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CAPES, CNPq O equilíbrio estático corporal é comandado por três sistemas sensoriais: o sistema vestibular, responsável pelas informações sobre a posição e os movimentos da cabeça; o sistema visual, que informa a posição espacial dos objetos em relação ao nosso corpo; e o sistema proprioceptivo, que controla a postura e a movimentação corporal. Estes três sistemas devem funcionar sempre em sintonia, caso contrário, o indivíduo apresentará problemas de equilíbrio. Dessa forma, é importante caracterizar as regiões corticais, bem como suas interações, envolvidas neste processo. Para isto, é necessário a utilização de técnicas de neuroimagem funcional, sendo a ressonância magnética funcional (RMf) uma das técnicas mais utilizadas neste campo nos dias de hoje. Entretanto, uma grande parte dos experimentos de RMf requer o uso de aparelhos eletrônicos para produzir estimulações somatosensoriais no corpo humano, onde a principal dificuldade é o seu ambiente hostil aos circuitos eletrônicos. A estimulação galvânica vestibular é um dos métodos mais utilizados para estimular o sistema vestibular. Esta consiste em fornecer uma corrente de baixa amplitude diretamente nas aferências vestibulares, a qual atua no disparo dos neurônios vestibulares primários atingindo principalmente as aferências otolíticas e as fibras dos canais semicirculares. O objetivo deste trabalho é analisar e avaliar as áreas cerebrais envolvidas com as estimulações visual e galvânica vestibular e suas interações, utilizando a técnica de RMf e um estimulador galvânico vestibular. Para tanto, como primeira etapa desta pesquisa, validou-se in vivo um estimulador galvânico vestibular. O estimulador elétrico não interferiu de forma significativa na qualidade das imagens de ressonância magnética e pode ser utilizado com segurança nos experimentos de RMf. Testes foram realizados para determinar um eletrodo suficientemente confortável para o voluntário durante a estimulação galvânica vestibular e que não causasse artefato nas imagens. Após estas etapas concluídas, 24 voluntários foram selecionados para realizarem três tarefas: uma puramente visual (um tabuleiro de xadrez piscante no centro da tela), uma puramente vestibular (pela aplicação da estimulação galvânica vestibular) e uma simultânea, com a apresentação em conjunto dos estímulos visual e vestibular. A estimulação puramente visual mostrou ativação dos córtices visual primário e associativo, enquanto que a estimulação puramente vestibular levou a ativação das principais áreas envolvidas com a função multimodal do sistema vestibular, como o córtex parietoinsular vestibular, o lóbulo parietal inferior, o giro temporal superior, o giro pré-central e o cerebelo. A estimulação simultânea dos sistemas visual e vestibular resultou na ativação dos giros frontal médio e inferior. Além do padrão de interação visual-vestibular inibitório recíproco ter sido mais evidente durante a condição simultânea, observou-se que as regiões frontais (córtex dorsomedial pré-frontal e giro frontal superior) estão envolvidas com o processamento da função executiva quando existem informações conflitantes dos sistemas visual e vestibular. The static body equilibrium is controlled by three sensory systems: the vestibular system, responsible for informing the position and the movements of the head; the visual system, which informs the spatial objects position relative to the body; and the proprioceptive system, which controls posture and body movements. These three systems must always work in harmony, otherwise the individual will present balance problems. Thus, it is important to characterize the cortical regions, as well as their interactions, involved in this process. For this it is necessary to use functional neuroimaging techniques, the functional magnetic resonance imaging (fMRI) is one of the most used techniques in this field nowadays. However, a large fMRI experiments require the use of electronic devices for producing somatosensory stimulation in the human body, where the main difficulty is its hostile environment for electronic circuits. The galvanic vestibular stimulation is one of the most used methods to stimulate the vestibular system. This stimulation consist of applying a low current amplitude directly on vestibular afferents, which acts firing the primary vestibular neurons, affecting the otolithic afferents and the semicircular canals fibers. The objective of this work is to evaluate and analyze the brain areas involved with visual and galvanic vestibular stimulations and their interactions using fMRI. Therefore, as a first step of this research, a galvanic vestibular stimulator was validated in vivo. The electrical stimulator did not interfere in a significance way on magnetic resonance images quality and could be safely used in fMRI experiments. Tests were performed to select an electrode sufficiently comfortable for the volunteer during the galvanic vestibular stimulation and that do not cause artifacts in the images. After completed these steps, 24 subjects were selected to perform three tasks: a purely visual (a flashing checkerboard in the center of the screen), a purely vestibular (with application of galvanic vestibular stimulation) and a simultaneous, presenting the visual and vestibular stimuli together. The purely visual stimulation showed activation of the primary and associative visual cortices, while the purely vestibular stimulation led to activation of areas involved in multimodal function of the vestibular system, such as the parieto-insular vestibular cortex, the inferior parietal lobe, the superior temporal gyrus, the precentral gyrus and the cerebellum. The simultaneous stimulation of visual and vestibular systems resulted in activation of the middle and inferior frontal gyri. In addition to the reciprocal inhibitory visualvestibular interaction pattern had been more evident during the simultaneous condition, it was observed that frontal regions (dorsomedial prefrontal cortex and superior frontal gyrus) are involved with the executive function processing when there is conflicting information of visual and vestibular systems.

This study examined the dissociable neural effects of anapanasati (focused-attention meditation, FAM) and metta (loving-kindness meditation, LKM) on BOLD signals during cognitive (continuous performance test, CPT) and affective (emotion-processing task, EPT, in which participants viewed affective pictures) processing. Twenty-two male Chinese expert meditators (11 FAM experts, 11 LKM experts) and 22 male Chinese novice meditators (11 FAM novices, 11 LKM novices) had their brain activity monitored by a 3T MRI scanner while performing the cognitive and affective tasks in both meditation and baseline states. We examined the interaction between state (meditation vs. baseline) and expertise (expert vs. novice) separately during LKM and FAM, using a conjunction approach to reveal common regions sensitive to the expert meditative state. Additionally, exclusive masking techniques revealed distinct interactions between state and group during LKM and FAM. Specifically, we demonstrated that the practice of FAM was associated with expertise-related behavioral improvements and neural activation differences in attention task performance. However, the effect of state LKM meditation did not carry over to attention task performance. On the other hand, both FAM and LKM practice appeared to affect the neural responses to affective pictures. For viewing sad faces, the regions activated for FAM practitioners were consistent with attention-related processing; whereas responses of LKM experts to sad pictures were more in line with differentiating emotional contagion from compassion/emotional regulation processes. Our findings provide the first report of distinct neural activity associated with forms of meditation during sustained attention and emotion processing., published_or_final_version

Feeling the beat and meter is fundamental to the experience of music. However, how these periodicities are represented in the brain remains largely unknown. Here, we test whether this function emerges from the entrainment of neurons resonating to the beat and meter. We recorded the electroencephalogram while participants listened to a musical beat and imagined a binary or a ternary meter on this beat (i.e., a march or a waltz). We found that the beat elicits a sustained periodic EEG response tuned to the beat frequency. Most importantly, we found that meter imagery elicits an additional frequency tuned to the corresponding metric interpretation of this beat. These results provide compelling evidence that neural entrainment to beat and meter can be captured directly in the electroencephalogram. More generally, our results suggest that music constitutes a unique context to explore entrainment phenomena in dynamic cognitive processing at the level of neural networks.

Neurophysiological studies in monkeys show that activity of neurons in primary cortex (M1), pre-motor cortex (PMC), and cerebellum varies systematically with the direction of reaching movements. These neurons exhibit preferred direction tuning, where the level of neural activity is highest when movements are made in the preferred direction (PD), and gets progressively lower as movements are made at increasing degrees of offset from the PD. Using a functional magnetic resonance imaging adaptation (fMRI-A) paradigm, we show that PD coding does exist in regions of the human motor system that are homologous to those observed in non-human primates. Consistent with predictions of the PD model, we show adaptation (i.e., a lower level) of the blood oxygen level dependent (BOLD) time-course signal in M1, PMC, SMA, and cerebellum when consecutive wrist movements were made in the same direction (0° offset) relative to movements offset by 90° or 180°. The BOLD signal in dorsolateral prefrontal cortex adapted equally in all movement offset conditions, mitigating against the possibility that the present results are the consequence of differential task complexity or attention to action in each movement offset condition. Copyright: © 2010 Cowper-Smith et al., published_or_final_version

The neural correlates of lying about affective information were studied using a functional magnetic resonance imaging (fMRI) methodology. Specifically, 13 healthy right-handed Chinese men were instructed to lie about the valence, positive or negative, of pictures selected from the International Affective Picture System (IAPS) while their brain activity was scanned by a 3T Philip Achieva scanner. The key finding is that the neural activity associated with deception is valence-related. Comparing to telling the truth, deception about the valence of the affectively positive pictures was associated with activity in the inferior frontal, cingulate, inferior parietal, precuneus, and middle temporal regions. Lying about the valence of the affectively negative pictures, on the other hand, was associated with activity in the orbital and medial frontal regions. While a clear valence-related effect on deception was observed, common neural regions were also recruited for the process of deception about the valence of the affective pictures. These regions included the lateral prefrontal and inferior parietal regions. Activity in these regions has been widely reported in fMRI studies on deception using affectively-neutral stimuli. The findings of this study reveal the effect of valence on the neural activity associated with deception. Furthermore, the data also help to illustrate the complexity of the neural mechanisms underlying deception. © 2010 Lee et al., published_or_final_version

The Iowa Gambling Task (IGT) is a sensitive test for the detection of decision-making impairments in several neurological and psychiatric populations. Very few studies have employed the IGT in functional magnetic resonance imaging (fMRI) investigations, in part, because the task is cognitively complex. Here we report a method for exploring brain activity using fMRI during performance of the IGT. Decision-making during the IGT was associated with activity in several brain regions in a group of healthy individuals. The activated regions were consistent with the neural circuitry hypothesized to underlie somatic marker activation and decision-making. Specifically, a neural circuitry involving the dorsolateral prefrontal cortex (for working memory), the insula and posterior cingulate cortex (for representations of emotional states), the mesial orbitofrontal and ventromedial prefrontal cortex (for coupling the two previous processes), the ventral striatum and anterior cingulate/SMA (supplementary motor area) for implementing behavioral decisions was engaged. These results have implications for using the IGT to study abnormal mechanisms of decision making in a variety of clinical populations. © 2009 Wiley-Liss, Inc., link_to_OA_fulltext

Scientists have for centuries tried to localize and define artistic talent. Modern diagnostic techniques that enable visualization and measurement of brain morphology and function are positron emission tomography (PET), magnetic resonance imaging (MRI), functional transcranial Doppler (fTOD) and some biochemical methods. In the majority of people, the left hemisphere is dominant, but the right hemisphere is considered to be creative, visual, imaginative and intuitive. Right hemisphere is associated with musical skills and good three-dimensional orientation. It is also associated with good coordination and athletic skills. Creative people have less marked hemispheric dominance. Using the functional (fMRI) technique, the activation of visual cortex while watching different kinds of compositions was visible; the specific pattern of cortical activation was identified for looking at the landscapes, portraits, abstract compositions or different combination of colors. For music perception, the interplay of activity on both sides of the brain is necessary. In the right side, the centers for perceiving pitch, certain aspects of melody, harmony, timbre and rhythm are placed, and in the left side the processes of rapid changes in frequency and intensity, both in music and words are taking place. Adaptation of the brain, i.e. brain plasticity can arise upon listening or performing music. It is possible to use music, painting and dancing as an aid in the treatment of somatic, neurologic or psychiatric disorders., Stoljećima znanstvenici pokušavaju lokalizirati i definirati umjetnički talent. Pozitronska emisijska tomografja (PET), funkcionalna magnetska rezonanca (fMRI) i funkcionalna dopler sonografija (fTCD) su moderne dijagnostičke metode koje omogućavaju vizualizaciju moždane morfologije i funkcije. U većine osoba dominantna je lijeva hemisfera, dok se za desnu hemisferu smatra da je kreativna, vizualna, intuitivna i zadužena za maštu, dobru trodimenzionalnu orijentaciju, koordinaciju, sportske i glazbene vještine. U kreativnih osoba dominantnost hemisfera je manje izražena. fMRI omogućuje registriranje aktivacije vidne kore za vrijeme promatranja različitih kompozicija poput pejzaža. portreta, apstraktnih kompozicija i kombinacija boja. Za percepciju glazbe potrebna je suradnja obiju hemisfera. U desnoj hemisferi se registrira ton, melodija, ritam i harmonija, dok su centri za brzu promjenu frekvencija u lijevoj hemisferi. Glazba potiče procese neuroplastičnosti. Glazbu, slikarstvo i ples moguće je koristiti kao pomoćno sredstvo u liječenju somatskih, neuroloških i psihijatrijskih poremećaja.

Scientists have for centuries tried to localize and define artistic talent. Modern diagnostic techniques that enable visualization and measurement ofbrain morphology and function are positron emission tomography (PET), magnetic resonance imaging (MRI), functional transcranial Doppler (f'I'OD) and some biochemical methods. In the majority ofpeople, the left hemisphere is dominant, but the right hemisphere is considered to be creative, visual, imaginative and intuitive. Right hemisphere is associated with musical skills and good three-dimensional orientation. It is also associated with good coordination and athletic skills. Creative people have less marked hemispheric dominance. Using the functional (fJ\1RI) technique, the activation ofvisual cortex while watching different kinds of compositions was visible ; the specific pattern of cortical activation was identified for looking at the landscapes, portraits, abstract compositions or different combination of colors. For music perception, the interplay of activity on both sides of the brain is necessary. In the right side, the centers for perceiving pitch, certain aspects of melody, harmony, timbre and rhythm are placed, and in the left side the processes of rapid changes in frequency and intensity, both in music and words are taking place. Adaptation of the brain, i.e. brain plasticity can arise upon listening or performing music. It is possible to use music, painting and dancing as an aid in the treatment of somatic, neurologic or psychiatric disorders.

Mirror illusion means that standing in front of a mirror placed in sagittal plane, with the head tilted on one side and one arm stretched forward, one side of the body is reflected as if it were the other side by mirror visual feedback. The aim of this study was to monitor blood flow changes in middle cerebral artery (MCA) by use of transcranial Doppler (TCD) in individuals during motor tasks and tasks using mirror visual feedback. Eight young healthy volunteers (four male and four female) were included in the study. TCD recording in MCA was done during each task consisting of various motor and visuomotor activities using mirror illusion. Both MCA mean blow flow velocity (MBFV) was measured while the subjects were seated in a comfortable chair. The MCA MBFV recordings are presented as baseline values. During the illusion of motor hand activation, when the subject was making right hand flexions and watching its reflection in the mirror, with the left hand immobile, an increase was observed the contralateral MCA MBFV (task 3, +4.5% baseline value; P=0.017). Furthermore, when the subject made left hand flexions while watching the reflection of the immobile right hand in the mirror, there was an increase in the right MCA MBFV (+5.6% baseline value; P=0.044), which was more pronounced than during the illusion of motor hand activation (task 3) and less than during direct vision of hand flexion (task 2, +6.3% baseline value; P=0.005). Our data showed that visual illusion of action, as well as direct action observation could increase the MCA MBFV, which brings forward the possible usage of mirror illusion as a tool in motor neurorehabilitation., Iluzija zrcala očituje se time da stojeći ispred zrcala položenog u sagitalnu ravninu, gledajući na jednu stranu gdje nam je ispružena i jedna ruka, vidimo odraz kao da se radi o drugoj strani tijela zahvaljujući vizualnom zrcalnom povratu. Cilj ove studije bio je pokazati promjene brzine protoka krvi u srednjoj moždanoj arteriji (ACM) pomoću transkranijskog doplera (TCD) tijekom različitih motoričkih zadataka i zadataka s upotrebom zrcala. Osmoro mladih, zdravih dobrovoljaca (četiri muškarca i četiri žene) sudjelovalo je u ovom istraživanju. Pomoću TCD bilježile su se vrijednosti brzine protoka te promjene brzine u obje ACM, dok su ispitanici obavljali zadatke sjedeći u stolici. Snimljene vrijednosti prikazane su kao srednje vrijednosti. Tijekom iluzije o motoričkoj aktivnosti lijeve ruke pri pomicanju samo desne te gledanju njenog odraza u zrcalu zabilježeno je povećanje srednje brzine strujanja krvi u kontralateralnoj ACM (3. zadatak, porast za 4,5% u odnosu na bazalnu vrijednost, P=0,017). Nadalje, pri pomicanju lijeve ruke dok ispitanik promatra odraz nepomične desne također je došlo do porasta brzine u desnoj ACM (porast za 5,6% u odnosu na bazalnu vrijednost, P=0,044), koji je bio veći nego pri samoj iluziji motoričke aktivnosti (3. zadatak), a manji od porasta tijekom gledanja izravno u ruku koja se pomiče (2. zadatak, porast za 6,3%, P=0,005). Rezultati ovoga istraživanja pokazali su kako vizualna iluzija kretanja, kao i izravno promatranje aktivnosti povećava brzinu protoka krvi u ACM, što upućuje na mogućnost primjene iluzije zrcala u motoričkoj neurorehabilitaciji.

For centuries, the relation of the human mind to the brain has been debated. How can seemingly immaterial entities such as thoughts and memories arise from biological material? Advances in neuroscience have now led to wide acceptance in science and medicine that all aspects of our mental life—our

Mirror illusion means that standing in front of a mirror placed in sagittal plane, with the head tilted on one side and one arm stretched forward, one side of the body is reflected as if it were the other side by mirror visual feedback. The aim of this study was to monitor blood flow changes in middle cerebral artery (MCA) by use of transcranial Doppler (TCD) in individuals during motor tasks and tasks using mirror visual feedback. Eight young healthy volunteers (four male and four female) were included in the study. TCD recording in MCA was done during each task consisting of various motor and visuomotor activities using mirror illusion. Both MCA mean blow flow velocity (MBFV) was measured while the subjects were seated in a comfortable chair. The MCA MBFV recordings are presented as baseline values. During the illusion of motor hand activation, when the subject was making right hand flexions and watching its reflection in the mirror, with the left hand immobile, an increase was observed the contralateral MCA MBFV (task 3, +4.5% baseline value ; P=0.017). Furthermore, when the subject made left hand flexions while watching the reflection of the immobile right hand in the mirror, there was an increase in the right MCA MBFV (+5.6% baseline value ; P=0.044), which was more pronounced than during the illusion of motor hand activation (task 3) and less than during direct vision of hand flexion (task 2, +6.3% baseline value ; P=0.005). Our data showed that visual illusion of action, as well as direct action observation could increase the MCA MBFV, which brings forward the possible usage of mirror illusion as a tool in motor neurorehabilitation.