Differences between hemispheres and in saccade latency regarding volleyball athletes and non-athletes during saccadic eye movements: an analysis using EEG.

BACKGROUND: The saccadic eye movement is responsible for providing focus to a visual object of interest to the retina. In sports like volleyball, identifying relevant targets quickly is essential to a masterful performance. The training improves cortical regions underlying saccadic action, enabling more automated processing in athletes. OBJECTIVE: We investigated changes in the latency during the saccadic eye movement and the absolute theta power on the frontal and prefrontal cortices during the execution of the saccadic eye movement task in volleyball athletes and non-athletes. We hypothesized that the saccade latency and theta power would be lower due to training and perceptual-cognitive enhancement in volleyball players. METHODS: We recruited 30 healthy volunteers: 15 volleyball athletes (11 men and 4 women; mean age: 15.08 ± 1.06 years) and 15 non-athletes (5 men and 10 women; mean age: 18.00 ± 1.46 years). All tasks were performed simultaneously with electroencephalography signal recording. RESULTS: The latency of the saccadic eye movement presented a significant difference between the groups; a shorter time was observed among the athletes, associated with the players' superiority in terms of attention level. During the experiment, the athletes observed a decrease in absolute theta power compared to non-athletes on the electrodes of each frontal and prefrontal area. CONCLUSION: In the present study, we observed the behavior of reaction time and absolute theta power in athletes and non-athletes during a saccadic movement task. Our findings corroborate the premise of cognitive improvement, mainly due to the reduction of saccadic latency and lower beta power, validating the neural efficiency hypothesis.

ANTECEDENTES: O movimento ocular sacádico é responsável por dar foco a um objeto visual de interesse para a retina. Em esportes como o vôlei, identificar alvos relevantes o mais rápido possível é essencial para se ter um desempenho magistral. O treinamento melhora as regiões corticais subjacentes à ação sacádica, e permite um processamento mais automatizado em atletas. OBJETIVO: Investigamos as mudanças na latência durante o movimento ocular sacádico e a potência teta absoluta nos córtices frontal e pré-frontal durante a execução da tarefa de movimento ocular sacádico em atletas e não atletas de voleibol. Nossa hipótese é a de que a latência sacádica e a potência teta seriam menores em atletas devido ao treinamento e ao aprimoramento perceptivo-cognitivo em jogadores de voleibol. MéTODOS: Ao todo, 30 voluntários saudáveis foram recrutados para este estudo: 15 atletas de voleibol (11 homens e 4 mulheres; idade média: 15,08 ± 1,06 anos) e 15 não atletas (5 homens e 10 mulheres; idade média: 18,00 ± 1,46 anos). Todas as tarefas foram realizadas simultaneamente com o registro do sinal eletroencefalográfico. RESULTADOS: O resultado da latência do movimento ocular sacádico apresentou diferença significativa entre os grupos, sendo observado menor tempo entre os atletas, associado à superioridade dos jogadores em termos de nível de atenção. Durante o experimento, nos eletrodos de cada área frontal e pré-frontal, observou-se uma diminuição na potência teta absoluta nos atletas em comparação aos não atletas. CONCLUSãO: Neste estudo, observou-se o comportamento do tempo de reação e da potência teta absoluta em atletas e não atletas durante uma tarefa de movimento sacádico. Nossos achados corroboram a premissa de melhora cognitiva, principalmente pela redução da latência sacádica e menor potência beta, o que valida a hipótese de eficiência neural.

Differences between hemispheres and in saccade latency regarding volleyball athletes and non-athletes during saccadic eye movements: an analysis using EEG / Diferenças inter-hemisféricas e na latência sacádica entre atletas de voleibol e não atletas durante movimentos oculares sacádicos: uma análise usando EEG

Abstract Background The saccadic eye movement is responsible for providing focus to a visual object of interest to the retina. In sports like volleyball, identifying relevant targets quickly is essential to a masterful performance. The training improves cortical regions underlying saccadic action, enabling more automated processing in athletes. Objective We investigated changes in the latency during the saccadic eye movement and the absolute theta power on the frontal and prefrontal cortices during the execution of the saccadic eye movement task in volleyball athletes and non-athletes. We hypothesized that the saccade latency and theta power would be lower due to training and perceptual-cognitive enhancement in volleyball players. Methods We recruited 30 healthy volunteers: 15 volleyball athletes (11 men and 4 women; mean age: 15.08 ± 1.06 years) and 15 non-athletes (5 men and 10 women; mean age: 18.00 ± 1.46 years). All tasks were performed simultaneously with electroencephalography signal recording. Results The latency of the saccadic eye movement presented a significant difference between the groups; a shorter time was observed among the athletes, associated with the players' superiority in terms of attention level. During the experiment, the athletes observed a decrease in absolute theta power compared to non-athletes on the electrodes of each frontal and prefrontal area. Conclusion In the present study, we observed the behavior of reaction time and absolute theta power in athletes and non-athletes during a saccadic movement task. Our findings corroborate the premise of cognitive improvement, mainly due to the reduction of saccadic latency and lower beta power, validating the neural efficiency hypothesis.

Resumo Antecedentes O movimento ocular sacádico é responsável por dar foco a um objeto visual de interesse para a retina. Em esportes como o vôlei, identificar alvos relevantes o mais rápido possível é essencial para se ter um desempenho magistral. O treinamento melhora as regiões corticais subjacentes à ação sacádica, e permite um processamento mais automatizado em atletas. Objetivo Investigamos as mudanças na latência durante o movimento ocular sacádico e a potência teta absoluta nos córtices frontal e pré-frontal durante a execução da tarefa de movimento ocular sacádico em atletas e não atletas de voleibol. Nossa hipótese é a de que a latência sacádica e a potência teta seriam menores em atletas devido ao treinamento e ao aprimoramento perceptivo-cognitivo em jogadores de voleibol. Métodos Ao todo, 30 voluntários saudáveis foram recrutados para este estudo: 15 atletas de voleibol (11 homens e 4 mulheres; idade média: 15,08 ± 1,06 anos) e 15 não atletas (5 homens e 10 mulheres; idade média: 18,00 ± 1,46 anos). Todas as tarefas foram realizadas simultaneamente com o registro do sinal eletroencefalográfico. Resultados O resultado da latência do movimento ocular sacádico apresentou diferença significativa entre os grupos, sendo observado menor tempo entre os atletas, associado à superioridade dos jogadores em termos de nível de atenção. Durante o experimento, nos eletrodos de cada área frontal e pré-frontal, observou-se uma diminuição na potência teta absoluta nos atletas em comparação aos não atletas. Conclusão Neste estudo, observou-se o comportamento do tempo de reação e da potência teta absoluta em atletas e não atletas durante uma tarefa de movimento sacádico. Nossos achados corroboram a premissa de melhora cognitiva, principalmente pela redução da latência sacádica e menor potência beta, o que valida a hipótese de eficiência neural.

Open monitoring meditation alters the EEG gamma coherence in experts meditators: The expert practice exhibit greater right intra-hemispheric functional coupling.

AIM: This study investigated the differences in frontoparietal EEG gamma coherence between expert meditators (EM) and naïve meditators (NM). MATERIAL AND METHODS: This is a cross-sectional study with a sample of twenty-one healthy adults divided under two groups (experts meditators vs. naive-meditators), with analyzing the intra-hemispheric coherence of frontoparietal gamma oscillations by electroencephalography during the study steps: EEG resting-state 1, during the open presence meditation practice, and EEG resting-state 2. RESULTS: The findings demonstrated greater frontoparietal EEG coherence in gamma for experts meditators in the Fp1-P3, F4-P4, F8-P4 electrode pairs during rest 1 and rest 2 (p ≤ 0.0083). In addition, we evidenced differences in the frontoparietal EEG coherence for expert meditators in F4-P4, F8-P4 during the meditation (p ≤ 0.0083). CONCLUSION: Our results can support evidence that the connectivity of the right frontoparietal network acts as a biomarker of the enhanced Open monitoring meditation training.

Bromazepam increases the error of the time interval judgments and modulates the EEG alpha asymmetry during time estimation.

AIM: This study investigated the bromazepam effects in male subjects during the time estimation performance and EEG alpha asymmetry in electrodes associated with the frontal and motor cortex. MATERIAL AND METHODS: This is a double-blind, crossover study with a sample of 32 healthy adults under control (placebo) vs. experimental (bromazepam) during visual time-estimation task in combination with electroencephalographic analysis. RESULTS: The results demonstrated that the bromazepam increased the relative error in the 4 s, 7 s, and 9 s intervals (p = 0.001). In addition, oral bromazepam modulated the EEG alpha asymmetry in cortical areas during the time judgment (p ≤ 0.025). CONCLUSION: The bromazepam decreases the precision of time estimation judgments and modulates the EEG alpha asymmetry, with greater left hemispheric dominance during time perception. Our findings suggest that bromazepam influences internal clock synchronization via the modulation of GABAergic receptors, strongly relating to attention, conscious perception, and behavioral performance.

Non-immersive 3D virtual stimulus alter the time production task performance and increase the EEG theta power in dorsolateral prefrontal cortex.

AIM: The study investigated the cortical activity changes and time production task performance induced by changes in motion speed of a non-immersive 3D virtual stimulus. MATERIAL AND METHODS: Twenty-one individuals were participated in the crossover study with the visual-time reproduction task under three-speed conditions: original, slow and fast virtual stimulus. In addition, the electroencephalographic analysis of the theta band power in the dorsolateral prefrontal cortex was done simultaneously with time production task execution. RESULTS: The results demonstrated that in the slow speed condition, there is an increase in the error in the time production task after virtual reality (p < 0.05). There is also increased EEG theta power in the right dorsolateral prefrontal cortex in all speed conditions (p < 0.05). CONCLUSIONS: We propose that the modulations of speed of virtual stimulus may underlie the accumulation of temporal pulses, which could be responsible for changes in the performance of the production task of the time intervals and a substantial increase in right dorsolateral prefrontal cortex activity related to attention and memory, acting in cognitive domains of supraseconds.

Development of a Classical Conditioning Task for Humans Examining Phasic Heart Rate Responses to Signaled Appetitive Stimuli: A Pilot Study.

Cardiac responses to appetitive stimuli have been studied as indices of motivational states and attentional processes, the former being associated with cardiac acceleration and latter deceleration. Very few studies have examined heart rate changes in appetitive classical conditioning in humans. The current study describes the development and pilot testing of a classical conditioning task to assess cardiac responses to appetitive stimuli and cues that reliably precede them. Data from 18 adults were examined. They were shown initially neutral visual stimuli (putative CS) on a computer screen followed by pictures of high-caloric food (US). Phasic cardiac deceleration to food images was observed, consistent with an orienting response to motivationally significant stimuli. Similar responses were observed to non-appetitive stimuli when they were preceded by the cue associated with the food images, suggesting that attentional processes were engaged by conditioned stimuli. These autonomic changes provide significant information about classical conditioning effects in humans.

Repetitive transcranial magnetic stimulation changes cognitive/motor tasks performance: An absolute alpha and beta power study.

The voluntary movement demands integration between cognitive and motor functions. During the initial stages of motor learning until mastery of a new motor task, and during a demanding task that is not automatic, cognitive and motor functions can be perceived as independent from each other. Areas used for actually performing motor tasks are essentially the same used by Motor Imagery (MI). The main objective of this study was to investigate inhibition effects on cognitive functions of motor skills induced by low-frequency (1 Hz) Repetitive Transcranial Magnetic Stimulation (rTMS) at the sensory-motor integration site (Cz). In particular, the goal was to examine absolute alpha and beta power changes on frontal regions during Execution, Action observation, and Motor Imagery of finger movement tasks. Eleven healthy, right-handed volunteers of both sexes (5 males, 6 females; mean age 28 ± 5 years), with no history of psychiatric or neurological disorders, participated in the experiment. The execution task consisted of the subject flexing and extending the index finger. The action observation task involved watching a video of the same movement. The motor imagery task was imagining the flexion and extension of the index finger movement. After performing the tasks randomly, subjects were submitted to 15 min of low-frequency rTMS and performed the tasks again. All tasks were executed simultaneously with EEG signals recording. Our results demonstrated a significant interaction between rTMS and the three tasks in almost all analyzed regions showing that rTMS can affect the frontal region regarding Execution, Action observation, and Motor Imagery tasks.

Methylphenidate decreases the EEG mu power in the right primary motor cortex in healthy adults during motor imagery and execution.

This study investigated the effects of dopaminergic drugs on the EEG mu power during motor imagery, action observation, and execution. This is a double-blind, crossover study with a sample of 15 healthy adults under placebo vs. methylphenidate vs. risperidone conditions during motor imagery, action observation, and execution tasks. The participants had drug dosage adjustment based on body weight/dose (mg/kg). We also analyzed the mu band power by electroencephalography during the study steps. The main result is the interaction between the condition and task factors for the C3 and C4 electrodes, with decreasing EEG mu power in the methylphenidate when compared to risperidone (p ≤ 0.0083). Our results can indicate that the methylphenidate decreases the neurophysiological activity in the central cortical regions during the perceptual experience of tasks with or without body movement.

Event-related potential (P300): the effects of levetiracetam in cognitive performance.

BACKGROUND: The current study is a reanalysis in the time domain of EEG data collection in healthy adults during an oddball paradigm using levetiracetam (LEV) vs. placebo acute administration. Specifically, the event-related potential (ERP) technique provides a tool for exploring the EEG responses to a specific event/stimulus. One of the ERP components widely studied is the P300 component, which is associated with the last stage of information processing and a general measurement of "cognitive efficiency." METHODS: The sample was composed of thirteen healthy right-handed individuals randomized to participate under two conditions: LEV and placebo. Electrophysiological measures were collected before and after drug intake. We explored the oddball paradigm, which is commonly used with healthy individuals to investigate the stages of information processing. RESULTS: The electrophysiological results showed a main effect of condition on P300 amplitude for the frontal (F3, Fz, F4), central (C3, Cz, C4), and parietal electrodes (P3, Pz, P4). The post hoc comparisons (Scheffé's test) demonstrated the significant differences between electrodes. Regarding P300 latency, all regions represented a main effect of condition. A P300 latency reduction was observed during LEV condition compared with placebo. CONCLUSION: Our study observed the ERP component-P300-through the variation of its amplitude and latency to evaluate a supposed higher CNS efficiency when participants were under the LEV effect. Our findings sustain this premise, mainly due to reducing in P300 latency for the LEV condition, supporting the neural efficiency hypothesis.

Unskilled shooters improve both accuracy and grouping shot having as reference skilled shooters cortical area: An EEG and tDCS study.

Transcranial direct current stimulation (tDCS) has been used as a non-invasive method for enhanced motor and cognitive abilities. However, no previous study has investigated if the tDCS application in unskilled shooters on cortical sites, selected based on the cortical activity of skilled shooters, improves the accuracy and shot grouping. Sixty participants were selected, which included 10 skilled shooters and 50 unskilled shooters. After we identified the right dorsolateral prefrontal cortex (DLPFC) as the area with the highest activity in skilled shooters, we applied anodal tDCS over the right DLPFC in the unskilled shooters under two conditions: sham-tDCS (placebo) and real-tDCS (anodal tDCS). We also analyzed electroencephalography. Our results indicated that anodal tDCS application enhanced the shot accuracy (p = 0.001). Furthermore, the beta power in the EEG recording was higher in the left DLPFC, left and right parietal cortex (p = 0,001) after applying anodal tDCS, while the low-gamma power was higher in the right DLPFC in sham-tDCS (p = 0.001) and right parietal cortex after anodal-tDCS (p = 0.001). Our findings indicate that anodal tDCS can improve accuracy and shot grouping when applied over the unskilled shooters' right DLPFC. Furthermore, beta and low-gamma bands are influenced by anodal tDCS over the right DLPFC, which may be predictive of skill improvement.

Dopaminergic drugs alter beta coherence during motor imagery and motor execution in healthy adults.

BACKGROUND: Motor Imagery (MI) represents the cognitive component of the movement and recruits dopaminergic systems. OBJECTIVE: To investigate the role of dopaminergic system through the action of methylphenidate and risperidone over beta coherence during execution, action observation and motor imagery. METHODS: Electroencephalography (EEG) data were recorded before and after the substance intake. For statistical analysis, a three-way ANOVA was used to identify changes in beta coherence induced by the group, task and the moment variables. Statistical significance was set at p≤0.007. RESULTS: We found a main effect for group for C3/CZ, and a main effect for task for CZ/C4 pairs of electrodes. Furthermore, significant differences were found in the post-drug administration between groups for C3/CZ pair of electrodes, and between task for C4/CZ pair of electrodes. CONCLUSION: The administration of methylphenidate and risperidone was able to produce electrocortical changes of the cortical central regions, even when featuring antagonistic effects on the dopaminergic pathways. Moreover, the execution task allowed beta-band modulation increase.

Dopaminergic drugs alter beta coherence during motor imagery and motor execution in healthy adults / Drogas dopaminérgicas alteram a coerência beta durante a imagética motora e a execução motora em adultos saudáveis

Abstract Background: Motor Imagery (MI) represents the cognitive component of the movement and recruits dopaminergic systems. Objective: To investigate the role of dopaminergic system through the action of methylphenidate and risperidone over beta coherence during execution, action observation and motor imagery. Methods: Electroencephalography (EEG) data were recorded before and after the substance intake. For statistical analysis, a three-way ANOVA was used to identify changes in beta coherence induced by the group, task and the moment variables. Statistical significance was set at p≤0.007. Results: We found a main effect for group for C3/CZ, and a main effect for task for CZ/C4 pairs of electrodes. Furthermore, significant differences were found in the post-drug administration between groups for C3/CZ pair of electrodes, and between task for C4/CZ pair of electrodes. Conclusion: The administration of methylphenidate and risperidone was able to produce electrocortical changes of the cortical central regions, even when featuring antagonistic effects on the dopaminergic pathways. Moreover, the execution task allowed beta-band modulation increase.

Resumo Introdução: A imagética motora (IM) representa o componente cognitivo do movimento e recruta os sistemas dopaminérgicos. Objetivo: Investigar o papel do sistema dopaminérgico por meio da ação do metilfenidato e da risperidona sobre a coerência em beta durante a execução, observação de ação e imagética motora. Métodos: Os dados de eletroencefalografia (EEG) foram registrados antes e depois da ingestão das substâncias. Para a análise estatística, uma ANOVA de três vias foi utilizada para identificar mudanças na coerência beta induzidas pelas variáveis grupo, tarefa e momento. A significância estatística foi estabelecida em p≤0,007. Resultados: Encontramos um efeito principal para o grupo C3/CZ e um efeito principal para a tarefa nos pares de eletrodos CZ/C4. Além disso, diferenças significativas foram encontradas após a administração da droga entre os grupos para o par de eletrodos C3/CZ e entre tarefa para o par de eletrodos C4/CZ. Conclusão: A administração de metilfenidato e risperidona foi capaz de produzir alterações eletrocorticais das regiões somatomotoras, mesmo apresentando efeitos antagônicos nas vias dopaminérgicas. Além disso, a tarefa de execução provocou maior modulação da banda beta.

Time estimation exposure modifies cognitive aspects and cortical activity of attention deficit hyperactivity disorder adults.

AIM: This study investigated whether time-estimation task exposure influences the severity of Attention Deficit Hyperactivity Disorder (ADHD), as well as theta band activity in the dorsolateral prefrontal cortex and ventrolateral prefrontal cortex. MATERIAL AND METHODS: Twenty-two patients with ADHD participated in a crossover experiment with a visual time-estimation task under control conditions (without exposure to time estimation tasks) and experimental (thirty days exposure to time-estimation tasks) in association with electroencephalographic analysis of theta band. RESULTS: ADHD patients with thirty days of time-estimation task exposure presented a worse performance of the time-estimation task, as revealed by the measurements of the absolute error and relative error (p ≤ 0.05). However, our findings show the improvement of self-reported symptoms of attention, impulsivity, and emotional control in patients after the time-estimation task exposure (p = 0.0001). Moreover, the theta band oscillations in the right dorsolateral prefrontal cortex and in the ventrolateral prefrontal increased with thirty days of time-estimation task exposure (p ≤ 0.05). CONCLUSION: We propose that the decrease in EEG theta power may indicate an efficient accumulation of temporal pulses, which could be responsible for the improvement in the patient cognitive aspects as demonstrated by the current study. Time-estimation task improves ADHD cognitive symptoms, with a substantial increase in cortical areas activity related to attention and memory, suggesting its use as a tool for cognitive timing function management and non-invasive therapeutic aid in ADHD.

The role of low-frequency rTMS in the superior parietal cortex during time estimation.

The low-frequency repetitive transcranial magnetic stimulation (rTMS) application has been associated with changes in cognitive processes embedded during time perception tasks. Although several studies have investigated the influence of neuromodulation on time perception, the effect of the 1-Hz rTMS application on the superior parietal cortex is not clearly understood. This study analyzes the effect of the low-frequency rTMS on time estimation when applied in the parietal medial longitudinal fissure. For the proposed study, 20 subjects were randomly selected for a crossover study with two conditions (sham and 1 Hz). Our findings reveal that participant underestimate 1-s time interval and overestimate 4-s and 9-s time intervals after 1-Hz rTMS (p ≤ 0.05). We conclude that the 1-Hz rTMS in the parietal medial longitudinal fissure delays short interval and speed up long time intervals. This could be due to the effect of parietal inhibition on the attentional level and working memory functions during time estimation.

Análise do tempo de reação simples e do paradigma oddball em estudantes antes e após participação em atividades acadêmicas: uma análise da neurociência aplicada a educação / Analysis of simple reaction time and the oddball paradigm in students before and after participation in academic activities: an analysis of neuroscience applied to education

Introdução: O tempo de reação é uma medida que indica o tempo que uma pessoa leva para iniciar um movimento. Há situações em que o tempo de reação encontra-se alterado, comprometendo o processamento da informação, com diminuição na detecção, transmissão e processamento dos estí­mulos. Objetivo: Investigar o tempo de reação visual em acadêmicos antes e após atividades avaliativas, nas diversas disciplinas. Metodologia: 50 acadêmicos foram analisados antes e após atividades avaliativas por meio do tempo de reação simples e paradigma oddball. Resultados: Com relação ao tempo de reação simples, o tempo de reação visual antes das atividades avaliativas foi menor que após, em contradição com o paradigma oddball. Verificou-se que a média geral do tempo de reação simples para prova prática foi maior comparado às demais, já no paradigma oddball verificou-se que a média geral para apresentação de seminário foi maior, comparado às demais. Conclusão: Diferenças significativas no tempo de reação simples e tempo de reação segundo paradigma oddball foram encontrados entre acadêmicos antes e após atividades avaliativas. Porém no tempo de reação simples foram encontrados valores menores antes das atividades, quando comparados com após, e o contrário foi encontrado no paradigma oddball. (AU)

Introduction: Reaction time is a measure of how long a person takes to start a movement. There are situations in which the reaction time is altered, compromising the information processing, with a decrease in the detection, transmission and processing of the stimuli. Objective: To investigate the time of visual reaction in academics before and after evaluative activities in different disciplines. Methodology: 50 academics were analyzed before and after evaluative activities through simple reaction time and oddball paradigm. Results: Relative to the time of simple reaction, the visual reaction time before the evaluative activities was smaller than after, in contradiction with the oddball paradigm. It was verified that the general mean of the simple reaction time for practical test was higher compared to the others, already in the oddball paradigm it was verified that the general average for seminar presentation was higher, compared to the others. Conclusion: Significant differences in the time of simple reaction and reaction time according to the oddball paradigm were found among academics before and after evaluative activities. However, in the simple reaction time smaller values were found before the activities, when compared with after, and the opposite was found in the oddball paradigm. (AU)

EEG coherence as a diagnostic tool to measure the initial stages of Parkinson Disease.

Although Parkinson Disease was described a long time ago by James Parkinson and several biomarkers were used to predict the symptoms of PD, there is no accepted tool to distinguish the initial stages of this pathology. The present hypothesis discusses the Coherence Function, an Electroencephalography measure which could be used as a simple, and low-cost tool to describe the onset of cardinal signals of PD. Our hypothesis is based on three factors: beta frequency related to movement, motor action over particular cortical regions, and cortical coupling between cortical areas involved in the execution of voluntary movement. We believe that these factors support our hypothesis pointing out coherence function as an interesting measure to detect initial stages of PD.

Methylphenidate modifies activity in the prefrontal and parietal cortex accelerating the time judgment.

Methylphenidate produces its effects via actions on cortical areas involved with attention and working memory, which have a direct role in time estimation judgment tasks. In particular, the prefrontal and parietal cortex has been the target of several studies to understand the effect of methylphenidate on executive functions and time interval perception. However, it has not yet been studied whether acute administration of methylphenidate influences performance in time estimation task and the changes in alpha band absolute power in the prefrontal and parietal cortex. The current study investigates the influence of the acute use of methylphenidate in both performance and judgment in the time estimation interpretation through the alpha band absolute power activity in the prefrontal and parietal cortex. This is a double-blind, crossover study with a sample of 32 subjects under control (placebo) and experimental (methylphenidate) conditions with absolute alpha band power analysis during a time estimation task. We observed that methylphenidate does not influence task performance (p > 0.05), but it increases the time interval underestimation by over 7 s (p < 0.001) with a concomitant decrease in absolute alpha band power in the ventrolateral prefrontal cortex and dorsolateral prefrontal cortex and parietal cortex (p < 0.001). Acute use of methylphenidate increases the time interval underestimation, consistent with reduced accuracy of the internal clock mechanisms. Furthermore, acute use of methylphenidate influences the absolute alpha band power over the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, and parietal cortex.

Neurophysiological changes after cognitive-motor tasks in Parkinson's disease patients with deep brain stimulation.

Chronic deep brain stimulation (CDBS) is a surgical treatment that reduces the cardinal signs of Parkinson's disease (PD). Although CDBS has been in use for a long time, very little has been reported on its supposed effects on cognition, particularly in relation to implants in the subthalamic nucleus. The results of the rare studies that do exist are controversial, and in many cases the studies have several design flaws. The present study compared cortical activation during three tasks (action execution, action observation and motor imagery) in PD patients with and without subthalamic implants. The study sample consisted of 36 volunteers, divided into three groups: healthy controls, PD patients with CDBS of the subthalamic nucleus, and PD patients without CDBS. Through a quantitative electroencephalogram assessment, absolute beta power was examined to observe the interaction between group and cognitive motor tasks. The electrodes at sites Fp1, Fp2, F7, F8, F3, Fz and F4, located in the prefrontal and frontal regions, were analyzed and a Group x Task interaction (p < 0.05) was observed for all of them. These findings suggest that CDBS of the subthalamic nucleus is efficient in reducing some of the effects of PD in these study tasks. At the same time, the dysfunctions found in several cortical areas, characteristic of PD, limited the effects of the CDBS. The results of this study suggest that CDBS of the subthalamic nucleus can modulate cognitive-motor aspects of PD.

The SLC6A3 3'-UTR VNTR and intron 8 VNTR polymorphisms association in the time estimation.

OBJECTIVE: The present study investigated the association of 3'-UTR VNTR and intron 8 VNTR polymorphisms with a time estimation task performance. MATERIALS AND METHODS: One hundred and eight men in a Brazilian Northeast population (18-32 years old) participated in the experiment. The 3'-UTR VNTR and intron 8 VNTR polymorphisms were associated alone and combined to absolute error (AE) and relative error (RE) in a time estimation task (target duration: 1 s, 4 s, 7 s and 9 s). RESULTS: We found an association of the behavioral variable with intron 8 VNTR for the time intervals of 1 s and 9 s (p < 0.001) and polymorphisms combinatorial effect for 1 s (p ≤ 0.05). CONCLUSION: The intron 8 VNTR polymorphism and the combinatorial effect can modulate the time estimate in the domain of supra seconds, and thus our study indicates a role of the dopamine transporter in the neurobiological areas related to the time intervals judgment.

Low-frequency rTMS stimulation over superior parietal cortex medially improves time reproduction and increases the right dorsolateral prefrontal cortex predominance.

AIM OF THE STUDY: Previous studies have shown that several cortical regions are involved in temporal tasks in multiple timescales. However, the hemispheric predominance of the dorsolateral prefrontal cortex (DLPFC) during time reproduction after repetitive low-frequency transcranial magnetic stimulation (rTMS) is relatively unexplored. Here, we study the effects of 1 Hz rTMS and sham stimulation applied medially over the superior parietal cortex (SPC) on the DLPFC alpha and beta band asymmetry and on time reproduction. MATERIALS AND METHODS: For this purpose, we have combined rTMS with electroencephalography in 20 healthy subjects who performed the time reproduction task in two conditions (sham and 1 Hz). RESULTS: The worst performance was observed in sham and 1Hz conditions for longer time intervals (p < .05), with the 1Hz condition subjects sub-reproducing the time interval, closer to the target interval (p < .05). The right DLPFC hemispheric predominance was found in both conditions, but after low-frequency rTMS, the right hemisphere predominance increased in the 1Hz condition (p < .05). CONCLUSIONS: Results of this study suggest that rTMS applied over the SPC influences time interval interpretation and the DLPFC functions. Future studies would explore the effects of the rTMS application to other cortical areas, and study how it influences time interval interpretation.