RESUMO
During natural behavior, an action often needs to be suddenly stopped in response to an unexpected sensory input-referred to as reactive stopping. Reactive stopping has been mostly investigated in humans, which led to hypotheses about the involvement of different brain structures, in particular the hyperdirect pathway. Here, we directly investigate the contribution and interaction of two key regions of the hyperdirect pathway, the orbitofrontal cortex (OFC) and subthalamic nucleus (STN), using dual-area, multielectrode recordings in male rats performing a stop-signal task. In this task, rats have to initiate movement to a go-signal, and occasionally stop their movement to the go-signal side after a stop-signal, presented at various stop-signal delays. Both the OFC and STN show near-simultaneous field potential reductions in the beta frequency range (12-30â Hz) compared with the period preceding the go-signal and the movement period. These transient reductions (â¼200â ms) only happen during reactive stopping, which is when the stop-signal was received after action initiation, and are well timed after stop-signal onset and before the estimated time of stopping. Phase synchronization analysis also showed a transient attenuation of synchronization between the OFC and STN in the beta range during reactive stopping. The present results provide the first direct quantification of local neural oscillatory activity in the OFC and STN and interareal synchronization specifically timed during reactive stopping.
Assuntos
Ritmo beta , Córtex Pré-Frontal , Núcleo Subtalâmico , Animais , Masculino , Ratos , Núcleo Subtalâmico/fisiologia , Ritmo beta/fisiologia , Córtex Pré-Frontal/fisiologia , Sincronização Cortical/fisiologia , Desempenho Psicomotor/fisiologia , Ratos Long-Evans , Inibição Psicológica , Tempo de Reação/fisiologiaRESUMO
Autism is characterized by atypical social communication styles. To investigate whether individuals with high autistic traits could still have effective social communication among each other, we compared the behavioral patterns and communication quality within 64 dyads of college students paired with both high, both low, and mixed high-low (HL) autistic traits, with their gender matched. Results revealed that the high-high (HH) autistic dyads exhibited atypical behavioral patterns during conversations, including reduced mutual gaze, communicational turns, and emotional sharing compared with the low-low and/or HL autistic dyads. However, the HH autistic dyads displayed enhanced interpersonal neural synchronization during social communications measured by functional near-infrared spectroscopy, suggesting an effective communication style. Besides, they also provided more positive subjective evaluations of the conversations. These findings highlight the potential for alternative pathways to effectively communicate with the autistic community, contribute to a deeper understanding of how high autistic traits influence social communication dynamics among autistic individuals, and provide important insights for the clinical practices for supporting autistic people.
Assuntos
Transtorno Autístico , Comunicação , Espectroscopia de Luz Próxima ao Infravermelho , Humanos , Masculino , Feminino , Adulto Jovem , Transtorno Autístico/psicologia , Transtorno Autístico/fisiopatologia , Relações Interpessoais , Comportamento Social , Interação Social , Encéfalo/fisiopatologia , Encéfalo/fisiologia , Adulto , Sincronização Cortical/fisiologia , AdolescenteRESUMO
When two conflicting images are presented to each eye, a phenomenon called binocular rivalry occurs in which we initially perceive one image, and then our perception switches to the other over time. An enhancement of θ-band phase coherence in visual mismatch oscillatory response (vMOR) is reported to be involved in the facilitation of perceptual alternation when the deviant stimulus is presented unconsciously. In this study, we investigated the modulation effect of θ-band transcranial alternating current stimulation (tACS) on perceptual alternation in binocular rivalry, with a focus on its relationship with the θ-band vMOR. The results showed that tACS had no significant effect on the mean proportion of perceptual alternation. Analyzing the differential effects of the modulation, however, we found a positive correlation between the increase in inter-trial phase coherence of the vMOR and the promotion of perceptual alternation under the unconscious deviant condition. Additionally, our findings indicate that the θ-band phase synchrony between frontal and occipital electrode sides, as measured by the phase lag index, is implicated in perceptual alternation, with an increase (decrease) in connection density observed in participants whose perceptual alternation was increased (decreased) by tACS. These results support the hypothesis that deviant visual stimuli evoke θ-band phase synchrony between the frontal and occipital cortices, thereby enhancing perceptual alternation in binocular rivalry.
Assuntos
Estimulação Luminosa , Ritmo Teta , Estimulação Transcraniana por Corrente Contínua , Visão Binocular , Percepção Visual , Humanos , Masculino , Feminino , Adulto Jovem , Visão Binocular/fisiologia , Estimulação Transcraniana por Corrente Contínua/métodos , Percepção Visual/fisiologia , Adulto , Ritmo Teta/fisiologia , Estimulação Luminosa/métodos , Sincronização Cortical/fisiologiaRESUMO
Parkinson's disease (PD) is characterized by the disruption of repetitive, concurrent and sequential motor actions due to compromised timing-functions principally located in cortex-basal ganglia (BG) circuits. Increasing evidence suggests that motor impairments in untreated PD patients are linked to an excessive synchronization of cortex-BG activity at beta frequencies (13-30 Hz). Levodopa and subthalamic nucleus deep brain stimulation (STN-DBS) suppress pathological beta-band reverberation and improve the motor symptoms in PD. Yet a dynamic tuning of beta oscillations in BG-cortical loops is fundamental for movement-timing and synchronization, and the impact of PD therapies on sensorimotor functions relying on neural transmission in the beta frequency-range remains controversial. Here, we set out to determine the differential effects of network neuromodulation through dopaminergic medication (ON and OFF levodopa) and STN-DBS (ON-DBS, OFF-DBS) on tapping synchronization and accompanying cortical activities. To this end, we conducted a rhythmic finger-tapping study with high-density EEG-recordings in 12 PD patients before and after surgery for STN-DBS and in 12 healthy controls. STN-DBS significantly ameliorated tapping parameters as frequency, amplitude and synchrony to the given auditory rhythms. Aberrant neurophysiologic signatures of sensorimotor feedback in the beta-range were found in PD patients: their neural modulation was weaker, temporally sluggish and less distributed over the right cortex in comparison to controls. Levodopa and STN-DBS boosted the dynamics of beta-band modulation over the right hemisphere, hinting to an improved timing of movements relying on tactile feedback. The strength of the post-event beta rebound over the supplementary motor area correlated significantly with the tapping asynchrony in patients, thus indexing the sensorimotor match between the external auditory pacing signals and the performed taps. PD patients showed an excessive interhemispheric coherence in the beta-frequency range during the finger-tapping task, while under DBS-ON the cortico-cortical connectivity in the beta-band was normalized. Ultimately, therapeutic DBS significantly ameliorated the auditory-motor coupling of PD patients, enhancing the electrophysiological processing of sensorimotor feedback-information related to beta-band activity, and thus allowing a more precise cued-tapping performance.
Assuntos
Ritmo beta , Sincronização Cortical , Estimulação Encefálica Profunda , Dedos , Levodopa , Córtex Motor , Doença de Parkinson , Núcleo Subtalâmico , Humanos , Doença de Parkinson/terapia , Doença de Parkinson/fisiopatologia , Masculino , Feminino , Pessoa de Meia-Idade , Estimulação Encefálica Profunda/métodos , Idoso , Ritmo beta/fisiologia , Córtex Motor/fisiopatologia , Córtex Motor/fisiologia , Sincronização Cortical/fisiologia , Levodopa/uso terapêutico , Núcleo Subtalâmico/fisiopatologia , Antiparkinsonianos/uso terapêutico , EletroencefalografiaRESUMO
Punishment of moral norm violators is instrumental for human cooperation. Yet, social and affective neuroscience research has primarily focused on second- and third-party norm enforcement, neglecting the neural architecture underlying observed (vicarious) punishment of moral wrongdoers. We used naturalistic television drama as a sampling space for observing outcomes of morally-relevant behaviors to assess how individuals cognitively process dynamically evolving moral actions and their consequences. Drawing on Affective Disposition Theory, we derived hypotheses linking character morality with viewers' neural processing of characters' rewards and punishments. We used functional magnetic resonance imaging (fMRI) to examine neural responses of 28 female participants while free-viewing 15 short story summary video clips of episodes from a popular US television soap opera. Each summary included a complete narrative structure, fully crossing main character behaviors (moral/immoral) and the consequences (reward/punishment) characters faced for their actions. Narrative engagement was examined via intersubject correlation and representational similarity analysis. Highest cortical synchronization in 9 specifically selected regions previously implicated in processing moral information was observed when characters who act immorally are punished for their actions with participants' empathy as an important moderator. The results advance our understanding of the moral brain and the role of normative considerations and character outcomes in viewers' engagement with popular narratives.
Assuntos
Drama , Imageamento por Ressonância Magnética , Princípios Morais , Punição , Humanos , Feminino , Punição/psicologia , Adulto , Adulto Jovem , Sincronização Cortical/fisiologia , Empatia/fisiologia , Córtex Cerebral/fisiologia , Córtex Cerebral/diagnóstico por imagem , NarraçãoRESUMO
BACKGROUND: Motor preparation and execution can be impaired in patients with multiple sclerosis (pwMS). These neural processes can be assessed using electroencephalography (EEG). During a self-paced movement, EEG signal amplitude decreases before movement (event-related desynchronization, ERD) and increases after movement (event-related synchronization, ERS). OBJECTIVE: To reappraise ERD/ERS changes in pwMS compared to healthy controls (HC). METHODS: This single-center study included 13 pwMS and 10 sex/age-matched HC. 60-channel EEG was recorded during two self-paced movements of the right hand: a simple index finger extension task and a more complex finger tapping task. Clinical variables included MS type, sex, age, disease duration, disability, grip strength, fatigue and attentional performance. EEG variables included ERD and ERS onset latency, duration, and amplitude determined using two methods of signal analyses (based on visual or automated determination) in the alpha and beta frequency bands in five cortical regions: right and left frontocentral and centroparietal regions and a midline region. Neuroimaging variables included the volumes of four deep brain structures (thalamus, putamen, pallidum and caudate nucleus) and the relative lesion load. RESULTS: ERD/ERS changes in pwMS compared to HC were observed only in the beta band. In pwMS, beta-ERD had a delayed onset in the midline and right parietocentral regions and a shortened duration or increased amplitude in the parietocentral region; beta-ERS had a shorter duration, delayed onset, or reduced amplitude in the left parieto/frontocentral region. In addition, pwMS with a more delayed beta-ERD in the midline region had less impaired executive functions but increased caudate nuclei volume, while pwMS with a more delayed beta-ERS in the parietocentral region contralateral to the movement had less fatigue but increased thalami volume. CONCLUSION: This study confirms an alteration of movement preparation and execution in pwMS, mainly characterized by a delayed cortical activation (ERD) and a delayed and reduced post-movement inhibition (ERS) in the beta band. Compensatory mechanisms could be involved in these changes, associating more preserved clinical performance and overactivation of deep brain structures.
Assuntos
Eletroencefalografia , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/diagnóstico por imagem , Sincronização Cortical/fisiologia , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Desempenho Psicomotor/fisiologiaRESUMO
In recent years, researchers have used hyperscanning techniques to explore how brains interact during various human activities. These studies have revealed a phenomenon called interpersonal neural synchronization (INS), but little research has focused on the overall effect of INS in close relationships. To address this gap, this study aims to synthesize and analyze the existing literature on INS during social interactions in close relationships. We conducted a meta-analysis of 17 functional near-infrared spectroscopy (fNIRS) hyperscanning studies involving 1149 dyads participants, including romantic couples and parent-child dyads. The results revealed robust and consistent INS in the frontal, temporal, and parietal regions of the brain and found similar INS patterns in couples and parent-child studies, providing solid empirical evidence for the attachment theory. Moreover, the age of children and brain areas were significant predictors of the effect size in parent-child research. The developmental stage of children and the mismatched development of brain structures might be the crucial factors for the difference in neural performance in social and cognitive behaviors in parent-child dyads.
Assuntos
Interação Social , Espectroscopia de Luz Próxima ao Infravermelho , Humanos , Relações Interpessoais , Relações Pais-Filho , Encéfalo/fisiologia , Encéfalo/diagnóstico por imagem , Sincronização Cortical/fisiologia , Neuroimagem FuncionalRESUMO
Color has meaning in particular contexts, and the meaning of color can impact behavioral performance. For example, the meaning of color about traffic rules (blue/green and red mean "go" and "stop" respectively) influences reaction times (RTs) to signals. Specifically, in a Go/No-go task, RTs have been reported to be longer when responding to a red signal and withholding the response to a blue signal (Red Go/Blue No-go task) than when responding to a blue signal and withholding the response to a red signal (Blue Go/Red No-go task). However, the neurophysiological background of this phenomenon has not been fully understood. The purpose of this study was to investigate the brain oscillatory activity associated with the effect of meaning of color on RTs in the Go/No-go task. Twenty participants performed a Blue simple reaction task, a Red simple reaction task, a Blue Go/Red No-go task, and a Red Go/Blue No-go task. We recorded responses to signals and electroencephalogram (EEG) during the tasks and evaluated RTs and changes in spectral power over time, referred to as event-related synchronization (ERS) and event-related desynchronization (ERD). The behavioral results were similar to previous studies. The EEG results showed that frontal beta ERD and theta ERS were greater when signals were presented in blue than red color in both simple reaction and Go/No-go tasks. In addition, the onset of theta ERS was delayed in the Red Go than Blue Go trial in the Go/No-go task. The enhanced beta ERD may indicate that blue signals facilitate motor response, and the delayed onset of theta ERS may indicate the delayed onset of cognitive process when responding to red signals as compared to blue signals in the Go/No-go task. Thus, this delay in cognitive process can be involved in the slow response in the Red Go/Blue No-go task.
Assuntos
Encéfalo , Eletroencefalografia , Humanos , Tempo de Reação/fisiologia , Encéfalo/fisiologia , Sincronização Cortical/fisiologiaRESUMO
Symptoms in patients with obsessive-compulsive disorder (OCD) are associated with impairment in cognitive control, attention, and action inhibition. We investigated OCD group differences relative to healthy subjects in terms of event-related alpha and beta range synchronization (ERS) and desynchronization (ERD) during a visually cued Go/NoGo task. Subjects were 62 OCD patients and 296 healthy controls (HC). The OCD group in comparison with HC, showed a changed value of alpha/beta oscillatory power over the central cortex, in particular, an increase in the alpha/beta ERD over the central-parietal cortex during the interstimulus interval (Cue condition) as well as changes in the postmovement beta synchronization topography and frequency. Over the frontal cortex, the OCD group showed an increase in magnitude of the beta ERS in NoGo condition. Within the parietal-occipital ERS/ERD modulations, the OCD group showed an increase in the alpha/beta ERD over the parietal cortex after the presentation of the visual stimuli as well as a decrease in the beta ERD over the occipital cortex after the presentation of the Cue and Go stimuli. The specific properties in the ERS/ERD patterns observed in the OCD group may reflect high involvement of the frontal and central cortex in action preparation and action inhibition processes and, possibly, in maintaining the motor program, which might be a result of the dysfunction of the cortico-striato-thalamo-cortical circuits involving prefrontal cortex. The data about enhanced involvement of the parietal cortex in the evaluation of the visual stimuli are in line with the assumption about overfocused attention in OCD.
Assuntos
Sincronização Cortical , Transtorno Obsessivo-Compulsivo , Humanos , Sincronização Cortical/fisiologia , Lobo Occipital , Córtex Pré-Frontal , Lobo Parietal , EletroencefalografiaRESUMO
Cognitive tasks in the human brain are performed by various cortical areas located in the cerebral cortex. The cerebral cortex is separated into different areas in the right and left hemispheres. We consider one human cerebral cortex according to a network composed of coupled subnetworks with small-world properties. We study the burst synchronization and desynchronization in a human neuronal network under external periodic and random pulsed currents. With and without external perturbations, the emergence of bursting synchronization is observed. Synchronization can contribute to the processing of information, however, there are evidences that it can be related to some neurological disorders. Our results show that synchronous behavior can be suppressed by means of external pulsed currents.
Assuntos
Rede Nervosa , Neurônios , Humanos , Potenciais de Ação/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Encéfalo , Córtex Cerebral , Modelos Neurológicos , Sincronização Cortical/fisiologiaRESUMO
Neural mechanisms of human standing are expected to be elucidated for preventing fallings. Postural response evoked by sudden external perturbation originates from various areas in the central nervous system. Recent studies have revealed that the corticospinal pathway is one of the key nodes for an appropriate postural response. The corticospinal pathway that mediates the early part of the electromyographic response is modulated with prediction before a perturbation occurs. Temporal prediction explicitly exhibiting an onset timing contributes to enhancing corticospinal excitability. However, how the cortical activities in the sensorimotor area with temporal prediction are processed before the corticospinal pathway enhancement remains unclear. In this study, using electroencephalography, we investigated how temporal prediction affects both neural oscillations and synchronization between sensorimotor and distal areas. Our results revealed that desynchronization of cortical oscillation at α- and ß-bands was observed in the sensorimotor and parietooccipital areas (Cz, CPz, Pz and POz), and those are nested in the phase at θ-band frequency. Furthermore, a reduction in the interareal phase synchrony in the α-band was induced after the timing cue for the perturbation onset. The phase synchrony at the low frequency can relay the temporal prediction among the distant areas and initiate the modulation of the local cortical activities. Such modulations contribute to the preparation for sensory processing and motor execution that are necessary for optimal responses.
Assuntos
Sincronização Cortical , Eletroencefalografia , Humanos , Sincronização Cortical/fisiologiaRESUMO
Gamma band synchronization can facilitate local and long-range neural communication. In the primary visual cortex, visual stimulus properties within a specific location determine local synchronization strength, while the match of stimulus properties between distant locations controls long-range synchronization. The neural basis for the differential control of local and global gamma band synchronization is unknown. Combining electrophysiology, optogenetics, and computational modeling, we found that VIP disinhibitory interneurons in mouse cortex linearly scale gamma power locally without changing its stimulus tuning. Conversely, they suppress long-range synchronization when two regions process non-matched stimuli, tuning gamma coherence globally. Modeling shows that like-to-like connectivity across space and specific VIPâSST inhibition capture these opposing effects. VIP neurons thus differentially impact local and global properties of gamma rhythms depending on visual stimulus statistics. They may thereby construct gamma-band filters for spatially extended but continuous image features, such as contours, facilitating the downstream generation of coherent visual percepts.
Assuntos
Ritmo Gama , Córtex Visual , Camundongos , Animais , Córtex Visual/fisiologia , Neurônios/fisiologia , Interneurônios/fisiologia , Simulação por Computador , Sincronização Cortical/fisiologiaRESUMO
Many pregnant women report impairments in their attentional capacities. However, comparative studies between pregnant and non-pregnant women using standardised attention paradigms are rare and inconsistent. During attention tasks alpha activity is known to suppress irrelevant sensory inputs and previous studies show that a large event-related desynchronisation (ERD) in the alpha range prior to target-onset predicts enhanced attentional processing. We quantified the relationship between performance (accuracy, response time) in a standardised visuo-spatial attention task and alpha ERD (â¼6-12 Hz) as well as saliva estradiol level in fifteen pregnant women (M = 26.6, SD = 3.0 years) compared to fifteen non-pregnant, naturally cycling women (M = 23.1, SD = 4.3 years). Compared to non-pregnant women, alpha frequency was increased in pregnant women. Furthermore, pregnant women showed a greater magnitude of the alpha ERD prior to target-onset and a moderate increase in accuracy compared to non-pregnant women. In addition, accuracy correlated negatively with estradiol in pregnant women as well as with frontal alpha ERD in all women. These correlational findings indicate that pregnancy-related enhancement in alpha desynchronisation in a fronto-parietal network might modulate accuracy during a visuo-spatial attention task.
Assuntos
Ritmo alfa , Atenção , Humanos , Feminino , Ritmo alfa/fisiologia , Atenção/fisiologia , Tempo de Reação/fisiologia , Estradiol , Eletroencefalografia , Sincronização Cortical/fisiologiaRESUMO
OBJECTIVE: The study aimed to examine the clinical and neurophysiological predictors of motor event-related desynchronization (ERD) and synchronization (ERS) in patients with chronic pain due to knee osteoarthritis (KOA). METHODS: We performed a cross-sectional analysis of our cohort study (DEFINE cohort), KOA arm, with 71 patients, including demographic, functionality, genetic and neurophysiological measures. ERD/ERS was evaluated during hand motor tasks (motor execution, active and passive observation, and imagery). Multivariate regression models were used to explore predictors of ERD/ERS. RESULTS: Although we found an altered ERD/ERS pattern during motor execution and active observation, the ERS pattern could only be clearly differentiated after passive observation.`. We found no predictors of ERD (excitatory biomarker). For ERS (inhibitory biomarker), our results showed that the main predictors differ across EEG frequency bands. Considering pain measures, we found that visual analogue scale (VAS, right knee) and chronicity of pain negatively predict low beta and high beta ERS, respectively. Pain threshold was positively correlated with alpha ERS, while 36-Item Short Form Survey (SF-36) emotional domain positively predicted beta ERS. Regarding transcranial magnetic stimulation (TMS) markers, intracortical inhibition (ICF) negatively predicted beta and low beta ERS, and left hemisphere cortical silent period (CSP) negatively predicted low beta ERS. CONCLUSION: Considering that higher power of ERS indicates a stronger cortical organization and inhibitory drive, our results show that limitation of activities due to emotional factors, lower pain threshold, higher VAS pain, and longer duration of pain are associated with lower ERS power (in alpha and beta frequencies), thus indicating a lower inhibitory drive. In the same direction, a lower inhibitory drive as indicated by higher ERS power is associated with higher ICF amplitude. Although there was a negative association between ERS and CSP, this may indicate that ICF values are adjusting CSP results. Our findings support the idea that a less organized cortical response as indicated by changes to the ERS is associated with higher pain correlates in subjects with KOA.
Assuntos
Córtex Motor , Osteoartrite do Joelho , Humanos , Sincronização Cortical/fisiologia , Córtex Motor/fisiologia , Eletroencefalografia , Medição da Dor , Osteoartrite do Joelho/complicações , Estudos de Coortes , Estudos Transversais , Biomarcadores , DorRESUMO
Visual plasticity declines sharply after the critical period, yet we easily learn to recognize new faces and places, even as adults. Such learning is often characterized by a "moment of insight," an abrupt and dramatic improvement in recognition. The mechanisms that support abrupt learning are unknown, but one hypothesis is that they involve changes in synchronization between brain regions. To test this hypothesis, we used a behavioral task in which non-human primates rapidly learned to recognize novel images and to associate them with specific responses. Simultaneous recordings from inferotemporal and prefrontal cortices revealed a transient synchronization of neural activity between these areas that peaked around the moment of insight. Synchronization was strongest between inferotemporal sites that encoded images and reward-sensitive prefrontal sites. Moreover, its magnitude intensified gradually over image exposures, suggesting that abrupt learning is the culmination of a search for informative signals within a circuit linking sensory information to task demands.
Assuntos
Sincronização Cortical , Córtex Pré-Frontal , Animais , Sincronização Cortical/fisiologia , Córtex Pré-Frontal/fisiologia , Reconhecimento Psicológico , Recompensa , Aprendizagem EspacialRESUMO
The brain naturally binds events from different sources in unique concepts. It is hypothesized that this process occurs through the transient mutual synchronization of neurons located in different regions of the brain when the stimulus is presented. This mechanism of 'binding through synchronization' can be directly implemented in neural networks composed of coupled oscillators. To do so, the oscillators must be able to mutually synchronize for the range of inputs corresponding to a single class, and otherwise remain desynchronized. Here we show that the outstanding ability of spintronic nano-oscillators to mutually synchronize and the possibility to precisely control the occurrence of mutual synchronization by tuning the oscillator frequencies over wide ranges allows pattern recognition. We demonstrate experimentally on a simple task that three spintronic nano-oscillators can bind consecutive events and thus recognize and distinguish temporal sequences. This work is a step forward in the construction of neural networks that exploit the non-linear dynamic properties of their components to perform brain-inspired computations.
Assuntos
Encéfalo/fisiologia , Sincronização Cortical/fisiologia , Rede Nervosa/fisiologia , Redes Neurais de Computação , Animais , Simulação por Computador , Humanos , Modelos Neurológicos , Neurônios/fisiologiaRESUMO
Organizing sensory information into coherent perceptual objects is fundamental to everyday perception and communication. In the visual domain, indirect evidence from cortical responses suggests that children with autism spectrum disorder (ASD) have anomalous figure-ground segregation. While auditory processing abnormalities are common in ASD, especially in environments with multiple sound sources, to date, the question of scene segregation in ASD has not been directly investigated in audition. Using magnetoencephalography, we measured cortical responses to unattended (passively experienced) auditory stimuli while parametrically manipulating the degree of temporal coherence that facilitates auditory figure-ground segregation. Results from 21 children with ASD (aged 7-17 years) and 26 age- and IQ-matched typically developing children provide evidence that children with ASD show anomalous growth of cortical neural responses with increasing temporal coherence of the auditory figure. The documented neurophysiological abnormalities did not depend on age, and were reflected both in the response evoked by changes in temporal coherence of the auditory scene and in the associated induced gamma rhythms. Furthermore, the individual neural measures were predictive of diagnosis (83% accuracy) and also correlated with behavioral measures of ASD severity and auditory processing abnormalities. These findings offer new insight into the neural mechanisms underlying auditory perceptual deficits and sensory overload in ASD, and suggest that temporal-coherence-based auditory scene analysis and suprathreshold processing of coherent auditory objects may be atypical in ASD.
Assuntos
Percepção Auditiva/fisiologia , Transtorno do Espectro Autista/fisiopatologia , Sincronização Cortical/fisiologia , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica/métodos , Adolescente , Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/psicologia , Criança , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino , Tempo de Reação/fisiologiaRESUMO
Synaptic cell-adhesion molecules (CAMs) organize the architecture and properties of neural circuits. However, whether synaptic CAMs are involved in activity-dependent remodeling of specific neural circuits is incompletely understood. Leucine-rich repeat transmembrane protein 3 (LRRTM3) is required for the excitatory synapse development of hippocampal dentate gyrus (DG) granule neurons. Here, we report that Lrrtm3-deficient mice exhibit selective reductions in excitatory synapse density and synaptic strength in projections involving the medial entorhinal cortex (MEC) and DG granule neurons, accompanied by increased neurotransmitter release and decreased excitability of granule neurons. LRRTM3 deletion significantly reduced excitatory synaptic innervation of hippocampal mossy fibers (Mf) of DG granule neurons onto thorny excrescences in hippocampal CA3 neurons. Moreover, LRRTM3 loss in DG neurons significantly decreased mossy fiber long-term potentiation (Mf-LTP). Remarkably, silencing MEC-DG circuits protected against the decrease in the excitatory synaptic inputs onto DG and CA3 neurons, excitability of DG granule neurons, and Mf-LTP in Lrrtm3-deficient mice. These results suggest that LRRTM3 may be a critical factor in activity-dependent synchronization of the topography of MEC-DG-CA3 excitatory synaptic connections. Collectively, our data propose that LRRTM3 shapes the target-specific structural and functional properties of specific hippocampal circuits.
Assuntos
Sincronização Cortical/fisiologia , Hipocampo/fisiologia , Proteínas de Membrana/metabolismo , Rede Nervosa/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Sinapses/fisiologia , Animais , Região CA3 Hipocampal/metabolismo , Giro Denteado/metabolismo , Córtex Entorrinal/metabolismo , Potenciação de Longa Duração , Proteínas de Membrana/deficiência , Camundongos Knockout , Fibras Musgosas Hipocampais/metabolismo , Proteínas do Tecido Nervoso/deficiência , Neurônios/metabolismo , Pseudópodes/metabolismo , Transmissão Sináptica/fisiologiaRESUMO
Deficits in response inhibition are a central feature of the highly prevalent dysexecutive syndrome found in Parkinson's disease (PD). Such deficits are related to a range of common clinically relevant symptoms including cognitive impairment as well as impulsive and compulsive behaviors. In this study, we explored the cortical dynamics underlying response inhibition during the mental preparation for the antisaccade task by recording magnetoencephalography (MEG) and eye-movements in 21 non-demented patients with early to mid-stage Parkinson's disease and 21 age-matched healthy control participants (HC). During the pre-stimulus preparatory period for antisaccades we observed: Taken together, the results indicate that alterations in pre-stimulus prefrontal alpha and beta activity hinder proactive response inhibition and in turn result in higher error rates and prolonged response latencies in PD.
Assuntos
Ondas Encefálicas/fisiologia , Disfunção Cognitiva/fisiopatologia , Sincronização Cortical/fisiologia , Função Executiva/fisiologia , Inibição Psicológica , Doença de Parkinson/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Movimentos Sacádicos/fisiologia , Idoso , Disfunção Cognitiva/etiologia , Feminino , Humanos , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/complicaçõesRESUMO
Synchronization has an important role in neural networks dynamics that is mostly accompanied by cognitive activities such as memory, learning, and perception. These activities arise from collective neural behaviors and are not totally understood yet. This paper aims to investigate a cortical model from this perspective. Historically, epilepsy has been regarded as a functional brain disorder associated with excessive synchronization of large neural populations. Epilepsy is believed to arise as a result of complex interactions between neural networks characterized by dynamic synchronization. In this paper, we investigated a network of neural populations in a way the dynamics of each node corresponded to the Jansen-Rit neural mass model. First, we study a one-column Jansen-Rit neural mass model for four different input levels. Then, we considered a Watts-Strogatz network of Jansen-Rit oscillators. We observed an epileptic activity in the weak input level. The network is considered to change various parameters. The detailed results including the mean time series, phase spaces, and power spectrum revealed a wide range of different behaviors such as epilepsy, healthy, and a transition between synchrony and asynchrony states. In some points of coupling coefficients, there is an abrupt change in the order parameters. Since the critical state is a dynamic candidate for healthy brains, we considered some measures of criticality and investigated them at these points. According to our study, some markers of criticality can occur at these points, while others may not. This occurrence is a result of the nature of the specific order parameter selected to observe these markers. In fact, The definition of a proper order parameter is key and must be defined properly. Our view is that the critical points exhibit clear characteristics and invariance of scale, instead of some types of markers. As a result, these phase transition points are not critical as they show no evidence of scaling invariance.