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1.
Acta Neuropsychiatr ; : 1-8, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38623725

RESUMO

OBJECTIVE: Divergent thinking is a critical creative cognitive process. Its neural mechanisms have been well-studied through structural and functional imaging in healthy individuals but are less explored in patients with bipolar disorder (BD). Because of the traditional link between creativity and BD, this study investigated the structural correlates of divergent thinking in patients with BD through surface-based morphometry. METHODS: Fifty-nine patients diagnosed with BD I or BD II (35.3 ± 8.5 years) and 56 age- and sex-matched controls (33.9 ± 7.4 years) were recruited. The participants underwent structural magnetic resonance imaging and an evaluation of divergent thinking by using the Chinese version of the Abbreviated Torrance Test for Adults (ATTA). FreeSurfer 7.0 was used to generate thickness and surface area maps for each participant. Brainwise regression of the association between cortical thickness or surface area and ATTA performance was conducted using general linear models. RESULTS: Divergent thinking performance did not differ significantly between the patients with BD and the healthy controls. In these patients, total ATTA score was negatively correlated with cortical thickness in the right middle frontal gyrus, right occipital, and left precuneus but positively correlated with the surface area of the right superior frontal gyrus. By contrast, total ATTA scores and cortical thickness or surface area were not significantly correlated among the controls. CONCLUSION: The findings indicate that divergent thinking involves cerebral structures for executive control, mental imagery, and visual processing in patients with BD, and the right prefrontal cortex might be the most crucial of these structures.

3.
Neuroscience ; 544: 128-137, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38447690

RESUMO

In Robo3cKO mice, midline crossing defects of the trigeminothalamic projections from the trigeminal principal sensory nucleus result in bilateral whisker maps in the somatosensory thalamus and consequently in the face representation area of the primary somatosensory (S1) cortex (Renier et al., 2017; Tsytsarev et al., 2017). We investigated whether this bilateral sensory representation in the whisker-barrel cortex is also reflected in the downstream projections from the S1 to the primary motor (M1) cortex. To label these projections, we injected anterograde viral axonal tracer in S1 cortex. Corticocortical projections from the S1 distribute to similar areas across the ipsilateral hemisphere in control and Robo3cKO mice. Namely, in both genotypes they extend to the M1, premotor/prefrontal cortex (PMPF), secondary somatosensory (S2) cortex. Next, we performed voltage-sensitive dye imaging (VSDi) in the left hemisphere following ipsilateral and contralateral single whisker stimulation. While controls showed only activation in the contralateral whisker barrel cortex and M1 cortex, the Robo3cKO mouse left hemisphere was activated bilaterally in both the barrel cortex and the M1 cortex. We conclude that the midline crossing defect of the trigeminothalamic projections leads to bilateral whisker representations not only in the thalamus and the S1 cortex but also downstream from the S1, in the M1 cortex.


Assuntos
Córtex Motor , Córtex Somatossensorial , Camundongos , Animais , Córtex Somatossensorial/fisiologia , Vibrissas/fisiologia , Córtex Motor/fisiologia , Tálamo/diagnóstico por imagem , Núcleos do Trigêmeo
4.
J Med Case Rep ; 18(1): 125, 2024 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-38521912

RESUMO

BACKGROUND: Dry needling is an intervention used by physiotherapists to manage muscle spasticity. We report the effects of three sessions of dry needling on ankle plantar flexor muscle spasticity and cortical excitability in a patient with multiple sclerosis. CASE PRESENTATION: The patient was a 40-year-old Iranian woman with an 11-year history of multiple sclerosis. The study outcomes were measured by the modified modified Ashworth scale, transcranial magnetic stimulation parameters, and active and passive ankle range of motion. They were assessed before (T0), after three sessions of dry needling (T1), and at 2-week follow-up (T2). Our result showed: the modified modified Ashworth scale was improved at T2 from, 2 to 1. The resting motor threshold decreased from 63 to 61 and 57 at T1 and T2, respectively. The single test motor evokes potential increased from 76.2 to 78.3. The short intracortical inhibition increased from 23.6 to 35.4 at T2. The intracortical facilitation increased from 52 to 76 at T2. The ankle active and passive dorsiflexion ROM increased ~ 10° and ~ 6° at T2, respectively. CONCLUSION: This case study presented a patient with multiple sclerosis who underwent dry needling of ankle plantar flexors with severe spasticity, and highlighted the successful use of dry needling in the management of spasticity, ankle dorsiflexion, and cortical excitability. Further rigorous investigations are warranted, employing randomized controlled trials with a sufficient sample of patients with multiple sclerosis. Trial registration IRCT20230206057343N1, registered 9 February 2023, https://en.irct.ir/trial/68454.


Assuntos
Excitabilidade Cortical , Esclerose Múltipla , Adulto , Feminino , Humanos , Irã (Geográfico) , Esclerose Múltipla/complicações , Esclerose Múltipla/terapia , Espasticidade Muscular/terapia , Espasticidade Muscular/etiologia , Indução Percutânea de Colágeno , Amplitude de Movimento Articular/fisiologia
5.
J Alzheimers Dis ; 98(3): 1017-1027, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38489189

RESUMO

Background: Lifestyle factors are linked to differences in brain aging and risk for Alzheimer's disease, underscored by concepts like 'cognitive reserve' and 'brain maintenance'. The Resilience Index (RI), a composite of 6 factors (cognitive reserve, physical and cognitive activities, social engagement, diet, and mindfulness) provides such a holistic measure. Objective: This study aims to examine the association of RI scores with cognitive function and assess the mediating role of cortical atrophy. Methods: Baseline data from 113 participants (aged 45+, 68% female) from the Healthy Brain Initiative were included. Life course resilience was estimated with the RI, cognitive performance with Cognivue®, and brain health using a machine learning derived Cortical Atrophy Score (CAS). Mediation analysis probed the relationship between RI, cognitive outcomes, and cortical atrophy. Results: In age and sex adjusted models, the RI was significantly associated with CAS (ß= -0.25, p = 0.006) and Cognivue® scores (ß= 0.32, p < 0.001). The RI-Cognivue® association was partially mediated by CAS (ß= 0.07; 95% CI [0.02, 0.14]). Conclusions: Findings revealed that the collective effect of early and late-life lifestyle resilience factors on cognition are partially explained by their association with less brain atrophy. These findings underscore the value of comprehensive lifestyle assessments in understanding the risk and progression of cognitive decline and Alzheimer's disease in an aging population.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Resiliência Psicológica , Humanos , Feminino , Idoso , Masculino , Doença de Alzheimer/patologia , Imageamento por Ressonância Magnética , Testes Neuropsicológicos , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Cognição , Disfunção Cognitiva/psicologia , Atrofia/patologia
6.
Curr Biol ; 34(4): 727-739.e5, 2024 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-38262418

RESUMO

Sustained visual attention allows us to process and react to unpredictable, behaviorally relevant sensory input. Sustained attention engages communication between the higher-order visual thalamus and its connected cortical regions. However, it remains unclear whether there is a causal relationship between oscillatory circuit dynamics and attentional behavior in these thalamo-cortical circuits. By using rhythmic optogenetic stimulation in the ferret, we provide causal evidence that higher-order visual thalamus coordinates thalamo-cortical and cortico-cortical functional connectivity during sustained attention via spike-field phase locking. Increasing theta but not alpha power in the thalamus improved accuracy and reduced omission rates in a sustained attention task. Further, the enhancement of effective connectivity by stimulation was correlated with improved behavioral performance. Our work demonstrates a potential circuit-level causal mechanism for how the higher-order visual thalamus modulates cortical communication through rhythmic synchronization during sustained attention.


Assuntos
Furões , Córtex Visual , Animais , Tálamo/fisiologia , Córtex Visual/fisiologia
7.
Parkinsonism Relat Disord ; 121: 106010, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38245382

RESUMO

Neurofeedback (NF) techniques support individuals to self-regulate specific features of brain activity, which has been shown to impact behavior and potentially ameliorate clinical symptoms. Electrophysiological NF (epNF) may be particularly impactful for patients with Parkinson's disease (PD), as evidence mounts to suggest a central role of pathological neural oscillations underlying symptoms in PD. Exaggerated beta oscillations (12-30 Hz) in the basal ganglia-cortical network are linked to motor symptoms (e.g., bradykinesia, rigidity), and beta is reduced by successful therapy with dopaminergic medication and Deep Brain Stimulation (DBS). PD patients also experience non-motor symptoms related to sleep, mood, motivation, and cognitive control. Although less is known about the mechanisms of non-motor symptoms in PD and how to successfully treat them, low frequency neural oscillations (1-12 Hz) in the basal ganglia-cortical network are particularly implicated in non-motor symptoms. Here, we review how cortical and subcortical epNF could be used to target motor and non-motor specific oscillations, and potentially serve as an adjunct therapy that enables PD patients to endogenously control their own pathological neural activities. Recent studies have demonstrated that epNF protocols can successfully support volitional control of cortical and subcortical beta rhythms. Importantly, this endogenous control of beta has been linked to changes in motor behavior. epNF for PD, as a casual intervention on neural signals, has the potential to increase understanding of the neurophysiology of movement, mood, and cognition and to identify new therapeutic approaches for motor and non-motor symptoms.


Assuntos
Estimulação Encefálica Profunda , Neurorretroalimentação , Doença de Parkinson , Humanos , Doença de Parkinson/terapia , Doença de Parkinson/patologia , Gânglios da Base/patologia , Movimento , Ritmo beta/fisiologia , Estimulação Encefálica Profunda/métodos
8.
Int J Mol Sci ; 25(2)2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38255981

RESUMO

High-pressure and temperature extraction (HPTE) can effectively recover bioactive compounds from olive pomace (OP). HPTE extract obtained by extracting OP with ethanol and water (50:50 v/v) at 180 °C for 90 min demonstrated a pronounced ability to preserve intracellular calcium homeostasis, shielding neurons from the harmful effects induced by N-methyl-d-aspartate (NMDA) receptor (NMDAR) overactivation, such as aberrant calpain activation. In this study, the extraction temperature was changed from 37 to 180 °C, and the extracts were evaluated for their antioxidant potency and ability to preserve crucial intracellular Ca2+-homeostasis necessary for neuronal survival. Additionally, to verify the temperature-induced activity of the extract, further extractions on the exhausted olive pomace were conducted, aiming to identify variations in the quality and quantity of extracted phenolic molecules through HPLC analysis. The results revealed a significant increase in bioactive compounds as a function of temperature variation, reaching 6.31 ± 0.09 mgCAE/mL extract for the extraction performed at 180 °C. Subsequent extraction of the exhausted residues yielded extracts that remained active in preventing calcium-induced cell death. Moreover, despite increased antiradical power, extracts re-treated at 180 °C did not display cell protection activity. Our results indicate that the molecules able to maintain physiological Ca2+-homeostasis in murine cortical neurons in conditions of cytotoxic stimulation of NMDAR are wholly recovered from olive pomace only following extraction performed at 180 °C.


Assuntos
Olea , Animais , Camundongos , Cálcio , Temperatura , Neurônios , Receptores de N-Metil-D-Aspartato , Extratos Vegetais/farmacologia
9.
Proc Natl Acad Sci U S A ; 121(4): e2313048121, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38241439

RESUMO

The thalamus provides the principal input to the cortex and therefore understanding the mechanisms underlying cortical integration of sensory inputs requires to characterize the thalamocortical connectivity in behaving animals. Here, we propose tangential insertions of high-density electrodes into mouse cortical layer 4 as a method to capture the activity of thalamocortical axons simultaneously with their synaptically connected cortical neurons. This technique can reliably monitor multiple parallel thalamic synaptic inputs to cortical neurons, providing an efficient approach to map thalamocortical connectivity in both awake and anesthetized mice.


Assuntos
Neurônios , Tálamo , Camundongos , Animais , Neurônios/fisiologia , Tálamo/fisiologia , Axônios/fisiologia , Córtex Cerebral/fisiologia , Vias Neurais/fisiologia
10.
J Biophotonics ; 17(1): e202300145, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37403428

RESUMO

Photobiomodulation (PBM) therapy is an innovative treatment for neurological and psychological conditions. Complex IV of the mitochondrial respiratory chain can be stimulated by red light, which increases ATP synthesis. In addition, the ion channels' light absorption causes the release of Ca2+, which activates transcription factors and changes gene expression. Neuronal metabolism is improved by brain PBM therapy, which also promotes synaptogenesis and neurogenesis as well as anti-inflammatory. Its depression-treating potential is attracting attention for other conditions, including Parkinson's disease and dementia. Giving enough dosage for optimum stimulation using the transcranial PBM technique is challenging because of the rapidly increasing attenuation of light transmission in tissue. Different strategies like intranasal and intracranial light delivery systems have been proposed to overcome this restriction. The most recent preclinical and clinical data on the effectiveness of brain PBM therapy are studied in this review article.


Assuntos
Terapia com Luz de Baixa Intensidade , Terapia com Luz de Baixa Intensidade/métodos , Encéfalo , Neurônios , Neurogênese
11.
Cell Rep ; 43(1): 113590, 2024 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-38127620

RESUMO

The morphology and spatial distribution of axon arbors and boutons are crucial for neuron presynaptic functions. However, the principles governing their whole-brain organization at the single-neuron level remain unclear. We developed a machine-learning method to separate axon arbors from passing axons in single-neuron reconstruction from fluorescence micro-optical sectioning tomography imaging data and obtained 62,374 axon arbors that displayed distinct morphology, spatial patterns, and scaling laws dependent on neuron types and targeted brain areas. Focusing on the axon arbors in the thalamus and cortex, we revealed the segregated spatial distributions and distinct morphology but shared topographic gradients between feedforward and feedback projections. Furthermore, we uncovered an association between arbor complexity and microglia density. Finally, we found that the boutons on terminal arbors show branch-specific clustering with a log-normal distribution that again differed between feedforward and feedback terminal arbors. Together, our study revealed distinct presynaptic structural organizations underlying diverse functional innervation of single projection neurons.


Assuntos
Axônios , Terminações Pré-Sinápticas , Retroalimentação , Axônios/fisiologia , Tálamo , Córtex Cerebral
12.
Sensors (Basel) ; 23(23)2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-38067674

RESUMO

Stroke is a debilitating clinical condition resulting from a brain infarction or hemorrhage that poses significant challenges for motor function restoration. Previous studies have shown the potential of applying transcranial direct current stimulation (tDCS) to improve neuroplasticity in patients with neurological diseases or disorders. By modulating the cortical excitability, tDCS can enhance the effects of conventional therapies. While upper-limb recovery has been extensively studied, research on lower limbs is still limited, despite their important role in locomotion, independence, and good quality of life. As the life and social costs due to neuromuscular disability are significant, the relatively low cost, safety, and portability of tDCS devices, combined with low-cost robotic systems, can optimize therapy and reduce rehabilitation costs, increasing access to cutting-edge technologies for neuromuscular rehabilitation. This study explores a novel approach by utilizing the following processes in sequence: tDCS, a motor imagery (MI)-based brain-computer interface (BCI) with virtual reality (VR), and a motorized pedal end-effector. These are applied to enhance the brain plasticity and accelerate the motor recovery of post-stroke patients. The results are particularly relevant for post-stroke patients with severe lower-limb impairments, as the system proposed here provides motor training in a real-time closed-loop design, promoting cortical excitability around the foot area (Cz) while the patient directly commands with his/her brain signals the motorized pedal. This strategy has the potential to significantly improve rehabilitation outcomes. The study design follows an alternating treatment design (ATD), which involves a double-blind approach to measure improvements in both physical function and brain activity in post-stroke patients. The results indicate positive trends in the motor function, coordination, and speed of the affected limb, as well as sensory improvements. The analysis of event-related desynchronization (ERD) from EEG signals reveals significant modulations in Mu, low beta, and high beta rhythms. Although this study does not provide conclusive evidence for the superiority of adjuvant mental practice training over conventional therapy alone, it highlights the need for larger-scale investigations.


Assuntos
Interfaces Cérebro-Computador , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Estimulação Transcraniana por Corrente Contínua , Feminino , Humanos , Masculino , Qualidade de Vida , Recuperação de Função Fisiológica/fisiologia , Reabilitação do Acidente Vascular Cerebral/métodos , Estimulação Transcraniana por Corrente Contínua/métodos , Extremidade Superior , Método Duplo-Cego
13.
Brain Res Bull ; 205: 110837, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38043647

RESUMO

Neuroimaging research has revealed significant changes in brain structure and function in patients with cervical spondylotic myelopathy(CSM). The thalamus plays a crucial role in this process, although its mechanisms of action remain incompletely understood. This study aimed to investigate whether spinal cord compression leads to alterations in the functional connectivity between the thalamus and the cerebral cortex, and to determine if such changes are associated with structural and functional remodeling of the brain in patients with CSM, and to identify potential neuroimaging biomarkers for classification. The study included 40 patients with CSM and 34 healthy controls(HCs) who underwent resting-state functional magnetic resonance imaging(fMRI) and structural MRI scans. Brain structural and functional metrics were quantified using functional connectivity(FC), fractional amplitude of low-frequency fluctuations(fALFF), surface-based morphometry(SBM), and independent component analysis(ICA) based on functional and structural MRI. Patients with CSM exhibited significantly reduced fALFF in the bilateral lateral lingual gyrus, bilateral calcarine fissure, left precentral gyrus and postcentral gyrus, left middle and superior occipital gyrus, left superior marginal gyrus, left inferior parietal gyrus, and right Rolandic operculum. ICA results revealed weakened functional connectivity between the sensorimotor network (SMN) and the left and right frontoparietal network(FPN), and lateral visual network (lVN), along with decreased connectivity between lVN and rFPN, and increased connectivity between lFPN and rFPN. Patients with CSM also had decreased sulcus depth in the bilateral insula, left precentral and postcentral gyrus, and right lingual gyrus and calcarine fissure. Furthermore, cervical spondylotic myelopathy patients showed decreased functional connectivity between the left ventral posterolateral nucleus (VPL) of the thalamus and the right middle occipital gyrus (MOG). Finally,multimodal neuroimaging with support vector machine(SVM) classified patients with CSM and healthy controls with 86.00% accuracy. Our study revealed that the decrease in functional connectivity between the thalamus and cortex mediated by spinal cord compression leads to structural and functional reorganization of the cortex. Features based on neuroimaging markers have the potential to become neuroimaging biomarkers for CSM.


Assuntos
Compressão da Medula Espinal , Doenças da Medula Espinal , Humanos , Córtex Cerebral/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Tálamo/diagnóstico por imagem , Biomarcadores
14.
Cell ; 186(26): 5739-5750.e17, 2023 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-38070510

RESUMO

Conscious perception is greatly diminished during sleep, but the underlying circuit mechanism is poorly understood. We show that cortical ignition-a brain process shown to be associated with conscious awareness in humans and non-human primates-is strongly suppressed during non-rapid-eye-movement (NREM) sleep in mice due to reduced cholinergic modulation and rapid inhibition of cortical responses. Brain-wide functional ultrasound imaging and cell-type-specific calcium imaging combined with optogenetics showed that activity propagation from visual to frontal cortex is markedly reduced during NREM sleep due to strong inhibition of frontal pyramidal neurons. Chemogenetic activation and inactivation of basal forebrain cholinergic neurons powerfully increased and decreased visual-to-frontal activity propagation, respectively. Furthermore, although multiple subtypes of dendrite-targeting GABAergic interneurons in the frontal cortex are more active during wakefulness, soma-targeting parvalbumin-expressing interneurons are more active during sleep. Chemogenetic manipulation of parvalbumin interneurons showed that sleep/wake-dependent cortical ignition is strongly modulated by perisomatic inhibition of pyramidal neurons.


Assuntos
Eletroencefalografia , Parvalbuminas , Sono , Animais , Camundongos , Neurônios Colinérgicos/fisiologia , Lobo Frontal/metabolismo , Parvalbuminas/metabolismo , Sono/fisiologia , Vigília/fisiologia
15.
Curr Biol ; 33(23): 5185-5198.e4, 2023 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-37995696

RESUMO

Cortical neurons activated during recent experiences often reactivate with dorsal hippocampal CA1 ripples during subsequent rest. Less is known about cortical interactions with intermediate hippocampal CA1, whose connectivity, functions, and ripple events differ from dorsal CA1. We identified three clusters of putative excitatory neurons in mouse visual cortex that are preferentially excited together with either dorsal or intermediate CA1 ripples or suppressed before both ripples. Neurons in each cluster were evenly distributed across primary and higher visual cortices and co-active even in the absence of ripples. These ensembles exhibited similar visual responses but different coupling to thalamus and pupil-indexed arousal. We observed a consistent activity sequence preceding and predicting ripples: (1) suppression of ripple-suppressed cortical neurons, (2) thalamic silence, and (3) activation of intermediate CA1-ripple-activated cortical neurons. We propose that coordinated dynamics of these ensembles relay visual experiences to distinct hippocampal subregions for incorporation into different cognitive maps.


Assuntos
Hipocampo , Neurônios , Camundongos , Animais , Hipocampo/fisiologia , Neurônios/fisiologia , Tálamo , Lobo Parietal , Nível de Alerta
16.
Front Neurosci ; 17: 1288765, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37928733

RESUMO

Fibromyalgia, a common and enduring pain disorder, ranks as the second most prevalent rheumatic disease after osteoarthritis. Recent years have witnessed successful treatment using non-invasive brain stimulation. Transcranial magnetic stimulation, transcranial direct current stimulation, and electroconvulsion therapy have shown promise in treating chronic pain. This article reviews the literature concerning non-invasive stimulation for fibromyalgia treatment, its mechanisms, and establishes a scientific basis for rehabilitation, and discusses the future directions for research and development prospects of these techniques are discussed.

17.
Neuroimage ; 283: 120414, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37858906

RESUMO

The role of the thalamus in mediating the effects of lysergic acid diethylamide (LSD) was recently proposed in a model of communication and corroborated by imaging studies. However, a detailed analysis of LSD effects on nuclei-resolved thalamocortical connectivity is still missing. Here, in a group of healthy volunteers, we evaluated whether LSD intake alters the thalamocortical coupling in a nucleus-specific manner. Structural and resting-state functional Magnetic Resonance Imaging (MRI) data were acquired in a placebo-controlled study on subjects exposed to acute LSD administration. Structural MRI was used to parcel the thalamus into its constituent nuclei based on individual anatomy. Nucleus-specific changes of resting-state functional MRI (rs-fMRI) connectivity were mapped using a seed-based approach. LSD intake selectively increased the thalamocortical functional connectivity (FC) of the ventral complex, pulvinar, and non-specific nuclei. Functional coupling was increased between these nuclei and sensory cortices that include the somatosensory and auditory networks. The ventral and pulvinar nuclei also exhibited increased FC with parts of the associative cortex that are dense in serotonin type 2A receptors. These areas are hyperactive and hyper-connected upon LSD intake. At subcortical levels, LSD increased the functional coupling among the thalamus's ventral, pulvinar, and non-specific nuclei, but decreased the striatal-thalamic connectivity. These findings unravel some LSD effects on the modulation of subcortical-cortical circuits and associated behavioral outputs.


Assuntos
Pulvinar , Tálamo , Humanos , Tálamo/fisiologia , Imageamento por Ressonância Magnética , Córtex Cerebral/diagnóstico por imagem , Lobo Parietal , Vias Neurais
18.
J Neurosci ; 43(44): 7429-7440, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37793908

RESUMO

Selective attention to one of several competing speakers is required for comprehending a target speaker among other voices and for successful communication with them. It moreover has been found to involve the neural tracking of low-frequency speech rhythms in the auditory cortex. Effects of selective attention have also been found in subcortical neural activities, in particular regarding the frequency-following response related to the fundamental frequency of speech (speech-FFR). Recent investigations have, however, shown that the speech-FFR contains cortical contributions as well. It remains unclear whether these are also modulated by selective attention. Here we used magnetoencephalography to assess the attentional modulation of the cortical contributions to the speech-FFR. We presented both male and female participants with two competing speech signals and analyzed the cortical responses during attentional switching between the two speakers. Our findings revealed robust attentional modulation of the cortical contribution to the speech-FFR: the neural responses were higher when the speaker was attended than when they were ignored. We also found that, regardless of attention, a voice with a lower fundamental frequency elicited a larger cortical contribution to the speech-FFR than a voice with a higher fundamental frequency. Our results show that the attentional modulation of the speech-FFR does not only occur subcortically but extends to the auditory cortex as well.SIGNIFICANCE STATEMENT Understanding speech in noise requires attention to a target speaker. One of the speech features that a listener can use to identify a target voice among others and attend it is the fundamental frequency, together with its higher harmonics. The fundamental frequency arises from the opening and closing of the vocal folds and is tracked by high-frequency neural activity in the auditory brainstem and in the cortex. Previous investigations showed that the subcortical neural tracking is modulated by selective attention. Here we show that attention affects the cortical tracking of the fundamental frequency as well: it is stronger when a particular voice is attended than when it is ignored.


Assuntos
Córtex Auditivo , Percepção da Fala , Humanos , Masculino , Feminino , Fala , Percepção da Fala/fisiologia , Córtex Auditivo/fisiologia , Magnetoencefalografia , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Estimulação Acústica , Eletroencefalografia/métodos
19.
Brain Behav ; 13(12): e3296, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37904336

RESUMO

Extensive research has demonstrated the critical role of selenium (Se) and selenoproteins in brain function and cognition. However, the impact of Se on brain cortical structure remains enigmatic. Therefore, this study used Mendelian randomization (MR) analysis to investigate the causal effect between Se levels and brain cortical structure. METHODS: This study utilizes 11 genetic variants associated with Se level variations, extracted from a large-scale genome-wide association study (GWAS) encompassed circulating Se levels (n = 5477) and toenail Se levels (n = 4162) in the European population. Outcome data were sourced from the summary statistics of the ENIGMA Consortium, comprising GWAS data from 51,666 individuals. The variables include cortical surface area (SA), thickness (TH) at the global level, and 34 functional cortical regions evaluated by magnetic resonance imaging. The inverse-variance-weighted method was used as the primary estimate. Additionally, sensitivity analyses were conducted to detect potential violations of assumptions underlying MR. RESULTS: At the global level, Se levels were not correlated with SA but showed a significant negative correlation with TH (ß = -0.00485 mm, SE = 0.00192, p = .0115). Heterogeneity was observed across different brain regions, with positive correlations found between Se levels and the TH of the parahippocampal gyrus, superior frontal gyrus, and frontal pole, whereas negative correlations were found with the TH of the inferior parietal lobe and middle temporal lobe. Regarding SA, Se levels exhibit positive correlations with the pars triangularis, caudal anterior cingulate, inferior parietal lobe, and banks of the superior temporal sulcus. Conversely, negative correlations were observed with the medial orbitofrontal cortex, posterior cingulate gyrus, insula, and the middle, superior, and transverse gyrus of the temporal lobe. No pleiotropy was detected. RESULTS: This MR study indicated that Se levels causally influence the brain cortical structure.


Assuntos
Selênio , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia
20.
J Neural Eng ; 20(5)2023 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-37666246

RESUMO

Objective.Invasive brain-computer interfaces (BCIs) have shown promise in restoring motor function to those paralyzed by neurological injuries. These systems also have the ability to restore sensation via cortical electrostimulation. Cortical stimulation produces strong artifacts that can obscure neural signals or saturate recording amplifiers. While front-end hardware techniques can alleviate this problem, residual artifacts generally persist and must be suppressed by back-end methods.Approach.We have developed a technique based on pre-whitening and null projection (PWNP) and tested its ability to suppress stimulation artifacts in electroencephalogram (EEG), electrocorticogram (ECoG) and microelectrode array (MEA) signals from five human subjects.Main results.In EEG signals contaminated by narrow-band stimulation artifacts, the PWNP method achieved average artifact suppression between 32 and 34 dB, as measured by an increase in signal-to-interference ratio. In ECoG and MEA signals contaminated by broadband stimulation artifacts, our method suppressed artifacts by 78%-80% and 85%, respectively, as measured by a reduction in interference index. When compared to independent component analysis, which is considered the state-of-the-art technique for artifact suppression, our method achieved superior results, while being significantly easier to implement.Significance.PWNP can potentially act as an efficient method of artifact suppression to enable simultaneous stimulation and recording in bi-directional BCIs to biomimetically restore motor function.


Assuntos
Artefatos , Terapia por Estimulação Elétrica , Humanos , Eletrocorticografia , Eletroencefalografia , Amplificadores Eletrônicos
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