Environmental factors, familial aggregation and heritability of total cholesterol, low density lipoprotein-cholesterol and high density lipoprotein-cholesterol in a Brazilian population assisted by the Family Doctor Program.

OBJECTIVES: To estimate familial aggregation and the heritability of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and high density lipoprotein-cholesterol (HDL-C) in families assisted by the Family Doctor Program in a Brazilian city, and to evaluate associations between some environmental factors and familial aggregation of these lipids. STUDY DESIGN: Cross-sectional familial study. METHODS: The association of lipids with sociodemographic factors, lifestyle factors and comorbidities (e.g. physical activity, alcohol consumption, smoking, hypertension, impaired glucose tolerance, body mass index) was estimated using linear models and generalized estimating equations. Correlation of TC, LDL-C and HDL-C between pairs of relatives was estimated with the familial correlation procedure, and heritability was estimated with the ASSOC procedure. RESULTS: All associations were statistically significant. There was familial aggregation of TC (parent/offspring, r=0.33; sibling/sibling, r=0.37), LDL-C (parent/offspring, r=0.29; sibling/sibling, r=0.37) and HDL-C (parent/offspring, r=0.25; sibling/sibling, r=0.48), but less than 3%, 6% and 14%, respectively, which was explained by lifestyle factors. Correlation between pairs with genetic sharing (parent/offspring and sibling/sibling) was higher than that observed between father and mother. Heritability estimates ranged between 0.32 (HDL-C) and 0.50 (TC). Similar results were found for the two approaches used to estimate the contribution of genetic and environmental factors in the correlation of TC, LDL-C and HDL-C between the family pairs. CONCLUSION: The results showed that there is familial aggregation of TC, LDL-C and HDL-C, and point to the predominance of genetic factors because little influence of environmental variables was found.

Gamma band oscillations in parietooccipital areas during performance of a sensorimotor integration task: a qEEG coherence study / Oscilações na banda gama em áreas parieto-occipitais durante desempenho de uma tarefa sensório-motora: um estudo de coerência na EEGq

This study aimed to elucidate cortical mechanisms involved in anticipatory actions when 23 healthy right-handed subjects had to catch a free falling object through quantitative electroencephalogram (qEEG). For this reason, we used coherence that represents a measurement of linear covariation between two signals in the frequency domain. In addition, we investigated gamma-band (30-100 Hz) activity that is related to cognitive and somatosensory processes. We hypothesized that gamma coherence will be increase in both parietal and occipital areas during moment after ball drop, due to their involvement in manipulation of objects, visuospatial processing, visual perception, stimuli identification and attention processes. We confirmed our hypothesis, an increase in gamma coherence on P3-P4 (t= -2.15; p=0.033) and PZ-OZ (t= -2.16; p=0.034) electrode pairs was verified for a paired t-test. We conclude that to execute tasks involving anticipatory movements (feedforward mechanisms), like our own task, probably, there is no need of a strong participation of visual areas in the process of information organization to manipulate objects and to process visuospatial information regarding the contact hand-object.

Este estudo teve como objetivo elucidar os mecanismos corticais envolvidos em ações antecipatórias quando 23 indivíduos saudáveis destros tinham que apreender um objeto em queda livre, através da eletroencefalografia quantitativa (EEGq). Por esta razão, usamos a coerência que representa a covariação linear entre dois sinais no domínio da frequência. Além disso, investigamos a atividade da banda gama (30-100 Hz), que está relacionada à processos cognitivos e somato-sensoriais. Nossa hipótese é que a coerência de gama estará aumentada em ambas as áreas parietais e occipitais durante o momento pós-queda da bola, devido ao seu envolvimento na manipulação de objetos, processamento visuo-espacial, percepção visual, identificação de estímulos e processos de atenção. Confirmamos nossa hipótese. Um aumento de coerência em gama nos pares de eletrodos P3-P4 (t= -2,15; p=0,033) e PZ-OZ (t= -2,16; p=0,034) foi verificado por teste-t pareado. Conclui-se que, para executar tarefas que envolvem movimentos de antecipação (mecanismos de retro-alimentação) como a nossa própria tarefa, provavelmente, não há necessidade de forte participação de áreas visuais no processo de organização da informação como para manipular objetos e processar a informação visuo-espacial no contato mão-objeto.

Corticomuscular coherence behavior in fine motor control of force: a critical review.

INTRODUCTION: Understanding how the human motor control operates is an important issue to the neuroscience. One example is how the motor cortex controls muscle activity, which can be observed through corticomuscular coherence (CMC). AIM: Our study aimed to verify the influence of certain factors related to the fine motor control of force tasks on CMC. Our issue is if would be possible the strength of the coupling between the central and muscular systems measured by changes in oscillatory activity of beta- and gamma-band being influenced by these factors as much healthy subjects as patients. DEVELOPMENT: Beta-band CMC was especially important when executing sustaining accurate control tasks, which need more concentration and effort. However, we found that beta-band CMC was influenced by some factors. With regard to gamma-band CMC, apparently a complex and continuous dynamic integration of several mechanisms would be necessary to modulate gamma-band CMC, since it was not modulated by magnitude of force. Therefore, it seems these mechanisms would be required to an adequate and effective neural networks operation when a dynamic force output is required. CONCLUSION: Beta- and gamma-band CMC could enrich our understanding of the dynamic changes of the motor system not only in health subjects but also in neurological patients. It may serve as a sensitive index for quantifying dynamical changes in fine motor control of force. It has the potential to become a useful tool to characterize the patterns of changes in central nervous system's activities for the purposes of basic research, especially in restoring of motor function.

Effect of aerobic training on EEG alpha asymmetry and depressive symptoms in the elderly: a 1-year follow-up study

The effect of physical exercise on the treatment of depressive elderly adults has not been investigated thus far in terms of changes in cortical hemispheric activity. The objective of the present study was to identify changes in depressive symptoms, quality of life, and cortical asymmetry produced by aerobic activity. Elderly subjects with a diagnosis of major depressive disorder (DSM-IV) were included. Twenty patients (70 percent females, 71 ± 3 years) were divided into an exercise group (pharmacological treatment plus aerobic training) and a control group (undergoing pharmacological treatment) in a quasi-experimental design. Pharmacological treatment was maintained stable throughout the study (antidepressants and anxiolytics). Subjects were evaluated by depression scales (Beck Depression Inventory, Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale) and the Short Form Health Survey-36, and electroencephalographic measurements (frontal and parietal alpha asymmetry) before and after 1 year of treatment. After 1 year, the control group showed a decrease in cortical activity on the right hemisphere (increase of alpha power), which was not observed in the exercise group. The exercise group showed a significant decrease of depressive symptoms, which was not observed in the control group. This result was also accompanied by improved treatment response and remission rate after 1 year of aerobic exercise associated with treatment. This study provides support for the effect of aerobic training on alpha activity and on depressive symptoms in elderly patients. Exercise facilitates the treatment of depressive elderly adults, leading to clinical and physical improvement and protecting against a decrease in cortical activity.

Effect of aerobic training on EEG alpha asymmetry and depressive symptoms in the elderly: a 1-year follow-up study.

The effect of physical exercise on the treatment of depressive elderly adults has not been investigated thus far in terms of changes in cortical hemispheric activity. The objective of the present study was to identify changes in depressive symptoms, quality of life, and cortical asymmetry produced by aerobic activity. Elderly subjects with a diagnosis of major depressive disorder (DSM-IV) were included. Twenty patients (70% females, 71 +/- 3 years) were divided into an exercise group (pharmacological treatment plus aerobic training) and a control group (undergoing pharmacological treatment) in a quasi-experimental design. Pharmacological treatment was maintained stable throughout the study (antidepressants and anxiolytics). Subjects were evaluated by depression scales (Beck Depression Inventory, Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale) and the Short Form Health Survey-36, and electroencephalographic measurements (frontal and parietal alpha asymmetry) before and after 1 year of treatment. After 1 year, the control group showed a decrease in cortical activity on the right hemisphere (increase of alpha power), which was not observed in the exercise group. The exercise group showed a significant decrease of depressive symptoms, which was not observed in the control group. This result was also accompanied by improved treatment response and remission rate after 1 year of aerobic exercise associated with treatment. This study provides support for the effect of aerobic training on alpha activity and on depressive symptoms in elderly patients. Exercise facilitates the treatment of depressive elderly adults, leading to clinical and physical improvement and protecting against a decrease in cortical activity.

[The effects of bromazepam on the performance of a sensory-motor activity: an electroencephalographic study]. / Efectos del bromacepam en el desarrollo de una actividad sensoriomotora: un estudio electroencefalográfico.

AIMS: To investigate the effects of using bromazepam on the relative power in alpha while performing a typing task. Bearing in mind the particularities of each brain hemisphere, our hypothesis was that measuring the relative power would allow us to investigate the effects of bromazepam on specific areas of the cortex. More specifically, we expected to observe different patterns of powers in sensory-motor integration, attention and activation processes. SUBJECTS AND METHODS: The sample was made up of 39 subjects (15 males and 24 females) with a mean age of 30 +/- 10 years. The control (placebo) and experimental (3 mg and 6 mg of bromazepam) groups were trained in the typing task with a randomised double-blind model. RESULTS: A three-way ANOVA and Scheffé test were used to analyse interactions between the factors condition and moment, and between condition and sector. CONCLUSIONS: The doses used in this study facilitated motor performance of the typing task. In this study, the use of the drug did not prevent learning of the task, but it did appear to concentrate mental effort on more restricted and specific aspects of typing. It also seemed to influence the rhythm and effectiveness of the operations performed during mechanisms related to the encoding and storage of new information. Likewise, a predominance of activity was observed in the left (dominant) frontal area in the 3 mg bromazepam group, which indicates that this dose of the drug affords the subject a greater degree of directionality of cortical activity for planning and performing the task.

[The role played by the parietooccipital cortex in the process of sensory-motor integration: an electroencephalographic study]. / Participación de la corteza parietooccipital en el proceso de integración sensoriomotora: estudio electroencefalográfico.

INTRODUCTION: A fundamental aspect of planning future actions is the performance and control of motor tasks. This behaviour is done through sensory-motor integration. AIM: To explain the electrophysiological mechanisms in the cortex (modifications to the alpha band) that are involved in anticipatory actions when individuals have to catch a free-falling object. SUBJECTS AND METHODS: The sample was made up of 20 healthy subjects of both sexes (11 males and 9 females) with ages ranging between 25 and 40 years (32.5 +/- 7.5) who were free of mental or physical diseases (previous medical history); the subjects were right-handed (Edinburgh Inventory) and were not taking any psychoactive or psychotropic substances at the time of the study. The experiment consisted in a task in which subjects had to catch freely falling objects. The experiment was made up of six blocks of 15 tests, each of which lasted 2 minutes and 30 seconds, with a break of one minute between blocks. Data were captured by means of a quantitative electroencephalogram two seconds before and two seconds after each ball was dropped. RESULTS: An interaction of the factors moment and position was only observed for the right parietooccipital cortex, in the combination of electrodes P4-O2. CONCLUSION: These findings suggest that the right parietooccipital cortex plays an important role in increasing expectation and swiftness in the processes of preparing for a motor task.

[Learning and implicit memory: mechanisms and neuroplasticity]. / Aprendizaje y memoria implícita: mecanismos y neuroplasticidad.

INTRODUCTION: Learning and memory are complex processes that researchers have been attempting to unravel for over a century in order to gain a clear view of the underlying mechanisms. AIMS: To review the basic cellular and molecular mechanisms involved in the process of procedural retention, to offer an overall view of the fundamental mechanisms involved in storing information by means of theories and models of memory, and to discuss the different types of memory and the role played by the cerebellum as a modulator of procedural memory. DEVELOPMENT: Experimental results from recent decades have opened up new areas of study regarding the participation of the biochemical and cellular processes related to the consolidation of information in the nervous system. CONCLUSIONS: The neuronal circuits involved in acquiring and consolidating memory are still not fully understood and the exact location of memory in the nervous system remains unknown. A number of intrinsic and extrinsic factors interfere in these processes, such as molecular (long-term potentiation and depression) and cellular mechanisms, which respond to communication and transmission between nerve cells. There are also factors that have their origin in the outside environment, which use the association of events to bring about the formation of new memories or may divert the subject from his or her main focus. Memory is not a singular occurrence; it is sub-divided into declarative and non-declarative or, when talking about the time it lasts, into short and long-term memory. Moreover, given its relation with neuronal mechanisms of learning, memory cannot be said to constitute an isolated process.

Statistical analysis of event-related potential elicited by verb-complement merge in Brazilian Portuguese.

An interesting fact about language cognition is that stimulation involving incongruence in the merge operation between verb and complement has often been related to a negative event-related potential (ERP) of augmented amplitude and latency of ca. 400 ms - the N400. Using an automatic ERP latency and amplitude estimator to facilitate the recognition of waves with a low signal-to-noise ratio, the objective of the present study was to study the N400 statistically in 24 volunteers. Stimulation consisted of 80 experimental sentences (40 congruous and 40 incongruous), generated in Brazilian Portuguese, involving two distinct local verb-argument combinations (nominal object and pronominal object series). For each volunteer, the EEG was simultaneously acquired at 20 derivations, topographically localized according to the 10-20 International System. A computerized routine for automatic N400-peak marking (based on the ascendant zero-cross of the first waveform derivative) was applied to the estimated individual ERP waveform for congruous and incongruous sentences in both series for all ERP topographic derivations. Peak-to-peak N400 amplitude was significantly augmented (P < 0.05; one-sided Wilcoxon signed-rank test) due to incongruence in derivations F3, T3, C3, Cz, T5, P3, Pz, and P4 for nominal object series and in P3, Pz and P4 for pronominal object series. The results also indicated high inter-individual variability in ERP waveforms, suggesting that the usual procedure of grand averaging might not be considered a generally adequate approach. Hence, signal processing statistical techniques should be applied in neurolinguistic ERP studies allowing waveform analysis with low signal-to-noise ratio.

Statistical analysis of event-related potential elicited by verb-complement merge in Brazilian Portuguese

An interesting fact about language cognition is that stimulation involving incongruence in the merge operation between verb and complement has often been related to a negative event-related potential (ERP) of augmented amplitude and latency of ca. 400 ms - the N400. Using an automatic ERP latency and amplitude estimator to facilitate the recognition of waves with a low signal-to-noise ratio, the objective of the present study was to study the N400 statistically in 24 volunteers. Stimulation consisted of 80 experimental sentences (40 congruous and 40 incongruous), generated in Brazilian Portuguese, involving two distinct local verb-argument combinations (nominal object and pronominal object series). For each volunteer, the EEG was simultaneously acquired at 20 derivations, topographically localized according to the 10-20 International System. A computerized routine for automatic N400-peak marking (based on the ascendant zero-cross of the first waveform derivative) was applied to the estimated individual ERP waveform for congruous and incongruous sentences in both series for all ERP topographic derivations. Peak-to-peak N400 amplitude was significantly augmented (P < 0.05; one-sided Wilcoxon signed-rank test) due to incongruence in derivations F3, T3, C3, Cz, T5, P3, Pz, and P4 for nominal object series and in P3, Pz and P4 for pronominal object series. The results also indicated high inter-individual variability in ERP waveforms, suggesting that the usual procedure of grand averaging might not be considered a generally adequate approach. Hence, signal processing statistical techniques should be applied in neurolinguistic ERP studies allowing waveform analysis with low signal-to-noise ratio.

[The effects of bromazepam on contingent negative variation and reaction time in a visuomotor task]. / Efectos del bromacepam sobre la variación negativa contingente y el tiempo de reacción en una tarea visuomotora.

INTRODUCTION: Bromazepam is the second most commonly used benzodiazepine in Brazil. Psychophysiological research on this substance is still in its early stages. AIM: To determine the neurotoxicity of bromazepam by examining reaction times (RT) and contingent negative variations (CNV). SUBJECTS AND METHODS: Using a videogame produced in our laboratory for psychophysiological research purposes (Car Acquisition), 14 healthy volunteers (9 males) aged between 23 and 42 drove a vehicle along a road full of curves (i.e. distractors) while they had to respond to imperative stimuli (i.e. orders to press the button on the joystick) that were preceded by warnings (S1-S2-RM paradigm with distractor). We compared RT, amplitudes and latencies of the CNV at each of the three electrodes on the median line (Fz, Cz and Pz) one hour after random, double-blind and crossed administration of placebo (P), 3 mg of bromazepam (B3) or 6 mg of bromazepam (B6) on different days. STATISTICS: one-way ANOVA and Post Hoc Scheffé. RESULTS: No significant differences were observed in the RT. At Pz, the CNV amplitudes displayed significant differences for P, B3 and B6 (p = 0.006), and also for B3 and B6 (p = 0.018), with B6 > B3 = P. At Fz, a non-significant tendency (p = 0.074) suggested a difference between the latencies, shorter in B6 than in B3 (p = 0.098), both equivalent to placebo. The mean amplitudes ranged between 2.4 and 5.9 microV. CONCLUSIONS: Behavioural and neurophysiological neurotoxicity was insignificant one hour after administration of a single 3 or 6 mg dose of bromazepam in healthy young adults. Low mean amplitudes were compatible with the interference from distractors and did not result in floor effect.

Effects of caffeine on the electrophysiological, cognitive and motor responses of the central nervous system.

Caffeine is the most consumed psychoactive substance in the world. The effects of caffeine have been studied using cognitive and motor measures, quantitative electroencephalography (qEEG) and event-related potentials. However, these methods are not usually employed in combination, a fact that impairs the interpretation of the results. The objective of the present study was to analyze changes in electrophysiological, cognitive and motor variables with the ingestion of caffeine, and to relate central to peripheral responses. For this purpose we recorded event-related potentials and eyes-closed, resting EEG, applied the Stroop test, and measured reaction time. Fifteen volunteers took caffeine (400 mg) or placebo in a randomized, crossover, double-blind design. A significant reduction of alpha absolute power over the entire scalp and of P300 latency at the Fz electrode were observed after caffeine ingestion. These results are consistent with a stimulatory effect of caffeine, although there was no change in the attention (Stroop) test or in reaction time. The qEEG seems to be the most sensitive index of the changes produced by caffeine in the central nervous system since it proved to be capable of detecting changes that were not evident in the tests of cognitive or motor performance.

Effects of caffeine on the electrophysiological, cognitive and motor responses of the central nervous system

Caffeine is the most consumed psychoactive substance in the world. The effects of caffeine have been studied using cognitive and motor measures, quantitative electroencephalography (qEEG) and event-related potentials. However, these methods are not usually employed in combination, a fact that impairs the interpretation of the results. The objective of the present study was to analyze changes in electrophysiological, cognitive and motor variables with the ingestion of caffeine, and to relate central to peripheral responses. For this purpose we recorded event-related potentials and eyes-closed, resting EEG, applied the Stroop test, and measured reaction time. Fifteen volunteers took caffeine (400 mg) or placebo in a randomized, crossover, double-blind design. A significant reduction of alpha absolute power over the entire scalp and of P300 latency at the Fz electrode were observed after caffeine ingestion. These results are consistent with a stimulatory effect of caffeine, although there was no change in the attention (Stroop) test or in reaction time. The qEEG seems to be the most sensitive index of the changes produced by caffeine in the central nervous system since it proved to be capable of detecting changes that were not evident in the tests of cognitive or motor performance.

[Paraneoplastic subacute cerebellar degeneration: case report]. / Degeneração cerebelar subaguda paraneoplásica: relato de caso.

We report a 40-year-old woman with subacute cerebellar degeneration associated with ovarian cancer. We briefly review the clinical and laboratory features of this syndrome, and emphasize the importance of its prompt recognition, which many times makes possible the early detection and treatment of the primary disorder.

Monitorização do plano anestésico por técnicas estatísticas no domínio da freqüência / Monitoring depth of anaesthesia by frequency-domain statistical techniques

O potencial evocado auditivo de média latência (MLAEP) tem sido empregado na avaliação do nível anestésico, sendo usual a análise morfológica (AEPidx - Indice de Potencial Evocado Auditivo, e DT - Distância Taxonômica). Neste trabalho, técnicas de detecção objetiva de respostas no domínio da freqüência (MSC - Magnitude Quadrada da Coerência, e CSM - Medida de Sincronismo de Componentes) foram avaliadas a partir de EEG sob estimulação auditiva. Dez voluntários foram estimulados com cliques repetitivos (7,645 Hz, nível de pressão sonora de 75 dB SPL), sendo EEG adquirido na derivação Vértex - Lobo Auricular durante 10 min sem administração de anestésico e dois períodos consecutivos de infusão contínua de propofol (3 mg/Kg/h, sedação, e 9 mg/Kg/h, anestesia) de 45 min cada. O instante de perda de consciência foi estimado com base no pressionamento de uma maniqueta em resposta a estímulos luminosos a cada 15 s. MSC e CSM permitem a inferência estatística de ausência de resposta auditiva (valor crítico, para e.g. alfa = 1 por cento) ao longo do processo anestésico. Além disso, MSC(Ÿ) e CSM(Ÿ) se reduzem durante a infusão (mais expressivamente na anestesia), tendo maior concordância (diagramas de Bland-Altman) com os resultados da maniqueta que AEPidx e DT, e maior equivalência (Wilcoxon Signed-Rank Test, alfa = 5 por cento) que DT.

[Spontaneous intracranial hypotension: case report]. / Hipotensão intracraniana espontânea. Relato de caso.

Spontaneous intracranial hypotension is a rare syndrome associated with postural cephalalgia and low pressure of the cerebrospinal fluid. We report the case of a 45 years-old man with spontaneous intracranial hypotension with MRI diffuse meningeal enhancement.

Modelagem AR de sinais EEG multicanal usando o TMS320C30 / AR modelling of multicanal EEG signals using the TMS320C30

Uma placa processadora digital de sinais (DSP), com o TMS320C30, em conjunto com um PC foi empregada na modelagem autoregressiva (AR) de sinais EEG. O sistema PC-DSP mostrou-se capaz de realizar a análise espectral destes sinais com tempo de processamento compatível com monitoração em tempo real do espectro de 16 canais EEG.