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1.
Nat Commun ; 12(1): 6102, 2021 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-34671032

RESUMO

Damage to the primary visual cortex (V1) causes homonymous visual-field loss long considered intractable. Multiple studies now show that perceptual training can restore visual functions in chronic cortically-induced blindness (CB). A popular hypothesis is that training can harness residual visual functions by recruiting intact extrageniculostriate pathways. Training may also induce plastic changes within spared regions of the damaged V1. Here, we link changes in luminance detection sensitivity with retinotopic fMRI activity before and after visual discrimination training in eleven patients with chronic, stroke-induced CB. We show that spared V1 activity representing perimetrically-blind locations prior to training predicts the amount of training-induced recovery of luminance detection sensitivity. Additionally, training results in an enlargement of population receptive fields in perilesional V1, which increases blind-field coverage and may support further recovery with subsequent training. These findings uncover fundamental changes in perilesional V1 cortex underlying training-induced restoration of conscious luminance detection sensitivity in CB.


Assuntos
Cegueira Cortical/reabilitação , Aprendizagem/fisiologia , Visão Ocular/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Idoso , Cegueira Cortical/diagnóstico por imagem , Cegueira Cortical/fisiopatologia , Mapeamento Encefálico , Discriminação Psicológica/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Plasticidade Neuronal/fisiologia , Recuperação de Função Fisiológica/fisiologia , Córtex Visual/diagnóstico por imagem , Campos Visuais/fisiologia
2.
Nat Commun ; 12(1): 6114, 2021 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-34671042

RESUMO

In the hippocampal circuit CA3 input plays a critical role in the organization of CA1 population activity, both during learning and sleep. While integrated spatial representations have been observed across the two hemispheres of CA1, these regions lack direct connectivity and thus the circuitry responsible remains largely unexplored. Here we investigate the role of CA3 in organizing bilateral CA1 activity by blocking synaptic transmission at CA3 terminals through the inducible transgenic expression of tetanus toxin. Although the properties of single place cells in CA1 were comparable bilaterally, we find a decrease of ripple synchronization between left and right CA1 after silencing CA3. Further, during both exploration and rest, CA1 neuronal ensemble activity is less coordinated across hemispheres. This included degradation of the replay of previously explored spatial paths in CA1 during rest, consistent with the idea that CA3 bilateral projections integrate activity between left and right hemispheres and orchestrate bilateral hippocampal coding.


Assuntos
Região CA1 Hipocampal/fisiologia , Região CA3 Hipocampal/fisiologia , Lateralidade Funcional/fisiologia , Animais , Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/metabolismo , Potenciais Pós-Sinápticos Excitadores/fisiologia , Camundongos , Vias Neurais/fisiologia , Células de Lugar/fisiologia , Descanso/fisiologia , Transmissão Sináptica/genética , Toxina Tetânica/genética , Vigília/fisiologia
3.
PLoS One ; 16(9): e0257764, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34591878

RESUMO

Chicks trained to identify a target item in a sagittally-oriented series of identical items show a higher accuracy for the target on the left, rather than that on the right, at test when the series was rotated by 90°. Such bias seems to be due to a right hemispheric dominance in visuospatial tasks. Up to now, the bias was highlighted by looking at accuracy, the measure mostly used in non-human studies to detect spatial numerical association, SNA. In the present study, processing by each hemisphere was assessed by scoring three variables: accuracy, response times and direction of approach. Domestic chicks were tested under monocular vision conditions, as in the avian brain input to each eye is mostly processed by the contralateral hemisphere. Four-day-old chicks learnt to peck at the 4th element in a sagittal series of 10 identical elements. At test, when facing a series oriented fronto-parallel, birds confined their responses to the visible hemifield, with high accuracy for the 4th element. The first element in the series was also highly selected, suggesting an anchoring strategy to start the proto-counting at one end of the series. In the left monocular condition, chicks approached the series starting from the left, and in the right monocular condition, they started from the right. Both hemispheres appear to exploit the same strategy, scanning the series from the most lateral element in the clear hemifield. Remarkably, there was no effect in the response times: equal latency was scored for correct or incorrect and for left vs. right responses. Overall, these data indicate that the measures implying a direction of choice, accuracy and direction of approach, and not velocity, i.e., response times, can highlight SNA in this paradigm. We discuss the relevance of the selected measures to unveil SNA.


Assuntos
Galinhas/fisiologia , Tempo de Reação/fisiologia , Aprendizagem Espacial/fisiologia , Animais , Comportamento Animal/fisiologia , Lateralidade Funcional/fisiologia , Masculino , Percepção Espacial , Visão Monocular/fisiologia
4.
Neuroimage ; 240: 118405, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34280529

RESUMO

Ageing leads to a decline in white matter microstructure and dexterous function of the hand. In adolescents, it has previously been shown that the degree of right-left asymmetry in the corticospinal tract (CST) is linearly related with right-left asymmetry in dexterity. Here, we tested whether this association is also expressed in older adults. Participants completed a simple circle drawing task with their right and left hand as a measure of dexterity and underwent whole-brain diffusion weighted imaging at 3 Tesla (n = 199; aged 60-72 years). Fractional anisotropy and mean diffusivity of right and left CST were extracted from a manually defined region-of-interest. Linear regression analyses were computed to replicate the analyses in adolescents. Frequentist analyses were complemented with a Bayesian analytical framework. Outcome measures were compared with those previously reported in adolescents (aged 11-16 years). Asymmetries in white matter microstructure of the CST were evident and comparable to the degree of lateralisation observed in adolescence. Similarly, asymmetries in dexterity were evident, but to a lesser degree than in adolescents. Unlike in adolescents, we found no evidence of a linear relationship between asymmetries in CST microstructure and dexterity. Complementary Bayesian regression analysis provided moderate evidence in favour of the null hypothesis, pointing towards a lack of association between the structural and functional measures of right-left asymmetry. Our findings are compatible with the notion that, by late adulthood, a diverging impact of age on white matter structure and dexterous hand function dilutes the structure-function relationship between CST microstructure and manual proficiency that has been reported in adolescents.


Assuntos
Lateralidade Funcional/fisiologia , Imageamento por Ressonância Magnética/métodos , Desempenho Psicomotor/fisiologia , Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/fisiologia , Treinamento de Força/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
5.
Sci Rep ; 11(1): 13736, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215780

RESUMO

Stable walking relies critically on motor responses to signals of head motion provided by the vestibular system, which are phase-dependent and modulated differently within each muscle. It is unclear, however, whether these vestibular contributions also vary according to the stability of the walking task. Here we investigate how vestibular signals influence muscles relevant for gait stability (medial gastrocnemius, gluteus medius and erector spinae)-as well as their net effect on ground reaction forces-while humans walked normally, with mediolateral stabilization, wide and narrow steps. We estimated local dynamic stability of trunk kinematics together with coherence of electrical vestibular stimulation (EVS) with muscle activity and mediolateral ground reaction forces. Walking with external stabilization increased local dynamic stability and decreased coherence between EVS and all muscles/forces compared to normal walking. Wide-base walking also decreased vestibulomotor coherence, though local dynamic stability did not differ. Conversely, narrow-base walking increased local dynamic stability, but produced muscle-specific increases and decreases in coherence that resulted in a net increase in vestibulomotor coherence with ground reaction forces. Overall, our results show that while vestibular contributions may vary with gait stability, they more critically depend on the stabilization demands (i.e. control effort) needed to maintain a stable walking pattern.


Assuntos
Marcha/fisiologia , Músculo Esquelético/fisiologia , Vestíbulo do Labirinto/fisiologia , Caminhada/fisiologia , Adulto , Fenômenos Biomecânicos , Estimulação Elétrica , Eletromiografia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Modelos Biológicos , Músculo Esquelético/diagnóstico por imagem , Vestíbulo do Labirinto/diagnóstico por imagem , Vestíbulo do Labirinto/efeitos da radiação , Adulto Jovem
6.
Neuroimage ; 240: 118382, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34252524

RESUMO

Self-construal (orientations of independence and interdependence) is a fundamental concept that guides human behaviour, and it is linked to a large number of brain regions. However, understanding the connectivity of these regions and the critical principles underlying these self-functions are lacking. Because brain activity linked to self-related processes are intrinsic, the resting-state method has received substantial attention. Here, we focused on resting-state functional connectivity matrices based on brain asymmetry as indexed by the differential partition of the connectivity located in mirrored positions of the two hemispheres, hemispheric specialization measured using the intra-hemispheric (left or right) connectivity, brain communication via inter-hemispheric interactions, and global connectivity as the sum of the two intra-hemispheric connectivity. Combining machine learning techniques with hypothesis-driven network mapping approaches, we demonstrated that orientations of independence and interdependence were best predicted by the asymmetric matrix compared to brain communication, hemispheric specialization, and global connectivity matrices. The network results revealed that there were distinct asymmetric connections between the default mode network, the salience network and the executive control network which characterise independence and interdependence. These analyses shed light on the importance of brain asymmetry in understanding how complex self-functions are optimally represented in the brain networks.


Assuntos
Encéfalo/fisiologia , Rede de Modo Padrão/fisiologia , Função Executiva/fisiologia , Lateralidade Funcional/fisiologia , Aprendizado de Máquina , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Rede de Modo Padrão/diagnóstico por imagem , Feminino , Humanos , Masculino , Adulto Jovem
7.
Sci Rep ; 11(1): 13112, 2021 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-34162936

RESUMO

Recent studies show that during a simple movement imagery task, the power of sensorimotor rhythms differs according to handedness. However, the effects of motor imagery perspectives on these differences have not been investigated yet. Our study aimed to check how handedness impacts the activity of alpha (8-13 Hz) and beta (15-30 Hz) oscillations during creating a kinesthetic (KMI) or visual-motor (VMI) representation of movement. Forty subjects (20 right-handed and 20 left-handed) who participated in the experiment were tasked with imagining sequential finger movement from a visual or kinesthetic perspective. Both the electroencephalographic (EEG) activity and behavioral correctness of the imagery task performance were measured. After the registration, we used independent component analysis (ICA) on EEG data to localize visual- and motor-related EEG sources of activity shared by both motor imagery conditions. Significant differences were obtained in the visual cortex (the occipital ICs cluster) and the right motor-related area (right parietal ICs cluster). In comparison to right-handers who, regardless of the task, demonstrated the same pattern in the visual area, left-handers obtained higher power in the alpha waves in the VMI task and better performance in this condition. On the other hand, only the right-handed showed different patterns in the alpha waves in the right motor cortex during the KMI condition. The results indicate that left-handers imagine movement differently than right-handers, focusing on visual experience. This provides new empirical evidence on the influence of movement preferences on imagery processes and has possible future implications for research in the area of neurorehabilitation and motor imagery-based brain-computer interfaces (MI-BCIs).


Assuntos
Lateralidade Funcional/fisiologia , Imaginação/fisiologia , Cinestesia/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Adulto Jovem
8.
Clin Neurophysiol ; 132(8): 1790-1801, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34130247

RESUMO

OBJECTIVE: Age-related differences in neural strategies for motor learning are not fully understood. We determined the effects of age on the relationship between motor network connectivity and motor skill acquisition, consolidation, and interlimb transfer using dynamic imaging of coherent sources. METHODS: Healthy younger (n = 24, 18-24 y) and older (n = 24, 65-87 y) adults unilaterally practiced a visuomotor task and resting-state electroencephalographic data was acquired before and after practice as well as at retention. RESULTS: The results showed that right-hand skill acquisition and consolidation did not differ between age groups. However, age affected the ability to transfer the newly acquired motor skill to the non-practiced limb. Moreover, strengthened left- and right-primary motor cortex-related beta connectivity was negatively and positively associated with right-hand skill acquisition and left-hand skill consolidation in older adults, respectively. CONCLUSION: Age-dependent modulations of bilateral resting-state motor network connectivity indicate age-specific strategies for the acquisition, consolidation, and interlimb transfer of novel motor tasks. SIGNIFICANCE: The present results provide insights into the mechanisms underlying motor learning that are important for the development of interventions for patients with unilateral injuries.


Assuntos
Envelhecimento/fisiologia , Lateralidade Funcional/fisiologia , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Rede Nervosa/fisiologia , Transferência de Experiência/fisiologia , Adolescente , Idoso , Idoso de 80 Anos ou mais , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Consolidação da Memória/fisiologia , Córtex Motor/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Distribuição Aleatória , Adulto Jovem
9.
J Clin Neurosci ; 89: 139-143, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34119257

RESUMO

Functional movement disorder (FMD) presents as disabling motor symptoms that cannot be explained by organic processes. Despite the lack of lesion or known central nervous system dysfunction, distortion in sensorimotor processing in movement generation and execution is often observed. A person's capacity to judge laterality of a body part requires processing of sensorimotor information. This prospective observational study compared reaction time (RT) and accuracy (ACC) of hand laterality recognition between 30 people diagnosed with FMD and 30 age-matched healthy control participants. The association of RT and ACC with severity of FMD as measured by the Simplified Functional Movement Disorders Rating Scale (SFMDRS) was also explored. RT was on average 0.6 s slower (95% CI 0.4 - 0.8 s, p < 0.001) in patients with FMD (mean 2.2 s, standard deviation (SD) 0.5) than controls (mean 1.7 s, SD 0.3). ACC was on average 8.9% lower (95% CI -15.7 - -2.2, p = 0.01) in patients with FMD (mean 79.6%, SD 16.6) than controls (mean 88.5%, SD 8.1). When adjusted for SFMDRS using robust regression, RT was 0.3 s slower (95% CI 0.01 - 0.5, p = 0.04) in cases than in controls, but ACC was no longer different between groups. There was a moderate negative correlation between RT and ACC in FMD patients (ρ -0.58, p < 0.001 but not in controls (ρ -0.26, p = 0.17). People with FMD had significantly slower RT and lower ACC compared to the control group. These results provide new insights into underlying sensorimotor processing deficits in those with FMD.


Assuntos
Lateralidade Funcional/fisiologia , Mãos/fisiologia , Imaginação/fisiologia , Transtornos dos Movimentos/fisiopatologia , Movimento/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos dos Movimentos/diagnóstico , Transtornos dos Movimentos/psicologia , Estudos Prospectivos , Tempo de Reação/fisiologia
10.
PLoS One ; 16(6): e0253550, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34166461

RESUMO

A wide body of literature has demonstrated that the neural representation of healthy swallowing is mostly bilateral, with one hemisphere dominant over the other. While several studies have demonstrated the presence of laterality for swallowing related functions among young adults, the data on older adults are still growing. The purpose of this paper is to investigate potential changes in hemispheric dominance in healthy aging adults for swallowing related tasks using a behavioral dual-task paradigm. A modified dual-task paradigm was designed to investigate the potential reduction in hemispherical specialization for swallowing function. Eighty healthy right-handed participants in the study were divided into two groups [Group 1: young adults (18-40 years) and Group 2: older adults (65 and above)]. All the participants performed a timed water swallow test at baseline and with two interference conditions (silent word repetition, and facial recognition). The results of the study revealed the following 1) a statistically significant effect of age on swallow performance; 2) statistically significant effect of each of the interference tasks on two of the swallow measures (VPS and VPT) in younger adults; and 3) no significant effect of the interference tasks on the swallowing performance of older adults. These findings suggest that aging substantially affects swallowing in older individuals, and this potentially accompanies a reduction in the hemispheric specialization for swallowing related tasks.


Assuntos
Envelhecimento/fisiologia , Cognição/fisiologia , Deglutição/fisiologia , Lateralidade Funcional/fisiologia , Envelhecimento Saudável/fisiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino
11.
PLoS One ; 16(6): e0252870, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34138903

RESUMO

The Delft Self-Grasping Hand is an adjustable passive prosthesis operated using the concept of tenodesis (where opening and closing of the hand is mechanically linked to the flexion and extension of the wrist). As a purely mechanical device that does not require harnessing, the Self-Grasping Hand offers a promising alternative to current prostheses. However, the contralateral hand is almost always required to operate the mechanism to release a grasp and is sometimes also used to help form the grasp; hence limiting the time it is available for other purposes. In this study we quantified the amount of time the contralateral hand was occupied with operating the Self-Grasping Hand, classified as either direct or indirect interaction, and investigated how these periods changed with practice. We studied 10 anatomically intact participants learning to use the Self-Grasping Hand fitted to a prosthesis simulator. The learning process involved 10 repeats of a feasible subset of the tasks in the Southampton Hand Assessment Procedure (SHAP). Video footage was analysed, and the time that the contralateral hand was engaged in grasping or releasing was calculated. Functionality scores increased for all participants, plateauing at an Index of Functionality of 33.5 after 5 SHAP attempts. Contralateral hand involvement reduced significantly from 6.47 (first 3 attempts) to 4.68 seconds (last three attempts), but as a proportion of total task time remained relatively steady (increasing from 29% to 32%). For 9/10 participants most of this time was supporting the initiation of grasps rather than releases. The reliance on direct or indirect interactions between the contralateral hand and the prosthesis varied between participants but appeared to remain relatively unchanged with practice. Future studies should consider evaluating the impact of reliance on the contralateral limb in day-to-day life and development of suitable training methods.


Assuntos
Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Aprendizagem/fisiologia , Membros Artificiais , Simulação por Computador , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fatores de Tempo , Gravação em Vídeo
12.
Neuron ; 109(15): 2457-2468.e12, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34146468

RESUMO

Segregation of retinal ganglion cell (RGC) axons by type and eye of origin is considered a hallmark of dorsal lateral geniculate nucleus (dLGN) structure. However, recent anatomical studies have shown that neurons in mouse dLGN receive input from multiple RGC types of both retinae. Whether convergent input leads to relevant functional interactions is unclear. We studied functional eye-specific retinogeniculate convergence using dual-color optogenetics in vitro. dLGN neurons were strongly dominated by input from one eye. Most neurons received detectable input from the non-dominant eye, but this input was weak, with a prominently reduced AMPAR:NMDAR ratio. Consistent with this, only a small fraction of thalamocortical neurons was binocular in vivo across visual stimuli and cortical projection layers. Anatomical overlap between RGC axons and dLGN neuron dendrites alone did not explain the strong bias toward monocularity. We conclude that functional eye-specific input selection and refinement limit convergent interactions in dLGN, favoring monocularity.


Assuntos
Lateralidade Funcional/fisiologia , Corpos Geniculados/citologia , Células Ganglionares da Retina/citologia , Visão Binocular/fisiologia , Vias Visuais/citologia , Animais , Corpos Geniculados/fisiologia , Camundongos , Células Ganglionares da Retina/fisiologia , Vias Visuais/fisiologia
13.
Neuroimage ; 237: 118182, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34020020

RESUMO

Gestures are an integral part of in-person conversations and complement the meaning of the speech they accompany. The neural processing of co-speech gestures is supported by a mostly left-lateralized network of fronto-temporal regions. However, in contrast to iconic gestures, metaphoric as well as unrelated gestures have been found to more strongly engage the left and right inferior frontal gyrus (IFG), respectively. With this study, we conducted the first systematic comparison of all three types of gestures and resulting potential laterality effects. During collection of functional imaging data, 74 subjects were presented with 5 s videos of abstract speech with related metaphoric gestures, concrete speech with related iconic gestures and concrete speech with unrelated gestures. They were asked to judge whether the content of the speech and gesture matched or not. Differential contrasts revealed that both abstract related and concrete unrelated compared to concrete related stimuli elicited stronger activation of the bilateral IFG. Analyses of lateralization indices for IFG activation further showed a left hemispheric dominance for metaphoric gestures and a right hemispheric dominance for unrelated gestures. Our results give support to the hypothesis that the bilateral IFG is activated specifically when processing load for speech-gesture combinations is high. In addition, laterality effects indicate a stronger involvement of the right IFG in mismatch detection and conflict processing, whereas the left IFG performs the actual integration of information from speech and gesture.


Assuntos
Lateralidade Funcional/fisiologia , Gestos , Metáfora , Córtex Pré-Frontal/fisiologia , Psicolinguística , Percepção Social , Percepção da Fala/fisiologia , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Individualidade , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Córtex Pré-Frontal/diagnóstico por imagem , Adulto Jovem
14.
Nat Commun ; 12(1): 2514, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33947840

RESUMO

Primates use their arms in complex ways that frequently require coordination between the two arms. Yet the planning of bimanual movements has not been well-studied. We recorded spikes and local field potentials (LFP) from the parietal reach region (PRR) in both hemispheres simultaneously while monkeys planned and executed unimanual and bimanual reaches. From analyses of interhemispheric LFP-LFP and spike-LFP coherence, we found that task-specific information is shared across hemispheres in a frequency-specific manner. This shared information could arise from common input or from direct communication. The population average unit activity in PRR, representing PRR output, encodes only planned contralateral arm movements while beta-band LFP power, a putative PRR input, reflects the pattern of planned bimanual movement. A parsimonious interpretation of these data is that PRR integrates information about the movement of the left and right limbs, perhaps in service of bimanual coordination.


Assuntos
Potenciais de Ação/fisiologia , Movimento/fisiologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Animais , Escala de Avaliação Comportamental , Eletrofisiologia , Lateralidade Funcional/fisiologia , Macaca mulatta , Masculino , Córtex Motor/fisiologia , Neurônios/fisiologia , Movimentos Sacádicos/fisiologia , Transdução de Sinais/fisiologia
15.
Neuroimage ; 236: 118023, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-33862241

RESUMO

Studies of occipital cortex plasticity in blindness provide insight into how intrinsic constraints interact with experience to determine cortical specialization. We tested the cognitive nature and anatomical origins of occipital responses during non-verbal, non-spatial auditory tasks. In a go/no-go task, congenitally blind (N=23) and sighted (N=24) individuals heard rapidly occurring (<1/s) non-verbal sounds and made one of two button presses (frequent-go 50%, infrequent-go 25%) or withheld a response (no-go, 25%). Rapid and frequent button presses heighten response selection/inhibition demands on the no-go trials: In sighted and blind adults a right-lateralized prefrontal (PFC) network responded most to no-go trials, followed by infrequent-go and finally frequent-go trials. In the blind group only, a right-lateralized occipital network showed the same response profile and the laterality of occipital and PFC responses was correlated across blind individuals. A second experiment with spoken sentences and equations (N=16) found that no-go responses in occipital cortex are distinct from previously identified occipital responses to spoken language. Finally, in resting-state data (N=30 blind, N=31 blindfolded sighted), no-go responsive 'visual' cortex of blind relative to sighted participants was more synchronized with PFC and less synchronized with primary auditory and sensory-motor cortices. No-go responsive occipital cortex showed higher resting-state correlations with no-go responsive PFC than language responsive inferior frontal cortex. We conclude that in blindness, a right-lateralized occipital network responds to non-verbal executive processes, including response selection. These results suggest that connectivity with fronto-parietal executive networks is a key mechanism for plasticity in blindness.


Assuntos
Percepção Auditiva/fisiologia , Cegueira/congênito , Cegueira/fisiopatologia , Função Executiva/fisiologia , Inibição Psicológica , Rede Nervosa/fisiopatologia , Plasticidade Neuronal/fisiologia , Lobo Occipital/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Desempenho Psicomotor/fisiologia , Adulto , Cegueira/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Lateralidade Funcional/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Lobo Occipital/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem , Percepção da Fala/fisiologia
16.
Invest Ophthalmol Vis Sci ; 62(4): 9, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33825854

RESUMO

Purpose: The dorsal attention network (DAN) and the ventral attention network (VAN) are known to support visual attention, but the influences of ocular dominance on the attention networks are unclear. We aimed to explore how visual cortical asymmetry of the attention networks correlate with neurophysiological oscillation and connectivity markers of attentional processes. Methods: An oddball task with concentric circle stimuli of three different sizes (i.e., spot size of 5°, 20°, or 30° of visual angle) was used to vary task difficulty. Event-related oscillations and interareal communication were tested with an electroencephalogram-based visual evoked components as a function of ocular dominance in 30 healthy subjects. Results: Accuracy rates were higher in the dominant eyes compared with the nondominant eyes. Compared with the nondominant eyes, the dominant eyes had higher theta, low-alpha, and low-beta powers and lower high-alpha powers within the nodes of VAN and DAN. Furthermore, visual information processed by the dominant and nondominant eye had different fates, that is, the dominant eyes mainly relied on theta and low-alpha connectivity within both the VAN and the DAN, whereas the nondominant eyes mainly relied on theta connectivity within the VAN and high-alpha connectivity within the DAN. The difference in accuracy rate between the two eyes was correlated with the low-alpha oscillations in the anterior DAN area and low-alpha connectivity of the left DAN. Conclusions: The ocular dominance processing and interareal communication reveal a cortical asymmetry underlying attention, and this reflects a two-way modulatory mechanism within attention networks in the human brain.


Assuntos
Atenção/fisiologia , Mapeamento Encefálico/métodos , Dominância Ocular/fisiologia , Lateralidade Funcional/fisiologia , Córtex Visual/fisiopatologia , Adulto , Eletroencefalografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Córtex Visual/fisiologia , Adulto Jovem
17.
Sci Rep ; 11(1): 7868, 2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33846508

RESUMO

The sensory dominance effect refers to the phenomenon that one sensory modality more frequently receives preferential processing (and eventually dominates consciousness and behavior) over and above other modalities. On the other hand, hand dominance is an innate aspect of the human motor system. To investigate how the sensory dominance effect interacts with hand dominance, we applied the adapted Colavita paradigm and recruited a large cohort of healthy right-handed participants (n = 119). While the visual dominance effect in bimodal trials was observed for the whole group (n = 119), about half of the right-handers (48%) showed a visual preference, i.e., their dominant hand effect manifested in responding to the visual stimuli. By contrast, 39% of the right-handers exhibited an auditory preference, i.e., the dominant hand effect occurred for the auditory responses. The remaining participants (13%) did not show any dominant hand preference for either visual or auditory responses. For the first time, the current behavioral data revealed that human beings possess a characteristic and persistent preferential link between different sensory modalities and the dominant vs. non-dominant hand. Whenever this preferential link between the sensory and the motor system was adopted, one dominance effect peaks upon the other dominance effect's best performance.


Assuntos
Percepção Auditiva/fisiologia , Lateralidade Funcional/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Humanos , Adulto Jovem
18.
Neuroimage ; 237: 118030, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-33836272

RESUMO

Recent advances have made it possible to decode various aspects of visually presented stimuli from patterns of scalp EEG measurements. As of recently, such multivariate methods have been commonly used to decode visual-spatial features such as location, orientation, or spatial frequency. In the current study, we show that it is also possible to track visual colour processing by using Linear Discriminant Analysis on patterns of EEG activity. Building on other recent demonstrations, we show that colour decoding: (1) reflects sensory qualities (as opposed to, for example, verbal labelling) with a prominent contribution from posterior electrodes contralateral to the stimulus, (2) conforms to a parametric coding space, (3) is possible in multi-item displays, and (4) is comparable in magnitude to the decoding of visual stimulus orientation. Through subsampling our data, we also provide an estimate of the approximate number of trials and participants required for robust decoding. Finally, we show that while colour decoding can be sensitive to subtle differences in luminance, our colour decoding results are primarily driven by measured colour differences between stimuli. Colour decoding opens a relevant new dimension in which to track visual processing using scalp EEG measurements, while bypassing potential confounds associated with decoding approaches that focus on spatial features.


Assuntos
Córtex Cerebral/fisiologia , Percepção de Cores/fisiologia , Eletroencefalografia/métodos , Neuroimagem Funcional/métodos , Reconhecimento Visual de Modelos/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Sensibilidades de Contraste/fisiologia , Eletroculografia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Processamento de Sinais Assistido por Computador , Aprendizado de Máquina Supervisionado , Adulto Jovem
19.
Nat Commun ; 12(1): 2449, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33907194

RESUMO

In the developing auditory system, spontaneous activity generated in the cochleae propagates into the central nervous system to promote circuit formation. The effects of peripheral firing patterns on spontaneous activity in the central auditory system are not well understood. Here, we describe wide-spread bilateral coupling of spontaneous activity that coincides with the period of transient efferent modulation of inner hair cells from the brainstem medial olivocochlear system. Knocking out α9/α10 nicotinic acetylcholine receptors, a requisite part of the efferent pathway, profoundly reduces bilateral correlations. Pharmacological and chemogenetic experiments confirm that the efferent system is necessary for normal bilateral coupling. Moreover, auditory sensitivity at hearing onset is reduced in the absence of pre-hearing efferent modulation. Together, these results demonstrate how afferent and efferent pathways collectively shape spontaneous activity patterns and reveal the important role of efferents in coordinating bilateral spontaneous activity and the emergence of functional responses during the prehearing period.


Assuntos
Vias Auditivas/fisiologia , Cóclea/fisiologia , Vias Eferentes/fisiologia , Retroalimentação Fisiológica , Receptores Nicotínicos/genética , Estimulação Acústica , Animais , Vias Auditivas/citologia , Cóclea/citologia , Lateralidade Funcional/fisiologia , Expressão Gênica , Células Ciliadas Auditivas Internas/citologia , Células Ciliadas Auditivas Internas/fisiologia , Colículos Inferiores/citologia , Colículos Inferiores/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Núcleo Olivar/citologia , Núcleo Olivar/fisiologia , Receptores Nicotínicos/deficiência
20.
Dev Med Child Neurol ; 63(7): 874-882, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33720409

RESUMO

AIM: We explored the psychometric properties of the recently developed Tyneside Pegboard Test (TPT) for unimanual and bimanual dexterity in children with unilateral cerebral palsy (CP) and investigated the impact of sensorimotor impairments on manual dexterity. METHOD: In this cross-sectional study, the TPT was assessed in 49 children with unilateral CP (mean age 9y 8mo, SD 1y 11mo, range 6-15y; 30 males, 19 females; 23 with right unilateral CP). All participants additionally underwent a standardized upper limb evaluation at body function and activity level. We investigated: (1) known-group, concurrent, and construct validity and (2) impact of sensorimotor impairments including spasticity, grip force, stereognosis, and mirror movements using analysis of covariance, Spearman's rank correlation (r), and multiple linear regression (R2 ) respectively. RESULTS: TPT outcomes significantly differed according to the Manual Ability Classification System (p<0.001, known-group validity). Relationships were found between the unimanual TPT tasks and the Jebsen-Taylor Hand Function Test (r=0.86-0.88, concurrent validity). Bimanual TPT tasks were negatively correlated with the Assisting Hand Assessment, ABILHAND-Kids, and Children's Hand-use Experience Questionnaire (r=-0.38 to -0.78, construct validity). Stereognosis was the main determinant influencing all tasks (p<0.001, R2 =37-50%). Unimanual dexterity was additionally determined by grip strength (p<0.05, R2 =8-9%) and mirror movements in the more impaired hand (p<0.05, R2 =4-8%). Bimanual dexterity was also explained by mirror movements in the more impaired hand (p<0.01, R2 =10-16%) and spasticity (p=0.04, R2 =5%). INTERPRETATION: The TPT is a valid test to measure unimanual and bimanual dexterity in unilateral CP. The results further emphasize the importance of somatosensory impairments in children with unilateral CP. What this paper adds The Tyneside Pegboard Test is valid for measuring unimanual and bimanual dexterity in unilateral cerebral palsy. Children with poorer manual ability show worse unimanual and bimanual dexterity. Stereognosis is the main predictor of both unimanual and bimanual dexterity. Stronger mirror movements in the more impaired hand result in worse bimanual dexterity.


Assuntos
Paralisia Cerebral/fisiopatologia , Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Destreza Motora/fisiologia , Extremidade Superior/fisiopatologia , Adolescente , Criança , Estudos Transversais , Feminino , Mãos/fisiopatologia , Humanos , Masculino , Psicometria
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