National Institute of Traumatology and Orthopaedics NITO

Rio de Janeiro, Brazil

National Institute of Traumatology and Orthopaedics NITO

Rio de Janeiro, Brazil
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Bittencourt J.,Federal University of Rio de Janeiro | Machado S.,Federal University of Rio de Janeiro | Machado S.,Institute of Applied Neuroscience INA | Machado S.,National Institute of Translational Medicine INCT TM | And 17 more authors.
Neuroscience Letters | Year: 2012

Introduction: The saccadic paradigm has been used to investigate specific cortical networks involving attention. The behavioral and electrophysiological investigations of the SEM contribute significantly to the understanding of attentive patterns presented of neurological and psychiatric disorders and sports performance. Objective: The current study aimed to investigate absolute alpha power changes in sensorimotor brain regions and the frontal eye fields during the execution of a saccadic task. Methods: Twelve healthy volunteers (mean age: 26.25; SD: ±4.13) performed a saccadic task while the electroencephalographic signal was simultaneously recorded for the cerebral cortex electrodes. The participants were instructed to follow the LEDs with their eyes, being submitted to two different task conditions: a fixed pattern versus a random pattern. Results: We found a moment main effect for the C3, C4, F3 and F4 electrodes and a condition main effect for the F3 electrode. We also found interaction between factor conditions and frontal electrodes. Conclusions: We conclude that absolute alpha power in the left frontal cortex discriminates the execution of the two stimulus presentation patterns during SEM. © 2012 Elsevier Ireland Ltd.


Velasques B.,Federal University of Rio de Janeiro | Velasques B.,Institute of Applied Neuroscience INA | Velasques B.,National Institute of Traumatology and Orthopaedics NITO | Machado S.,Federal University of Rio de Janeiro | And 17 more authors.
Neuroscience Letters | Year: 2011

Although several electrophysiological studies have demonstrated the role of theta band during the execution of different visuospatial attention tasks, this study is the first to directly investigate the role of theta power during the planning, execution and cognitive control of saccadic eye movements (SEMs). The current study aims at addressing this issue by investigating absolute theta power over the frontal cortex during the execution of random and fixed SEMs. Twelve healthy volunteers, performed two tasks involving different conditions in the planning, execution and cognitive control of SEMs while their brain activity pattern was recorded using quantitative electroencephalography. We found an interaction between SEM condition and electrode (F3, F4, Fz), and a main effect of time point and electrode. Our key finding revealed that the stimulus presentation induces different patterns over frontal theta power increase between the left and right hemisphere. We conclude that right and left frontal regions are an important factor to discriminate between memory- versus stimulus-driven SEMs, and speculate on their different contributions to visuospatial attention. © 2011 Elsevier Ireland Ltd.


Cartier C.,Federal University of Rio de Janeiro | Cartier C.,Institute of Applied Neuroscience IAN | Bittencourt J.,Federal University of Rio de Janeiro | Bittencourt J.,Institute of Applied Neuroscience IAN | And 23 more authors.
Brain Research Bulletin | Year: 2012

The saccadic paradigm has been used to investigate specific cortical networks involving visuospatial attention. We examined whether asymmetry in theta and beta band differentiates the role of the hemispheres during the execution of two different prosacadic conditions: a fixed condition, where the stimulus was presented at the same location; and a random condition, where the stimulus was unpredictable. Twelve healthy volunteers (3 male; mean age: 26.25) performed the task while their brain activity pattern was recorded using quantitative electroencephalography. We did not find any significant difference for beta, slow- and fast-alpha frequencies for the pairs of electrodes analyzed. The results for theta band showed a superiority of the left hemisphere in the frontal region when responding to the random condition on the right, which is related to the planning and selection of responses, and also a greater activation of the right hemisphere during the random condition, in the occipital region, related to the identification and recognition of patterns. These results indicate that asymmetries in the premotor area and the occipital cortex differentiate memory- and stimulus-driven tasks. © 2011 Elsevier Inc.


Araujo F.,Federal University of Rio de Janeiro | Machado S.,Federal University of Rio de Janeiro | Machado S.,Institute of Applied Neuroscience INA | Paes F.,Federal University of Rio de Janeiro | And 15 more authors.
Neuroscience Letters | Year: 2011

This study investigated the effects of bromazepam on qEEG when 14 healthy subjects were asked to perform a visuomotor task (i.e., motor vehicle driving task). The subjects were exposed to two experimental conditions: the placebo (PL) and 6. mg of bromazepam (Br 6. mg), following a randomized, double-blind design on different days. Specifically, we observe absolute power extracted from qEEG data for theta band. We expected to see a decrease in absolute theta power in the temporal and parietal areas due to the influence of bromazepam for the experimental group when compared with the placebo group. We found a main effect for the condition factor for electrodes T3, T4, P3 and P4. We also observed a main effect for the period factor for electrodes P3 and P4. We observed that the ingestion of 6. mg of bromazepam induces different patterns in theta power at the temporal and parietal sites. We concluded that 6. mg of bromazepam was an important factor in the fluctuation of the activities in the temporal and parietal areas. We then hypothesize about the specific role of this drug during the execution of a visuomotor task and within the sensorimotor integration process. © 2011 Elsevier Ireland Ltd.


Salles J.I.,National Institute of Traumatology and Orthopaedics NITO | Alves H.,Federal University of Rio de Janeiro | Costa F.,Federal University of Rio de Janeiro | Cunha-Cruz V.,Federal University of Rio de Janeiro | And 4 more authors.
Neuroscience Letters | Year: 2011

The goal of the present study was to determine the electrophysiological correlate of the threshold of perception of passive motion (TPPM) in a group of healthy individuals. We expect a different pattern of activation over the frontoparietal network produced by the conscious perception of the passive movement. Ten right-handed male volunteers, between 20 and 30 years of age, were submitted to the threshold of perception of passive motion (TPPM) task in a proprioception testing device (PTD). The device was designed to passively move the arm in internal and external rotations about the shoulder joint. Participants were instructed to press a hand-held switch every time movement of the shoulder was detected. Electromyographic (EMG) and electroencephalographic (EEG) activities were acquired during the task. Passive movement of the shoulder joint was followed by a clear and prolonged decrease in the signal magnitude of the electroencephalogram. The electrophysiological correlate of the TPPM was characterized by the establishment of a frontoparietal network, during the processing of somatosensory information. © 2011 Elsevier Ireland Ltd.


Velasques B.,Federal University of Rio de Janeiro | Velasques B.,Institute of Applied Neuroscience IAN | Velasques B.,National Institute of Traumatology and Orthopaedics NITO | Bittencourt J.,Federal University of Rio de Janeiro | And 24 more authors.
Journal of Affective Disorders | Year: 2013

Background: There is increasing evidence that neurocognitive dysfunction is associated with the different states in Bipolar Disorder. Gamma coherence is strongly related to cognitive processes and cortico-cortical communication. This paper aims at shedding light on the relationship between cortical gamma coherence within bipolar patients and a control group during a prosaccadic attention task. We hypothesized that gamma coherence oscillations act as a main neural mechanism underlying information processing which changes in bipolar patients. Method: Thirty-two (12 healthy controls and 20 bipolar patients) subjects were enrolled in this study. The subjects performed a prosaccadic attention task while their brain activity pattern was recorded using quantitative electroencephalography (20 channels). Results: We observed that the maniac group presented lower saccade latency when compared to depression and control groups. The main finding was a greater gamma coherence for control group in the right hemisphere of both frontal and motor cortices caused by the execution of a prosaccadic attention task. Limitations: The findings need to be confirmed in larger samples and in bipolar patients before start the pharmacological treatment. Conclusions: Our findings suggest a disrupted connection of the brain's entire functioning of maniac patients and represent a deregulation in cortical inhibitory mechanism. Thus, our results reinforce our hypothesis that greater gamma coherence in the right and left frontal cortices for the maniac group produces a noise during information processing and highlights that gamma coherence might be a biomarker for cognitive dysfunction during the manic state. © 2012 Elsevier B.V.

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