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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.


Sanfim A.,Federal University of Rio de Janeiro | Velasques B.,Federal University of Rio de Janeiro | Velasques B.,Institute of Applied Neuroscience INA | Velasques B.,National Institute of Traumatology and Orthopaedics NITO | And 19 more authors.
Journal of the Neurological Sciences | Year: 2012

This study aimed at analyzing the relationship between slow- and fast-alpha asymmetry within frontal cortex and the planning, execution and voluntary control of saccadic eye movements (SEM), and quantitative electroencephalography (qEEG) was recorded using a 20-channel EEG system in 12 healthy participants performing a fixed (i.e., memory-driven) and a random SEM (i.e., stimulus-driven) condition. We find main effects for SEM condition in slow- and fast-alpha asymmetry at electrodes F3-F4, which are located over premotor cortex, specifically a negative asymmetry between conditions. When analyzing electrodes F7-F8, which are located over prefrontal cortex, we found a main effect for condition in slow-alpha asymmetry, particularly a positive asymmetry between conditions. In conclusion, the present approach supports the association of slow- and fast-alpha bands with the planning and preparation of SEM, and the specific role of these sub-bands for both, the attention network and the coordination and integration of sensory information with a (oculo)-motor response. © 2011 Elsevier B.V.


Diniz C.,Federal University of Rio de Janeiro | Diniz C.,Institute of Applied Neuroscience IAN | Velasques B.,National Institute of Traumatology and Orthopaedics NITO | Velasques B.,Federal University of Rio de Janeiro | And 20 more authors.
Arquivos de Neuro-Psiquiatria | Year: 2012

The saccadic movement is an important behavioral measure used to investigate several cognitive processes, including attention and sen-sorimotor integration. The present study aimed at investigating changes in beta coherence over frontal, motor, occipital, and parietal cortices during the performance of two different conditions of a prosacadic paradigm. The conditions involved a different pattern of stimulus presentation: a fxed and random stimulus presentation. Twelve healthy volunteers (three male, mean age of 26.25 (SD=4.13) performed the task, while their brain activity pattern was recorded using quantitative electroencephalography. The results showed an interaction between factors condition and moment for the pair of electrode C3/C4. We observed a main effect for moment to CZ/C4, FZ/F3, and P3/PZ. We also found a main effect for condition to FZ/F4, P3/P4, and O1/O2. Our results demonstrated an important role of the inter-connection of the two hemispheres in visual search and movement preparation. The study demonstrates an automation of action and reduction of the focus of attention during the task. We also found that the inter-hemispheric beta coherence plays an important role in the differentiation of the two conditions, and that beta in the right frontal cortex is able to differentiate the conditions, demonstrating a greater involvement of procedural memory in fxed condition. Our results suggest a neuronal specialization in the execution of prosacadic paradigm involving motor task sequence.


Di Giorgio L.M.W.,Federal University of Rio de Janeiro | Velasques B.B.,Federal University of Rio de Janeiro | Velasques B.B.,Institute of Applied Neuroscience INA | Velasques B.B.,National Institute of Traumatology and Orthopaedics NITO | And 6 more authors.
CNS and Neurological Disorders - Drug Targets | Year: 2015

Researchers have been using the electroencephalogram to better understand the cognitive and neurobiological bases of panic disorder (PD) through the P300 component; this is an electric potential of the cerebral cortex that is generated in response to external sensorial stimuli and which involves more complex neurophysiological processes related to stimulus interpretation; it is then used to investigate possible alterations in the information processing and attention of patients suffering from this disorder. Aiming to verify the results found by experimental articles already published about P300 in PD patients and the information processing differences between PD patients and healthy controls, a systematic review of the PubMed and Institute for Scientific Information databases was conducted. The selection criterion involved those articles, written in English, which referred to an experimental research that focused on the P300 component, with a sample composed of PD (or panic attacks) patients. Seven articles were found that fit the selected criteria. Most of the articles show that these patients suffer from: impaired information processing and attention, an inability to automatically respond to new stimuli, and impaired interpretation of internal and external stimuli related to the disorder. Such impairment may be related to an unspecified dysfunction in the limbic-reticular structures, which would affect: active, focused and short-term attention, working and short-term memory, recognition and decision making. Some limitations were highlighted, such as the use of small samples and possible comorbidity with other disorders, which did not allow clearer results. This research can contribute to understand the neurobiological differences of PD patients and develop treatments based on such evidence. © 2015 Bentham Science Publishers.

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