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1.
Nat Commun ; 12(1): 360, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452252

RESUMO

Endogenous attention is the cognitive function that selects the relevant pieces of sensory information to achieve goals and it is known to be controlled by dorsal fronto-parietal brain areas. Here we expand this notion by identifying a control attention area located in the temporal lobe. By combining a demanding behavioral paradigm with functional neuroimaging and diffusion tractography, we show that like fronto-parietal attentional areas, the human posterior inferotemporal cortex exhibits significant attentional modulatory activity. This area is functionally distinct from surrounding cortical areas, and is directly connected to parietal and frontal attentional regions. These results show that attentional control spans three cortical lobes and overarches large distances through fiber pathways that run orthogonally to the dominant anterior-posterior axes of sensory processing, thus suggesting a different organizing principle for cognitive control.


Assuntos
Atenção/fisiologia , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Imagem de Tensor de Difusão , Feminino , Lobo Frontal/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Masculino , Percepção de Movimento/fisiologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa/métodos , Lobo Temporal/diagnóstico por imagem , Adulto Jovem
2.
Elife ; 92020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319745

RESUMO

Despite the importance of programming to modern society, the cognitive and neural bases of code comprehension are largely unknown. Programming languages might 'recycle' neurocognitive mechanisms originally developed for natural languages. Alternatively, comprehension of code could depend on fronto-parietal networks shared with other culturally-invented symbol systems, such as formal logic and symbolic math such as algebra. Expert programmers (average 11 years of programming experience) performed code comprehension and memory control tasks while undergoing fMRI. The same participants also performed formal logic, symbolic math, executive control, and language localizer tasks. A left-lateralized fronto-parietal network was recruited for code comprehension. Patterns of activity within this network distinguish between 'for' loops and 'if' conditional code functions. In terms of the underlying neural basis, code comprehension overlapped extensively with formal logic and to a lesser degree math. Overlap with executive processes and language was low, but laterality of language and code covaried across individuals. Cultural symbol systems, including code, depend on a distinctive fronto-parietal cortical network.


Assuntos
Cognição , Compreensão , Função Executiva , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Software , Adulto , Mapeamento Encefálico , Feminino , Lobo Frontal/diagnóstico por imagem , Lateralidade Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Adulto Jovem
3.
PLoS One ; 15(12): e0244491, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33373387

RESUMO

The default mode network (DMN) is the main large-scale network of the resting brain and the PCC/precuneus is a major hub of this network. Glutamate and GABA (γ-amino butyric acid) are the main excitatory and inhibitory neurotransmitters in the CNS, respectively. We studied glutamate and GABA concentrations in the PCC/precuneus via magnetic resonance spectroscopy (MRS) at 7T in relation to age and correlated them with functional connectivity between this region and other DMN nodes in ten healthy right-handed volunteers ranging in age between 23-68 years. Mean functional connectivity of the PCC/precuneus to the other DMN nodes and the glutamate/GABA ratio significantly correlated with age (r = 0.802, p = 0.005 and r = 0.793, p = 0.006, respectively) but not with each other. Glutamate and GABA alone did not significantly correlate with age nor with functional connectivity within the DMN. The glutamate/GABA ratio and functional connectivity of the PCC/precuneus are, therefore, independent age-related biomarkers of the DMN and may be combined in a multimodal pipeline to study DMN alterations in various disease states.


Assuntos
Ácido Glutâmico/análise , Rede Nervosa/fisiologia , Lobo Parietal/metabolismo , Descanso/fisiologia , Ácido gama-Aminobutírico/análise , Adulto , Fatores Etários , Idoso , Mapeamento Encefálico/métodos , Feminino , Ácido Glutâmico/metabolismo , Voluntários Saudáveis , Humanos , Espectroscopia de Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Imageamento por Ressonância Magnética Multiparamétrica/métodos , Rede Nervosa/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem , Adulto Jovem , Ácido gama-Aminobutírico/metabolismo
4.
J Clin Neurosci ; 79: 275-276, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33070912

RESUMO

Since the outbreak with novel corona virus in December 2019, a myriad of different neurological manifestations in patients with COVID-19 infection have been reported. We present a case of non-traumatic intracranial hemorrhage in the olfactory gyrus in a patient who tested positive for SARS-COV-2. The area of hemorrhage is not a common location for spontaneous hemorrhage. Given that loss of smell is considered a relatively common symptom of this pandemic, it is an intriguing association of COVID-19 and olfactory gyrus ICH for neurotropism of SARS-CoV2 for olfactory bulb and glia cells through nasal mucosa. Future studies will need to elucidate the exact mechanism of anosmia from COVID-19 and potential mechanisms leading to ICH.


Assuntos
Betacoronavirus , Hemorragia Cerebral/etiologia , Infecções por Coronavirus/complicações , Lobo Parietal/diagnóstico por imagem , Pneumonia Viral/complicações , Hemorragia Cerebral/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos do Olfato/etiologia , Pandemias , Olfato
5.
PLoS One ; 15(9): e0239577, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32986743

RESUMO

Mild Cognitive Impairment (MCI) is a border or precursor state of dementia. To optimize implemented interventions for MCI, it is essential to clarify the underlying neural mechanisms. However, knowledge regarding the brain regions responsible for MCI is still limited. Here, we implemented the Montreal Cognitive Assessment (MoCA) test, a screening tool for MCI, in 20 healthy elderly participants (mean age, 67.5 years), and then recorded magnetoencephalograms (MEG) while they performed a visual sequential memory task. In the task, each participant memorized the four possible directions of seven sequentially presented arrow images. Recall accuracy for beginning items of the memory sequence was significantly positively related with MoCA score. Meanwhile, MEG revealed stronger alpha-band (8-13 Hz) rhythm desynchronization bilaterally in the precuneus (PCu) for higher MoCA (normal) participants. Most importantly, this PCu desynchronization response weakened in correspondence with lower MoCA score during the beginning of sequential memory encoding, a time period that should rely on working memory and be affected by declined cognitive function. Our results suggest that deactivation of the PCu is associated with early MCI, and corroborate pathophysiological findings based on post-mortem tissue which have implicated hypoperfusion of the PCu in early stages of Alzheimer disease. Our results indicate the possibility that cognitive decline can be detected early and non-invasively by monitoring PCu activity with electrophysiological methods.


Assuntos
Doença de Alzheimer/patologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/fisiopatologia , Magnetoencefalografia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/patologia , Idoso , Doença de Alzheimer/diagnóstico por imagem , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Rememoração Mental/fisiologia , Testes de Estado Mental e Demência , Testes Neuropsicológicos , Psicometria/métodos
6.
PLoS Biol ; 18(9): e3000854, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32898172

RESUMO

Working memory is imprecise, and these imprecisions can be explained by the combined influences of random diffusive error and systematic drift toward a set of stable states ("attractors"). However, the neural correlates of diffusion and drift remain unknown. Here, we investigated how delay-period activity in frontal and parietal cortex, which is known to correlate with the decline in behavioral memory precision observed with increasing memory load, might relate to diffusion and drift. We analyzed data from an existing experiment in which subjects performed delayed recall for line orientation, at different loads, during functional magnetic resonance imaging (fMRI) scanning. To quantify the influence of drift and diffusion, we modeled subjects' behavior using a discrete attractor model and calculated within-subject correlation between frontal and parietal delay-period activity and whole-trial estimates of drift and diffusion. We found that although increases in frontal and parietal activity were associated with increases in both diffusion and drift, diffusion explained the most variance in frontal and parietal delay-period activity. In comparison, a subsequent whole-brain regression analysis showed that drift, rather than diffusion, explained the most variance in delay-period activity in lateral occipital cortex. These results are consistent with a model of the differential recruitment of general frontoparietal mechanisms in response to diffusive noise and of stimulus-specific biases in occipital cortex.


Assuntos
Lobo Frontal/fisiologia , Memória de Curto Prazo/fisiologia , Lobo Occipital/fisiologia , Lobo Parietal/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Viés , Mapeamento Encefálico/métodos , Feminino , Lobo Frontal/anatomia & histologia , Lobo Frontal/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Rememoração Mental/fisiologia , Lobo Occipital/anatomia & histologia , Lobo Occipital/diagnóstico por imagem , Lobo Parietal/anatomia & histologia , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa , Razão Sinal-Ruído , Fatores de Tempo , Vias Visuais/anatomia & histologia , Vias Visuais/diagnóstico por imagem , Vias Visuais/fisiologia , Adulto Jovem
7.
PLoS One ; 15(8): e0238022, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845918

RESUMO

Working memory (WM) is the key process linking perception to action. Several lines of research have, accordingly, highlighted WM's engagement in sensori-motor associations between retrospective stimuli and future behavior. Using human fMRI we investigated whether prior information about the effector used to respond in a WM task would have an impact on the way the same sensory stimulus is maintained in memory despite a behavioral response could not be readily planned. We focused on WM-related activity in posterior parietal cortex during the maintenance of spatial items for a subsequent match-to-sample comparison, which was reported either with a verbal or with a manual response. We expected WM activity to be higher for manual response trials, because of posterior parietal cortex's engagement in both spatial WM and hand movement preparation. Increased fMRI activity for manual response trials in bilateral anterior intraparietal sulcus confirmed our expectations. These results imply that the maintenance of sensory material in WM is optimized for motor context, i.e. for the effector that will be relevant in the upcoming behavioral responses.


Assuntos
Memória de Curto Prazo , Lobo Parietal/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa , Estudos Retrospectivos , Análise e Desempenho de Tarefas , Adulto Jovem
8.
PLoS Biol ; 18(8): e3000800, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776945

RESUMO

Studies of neural processes underlying delay of gratification usually focus on prefrontal networks related to curbing affective impulses. Here, we provide evidence for an alternative mechanism that facilitates delaying gratification by mental orientation towards the future. Combining continuous theta-burst stimulation (cTBS) with functional neuroimaging, we tested how the right temporoparietal junction (rTPJ) facilitates processing of future events and thereby promotes delay of gratification. Participants performed an intertemporal decision task and a mental time-travel task in the MRI scanner before and after receiving cTBS over the rTPJ or the vertex (control site). rTPJ cTBS led to both stronger temporal discounting for longer delays and reduced processing of future relative to past events in the mental time-travel task. This finding suggests that the rTPJ contributes to the ability to delay gratification by facilitating mental representation of outcomes in the future. On the neural level, rTPJ cTBS led to a reduction in the extent to which connectivity of rTPJ with striatum reflected the value of delayed rewards, indicating a role of rTPJ-striatum connectivity in constructing neural representations of future rewards. Together, our findings provide evidence that the rTPJ is an integral part of a brain network that promotes delay of gratification by facilitating mental orientation to future rewards.


Assuntos
Corpo Estriado/fisiologia , Tomada de Decisões/fisiologia , Desvalorização pelo Atraso/fisiologia , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Adulto , Mapeamento Encefálico , Corpo Estriado/anatomia & histologia , Corpo Estriado/diagnóstico por imagem , Feminino , Neuroimagem Funcional , Humanos , Comportamento Impulsivo/fisiologia , Masculino , Rede Nervosa/anatomia & histologia , Rede Nervosa/diagnóstico por imagem , Lobo Parietal/anatomia & histologia , Lobo Parietal/diagnóstico por imagem , Recompensa , Lobo Temporal/anatomia & histologia , Lobo Temporal/diagnóstico por imagem , Estimulação Magnética Transcraniana
9.
Proc Natl Acad Sci U S A ; 117(28): 16596-16605, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32581128

RESUMO

Humans accurately identify observed actions despite large dynamic changes in their retinal images and a variety of visual presentation formats. A large network of brain regions in primates participates in the processing of others' actions, with the anterior intraparietal area (AIP) playing a major role in routing information about observed manipulative actions (OMAs) to the other nodes of the network. This study investigated whether the AIP also contributes to invariant coding of OMAs across different visual formats. We recorded AIP neuronal activity from two macaques while they observed videos portraying seven manipulative actions (drag, drop, grasp, push, roll, rotate, squeeze) in four visual formats. Each format resulted from the combination of two actor's body postures (standing, sitting) and two viewpoints (lateral, frontal). Out of 297 recorded units, 38% were OMA-selective in at least one format. Robust population code for viewpoint and actor's body posture emerged shortly after stimulus presentation, followed by OMA selectivity. Although we found no fully invariant OMA-selective neuron, we discovered a population code that allowed us to classify action exemplars irrespective of the visual format. This code depends on a multiplicative mixing of signals about OMA identity and visual format, particularly evidenced by a set of units maintaining a relatively stable OMA selectivity across formats despite considerable rescaling of their firing rate depending on the visual specificities of each format. These findings suggest that the AIP integrates format-dependent information and the visual features of others' actions, leading to a stable readout of observed manipulative action identity.


Assuntos
Macaca/fisiologia , Neurônios/fisiologia , Lobo Parietal/fisiologia , Percepção Visual , Animais , Comportamento Animal , Feminino , Masculino , Lobo Parietal/diagnóstico por imagem
10.
J Neurosci ; 40(23): 4525-4535, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32354854

RESUMO

Coordinated reach-to-grasp movements are often accompanied by rapid eye movements (saccades) that displace the desired object image relative to the retina. Parietal cortex compensates for this by updating reach goals relative to current gaze direction, but its role in the integration of oculomotor and visual orientation signals for updating grasp plans is unknown. Based on a recent perceptual experiment, we hypothesized that inferior parietal cortex (specifically supramarginal gyrus [SMG]) integrates saccade and visual signals to update grasp plans in additional intraparietal/superior parietal regions. To test this hypothesis in humans (7 females, 6 males), we used a functional magnetic resonance paradigm, where saccades sometimes interrupted grasp preparation toward a briefly presented object that later reappeared (with the same/different orientation) just before movement. Right SMG and several parietal grasp regions, namely, left anterior intraparietal sulcus and bilateral superior parietal lobule, met our criteria for transsaccadic orientation integration: they showed task-dependent saccade modulations and, during grasp execution, they were specifically sensitive to changes in object orientation that followed saccades. Finally, SMG showed enhanced functional connectivity with both prefrontal saccade regions (consistent with oculomotor input) and anterior intraparietal sulcus/superior parietal lobule (consistent with sensorimotor output). These results support the general role of parietal cortex for the integration of visuospatial perturbations, and provide specific cortical modules for the integration of oculomotor and visual signals for grasp updating.SIGNIFICANCE STATEMENT How does the brain simultaneously compensate for both external and internally driven changes in visual input? For example, how do we grasp an unstable object while eye movements are simultaneously changing its retinal location? Here, we used fMRI to identify a group of inferior parietal (supramarginal gyrus) and superior parietal (intraparietal and superior parietal) regions that show saccade-specific modulations during unexpected changes in object/grasp orientation, and functional connectivity with frontal cortex saccade centers. This provides a network, complementary to the reach goal updater, that integrates visuospatial updating into grasp plans, and may help to explain some of the more complex symptoms associated with parietal damage, such as constructional ataxia.


Assuntos
Força da Mão/fisiologia , Orientação Espacial/fisiologia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Movimentos Sacádicos/fisiologia , Adulto , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Estimulação Luminosa/métodos , Adulto Jovem
11.
Sci Rep ; 10(1): 8186, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424290

RESUMO

Three major white matter pathways connect the posterior temporal region and the adjacent inferior parietal lobule with the lateral frontal cortex: the arcuate fasciculus (AF), and the second and third branches of the superior longitudinal fasciculus (SLF II and SLF III). These pathways are found also in nonhuman primate brains where they play specific roles in auditory and spatial processing. The precise origin, course, and termination of these pathways has been examined in invasive tract tracing studies in macaque monkeys. Here we use this prior knowledge to improve dissections of these pathways in vivo in the human brain using diffusion Magnetic Resonance Imaging (MRI) tractography. In this study, the AF, originating from the posterior temporal cortex, has been successfully separated from the SLF II and SLF III tracts originating from the angular and supramarginal gyri of the inferior parietal lobule, respectively. The latter two pathways, i.e. SLF II and SLF III, have also been clearly separated from each other. Furthermore, we report for the first time in the human brain the dorsal branch of the AF that targets the posterior dorsolateral frontal region. These improved dissection protocols provide a solid basis for exploring the respective functional roles of these major fasciculi.


Assuntos
Imagem de Tensor de Difusão , Lobo Frontal/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Lobo Parietal/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adolescente , Adulto , Feminino , Humanos , Masculino , Rede Nervosa/diagnóstico por imagem , Descanso , Adulto Jovem
12.
Proc Natl Acad Sci U S A ; 117(23): 13162-13167, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32457153

RESUMO

Keeping track of other people's gaze is an essential task in social cognition and key for successfully reading other people's intentions and beliefs (theory of mind). Recent behavioral evidence suggests that we construct an implicit model of other people's gaze, which may incorporate physically incoherent attributes such as a construct of force-carrying beams that emanate from the eyes. Here, we used functional magnetic resonance imaging and multivoxel pattern analysis to test the prediction that the brain encodes gaze as implied motion streaming from an agent toward a gazed-upon object. We found that a classifier, trained to discriminate the direction of visual motion, significantly decoded the gaze direction in static images depicting a sighted face, but not a blindfolded one, from brain activity patterns in the human motion-sensitive middle temporal complex (MT+) and temporo-parietal junction (TPJ). Our results demonstrate a link between the visual motion system and social brain mechanisms, in which the TPJ, a key node in theory of mind, works in concert with MT+ to encode gaze as implied motion. This model may be a fundamental aspect of social cognition that allows us to efficiently connect agents with the objects of their attention. It is as if the brain draws a quick visual sketch with moving arrows to help keep track of who is attending to what. This implicit, fluid-flow model of other people's gaze may help explain culturally universal myths about the mind as an energy-like, flowing essence.


Assuntos
Atenção/fisiologia , Fixação Ocular/fisiologia , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Feminino , Voluntários Saudáveis , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Estimulação Luminosa , Comportamento Social , Lobo Temporal/diagnóstico por imagem , Teoria da Mente , Adulto Jovem
13.
Nat Commun ; 11(1): 1682, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32245973

RESUMO

When learning about dynamic and uncertain environments, people should update their beliefs most strongly when new evidence is most informative, such as when the environment undergoes a surprising change or existing beliefs are highly uncertain. Here we show that modulations of surprise and uncertainty are encoded in a particular, temporally dynamic pattern of whole-brain functional connectivity, and this encoding is enhanced in individuals that adapt their learning dynamics more appropriately in response to these factors. The key feature of this whole-brain pattern of functional connectivity is stronger connectivity, or functional integration, between the fronto-parietal and other functional systems. Our results provide new insights regarding the association between dynamic adjustments in learning and dynamic, large-scale changes in functional connectivity across the brain.


Assuntos
Lobo Frontal/fisiologia , Aprendizagem/fisiologia , Modelos Neurológicos , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Adolescente , Adulto , Conectoma , Feminino , Lobo Frontal/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Incerteza , Adulto Jovem
14.
Sci Rep ; 10(1): 6744, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32317774

RESUMO

Non-pharmacological treatment (NPT) improves cognitive functions and behavioural disturbances in patients with dementia, but the underlying neural mechanisms are unclear. In this observational study, 21 patients with dementia received NPTs for several months. Patients were scanned using magnetoencephalography twice during the NPT period to evaluate NPT effects on resting-state brain activity. Additionally, cognitive functions and behavioural disturbances were measured using the Mini-Mental State Examination (MMSE-J) and a short version of the Dementia Behaviour Disturbance Scale (DBD-13) at the beginning and the end of the NPT period. In contrast to the average DBD-13 score, the average MMSE-J score improved after the NPT period. Magnetoencephalography data revealed a reduced alpha activity in the right temporal lobe and fusiform gyrus, as well as an increased low-gamma activity in the right angular gyrus. DBD-13 score changes were correlated with beta activity in the sensorimotor area. These findings corroborate previous studies confirming NPT effects on brain activity in healthy participants and people at risk of dementia. Our results provide additional evidence that brains of patients with dementia have the capacity for plasticity, which may be responsible for the observed NPT effects. In dementia, NPT might lead to improvements in the quality of life.


Assuntos
Doença de Alzheimer/terapia , Terapia Cognitivo-Comportamental/métodos , Demência Vascular/terapia , Horticultura Terapêutica/métodos , Lobo Parietal/fisiopatologia , Lobo Temporal/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Ritmo alfa/fisiologia , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/fisiopatologia , Ritmo beta/fisiologia , Cognição/fisiologia , Demência Vascular/diagnóstico por imagem , Demência Vascular/fisiopatologia , Exercício Físico/psicologia , Feminino , Ritmo Gama/fisiologia , Humanos , Magnetoencefalografia , Masculino , Testes de Estado Mental e Demência , Cuidados de Enfermagem/métodos , Lobo Parietal/diagnóstico por imagem , Qualidade de Vida/psicologia , Desempenho de Papéis , Lobo Temporal/diagnóstico por imagem
15.
Nat Hum Behav ; 4(8): 844-855, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32313233

RESUMO

Animal neurophysiological studies have identified neural signals within dorsal frontoparietal areas that trace a perceptual decision by accumulating sensory evidence over time and trigger action upon reaching a threshold. Although analogous accumulation-to-bound signals are identifiable on extracranial human electroencephalography, their cortical origins remain unknown. Here neural metrics of human evidence accumulation, predictive of the speed of perceptual reports, were isolated using electroencephalography and related to dorsal frontoparietal network (dFPN) connectivity using diffusion and resting-state functional magnetic resonance imaging. The build-up rate of evidence accumulation mediated the relationship between the white matter macrostructure of dFPN pathways and the efficiency of perceptual reports. This association between steeper build-up rates of evidence accumulation and the dFPN was recapitulated in the resting-state networks. Stronger connectivity between dFPN regions is thus associated with faster evidence accumulation and speeded perceptual decisions. Our findings identify an integrated network for perceptual decisions that may be targeted for neurorehabilitation in cognitive disorders.


Assuntos
Tomada de Decisões/fisiologia , Lobo Frontal/fisiologia , Lobo Parietal/fisiologia , Percepção/fisiologia , Adolescente , Eletroencefalografia , Feminino , Lobo Frontal/diagnóstico por imagem , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Lobo Parietal/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Substância Branca/fisiologia , Adulto Jovem
16.
Neurobiol Aging ; 91: 125-135, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32241582

RESUMO

Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current investigation used functional magnetic resonance imaging, transcranial direct current stimulation, and eyeblink classical conditioning to study brain processes related to contingency awareness as a function of age. Older adults were significantly less aware of the relationship between the tone-airpuff pairings than younger adults. Greater right parietal functional magnetic resonance imaging activation was associated with higher levels of contingency awareness for younger and older subjects. Cathodal transcranial direct current stimulation over the right parietal lobe led to lower levels of awareness in younger subjects without disrupting conditioned responses. Older adults exhibited hyperactivations in the parietal and medial temporal lobes, despite showing no conditioning deficits. These findings strongly support the idea that the parietal cortex serves as a substrate for contingency awareness and that age-related disruption of this region is sufficient to impair awareness, which may be a manifestation of some form of naturally occurring age-related neglect.


Assuntos
Envelhecimento/psicologia , Conscientização/fisiologia , Lobo Parietal/fisiologia , Adulto , Idoso , Piscadela , Condicionamento Clássico , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Adulto Jovem
17.
Psychiatry Res Neuroimaging ; 300: 111065, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32234640

RESUMO

A systematic review was implemented according to PRISMA guidelines on Pubmed, Psychinfo, Medline, Embase to fill the existing literature gap on the effectiveness of using Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) in Anorexia Nervosa (AN), Bulimia Nervosa (BN) and Binge Eating Disorder (BED). Twenty-two articles were included. Four studies reported an increased density in 5-hydroxytryptamine receptor (5-HT1A) in fronto-temporo-parietal regions in both affected and recovered AN as well as in BN. The 5-HT transporter (5-HTT) binding was increased or diminished in different specific cortical areas and in relation to Eating Disorder (ED) subtypes. Some evidences of blunted Dopamine (DA) release in the putamen in BN patients suggest that their DA function might be impaired as in addictive behaviours. Studies estimating the regional Cerebral Blood Flow (rCBF) with SPECT demonstrated that temporal areas seem to play a key role in ED corroborating the hypothesis of a cingulate-temporal cortical dysfunction in AN. In addition, alterations of both parietal and prefrontal cortex provide a possible common neural substrate in AN. Studies included in this review are heterogeneous preventing robust conclusions, however, our findings add knowledge on some of the neurotransmitters involved in ED.


Assuntos
Anorexia Nervosa/diagnóstico por imagem , Transtorno da Compulsão Alimentar/diagnóstico por imagem , Bulimia Nervosa/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada de Emissão de Fóton Único , Circulação Cerebrovascular , Humanos , Lobo Parietal/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem
18.
Neuropsychology ; 34(4): 479-492, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32134282

RESUMO

OBJECTIVE: It was suggested that the bimanual coupling effect might be linked to motor intentionality and planning, which are the top-down components of motor execution. However, previous results in pathological and healthy individuals have also underlined the pivotal role of bottom-up sensorimotor information. METHOD: In this single-case study, the Circles-Lines Coupling Task was administered to a left-parietal-brain-damaged individual. The cerebral lesion caused a central proprioceptive loss, relative to the impaired right hand, when out of the visual control. For the 1st time in literature, we sought to investigate whether the movement of the unaffected hand induced an efficient coupling effect on the movement of the affected one. The bimanual task was performed in the presence and absence of visual input. The patient's performance was compared with that of healthy controls. RESULTS: We observed the traditional bimanual coupling effect in healthy controls. Moreover, we also replicated the effect when they performed the task blindfolded. In the case of the patient, both hands showed the typical ovalization of the line trajectory when the task was performed in visual modality. It is interesting that when the patient performed the task blindfolded, the trajectories of the impaired right hand seemed to be not influenced by the concomitant circular movement of the spared left hand. CONCLUSIONS: The movement of the unaffected hand induced a bimanual coupling effect on the movement of the affected one only when the visual input was available. In absence of a visual feedback, the aberrant proprioceptive information might preclude the emerging of bimanual coupling, even in the case of a preserved motor intentionality and planning. (PsycInfo Database Record (c) 2020 APA, all rights reserved).


Assuntos
Dano Encefálico Crônico/etiologia , Dano Encefálico Crônico/psicologia , Propriocepção , Adulto , Dano Encefálico Crônico/diagnóstico por imagem , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/psicologia , Retroalimentação Sensorial , Feminino , Lateralidade Funcional , Mãos/fisiopatologia , Humanos , Imagem por Ressonância Magnética , Masculino , Meningioma/complicações , Meningioma/psicologia , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Desempenho Psicomotor
19.
J Clin Neurosci ; 75: 234-239, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32173155

RESUMO

Adult-onset tics represent either a secondary tic disorder ("tourettism") or a late presentation of childhood tics, which may have been previously unrecognised. Head trauma has been recognised as an infrequent cause of adult-onset tic disorder, which exhibits variable temporal relationship to the inciting injury and response to therapy. We present a patient who presented with late-onset tics seven years after a circumscribed brain injury, responding well to antidopaminergic treatment. A review of all the previously reported cases of post-traumatic tic disorder is provided. Our patient is unusual in that the injury presumed to be responsible for the development of tics was of a very focal nature, akin to previously described tic disorder following vascular insults. We discuss the rare occurrence of tourettism after such focal brain lesions and analyse the insights this provides into the anatomical substrates underlying tic disorders.


Assuntos
Lesões Encefálicas/diagnóstico por imagem , Traumatismos Cranianos Penetrantes/diagnóstico por imagem , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/lesões , Transtornos de Tique/diagnóstico por imagem , Adulto , Lesões Encefálicas/complicações , Lesões Encefálicas/terapia , Traumatismos Cranianos Penetrantes/complicações , Traumatismos Cranianos Penetrantes/terapia , Humanos , Masculino , Transtornos de Tique/etiologia , Transtornos de Tique/terapia
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