Neurofisiologia hipocampal durante sessões de sono intercaladas por exploração espacial: Reverberação do passado ou predição do futuro?

The ability to predict future rewards or threats is crucial for survival. Recent studies have addressed future event prediction by the hippocampus. Hippocampal neurons exhibit robust selectivity for spatial location. Thus, the activity of hippocampal neurons represents a cognitive map of space during navigation as well as during planning and recall. Spatial selectivity allows the hippocampus to be involved in the formation of spatial and episodic memories, including the sequential ordering of events. On the other hand, the discovery of reverberatory activity in multiple forebrain areas during slow wave and REM sleep underscored the role of sleep on the consolidation of recently acquired memory traces. To this date, there are no studies addressing whether neuronal activity in the hippocampus during sleep can predict regular environmental shifts. The aim of the present study was to investigate the activity of neuronal populations in the hippocampus during sleep sessions intercalated by spatial exploration periods, in which the location of reward changed in a predictable way. To this end, we performed the chronic implantation of 32-channel multielectrode arrays in the CA1 regions of the hippocampus in three male rats of the Wistar strain. In order to activate different neuronal subgroups at each cycle of the task, we exposed the animals to four spatial exploration sessions in a 4-arm elevated maze in which reward was delivered in a single arm per session. Reward location changed regularly at every session in a clockwise manner, traversing all the arms at the end of the daily recordings. Animals were recorded from 2-12 consecutive days. During spatial exploration of the 4-arm elevated maze, 67,5% of the recorded neurons showed firing rate differences across the maze arms. Furthermore, an average of 42% of the neurons showed increased correlation (R>0.3) between neuronal pairs in each arm. This allowed us to sort representative neuronal subgroups for each maze arm, and to analyze the activity of these subgroups across sleep sessions. We found that neuronal subgroups sorted by firing rate differences during spatial exploration sustained these differences across sleep sessions. This was not the case with neuronal subgroups sorted according to synchrony (correlation). In addition, the correlation levels between sleep sessions and waking patterns sampled in each arm were larger for the entire population of neurons than for the rate or synchrony subgroups. Neuronal activity during sleep of the entire neuronal population or subgroups did not show different correlations among the four arm mazes. On the other hand, we verified that neuronal activity during pre-exploration sleep sessions was significantly more similar to the activity patterns of the target arm than neuronal activity during pre-exploration sleep sessions. In other words, neuronal activity during sleep that precedes the task reflects more strongly the location of reward than neuronal activity during sleep that follows the task. Our results suggest that neuronal activity during sleep can predict regular environmental changes

Investigação da relação entre conteúdo onírico e aprendizado de uma tarefa cognitiva complexa

Several lines of evidence indicate that sleep is beneficial for learning, but there is no experimental evidence yet that the content of dreams is adaptive, i.e., that dreams help the dreamer to cope with challenges of the following day. Our aim here is to investigate the role of dreams in the acquisition of a complex cognitive task. We investigated electroencephalographic recordings and dream reports of adult subjects exposed to a computer game comprising perceptual, motor, spatial, emotional and higher-level cognitive aspects (Doom). Subjects slept two nights in the sleep laboratory, a completely dark room with a comfortable bed and controlled temperature. Electroencephalographic recordings with 28 channels were continuously performed throughout the experiment to identify episodes of rapid-eye-movement (REM) sleep. Behaviors were continuously recorded in audio and video with an infrared camera. Dream reports were collected upon forced awakening from late REM sleep, and again in the morning after spontaneous awakening. On day 1, subjects were habituated to the sleep laboratory, no computer game was played, and negative controls for gamerelated dream reports were collected. On day 2, subjects played the computer game before and after sleep. Each game session lasted for an hour, and sleep for 7-9 hours. 9 different measures of performance indicated significant improve overnight. 81% of the subjects experienced intrusion of elements of the game into their dreams, including potentially adaptative strategies (insights). There was a linear correlation between performance and dream intrusion as well as for game improval and quantity of reported dreaming. In the electrophysiological analysis we mapped the subjects brain activities in different stages (SWS 1, REM 1, SWS 2, REM 2, Game 1 and Game 2), and found a modest reverberation in motor areas related to the joystick control during the sleep. When separated by gender, we found a significant difference on female subjects in the channels that indicate motor learning. Analysis of dream reports showed that the amount of gamerelated elements in dreams correlated with performance gains according to an inverted-U function analogous to the Yerkes-Dodson law that governs the relationship between arousal and learning. The results indicate that dreaming is an adaptive behavior

O papel das rotas e da obtenção de informações sobre a eficiência no forrageio de dinoponera quadriceps em ambiente natural

In this study, we investigated the role of routes and information attainment for the queenless ant species Dinoponera quadriceps foraging efficiency. Two queenless ant colonies were observed in an area of Atlantic secondary Forest at the FLONA-ICMBio of Nisia Floresta, in the state of Rio Grande do Norte, northeastern Brazil, at least once a week. In the first stage of the study, we observed the workers, from leaving until returning to the colony. In the second stage, we introduced a acrylic plate (100 x 30 x 0,8 cm) on a selected entrance of the nest early in the morning before the ants left the nest. All behavioral recordings were done through focal time and all occurence samplings. The recording windows were of 15 minutes with 1 minute interval, and 5 minute intervals between each observation window. Foraging was the main activity when the workers were outside the nest. There was a positive correlation between time outside the nest and distance travelled by the ants. These variables influenced the proportion of resource that was taken to the nest, that is, the bigger its proportion, the longer the time outside and distance travelled during the search. That proportion also influenced the time the worker remained in the nest before a new trip, the bigger the proportion of the item, the shorter was the time in the nest. During all the study, workers showed fidelity to the route and to the sectors in the home range, even when the screen was in the ant´s way, once they deviated and kept the route. The features of foraging concerning time, distance, route and flexibility to go astray by the workers indicate that decisions are made by each individual and are optimal in terms of a cost-benefit relation. The strategy chosen by queenless ants fits the central place foraging and marginal value theorem theories and demonstrate its flexibility to new informations. This indicates that the workers can learn new environmental landmarks to guide their routes

Atividade multimodal no córtex sensorial primário de ratos.

The currently accepted model of sensory processing states that different senses are processed in parallel, and that the activity of specific cortical regions define the sensorial modality perceived by the subject. In this work we used chronic multielectrode extracellular recordings to investigate to which extent neurons in the visual and tactile primary cortices (V1 and S1) of anesthetized rats would respond to sensory modalities not traditionaly associated with these cortices. Visual stimulation yielded 87% of responsive neurons in V1, while 82% of S1 neurons responded to tactile stimulation. In the same stimulation sessions, we found 23% of V1 neurons responding to tactile stimuli and 22% of S1 neurons responding to visual stimuli. Our data supports an increasing body of evidence that indicates the existence multimodal processing in primary sensory cortices. Our data challenge the unimodal sensory processing paradigm, and suggest the need of a reinterpretation of the currently accepted model of cortical hierarchy.

Uso de rotas na área de uso e a relação com comportamento alimentar em Callithrix jacchus

Callithrix jacchus are small primates that live in cooperative reproductive family groups. They explore their home range in search of fruits, exudates and animal prey. In this study we investigate the existence of traveling routes and its relation with the feeding habits in a group of Callithrix jacchus. The group was followed for 6 months in an area of Atlantic secondary Forest at the FLONA-ICMBio of Nísia Floresta, Rio Grande do Norte. Two observers in alternated days collected data referring to the group s location using a GPS navigation device, plotting data in 5 minute intervals, and with a position accuracy under 9 meters. All behavioral recordings were done through focal time samplings. The recording windows were 15 minutes with 1 minute intervals. The main activity was foraging, which propelled the animals to explore the environment with inconsistent intensity through the months, and correlated with the location of fruits, exudates and sleeping sites. From another standpoint, most activities were focused in the core areas that featured most sleeping sites, exudates trees and fruit trees. Insects, mostly Orthopterans, were hunted in all areas. The greater ratio of movement was registered during the last hours of sunlight, when animals returned to the sleeping sites and ate a greater number of fruits. The spatial and seasonal distribution of fruits forced the animals to travel long routes. The capacity to remember the location and navigate efficiently through feeding sources is important to save energy and time costs. Learning and familiarizing with the environment through the use of landmarks and acquisition of new information is extremely important to increase the chances of survival in a constantly changing environment

Caracterização do repertório acústico do botocinza, sotalia guianensis, e impacto de embarcações no nordeste do brasil

The wide distribution along the Brazilian coast of specie Sotalia guianensis has been growing interest in searchers on the ecology of this species, addition to commercial interests by whalewatching. This work described the accoustic repertory of S. guianensis and their behavior associated and found if underwater noises affect this repertorie in Pipa-RN. It were analyzed 18:49h of recordings maked between april and june/2009. It were found 3258 whistles, 289 calls, 873 clicks and no gargle. The frequencies range of guiana dolphins was 1 a 48kHz and may be related to system response recorder and population s regionalization. The frequencies overlaps the noise made by motorboats, schooners and water bomb. The behavior travelling ocurred siletly in 72,58% and socialization presented no sound (56,4%) and presence of sound (43,6%). This great absence of sound may be relacioned to saving energy, probably because in this behaviors they can use physical and visual contacts. The foraging presented highest records of all class noise with 46,84% clicks, 33,84% whistles and 9,02% calls. All this sounds occurred differently in each behavior (travelling: x2 = 134,35 df = 3 p = 0,0001; foraging: x2 = 19,83 df = 3 p= 0,00018 and socialization x2 = 60,35 df = 3 p = 0,0001). It was possible to determine that underwater noise cause changes in the repertorie and does a considerable increase in whistle s number and reduce clicks. Also occurs changes in some whistles (FI: t=2,42, p=0,015; FF: t= -2,22, p=0,025), calls (FMI: t= -3,13, p=0,001; FMA: t= -3,49, p=0,0005; FD: t= -2,21, p=0,027; D: t=2,89, p=0,004) and clicks parameters (D: t= -3,85, p=0,0001; I: t= -5,32, p=0,0001) during presence of noise. These changes may be a strategy of these animals to win this sound barrier. We can not say which noise has more impact, ix however the water bomb seems to affect more the clicks and the motorboats seems to affect the others sounds. Little is know about auditive sensibility of this specie, but daily exposure to this noise may cause damage and this specie appears to have residence. The specie conservation is necessary because the population already seems to suffer damage as decrease in length of stay, number of individuals entering the inlet and the apparent diminution in the foragind during vessels presence and control standards and ambiental education can help. So, we can advance in knowledge about the ecology of this specie especially when it come to bioacoustics and their behaviors associated and reveals some of the impacts that the noise have brought to this population

Positive leader characteristics from high-speed video observations

Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values range from 0.3 to 6.0 x 10(5) ms(-1) with a mean of 2.7 x 10(5) ms(-1). Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.

Ações educativas com portadores de diabetes Mellitus através da educação popular em saúde

Popular Health Education in its emancipatory dimension refers to individuals and groups to exchange knowledge and experiences, allowing them to associate health to the outcomes of their living conditions. Under this view, health workers and health users are subjects of the educative process. Thus, this study aims to identify the key clinical and socio sanitary attributes and promote educational activities with patients with Diabetes Mellitus (DM) in a Family Health Care Unit of the Western Sanitary District, in the city of Natal / RN. It is an action research which uses the references of the Theory of Liberating Education, which is based on a problem-solving pedagogy and that values dialogue in the process of understanding oneself and the world. Thirty-six diabetics, who are residents of the area covered by the health care unit, and thirty health workers participated in the survey. Each group had an average of twelve participants, and the meetings took place at the Unit´s hall, using conversation wheels, group dynamics, life narratives, experiences telling, movie exhibition and discussions, music, knowledge telling, desires, limitations, beliefs and values socially constructed. Data collection took place during the second half of two thousand and thirteen through Free Word Association Technique (FWAT), recordings of conversation wheels, participative observation, group dynamics, testimonies, questionnaires, life narratives and photographs. The empirical material was organized and subjected to three analyzes: thematic content (Bardin), textual statistics analysis by software IRAMUTEQ (Ratinaud), and photographic analysis (Edmund Feldman). The data analyses originated words, expressions, categories, themes and creative situations showing that popular health education is in process of construction, but still very incipient in primary care. The National Policy on Popular Health Education shows us the necessary ways for the transformation of health practices and the build of a more shared and solidary society. The meetings could be place to reverse that normative logic that has been happening over the years in primary care, but that by itself is not enough. It is possible to conclude that the use of active practices, increasing of listening and training on Popular Health Education will enable changes in the scenario where users and health workers deal with diabetes mellitus. Thus we see the popular health education is being timidly incorporated to the educational process of the subjects involved in this study, and far away from the principles of participation, organization of political work, increase opportunities for dialogue, respect, solidarity and tolerance among different actors involved in addressing the health problems that are fundamental to the improvement in building healthy practices of primary care

Aquisição da coda vibrante: o estabelecimento de pistas fonético-acústicas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nasalance and nasality at experimental velopharyngeal openings in palatal prosthesis: a case study

The use of prosthetic devices for correction of velopharyngeal insufficiency (VPI) is an alternative treatment for patients with conditions that preclude surgery and for those individuals with a hypofunctional velopharynx (HV) with a poor prognosis for the surgical repair of VPI. Understanding the role and measuring the outcome of prosthetic treatment of velopharyngeal dysfunction requires the use of tools that allow for documenting pre- and post-treatment outcomes. Experimental openings in speech bulbs have been used for simulating VPI in studies documenting changes in aerodynamic, acoustic and kinematics aspects of speech associated with the use of palatal prosthetic devices. The use of nasometry to document changes in speech associated with experimental openings in speech bulbs, however, has not been described in the literature. Objective: This single-subject study investigated nasalance and nasality at the presence of experimental openings drilled through the speech bulb of a patient with HV. Material and Methods: Nasometric recordings of the word "pato" were obtained under 4 velopharyngeal conditions: no-opening (control condition), no speech bulb, speech bulb with a 20 mm(2) opening, and speech bulb with 30 mm(2) opening. Five speech-language pathologists performed auditory-perceptual ratings while the subject read an oral passage under all conditions. Results: Kruskal-Wallis test showed significant difference among conditions (p=0.0002), with Scheffe post hoc test indicating difference from the no-opening condition. Conclusion: The changes in nasalance observed after drilling holes of known sizes in a speech bulb suggest that nasometry reflect changes in transfer of sound energy related to different sizes of velopharyngeal opening.

Nasoendoscopy of velopharynx before and during diagnostic therapy

Nasoendoscopy is an important tool for assessing velopharyngeal function. The purpose of this study was to analyze velar and pharyngeal wall movement and velopharyngeal gap during nasoendoscopic evaluation of the velopharynx before and during diagnostic therapy. Nasoendoscopic recordings of 10 children with operated cleft lip and palate were analyzed according to the International Working Group Guidelines. Ratings of movement of velum and pharyngeal walls, and size, location and shape of gaps were analyzed by 3 speech-language pathologists (SLPs). Imaging was obtained during repetitions of the syllable /pa/ during a single nasoendoscopic evaluation: (a) before diagnostic therapy, and (b) after the children were instructed to impound and increase intraoral air pressure (diagnostic therapy). Once the patients impounded and directed air pressure orally, the displacement of the velum, right, left and posterior pharyngeal walls increased 40, 70, 80, and 10%, respectively. Statistical significance for displacement was found only for right and left lateral pharyngeal walls. Reduction in gap size was observed for 30% of the patients and other 40% of the gaps disappeared. Changes in gap size were found to be statistically significant between the two conditions. In nasoendoscopic assessment, the full potential of velopharyngeal displacement may not be completely elicited when the patient is asked only to repeat a speech stimulus. Optimization of information can be done with the use of diagnostic therapy's strategies to manipulate VP function. Assuring the participation of the SLP to conduct diagnostic therapy is essential for management of velopharyngeal dysfunction.

Effects of subcutaneous methadone, morphine, buprenorphine or saline on thermal and pressure thresholds in cats

This study compared pressure and thermal thresholds after administration of three opioids in eight cats. Pressure stimulation was performed via a bracelet taped around the forearm. Three ball-bearings were advanced against the forearm by inflation of a modified blood pressure bladder. Pressure in the cuff was recorded at the end point (leg shake and head turn). Thermal threshold was tested as previously reported using a heated probe held against the thorax [Dixon et al. (2002) Research in Veterinary Science, 72, 205]. After baseline recordings, each cat received subcutaneous methadone 0.2 mg/kg, morphine 0.2 mg/kg, buprenorphine 0.02 mg/kg or saline 0.3 mL in a four period cross-over study. Measurements were made at 15, 30, 45 min and 1, 2, 3, 4, 8, 12 and 24 h after the injection. Data were analysed by ANOVA (P < 0.05). There were no significant changes in thresholds after saline. Thermal threshold increased at 45 min after buprenorphine (maximum 2.8 +/- 3 degrees C), 1-3 h after methadone (maximum 3.4 +/- 1.9 degrees C) and 45 min to 1 h (maximum 3.4 +/- 2 degrees C) after morphine. Pressure threshold increased 30-45 min (maximum 238 +/- 206 mmHg) after buprenorphine, 45-60 min after methadone (maximum 255 +/- 232 mmHg) and 45-60 min and 3-6 h (maximum 255 +/- 232 mmHg) after morphine. Morphine provided the best analgesia, and methadone appears a promising alternative. Buprenorphines limited effect was probably related to the subcutaneous route of administration. Previously, buprenorphine has produced much greater effects when given by other routes.

Scintigraphic validation of AC Biosusceptometry to study the gastric motor activity and the intragastric distribution of food in humans

Abnormal intragastric distribution of food (IDF) and a phasic contractility in the proximal stomach have been related to dyspeptic symptoms. Thus, the behaviour of the stomach and the proximal region, in particular, continues to attract attention and demand for reliable and comfortable techniques. The aims of this study were to employ AC Biosus-ceptometry (ACB) and scintigraphy to evaluate IDF and gastric motor activity in humans. Fifteen healthy volunteers ingested 60 mL of yogurt containing 2 mCi of Tc-99m and 4 g of ferrite. Each volunteer had gastric motility and IDF evaluated twice on separate days; on one occasion by ACB and another by scintigraphy. Digital signal processing was performed in MatLab (Mathworks Inc., Natick, MA, USA). Results were expressed as mean +/- SD. Similar results of distal accumulation time (P < 0.001) were obtained for scintigraphy (6.93 +/- 3.25 min) and for ACB (7.04 +/- 3.65 min). Fast Fourier Transform revealed two dominant frequencies (P > 0.9). Besides the well-know frequency of 3 cpm, our results showed identical frequencies in proximal stomach recordings (P < 0.001) for scintigraphic (1.01 +/- 0.01 cpm) and ACB (0.98 +/- 0.06 cpm). In summary, our data showed that scintigraphy and ACB are promising techniques to evaluate several aspects of gastric motility. Moreover, ACB is non-invasive, radiation-free and deserves the same importance as conventional methods for this kind of analysis.

Influence of the elevation of the left ventricular diastolic pressure on the values of the first temporal derivative of the ventricular pressure (dP/dt)

PURPOSE: To assess the effects of the elevation of the left ventricular end-diastolic pressure (LVEDP) on the value of the 1st temporal derivative of the ventricular pressure (dP/dt). METHODS: Nineteen anesthetized dogs were studied. The dogs were mechanically ventilated and underwent thoracotomy with parasympathetic nervous system block. The LVEDP was controlled with the use of a perfusion circuit connected to the left atrium and adjusted to the height of a reservoir. The elevation of the LVEDP was achieved by a sudden increase in the height of a reservoir filled with blood. Continuous recordings of the electrocardiogram, the aortic and ventricular pressures and the dP/dt were performed. RESULTS: Elevation of the LVEDP did not result in any variation of the heart rate (167±16.0bpm, before the procedure; 167±15.5bpm, after the procedure). All the other variables assessed, including systolic blood pressure (128±18.3mmHg and 150±21.5mmHg), diastolic blood pressure (98±16.9mmHg and 115±19.8mmHg), LVEDP (5.5±2.49 and 9.3±3.60mmHg), and dP/dt (4,855 ± 1,082 mmHg/s and 5,149±1,242mmHg/s) showed significant increases following the expansion of the ventricular cavity. Although the elevation of the dP/dt was statistically significant, 6 dogs curiously showed a decrease in the values of dP/dt. CONCLUSION: Sudden elevation of the LVEDP resulted in increased values of dP/dt; however, in some dogs, this response was not uniform.

Agroindústria canavieira e unidade de conservação: Impactos Sociais na comunidade de pescadores de Baía Formosa (RN)

The conservation unities emerged in response to the environmental damages. In the Atlantic Forest of the Brazilian Northeast, the most of the damages come from the sugar-cane agro-industry, especially by the deforestation for the introduction of sugar-cane fields and installation of the industry structure. Besides the damages over the biodiversity, there are critical social problems that affect the communities which survive using directly or indirectly the biome from the Atlantic Forest. The objective of this research is to analyze the social impacts on the fishermen of Baía Formosa/RN generated by the changes and socio-environmental transformations occurred starting the installation of a sugar-cane factory and the creation of a conservation area in the municipality of Baía Formosa/RN community. The research is based on a qualitative and diachronic perspective, for both approach, it was used the method of oral history in conjunction with the literature search and some technical and research tools such as direct observation, interview, records images and recordings . The results show that social and symbolic practices of the community in the conservation unit Mata Estrela last more strongly presented. Today fewer natural resources are used, due to factors such as limit access to forest and disappearance of some natural resources by deforestation. It is believed that the loss of free access to space for the community is the most significant negative impact, as promoted changes in the relationship of the community with the Star Forest that contributed to the fading of their social and symbolic practices. The loss of free access caused the decline in the practice of agriculture, which resulted in the loss of one of the means of social reproduction of the community