized by significantly smaller characteristic path length and larger global efficiency than in response to nontargets. Our findings suggested that smaller characteristic path length and larger global efficiency could facilitate global integration of information and provide a substrate for more efficient perceptual processing of targets at attended location compared with processing of nontargets at ignored location, which revealed the neural mechanisms underlying visual spatial attention from the perspective of effective brain networks and graph theory for the first time and opened new vistas to interpret a cognitive process.


Assuntos
Ritmo alfa/fisiologia , Processamento Espacial/fisiologia , Percepção Visual/fisiologia , Atenção/fisiologia , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Estimulação Luminosa , Adulto Jovem
19.
Curr Opin Neurobiol ; 58: 148-154, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31581052

RESUMO

One challenge in neuroscience, as in other areas of science, is to make inferences about the underlying causal structure from correlational data. Here, we discuss this challenge in the context of choice correlations in sensory neurons, that is, trial-by-trial correlations, unexplained by the stimulus, between the activity of sensory neurons and an animal's perceptual choice. Do these choice-correlations reflect feedforward, feedback signalling, both, or neither? We highlight recent results of correlational and causal examinations of choice and choice-history signals in sensory, and in part sensorimotor, cortex and address formal statistical frameworks to infer causal interactions from data.


Assuntos
Comportamento de Escolha , Lobo Parietal , Animais , Macaca mulatta , Células Receptoras Sensoriais
20.
Nat Hum Behav ; 3(12): 1263-1270, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31477910

RESUMO

Attending to our inner world is a fundamental cognitive phenomenon1-3, yet its neural underpinnings remain largely unknown. Neuroimaging evidence implicates the default network (DN) and frontoparietal control network (FPCN)4; however, the electrophysiological basis for the interaction between these networks is unclear. Here we recorded intracranial electroencephalogram from DN and FPCN electrodes implanted in individuals undergoing presurgical monitoring for refractory epilepsy. Subjects performed an attention task during which they attended to tones (that is, externally directed attention) or ignored the tones and thought about whatever came to mind (that is, internally directed attention). Given the emerging role of theta band connectivity in attentional processes5,6, we examined the theta power correlation between DN and two subsystems of the FPCN as a function of attention states. We found increased connectivity between DN and FPCNA during internally directed attention compared to externally directed attention, which positively correlated with attention ratings. There was no statistically significant difference between attention states in the connectivity between DN and FPCNB. Our results indicate that enhanced theta band connectivity between the DN and FPCNA is a core electrophysiological mechanism that underlies internally directed attention.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Lobo Frontal/fisiologia , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Ritmo Teta , Adolescente , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Eletroencefalografia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Ritmo Teta/fisiologia , Adulto Jovem
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