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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 785-789, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36086395

RESUMO

In activities of daily living that require bimanual coordination, humans often assign a role to each hand. How do task requirements affect this role assignment? To address this question, we investigated how healthy right-handed participants bimanually manipulated a static or dynamic virtual object using wrist flexion/extension while receiving haptic feedback through the interacting object's torque. On selected trials, the object shook strongly to destabilize the bimanual grip. Our results show that participants reacted to the shaking by increasing their wrist co-contraction. Unlike in previous work, handedness was not the determining factor in choosing which wrist to co-contract to stabilize the object. However, each participant preferred to co-contract one hand over the other, a choice that was consistent for both the static and dynamic objects. While role allocation did not seem to be affected by task requirements, it may have resulted in different motor behaviours as indicated by the changes in the object torque. Further investigation is needed to elucidate the factors that determine the preference in stabilizing with either the dominant or non-dominant hand.


Assuntos
Atividades Cotidianas , Desempenho Psicomotor , Impedância Elétrica , Lateralidade Funcional , Mãos , Humanos
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 1493-1497, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36086495

RESUMO

Trimanual operation using a robotic supernumerary limb is a new and challenging mechanism for human operators that could enable a single user to perform tasks requiring more than two hands. Foot-controlled interfaces have previously proven able to be intuitively controlled, enabling simple tasks to be performed. However, the effect of going from unimanual to bimanual and then to trimanual tasks on subjects performance and coordination is not well understood. In this paper, unimanual, bimanual and trimanual teleoperation tasks were performed in a virtual reality scene to evaluate the impact of extending to trimanual actions. 15 participants were required to move their limbs together in a coordinated reaching activity. The results show that the addition of another hand resulted in an increase in operating time, where the time increased in going from unimanual to bimanual operation and then increased further when going from bimanual to trimanual. Moreover, the success rate for performing bimanual and trimanual tasks was strongly influenced by the subject's performance in ipsilateral hand-foot activities, where the ipsilateral combination had a lower success rate than contralateral limbs. The addition of a hand did not affect any two-hand coordination rate and even in some cases reduced coordination deviations. Clinical relevance - This work can contribute to build efficient training and learning framework on human multiple limbs motion control and coordination for both rehabilitation and augmentation.


Assuntos
Lateralidade Funcional , Robótica , Humanos , Desempenho Psicomotor , Extremidade Superior
3.
J Vis ; 22(10): 3, 2022 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-36069943

RESUMO

Patients with lesions of the parieto-occipital cortex typically misreach visual targets that they correctly perceive (optic ataxia). Although optic ataxia was described more than 30 years ago, distinguishing this condition from physiological behavior using kinematic data is still far from being an achievement. Here, combining kinematic analysis with machine learning methods, we compared the reaching performance of a patient with bilateral occipitoparietal damage with that of 10 healthy controls. They performed visually guided reaches toward targets located at different depths and directions. Using the horizontal, sagittal, and vertical deviation of the trajectories, we extracted classification accuracy in discriminating the reaching performance of patient from that of controls. Specifically, accurate predictions of the patient's deviations were detected after the 20% of the movement execution in all the spatial positions tested. This classification based on initial trajectory decoding was possible for both directional and depth components of the movement, suggesting the possibility of applying this method to characterize pathological motor behavior in wider frameworks.


Assuntos
Lateralidade Funcional , Desempenho Psicomotor , Braço , Ataxia , Fenômenos Biomecânicos , Lateralidade Funcional/fisiologia , Humanos , Aprendizado de Máquina , Desempenho Psicomotor/fisiologia
4.
Cortex ; 154: 390-404, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35930891

RESUMO

Cerebral asymmetry is a cardinal feature of functional organization in the human brain and an important biomarker of successful brain development. Studies have demonstrated that functional network asymmetries across hemispheres undergo significant development through childhood and adulthood. However, it remains unknown when such asymmetries of functional networks emerge and how they develop across the early months of infancy. To address this issue, we used multiple-channel functional near-infrared spectroscopy (fNIRS) imaging to record spontaneous brain activity in 66 healthy infants aged 3-9 months. We then adopted a graph-theory analysis approach to quantify the topological characteristics of hemispheric networks in each participant. Our results showed that infants aged 3 to 6 months old exhibited leftward asymmetries in local network efficiency, while infants aged 6 to 9 months old exhibited leftward asymmetries in global network efficiency. Importantly, the degree of leftward asymmetry in global network efficiency was increased over development from 3 to 9 months old, with a faster increase in the left hemisphere than in the right hemisphere. At the regional level, 3- to 6-month-old infants exhibited leftward asymmetries in functional connectivity strength (FCS) in the temporal cortex, whereas the FCS asymmetries were located in the temporal, frontal, and occipital cortexes for 6- to 9-month-old infants. Furthermore, the 6- to 9-month-old infants also exhibited leftward asymmetries in nodal efficiency around the frontal cortex. These combined findings demonstrate that functional asymmetric organization has emerged in early infancy, which could lay a critical foundation for the development of brain functions (e.g., language and social cognition functions) later in life.


Assuntos
Mapeamento Encefálico , Lateralidade Funcional , Adulto , Encéfalo , Criança , Humanos , Lactente , Idioma , Imageamento por Ressonância Magnética , Lobo Temporal
5.
Restor Neurol Neurosci ; 40(3): 125-135, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35964212

RESUMO

BACKGROUND: Traditional repetitive Transcranial Magnetic Stimulation (rTMS) remains applicable in speech studies on healthy participants. Although the procedure of inducing speech arrest by rTMS has been used for over 25 years, there are still significant discrepancies in its methodology. OBJECTIVE: The study aimed to simplify and improve the old methodology of triggering speech arrest by (rTMS). Our goal was to establish the best step-by-step algorithm and verify the procedure on a representative group of participants. METHODS: 47 healthy, right-handed volunteers (23 men and 24 women) at a median age of 23 (range 19-34) were included in the study. Handedness was determined using the Edinburgh Handedness Inventory Test. After setting the individual's motor threshold (MT) and heuristic choice of the place of stimulation, which targeted Inferior Frontal Gyrus (IFG), participants were asked to count downwards from 20 to 10. While counting, a series of 2-second pulses was generated at a frequency of 2 Hz at 120% or 150% of MT. The procedure was video-recorded and subsequently assessed by 3 independent reviewers and self-assessed by participants on visual analogue scales for the effect and comfort of stimulation. RESULTS: Speech arrest was induced in 45 people (95.7%). Language dominance was determined to be either left-sided (for 42.2%) or bilateral (55.3%). Total speech arrest was observed more often in participants for whom Broca's area was active exclusively in the left hemisphere. CONCLUSION: In our study, we present the step-by-step procedure for a simplified, as far as possible, methodology of inducing speech arrest using rTMS with its verification on a representative group of right-handed healthy individuals. Our results prove that the chosen stimulation parameters present a good efficacy ratio and seems to be justified. The traditional applications of rTMS in speech studies may be highly broadened if the methods used are further improved and simplified.


Assuntos
Fala , Estimulação Magnética Transcraniana , Feminino , Lateralidade Funcional/fisiologia , Humanos , Idioma , Masculino , Fala/fisiologia , Estimulação Magnética Transcraniana/métodos
6.
Behav Processes ; 201: 104718, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35914616

RESUMO

The majority of cetacean research suggests a right side/left cerebral hemisphere bias for processing visuospatial information and a left side/right cerebral hemisphere bias for processing social information. Beluga (Delphinapterus leucas) socio-sexual behavior involves motor skills coordination and is also hypothesized to serve a social function. The present study assessed whether 14 belugas in managed care displayed side bias in their lateral socio-sexual presentation behavior. No species-level bias was found, the majority of individuals did not display a side bias, and side use was not dependent on sex of the recipient, although some influence of swim direction was found. Only males had a statistically significant but small left side preference. Furthermore, there was a linear correlation with the left side being used increasingly more over Years 1-6 of life. This study suggests that belugas do not display consistent laterality of socio-sexual presentation behavior, which is in contrast to the laterality of mother-calf positions for belugas and the high levels of laterality that are reported for some behaviors of other cetacean species. Thus, it seems that beluga socio-sexual presentation behavior is flexible and may serve both motor skills practice and social functions, which likely involve both cerebral hemispheres as a cognitively engaging behavior.


Assuntos
Beluga , Animais , Feminino , Lateralidade Funcional , Gelatina , Humanos , Masculino , Comportamento Sexual , Natação
7.
BMC Neurol ; 22(1): 303, 2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-35982397

RESUMO

BACKGROUND: Polymicrogyria refers to the disruption of normal cerebral cortical development late in neuronal migration or in early cortical organization. Although patients with polymicrogyria feature relatively favorable motor outcomes, polymicrogyric lesions accompanied by extensive unilateral hemispheric atrophy and ipsilateral brainstem atrophy may induce poorer motor outcomes. This study is the first to employ transcranial magnetic stimulation (TMS) and diffusion tensor imaging (DTI) to characterize changes to motor organization and white matter tracts induced by polymicrogyria. CASE PRESENTATION: We document a case of a 16-year-old female with left hemiplegic unilateral polymicrogyria associated with ipsilateral brainstem atrophy. Magnetic resonance imaging (MRI) of the brain revealed unilateral polymicrogyria to have affected anterior cortical areas, including the perisylvian region on the right side. The right halves of the brain and brainstem were significantly smaller than the left halves. Although our patient was found to exhibit cortical dysplasia of the right frontoparietal and sylvian fissure areas and a decreased number of fibers in the corticospinal tract (CST) of the affected side on DTI, the connectivity of the CST was preserved up to the motor cortex. We also measured the cross-sectional area of the CST at the level of the pons. In TMS, contralateral motor evoked potentials (MEPs) were evoked from both hands, but the ipsilateral MEPs were evoked only from the left hand. The left hand featured a long duration, polyphasic pattern of contralateral MEPs. DISCUSSION AND CONCLUSION: TMS revealed that the concurrent bilateral projections to the paretic hand from the affected and unaffected hemispheres and contralateral MEPs in the paretic hand were polyphasic, indicating delayed electrophysiological maturation or a pathologic condition of the corticospinal motor pathways. In DTI, the cross-sectional area of the CST at the level of the pons on the affected side was smaller than that on the unaffected side. These DTI findings reveal an inadequate CST volume. Despite extensive brain malformation and ipsilateral brainstem atrophy, our patient had less severe motor dysfunction and presented with involuntary mirror movements. Mirror movements in the paretic hand are considered to indicate ipsilateral corticospinal projections from the unaffected hemisphere and may suggest favorable motor outcomes in early brain injury.


Assuntos
Córtex Motor , Transtornos dos Movimentos , Malformações do Sistema Nervoso , Polimicrogiria , Adolescente , Atrofia/patologia , Tronco Encefálico/diagnóstico por imagem , Tronco Encefálico/patologia , Imagem de Tensor de Difusão , Potencial Evocado Motor , Feminino , Lateralidade Funcional/fisiologia , Humanos , Córtex Motor/patologia , Transtornos dos Movimentos/patologia , Polimicrogiria/patologia , Tratos Piramidais/patologia , Estimulação Magnética Transcraniana/métodos
8.
Neuroimage ; 262: 119534, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-35931311

RESUMO

Lateralization is a fundamental characteristic of many behaviors and the organization of the brain, and atypical lateralization has been suggested to be linked to various brain-related disorders such as autism and schizophrenia. Right-handedness is one of the most prominent markers of human behavioural lateralization, yet its neurobiological basis remains to be determined. Here, we present a large-scale analysis of handedness, as measured by self-reported direction of hand preference, and its variability related to brain structural and functional organization in the UK Biobank (N = 36,024). A multivariate machine learning approach with multi-modalities of brain imaging data was adopted, to reveal how well brain imaging features could predict individual's handedness (i.e., right-handedness vs. non-right-handedness) and further identify the top brain signatures that contributed to the prediction. Overall, the results showed a good prediction performance, with an area under the receiver operating characteristic curve (AUROC) score of up to 0.72, driven largely by resting-state functional measures. Virtual lesion analysis and large-scale decoding analysis suggested that the brain networks with the highest importance in the prediction showed functional relevance to hand movement and several higher-level cognitive functions including language, arithmetic, and social interaction. Genetic analyses of contributions of common DNA polymorphisms to the imaging-derived handedness prediction score showed a significant heritability (h2=7.55%, p <0.001) that was similar to and slightly higher than that for the behavioural measure itself (h2=6.74%, p <0.001). The genetic correlation between the two was high (rg=0.71), suggesting that the imaging-derived score could be used as a surrogate in genetic studies where the behavioural measure is not available. This large-scale study using multimodal brain imaging and multivariate machine learning has shed new light on the neural correlates of human handedness.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Lateralidade Funcional , Humanos , Aprendizado de Máquina , Imageamento por Ressonância Magnética/métodos
9.
Epilepsy Behav ; 134: 108821, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35868157

RESUMO

Functional hemispherectomy results in good outcomes in cases of refractory epilepsy and constitutes a unique situation in which to study cerebral plasticity and the reorganization of lateralized functions of the brain, especially in cases of infancy or childhood surgery. Previous studies have highlighted the remarkable ability of the brain to recover language after left hemispherectomy. This leads to a reorganization of language networks toward right hemisphere, causing limitation in the development of visuo-spatial abilities, known as a crowding effect in the right hemisphere. Deficits in nonverbal functions have also been described as a more direct consequence of right hemipherectomy, but the results from case studies have sometimes been contradictory. We conducted a group study which may effectively compare patients with left and right hemispherectomy and address the effects of the age of seizure onset and surgery. We analyzed the general visuo-spatial and visuo-perceptive abilities, including face and emotional facial expression processing, in a group of 40 patients aged 7-16 years with left (n = 24) or right (n = 16) functional hemispherectomy. Although the groups did not differ, on average, in general visuo-spatial and visuo-perceptive skills, patients with right hemispherectomy were more impaired in the processing of faces and emotional facial expressions compared with patients with left hemispherectomy. This may reflect a specific deficit in the perceptual processing of faces after right hemispherectomy. Results are discussed in terms of limited plasticity of the left hemisphere for facial and configural processing.


Assuntos
Epilepsia Resistente a Medicamentos , Hemisferectomia , Criança , Lateralidade Funcional , Humanos , Idioma , Convulsões
10.
Epilepsy Behav ; 134: 108854, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35905518

RESUMO

Wada testing remains an important component of pre-surgical testing to assess the feasibility of temporal lobectomy for patients with intractable epilepsy. In this procedure, an anesthetic is injected into either internal carotid artery while memory and language testing is performed, simulating the effect of temporal lobe resection. The mechanism remains poorly understood because the hippocampal vasculature is predominantly via the posterior circulation. We recorded hippocampal EEG during bilateral methohexital Wada testing in three patients who had previously been implanted with a responsive neurostimulation system (RNS) to determine the effect of the injections on hippocampal activity. In all six injections from three patients, methohexital caused immediate, transient increases in hippocampal spikes. With at least two of these injections, the electrographic changes were consistent with electrographic seizures. In all cases, the epileptiform activity was not apparent on scalp EEG and was without obvious clinical correlate other than the negative findings expected from the anesthetic. The results demonstrate the utility of intracranial EEG during Wada testing and suggest that the elicitation of seizures or continuous spiking might contribute to dysfunction of the hippocampus during the Wada test. We hypothesize that this effect is due to disconnection and disinhibition of medial temporal structures.


Assuntos
Epilepsia do Lobo Temporal , Eletroencefalografia , Lateralidade Funcional , Hipocampo , Humanos , Metoexital , Convulsões
11.
Neurosci Lett ; 785: 136775, 2022 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-35817313

RESUMO

PURPOSE: Task complexity could affect acquisition efficiency of motor skills and interlimb transfer; however, how task complexity affects interlimb transfer remains unclear. We hypothesized that left- and right-handed participants may have different interlimb transfer efficiency depending on the task complexity. METHODS: Left-hand (n = 28) and right-hand (n = 28) dominant participants (age = 24.70 ± 4.02 years, male:female = 28:28) performed a finger sequence test with two levels of complexity (simple: one-digit with four fingers vs. complex: two-digit with five fingers) before and after ten trials of 2-min practice each on the same apparatus. The speed and task errors were measured and analyzed. RESULTS: Right-handed participants failed to improve performance on their right hand (non-trained hand) after contralateral left-hand practice in the simple finger sequence task. In contrast, the left-handed participants improved performance on non-trained hands both right and left after contralateral practices. In the complex task, however, both the left- and right-handed participants improved performance on non-trained hands by contralateral practices. CONCLUSION: Our results showed that task complexity of skilled practice gave different effects on interlimb transfer between right- and left-handed subjects. It appears that a certain level of appropriate complexity is necessary to detect inter-limb transfers in motor learning in right-handed subjects.


Assuntos
Lateralidade Funcional , Mãos , Adulto , Cognição , Feminino , Humanos , Masculino , Destreza Motora , Desempenho Psicomotor , Extremidade Superior , Adulto Jovem
12.
Elife ; 112022 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-35904242

RESUMO

The human cerebral cortex is symmetrically organized along large-scale axes but also presents inter-hemispheric differences in structure and function. The quantified contralateral homologous difference, that is asymmetry, is a key feature of the human brain left-right axis supporting functional processes, such as language. Here, we assessed whether the asymmetry of cortical functional organization is heritable and phylogenetically conserved between humans and macaques. Our findings indicate asymmetric organization along an axis describing a functional trajectory from perceptual/action to abstract cognition. Whereas language network showed leftward asymmetric organization, frontoparietal network showed rightward asymmetric organization in humans. These asymmetries were heritable in humans and showed a similar spatial distribution with macaques, in the case of intra-hemispheric asymmetry of functional hierarchy. This suggests (phylo)genetic conservation. However, both language and frontoparietal networks showed a qualitatively larger asymmetry in humans relative to macaques. Overall, our findings suggest a genetic basis for asymmetry in intrinsic functional organization, linked to higher order cognitive functions uniquely developed in humans.


Assuntos
Lateralidade Funcional , Imageamento por Ressonância Magnética , Animais , Encéfalo , Mapeamento Encefálico , Córtex Cerebral , Humanos , Idioma , Macaca
13.
Eur J Neurosci ; 56(4): 4455-4468, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35775788

RESUMO

Motor overflow (involuntary muscle activation) is common after stroke, particularly in the non-paretic upper limb. Two potential cortical mechanisms are as follows: (1) The contralesional hemisphere controls both limbs, and (2) inhibition from the ipsilesional to the contralesional hemisphere is diminished. Few studies have differentiated between these hypotheses or investigated motor overflow in the lower limb after stroke. To investigate these potential mechanisms, individuals with chronic stroke performed unilateral isometric and dynamic dorsiflexion. Motor overflow was quantified in the contralateral, resting (non-target) ankle. Transcranial magnetic stimulation (TMS) was applied, and responses were measured in both legs. Relations between motor overflow, excitability of ipsilateral motor pathways, and interhemispheric inhibition were assessed. Non-target muscle activity (motor overflow) was greater during isometric and dynamic conditions than rest in both legs (p ≤ 0.001) and was higher in the non-paretic than the paretic leg (p = 0.03). Some participants (25%) had motor overflow >4SD above the group mean in the non-paretic leg. Greater motor overflow in the non-paretic leg was associated with lesser inhibition from the ipsilesional to the contralesional hemisphere (p = 0.04). In both legs, non-target TMS responses were greater during the isometric and dynamic than the rest condition (p ≤ 0.01) but not when normalized to background muscle activity. Overall, motor overflow occurred in both legs after stroke, suggesting a common bilateral mechanism. Our correlational results suggest that alterations in interhemispheric inhibition may contribute to motor overflow. Furthermore, the lack of differences in non-target motor evoked potentials MEPs between rest, isometric, and dynamic conditions suggests that subcortical and/or spinal pathways may contribute to motor overflow.


Assuntos
Córtex Motor , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Potencial Evocado Motor/fisiologia , Lateralidade Funcional/fisiologia , Humanos , Extremidade Inferior/fisiologia , Córtex Motor/fisiologia , Acidente Vascular Cerebral/complicações , Reabilitação do Acidente Vascular Cerebral/métodos , Estimulação Magnética Transcraniana/métodos
14.
Commun Biol ; 5(1): 664, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35790815

RESUMO

Evolution of the direct, monosynaptic connection from the primary motor cortex to the spinal cord parallels acquisition of hand dexterity and lateralization of hand preference. In non-human mammals, the indirect, multi-synaptic connections between the bilateral primary motor cortices and the spinal cord also participates in controlling dexterous hand movement. However, it remains unknown how the direct and indirect corticospinal pathways work in concert to control unilateral hand movement with lateralized preference in humans. Here we demonstrated the asymmetric functional organization of the two corticospinal networks, by combining network modelling and simultaneous functional magnetic resonance imaging techniques of the brain and the spinal cord. Moreover, we also found that the degree of the involvement of the two corticospinal networks paralleled lateralization of hand preference. The present results pointed to the functionally lateralized motor nervous system that underlies the behavioral asymmetry of handedness in humans.


Assuntos
Imageamento por Ressonância Magnética , Medula Espinal , Animais , Encéfalo , Lateralidade Funcional , Mãos , Humanos , Mamíferos
15.
Exp Brain Res ; 240(9): 2359-2373, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35869986

RESUMO

The perceptual feature of a task such as how a task goal is perceived influences performance and coordination of bimanual actions in neurotypical adults. To assess how bimanual task goal modifies paretic and non-paretic arm performance and bimanual coordination in individuals with stroke affecting left and right hemispheres, 30 participants with hemispheric stroke (15 right-hemisphere damage-RHD); 15 left-hemisphere damage-LHD) and 10 age-matched controls performed reach-to-grasp and pick-up actions under bimanual common-goal (i.e., two physically coupled dowels), bimanual independent-goal (two physically uncoupled dowels), and unimanual conditions. Reach-to-grasp time and peak grasp aperture indexed motor performance, while time lags between peak reach velocities, peak grasp apertures, and peak pick-up velocities of the two hands characterized reach, grasp, and pick-up coordination, respectively. Compared to unimanual actions, bimanual actions significantly slowed non-paretic arm speed to match paretic arm speed, thus affording no benefit to paretic arm performance. Detriments in non-paretic arm performance during bimanual actions was more pronounced in the RHD group. Under common-goal conditions, movements were faster with smaller peak grasp apertures compared to independent-goal conditions for all groups. Compared to controls, individuals with stroke demonstrated poor grasp and pick-up coordination. Of the patient groups, patients with LHD showed more pronounced deficits in grasp coordination between hands. Finally, grasp coordination deficits related to paretic arm motor deficits (upper extremity Fugl-Meyer score) for LHD group, and to Trail-Making Test performance for RHD group. Findings suggest that task goal and distinct clinical deficits influence bimanual performance and coordination in patients with left- and right-hemispheric stroke.


Assuntos
Objetivos , Acidente Vascular Cerebral , Adulto , Lateralidade Funcional , Mãos , Força da Mão , Humanos , Movimento , Desempenho Psicomotor , Acidente Vascular Cerebral/complicações
16.
Exp Brain Res ; 240(9): 2311-2326, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35876852

RESUMO

The evidence for the hemispheric specialization of motor planning reveals several inconsistencies between the left-lateralized hypothesis and a distributed system across the hemispheres. We compared participants with left hemiplegic cerebral palsy (HCP) to right-handed control subjects in this study's first experiment by inviting them to perform a motor planning task. Participants were required to release the start button, grasp a hexagon, and rotate it according to the instructions. In the second experiment, we compared left-HCP subjects with right-HCP subjects inviting them to perform the same task (we used the data for left-HCP subjects from the first experiment). P2 amplitude, as well as planning time, grasping time, releasing time, and initial grip selection planning patterns, were used as outcome measures in both experiments. The first experiment revealed that controls acted more quickly and chose more effective planning patterns. Also, the P2 amplitude was smaller in left-HCP subjects than in control subjects. No significant group effect was observed in the second experiment for any movement-related measure or P2. At the neural level, however, there was an interaction between 'region' and 'group,' indicating the distinction between the two groups in the right region. The results are discussed in terms of motor planning's hemispheric distribution and individual differences in the HCP group.


Assuntos
Paralisia Cerebral , Paralisia Cerebral/complicações , Potenciais Evocados , Lateralidade Funcional , Força da Mão , Hemiplegia/etiologia , Humanos , Desempenho Psicomotor
17.
Cortex ; 154: 105-134, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35777191

RESUMO

BACKGROUND: Most people have strong left-brain lateralisation for language, with a minority showing right- or bilateral language representation. On some receptive language tasks, however, lateralisation appears to be reduced or absent. This contrasting pattern raises the question of whether and how language laterality may fractionate within individuals. Building on our prior work, we postulated (a) that there can be dissociations in lateralisation of different components of language, and (b) these would be more common in left-handers. A subsidiary hypothesis was that laterality indices will cluster according to two underlying factors corresponding to whether they involve generation of words or sentences, versus receptive language. METHODS: We tested these predictions in two stages: At Step 1 an online laterality battery (Dichotic listening, Rhyme Decision and Word Comprehension) was given to 621 individuals (56% left-handers); At Step 2, functional transcranial Doppler ultrasound (fTCD) was used with 230 of these individuals (51% left-handers). 108 left-handers and 101 right-handers gave useable data on a battery of three language generation and three receptive language tasks. RESULTS: Neither the online nor fTCD measures supported the notion of a single language laterality factor. In general, for both online and fTCD measures, tests of language generation were left-lateralised. In contrast, the receptive tasks were at best weakly left-lateralised or, in the case of Word Comprehension, slightly right-lateralised. The online measures were only weakly correlated, if at all, with fTCD measures. Most of the fTCD measures had split-half reliabilities of at least .7, and showed a distinctive pattern of intercorrelation, supporting a modified two-factor model in which Phonological Decision (generation) and Sentence Decision (reception) loaded on both factors. The same factor structure fitted data from left- and right-handers, but mean scores on the two factors were lower (less left-lateralised) in left-handers. CONCLUSIONS: There are at least two factors influencing language lateralization in individuals, but they do not correspond neatly to language generation and comprehension. Future fMRI studies could help clarify how far they reflect activity in specific brain regions.


Assuntos
Lateralidade Funcional , Idioma , Encéfalo , Circulação Cerebrovascular , Humanos , Ultrassonografia Doppler Transcraniana
18.
Sci Rep ; 12(1): 12169, 2022 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-35842454

RESUMO

Virtual reality (VR) technology has increased clinical attention in the health care of schizophrenia spectrum disorders in both diagnoses of the symptoms and assessment of schizotypal traits. However, the exact nature of VR-induced positive treatment effect in schizotypy is still unknown. In this study, VR technology was used as a non-invasive neurocognitive trigger to test the asymmetric visuospatial representational instability found in individuals with high schizotypy. The study aimed to reveal the brain functional hemispheric laterality in physical and virtual realities in individuals with schizotypal traits. Fifty-one healthy, right-handed participants (24 males and 27 females) were enrolled through public advertisements. Hemispheric functional asymmetry was measured by the Line Bisection Task (LBT). The results revealed that (a) LBT bias in the physical reality showed a handedness-related leftward pseudoneglect, however, similar handedness-related pseudoneglect in VR has not been found. (b) Comparing LBT bias in physically real and VR environments showed rightward drift in VR environments independently to the degree of handedness. (c) The schizotypy has no association with handedness, however, the cognitive schizotypy is related to the LBT bias. Higher cognitive schizotypy in VR associated with left hemispatial pseudoneglect. In conclusion, schizotypy is associated with ambiguous behavioral and cognitive functional laterality. In individuals with high cognitive schizotypy, the VR environment enhanced the representational articulation of the left hemispace. This effect may be originated from the enhancement of the right hemisphere overactivation and is followed by a lower mental control of the overt behavior.


Assuntos
Lateralidade Funcional , Transtorno da Personalidade Esquizotípica , Atenção , Computadores , Feminino , Lateralidade Funcional/fisiologia , Humanos , Idioma , Masculino
19.
J Clin Exp Neuropsychol ; 44(2): 163-170, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35819050

RESUMO

INTRODUCTION: Healthy persons demonstrate an upward bias on the vertical-line bisection test (vertical or "altitudinal" pseudoneglect). This bias might be sensory-attentional or action-intentional in origin. To test the action-intention hypothesis, we analyze whether the direction of action has an effect on altitudinal pseudoneglect. METHODS: Twenty-four healthy right-handed adults performed vertical-line bisection on an apparatus designed to distinguish the effects of sensory-attention and action-intention. Depending on hand placement, participants estimated line midpoints with a marker that moved in the same (congruent) or opposite (incongruent) direction as their hand movements. Two binary factors - hand movement in the upward versus downward direction and congruent vs incongruent hand movements - produced four conditions. RESULTS: There was upward deviation from the midline across all conditions. Bisections in the incongruent condition were higher than in the congruent condition. Bisections were also higher with upward hand movements than with downward hand movements. There was not a significant interaction between these factors. CONCLUSIONS: These results suggest that vertical pseudoneglect is primarily influenced by the allocation of allocentric attention, rather than action-intention. However, action-perceptual spatial incongruence increased this deviation. Perhaps the incongruent condition requires greater allocation of attention, but further exploration is needed. Additionally, these results suggest that visual attention follows the direction of motor action. Future studies of visual attention should consider the potential influence of this factor.


Assuntos
Mãos , Percepção Espacial , Adulto , Lateralidade Funcional , Humanos
20.
Neurocase ; 28(3): 283-291, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35858044

RESUMO

Training with an eyepatch or eyeglasses is one of the effective approaches for unilateral spatial neglect (USN), and it usually uses a device that covers the right side. However, few approaches are available for the left side. In this study, we examine the effect of motor tasks with left/right monocular eyeglasses on visual search and line-bisection performance in people with left USN. Seven participants with left USN admitted to convalescent hospitals were included. We conducted the Bells test, line-crossing test, and line-bisection test of the behavioral inattention test before/after the motor task. Our analyses focused on the improvement or decline in these assessment scores and the achievement/errors/non-smoothness scores of the motor task. When using the left monocular eyeglasses, the percentages of participants categorized as "improvement," "unchanged," and "decline" were 71.4%, 28.6%, and 0%, respectively (when using the right one they were 14.3%, 85.7%, and 0%). In the motor task, when using the left monocular eyeglasses, total achievement scores in five of seven participants were greater than those when using the right one, and they performed efficiently with fewer movement errors. These results suggest that training with left monocular eyeglasses might improve visual search performance in people with left USN.


Assuntos
Transtornos da Percepção , Acidente Vascular Cerebral , Óculos , Lateralidade Funcional , Humanos , Movimento , Transtornos da Percepção/etiologia
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