Neuronal Assembly Detection and Cell Membership Specification by Principal Component Analysis

LOPES-DOS-SANTOS, V. , CONDE-OCAZIONEZ, S. ; NICOLELIS, M. A. L. , RIBEIRO, S. T. , TORT, A. B. L. . Neuronal assembly detection and cell membership specification by principal component analysis. Plos One, v. 6, p. e20996, 2011.

Local Field Potentials in the Gustatory Cortex Carry Taste Information

It has been recently shownthat localfield potentials (LFPs)fromthe auditory and visual cortices carry information about sensory stimuli, but whether this is a universal property of sensory cortices remains to be determined. Moreover, little is known about the temporal dynamics of sensory information contained in LFPs following stimulus onset. Here we investigated the time course of the amount of stimulus information in LFPs and spikes from the gustatory cortex of awake rats subjected to tastants and water delivery on the tongue. We found that the phase and amplitude of multiple LFP frequencies carry information about stimuli, which have specific time courses after stimulus delivery. The information carried by LFP phase and amplitude was independent within frequency bands, since the joint information exhibited neither synergy nor redundancy. Tastant information in LFPs was also independent and had a different time course from the information carried by spikes. These findings support the hypothesis that the brain uses different frequency channels to dynamically code for multiple features of a stimulus.

Neuronal Assembly Detection and Cell Membership Specification by Principal Component Analysis

LOPES-DOS-SANTOS, V. , CONDE-OCAZIONEZ, S. ; NICOLELIS, M. A. L. , RIBEIRO, S. T. , TORT, A. B. L. . Neuronal assembly detection and cell membership specification by principal component analysis. Plos One, v. 6, p. e20996, 2011.

Local Field Potentials in the Gustatory Cortex Carry Taste Information

It has been recently shownthat localfield potentials (LFPs)fromthe auditory and visual cortices carry information about sensory stimuli, but whether this is a universal property of sensory cortices remains to be determined. Moreover, little is known about the temporal dynamics of sensory information contained in LFPs following stimulus onset. Here we investigated the time course of the amount of stimulus information in LFPs and spikes from the gustatory cortex of awake rats subjected to tastants and water delivery on the tongue. We found that the phase and amplitude of multiple LFP frequencies carry information about stimuli, which have specific time courses after stimulus delivery. The information carried by LFP phase and amplitude was independent within frequency bands, since the joint information exhibited neither synergy nor redundancy. Tastant information in LFPs was also independent and had a different time course from the information carried by spikes. These findings support the hypothesis that the brain uses different frequency channels to dynamically code for multiple features of a stimulus.

Theta-associated high-frequency oscillations (110–160 Hz) in the hippocampus and neocortex

TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013.

Úlceras de pressão: um estudo com pacientes de unidade de terapia intensiva

To characterize patients according to gender, age category, internment time, diagnostical hypothesis and location of the pressure ulcer; to identify the susceptibility conditions, intrinsical and extrinsical factors present on ICU patients and to verify on the existence of association between the susceptibility conditions and the intrinsecal and extrinsecal factors on the occurrence of PU. Methods: It is a descriptive study, of longitudinal design of the panel type, with quantitative approach, performed on two ICU s of a private hospital located in Natal/RN, with 40 patients interned at these units. The data collection was performed on all three shifts through a structured observation and physical exam of the patients' skin form seeking to identify the presence of PU. Results: The greatest occurence of PU was on individuals of the male gender (70%) when compared to the female gender (30%), that difference being statistically significant (p=0,0267), with the male gender presenting 4,3 times greater chance of developing PU than the female; the predominant age category was from 60 years of age on (85%), 60,0% presented 1 to 2 PU s after 7 (seven) days of permanence in the ICU s, the predominant diagnostical hypothesis on the patients with PU were the respiratory diseases (42,3%) and the most frequent locations of PU were the sacral region (40,0%) and heels (36,0%). 25 PU s of stage I were diagnosed on 50,0% of the followed patients, with general incidence of 50,0% on both ICUs. from the 88 variables researched, 75 were identified on the patients from the study, being the predominant conditions (anemia, hypotension, leukocytosis, other diseases hypertension blood pressure, cardiac insuffience, pneumonia - and ansiolythic), the intrinsecal factors (diminished muscular strenght and/or mass, discrete edema, totally compromised mobile coordination and total inability for movement on the bed) and the extrinsecal factors (inadequate mattress type, permanence on a single position for >2 hours, shearing/friction force, bed clothes with folds that leave marks on the body, pressure force) predominated on patients with PU. The male gender variables (p=0,0267,OR=4,3), sedation (p=0,0006,OR=4,1), psychomotive agitation (p=0,0375,OR=5,8) and leukocytosis (p=0,0285,OR=5,0) presented a significant statistical diference when analyzed independently. We verified an association of 17,3%, statistically significant (p=0,0384), between the susceptibility conditions (anemia, leukocytosis and hypotension), the intrinsecal factors (age equal or above 60 years, diminished/absent pain sensibility and smooth, fine or delicate skin) and the extrinsecal factors (inadequate mattress, pressure forces, shearing/friction force, permanence on a single position for more than 2 hours, elevation between 30 to 45 degrees and inadequate bed clothes' conditions), with a chance ratio of 4,6 times the risk of occurrence of PU on the patients that presented the referred association. Conclusion: The incidence of PU detected on the ICU-interned patients was high and we made evident the existence of association between the susceptibility conditions, the intrinsecal and extrinsecal factors on the occurrence of PU s on the ICUinterned patients, and thus we accept the alternative hypothesis proposed on the study

Estudo clínico e níveis de ansiedade em uma série de casos de líquen plano oral

Oral Lichen Planus (OLP) is a relatively common, cronic inflammatory disease. Its etiopathogenesis is no completely understood and several factors have proposed in attempt to explain the appearance, variety of clinical manifestations and periods of exacerbation and remission of the symptons of the lesions. The objective of the present study was to assess the presence of local factors, systemic diseases and levels of anxiety in patients with OLP, investigating their association with the clinical characteristics of the lesions. The sample consisted of 37 patients with histopathologically confirmed OLP that were submitted to a clinical exam to evaluate the presence of smoking habits, consumption of alcoholic beverages, diabetes mellitus, hypertension and hepatitis C virus (HCV) infection. The existence of skin lesions, as well as the time course, clinical form, symptomatology, number and location of the oral lesions were also registered. The trait anxiety was measured by Spielberger s Stai-Trait Anxiety Inventory (STAI), and to associate the variables we used the chi-square or Fisher s exact test. It was observed that females were the most affected (75%) and the mean age of the patients was 53,3 years. Most cases were non-smoker (97,3%) and none was drinker. Diabetes mellitus and hypertension were present in 10,8% e 16,2% of the sample, respectively and only one patient was HCV-seropositive (2,7%). Moderate levels of anxiety were seen in most cases (78,4%) and 21,6% had elevated levels. The oral lesions persisted in 95% of the cases for a period of 6 months to 13 years. The erosive form was the most prevalent (57,1%) and symptons were reported by 45,7% of the patients. Multiple lesions were frequent (60%), affecting mainly the buccal mucosa, followed by gums e tongue. There was no significant association of the presence of diabetes mellitus, hypertension and levels of anxiety with the clinical form or symptomatology of the oral lesions (p>0,005), despite a trend in patients with hypertension to have erosive lesions. It was concluded that, in the sample studied, moderate levels of anxiety were commonly observed, and the HCV infection apparently is not related to the onset of the OLP. In this study, the presence of diabetes mellitus, hypertension and levels of anxiety seem not to be associated with the clinical characteristics of the lesions of OLP

Oscilações Teta no hipocampo do rato durante tarefa de tomada de decisão espacial

The processing of spatial and episodic information during memory tasks depends on hippocampal theta oscillations. In the present study, I investigated the relationship between theta power and choice selection during spatial decision-making. I recorded local field potentials from the CA1 region of rats retrieving reward locations in a 4-arm maze. In trained but not in naïve animals, I observed a significant increase in theta power during decision-making, which could not be explained by changes in locomotion speed. Furthermore, a Bayesian decoder based on theta power predicted choice outcomes in speed-matched trials. The decoding time course revealed that performance increased above chance before the decision moment exclusively for theta power, remaining flat for other frequency bands. These results occurred for trained animals, but no significant prediction could be made for naïve animals. Altogether, the data support a mnemonic function of theta rhythm during spatial decision-making, indicating that these oscillations correlate with the retrieval of memories required for successful decisions

Pressão de sono e perfil acadêmico de estudante de medicina do 1º período da UFRN

Academic demands, new social context, new routines and decrease of the parental control, are factors that may influence the sleep pattern of freshman students at the University. Medical students from the Federal University of Rio Grande do Norte (UFRN) have a full-time course, subjects with high-level content, and, at the first semester, classes begin at 7 a.m. This group composed by young adults who still suffering with delayed sleep phase, common in adolescence, indicating that this class schedule can be inappropriate at this age. The reduction of nocturnal sleep during school days, and the attempt to recover sleep on free days – social jet lag (JLS), suggests that in the first semester, students suffer from high sleep pressure. High sleep pressure may reflect on cognitive tasks and performance. Therefore, the aim of this study was to investigate the relationship between sleep pressure and the academic profile of medical students from the first semester of UFRN, characterizing this population socio-demographically and investigating possible impacts on therestactivity rhytm and academic performance. A sample of 88 students, healthy men and women awswered the following questionnaires: Pittsburgh Sleep Quality (PSQI), Epworth Sleepiness Scale (ESS), Horne & Ostberg Chronotype (HO), Munich Chronotype (MCTQ) and “Health and Sleep” adapted. Actigraphy was used during 14 days to make actogramas and obtain non-parametric variables of the rest-activity rhythm and the grades of the morning schedule were used as academic performance. The JLS was used as a measure of sleep pressure. Statistics significance level was 95%. The population was sociodemographic homogeneous. Most students have healthy lifestyle, practice physical activity, use car to go to the university and take between 15 and 30 minutes for this route. Regarding CSV, most were classify as intermediate (38.6%) and evening (32%) chronotypes, needs to nap during the week, suffer daytime sleepiness and have poor sleep quality. 83% of the sample has at least 1h JLS, which led us to divide into two groups: Group <2h JLS (N = 44) and Group ≥ 2h JLS (N = 44). The groups have differences only in chronotype, showing that most evening individuals have more JLS, however, no differences were found in relation to sociodemographic aspect, rest-activity rhythm or academic performance. The homogeneity of the sample was limited to compare the groups, however, is alarming that students already present in the first half: JLG, poor sleep quality and excessive daytime sleepiness, which can be accentuated through the university years, with the emergence of night shifts and increased academic demand. Interventionsaddressingthe importance of good sleep habits and the change of the class start time are strategies aimed to improve student’s health.

Theta-associated high-frequency oscillations (110–160 Hz) in the hippocampus and neocortex

TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013.

Tornar-se, ser e viver do professorado: entre regularidades e variações identitárias

The main aim of this research has been to analyze the identity patterns of the teacher s staff of fundamental education public schools in the Metropolitan Area of Natal-RN. It sets out from the hypothesis that being a teacher within this context grows out of the regularities of a specific habitus, which, according to Bourdieu, develops into mental schemes of thought and action within a specific social group. This habitus forms the basis on which is built the social representation of being a teacher prevailing in the group, as well as the symbolic differences that typify its identity variations. Three data sources have been fundamental in building up this thesis: (a) formative essays of students graduating from a Higher Teacher s Formation Course, as well as observing some of the public defense of these essays during field work; (b) a questionnaire aimed at classifying economically, socially, and culturally a sample of public teachers of the Natal-RN county; and (c) submitting a sub-sample of this group to the process of Multiple Classification Procedures (MCP). The analysis of data was done according to the multidimensional, non-parametric statistical procedures of both the Category Content Analysis and Enunciation Analysis methods. The results of the analysis took into account an ample set of variables, its associations and implications, the cultural and social profile of the population under scrutiny, their life styles, as well as the strategies they developed in the process of becoming a teacher, and the social representation of being a teacher . We came to the conclusion that the social identity of the teachers corps, or as we prefer to say it being a teacher , is a result of a set of regularities produced by the habitus that gives social shape and meaning to the existence of the group proper. We note the existence of identity variations caused by the variables (a) educational level; and (b) mode of action in fundamental education (if these are the first or last grades where the subjects operate). However, these variations will not break the power of the regularities that give shape, meaning, and social visibility to the group. The social representation of being a teacher points to the tensions, ambiguities, and trends inherent to common sense, as well as to a strong tendency to reassign a new meaning to being a teacher. Our thesis, therefore, is that the identity configuration of the teachers corps under scrutiny is characterized by an integrative synthesis, by-product of a habitus that is superimposed, and at the same time co-exists with different identity variations