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Polimorfismos nos genes HTR1A e HTR2A influenciam o recrutamento de memória de trabalho visuoespacial no córtex frontopariental

Fri, 01 Jan 2021 00:00:00 GMT

Título: Polimorfismos nos genes HTR1A e HTR2A influenciam o recrutamento de memória de trabalho visuoespacial no córtex frontopariental Autor(es): Sousa, Vanessa Galeno de Primeiro Orientador: Yoshioka, France Keiko Nascimento Abstract: Working memory is defined as a system that provides temporary storage and manipulation of information in order to perform cognitive tasks. The performance of tasks that involve it has been associated with neurophysiological patterns in the prefrontal and pariental cortex, which are measured by electroencephalogram. The polymorphisms HTR1A -1019C/G, HTR2A T102C and HTR2A A-1438G have been associated with the availability of serotonin receptors, as well as with the understanding of the individual's spatial memory and the molecular dynamics involved in working memory. This study aimed to analyze the influence of polymorphisms in the HTR1A and HTR2A genes associated with performance and inter-individual differences during the visuospatial working memory task, in addition to theta band frequency modulations. A total of 178 male volunteers, aged between 18 and 32 years, with a mean age of 22.77 (± 2.97) years, who had not used psychotropic drugs and had no history of neurological diseases, were recruited. The analysis of the genotypic and allelic frequencies of the polymorphisms showed that the studied population is in Hardy-Weinberg equilibrium (p > 0.05). The allelic frequency observed was C = 48.5% and G = 51.4% for HTR1A -1019C/G, T = 40.7% and C = 59.2% for HTR2A T102C, A = 40.4% and G = 59.5% for HTR2A A-1438G. When analyzing the behavioral variable by ANOVA mixed factorial in relation to the task performed, based on the factors: genotypes and axis factor (horizontal plane: X and vertical plane: Y), it was found that the results showed a main effect for the axis for the three polymorphisms analyzed (p <0.0001), regardless of genotypic combinations and inter- and intragenic groupings. Therefore, it cannot be said that the genotypes do not interfere with the task performance, but that the randomness of the targeting stimulus activation plans, horizontal and vertical, influence the task performance, considering its rapid and individual nature. The result of binary logistic regression based on 5-HT expression: 5- HT low expression cluster vs. Normal 5-HT expression also did not indicate a statistically significant association for the task-related axes for any of the polymorphisms (p>0.05). The results observed in the neurophysiological analyzes by the three-way mixed factorial ANOVA test for the theta band, showed the significance of the genotypes with the mutant, hetero and homozygous allele, in the three studied polymorphisms, with the subareas of the prefrontal cortex and the pariental cortex, indicating greater neural recruitment of these regions to perform the task. It is concluded that the findings of this study allow us to verify that the studied polymorphisms do not seem to interfere directly in the behavioral analysis, suggesting that they are not related to fast tasks, but of a nature in which the memorization of multiple items. From a neurophysiological perspective, the alleles HTR1A -1019G, HTR2A 102C and HTR2A -1438G can modulate WM activity in the frontoparietal network, requiring greater activation of this area to perform spatial exercises. Instituição: Universidade Federal do Delta do Parnaíba Tipo: Dissertação

A doença do movimento visualmente induzida ocasionada pela realidade virtual interfere na atividade cortical durante a visualização de tarefas sacádicas de tomada de decisão orientadas por estimulos luminosos.

Wed, 06 Jun 2018 00:00:00 GMT

Título: A doença do movimento visualmente induzida ocasionada pela realidade virtual interfere na atividade cortical durante a visualização de tarefas sacádicas de tomada de decisão orientadas por estimulos luminosos. Autor(es): Pinheiro, Kelma Regina Galeno Primeiro Orientador: Bastos, Victor Hugo do Vale Abstract: Visually induced motion sickness (VIMS) is a generic term used to refer to a specific type of traditional movement disease known as Kinetosis. In virtual environments, it has been titled as cybersickness with side effects, such as eye fatigue, dizziness and nausea plus difficulty concentrating. Thus, the present study aims to demonstrate how the VIMS, caused by the virtual reality, interferes in the cortical activity during the visualization of luminous stimuli for the formation of the visual-saccadic decision by means of the electroencephalography having as reference the analysis of the absolute power of the beta band parietal and occipital. For this, 32 female participants, right-handed and with a mean age of 23.3 ± 3.2 years, were divided into control group (CG) and experimental group (EG), who developed VIMS. The participants performed 120 light stimuli, then made use of virtual reality and repeated the tracks again. The results demonstrated a statistically significant difference in the absolute power of the parietal and occipital beta bands bilaterally in the CG (p <0.001) and in the right occipital cortex in the EG (p <0.05), and the activity of this band in the CG remained higher during the whole task in relation to the CG. The study suggests that virtual reality causes a cognitive overload and an increase in the demand for visual attention to perform the task in both groups, and in individuals who are sensitive to VIMS the light stimulus itself can trigger sensory conflict. Instituição: Universidade Federal do Delta do Parnaíba Tipo: Dissertação

Estimar o intervalo de tempo aumenta a força muscular e a potência absoluta da banda alfa

Mon, 01 Jan 2018 00:00:00 GMT

Título: Estimar o intervalo de tempo aumenta a força muscular e a potência absoluta da banda alfa Autor(es): Santos, Kyvia Naysis de Araujo Primeiro Orientador: Teixeira, Silmar Silva Abstract: Cognitive tasks have been used to increase muscle strength through motor imagery training. However, it is still unknown if temporal perception tasks may accomplish this increase and what would be the neurobiological changes provided by the accomplishment of these tasks in the muscular force. This study aimed to analyze the cortical modifications and the induced muscular force in a time estimation task. For this proposition, we performed a counterbalanced crossover study with forty right-handed men, submitted to the Motor Imagery (MI) and Time Perception (TP) tasks. In both MI and TP conditions, muscle strength measurements were performed before and after treatment, with the subjects performing the manual grip on a dynamometer, simultaneously with the electroencephalograph signal. In the results, we found a difference in the muscle strength values after performing the cognitive tasks, with TP increasing the muscular strength of the subjects, while MI reduced it (p≤0.05). In addition, TP task promoted greater alpha band absolute power activity in the left dorsolateral prefrontal cortex and right ventrolateral prefrontal cortex than the MI task (p≤0.05). When analyzing whether cortical changes in both conditions could be associated with increased muscle strength, it was observed the activity in the left dorsolateral prefrontal cortex, left and right primary motor cortex, in the TP condition subjects promoted muscle strength increase in relation to the MI condition. The findings demonstrate TP modifies the cortical activity to improve muscle performance and thus, could be used as a cognitive method of muscle strengthening. Instituição: Universidade Federal do Delta do Parnaíba Tipo: Dissertação

Estudo do potencial antitumoral in vitro e in vivo de um heteropolissacarídeo extraído do exsudato do caule de Anacardium occidentale L.

Tue, 01 Jan 2019 00:00:00 GMT

Título: Estudo do potencial antitumoral in vitro e in vivo de um heteropolissacarídeo extraído do exsudato do caule de Anacardium occidentale L. Autor(es): Barros, Ayslan Batista Primeiro Orientador: Marinho Filho, José Delano Barreto Abstract: Cancer is characterized by a group of diseases related to the disordered growth of the cells, which invade tissues and organs. Several new drugs, derived from plants, algae, microorganisms and other sources, have been investigated due to their potential to treat different types of cancer. Polysaccharides extracted from plants have innumerable applications described in the literature, such as antibacterial, antifungal, antioxidant and antitumor activities, in vitro and in vivo. However, the antitumor effects of these polysaccharides are not fully elucidated yet. This study aimed to evaluate the antitumor potential of the cashew gum, through in vitro and in vivo models. The cashew gum did not demonstrate cytotoxic and antimigratory activity in vitro in murine and human tumor cells at the concentration of 100 μg / ml. In vivo assays showed that cashew gum was able to inhibit in 35% and 40% the tumor growth in murine metastatic melanoma (B16F-10), at doses of 50 and 100 mg / kg, respectively. In addition, the polysaccharide does not decrease the weight of the animals, since it is composed basically of sugar chains. Regarding hematological components, cashew gum did not cause leucopenia, and not significant hematological alterations, demonstrating that this polymer does not cause depletion of the immune system of the animal. Histological sections of the organs have shown that cashew gum did not caused toxic lesions in the liver, kidney, lung and spleen. Tumor slices indicated a cell death process indicative of apoptosis in treatment with cashew gum. The analysis of the tumor tissue by FTIR indicated a similar death process in treatments with cyclophosphamide and cashew gum, by the stretching of lipids representative bands, and groups present in the DNA. With regard to the analysis of enzymatic and non-enzymatic antioxidant components (GSH, MDA and MPO), Cashew gum did not indicate the production of these antioxidant agents, possibly demonstrating that this polymer does not cause tissue oxidative stress. Therefore, it is concluded that this polysaccharide could help in the treatment of neoplasias, by possibly reducing the side effects generated by the chemotherapeutic, besides helping in the tumor reduction. Instituição: Universidade Federal do Delta do Parnaíba Tipo: Dissertação