The distinctive sleep pattern of the human calcarine cortex: a stereo-electroencephalographic study.

STUDY OBJECTIVES: The aim of this study was to describe the spontaneous electroencephalographic (EEG) features of sleep in the human calcarine cortex, comparing them with the well-established pattern of the parietal cortex. METHODS: We analyzed presurgical intracerebral EEG activity in calcarine and parietal cortices during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep in seven patients with drug-resistant focal epilepsy. The time course of the EEG spectral power and NREM vs REM differences was assessed. Sleep spindles were automatically detected. To assess homeostatic dynamics, we considered the first vs second half of the night ratio in the delta frequency range (0.5-4 Hz) and the rise rate of delta activity during the first sleep cycle. RESULTS: While the parietal area showed the classically described NREM and REM sleep hallmarks, the calcarine cortex exhibited a distinctive pattern characterized by: (1) the absence of sleep spindles; (2) a large similarity between EEG power spectra of NREM and REM; and (3) reduced signs of homeostatic dynamics, with a decreased delta ratio between the first and the second half of the night, a reduced rise rate of delta activity during the first NREM sleep cycle, and lack of correlation between these measures. CONCLUSIONS: Besides describing for the first time the peculiar sleep EEG pattern in the human calcarine cortex, our findings provide evidence that different cortical areas may exhibit specific sleep EEG pattern, supporting the view of sleep as a local process and promoting the idea that the functional role of sleep EEG features should be considered at a regional level.

Occurrence of head lice in children and adolescents seen at a hospital in Uberlândia, central Brazil / Aparición de piojos en niños y adolescentes atendidos en un hospital de Uberlândia, centro de Brasil / Ocorrência de piolhos em crianças e adolescentes atendidos em um hospital de Uberlândia, região central do Brasil

The purpose of this study was to verify the occurrence of head lice in children at a public hospital in Uberlândia, MG and factors associated with pediculosis such as sex, age, hair characteristics and socioeconomic conditions, as well as obtaining information from their parents/guardians regarding the epidemiology, its transmission, prevention and control. To obtain the data, direct hair inspection and a characterization sheet and questionnaire were utilized. An occurrence rate of 6.1 % was found in 230 children examined in a public hospital, 111 females and 119 males with the highest rates observed in female children aged 4-8 with medium to long hair. Income, level of education, hair washing, hair type, color and thickness did not seem to influence the distribution of pediculosis in the children seen in the hospital in Uberlândia. The questionnaire answered by parents/guardians indicated that the children had had at least one infestation in their lifetime. The use of fine comb and pesticides were the most usual control methods adopted. The most frequent symptom was severe itching on the scalp. Although the occurrence of head pediculosis is declining, it is still a prevalent public health problem in the child population of Uberlândia, MG. Pediculosis may be associated with sex, age and hair characteristics. Variations in the degree of these influencing factors depend on the profile of the population studied. Additional studies are required in population groups over time, particularly in those that are inadequately assisted or lack state education and health assistance.

El propósito de este estudio fue verificar la ocurrencia de piojos en niños de un hospital público de Uberlândia, MG y factores asociados a la pediculosis como sexo, edad, características del cabello y condiciones socioeconómicas, así como obtener información de sus padres / tutores. en cuanto a la epidemiología, su transmisión, prevención y control. Para la obtención de los datos se utilizó inspección capilar directa y hoja de caracterización y cuestionario. Se encontró una tasa de ocurrencia del 6.1% en 230 niños examinados en un hospital público, 111 mujeres y 119 hombres, con las tasas más altas observadas en niñas de 4 a 8 años con cabello medio a largo. Los ingresos, el nivel de educación, el lavado del cabello, el tipo de cabello, el color y el grosor no parecen influir en la distribución de la pediculosis en los niños atendidos en el hospital de Uberlândia. El cuestionario respondido por los padres / tutores indicó que los niños habían tenido al menos una infestación en su vida. El uso de peine fino y pesticidas fueron los métodos de control más habituales adoptados. El síntoma más frecuente fue la picazón intensa en el cuero cabelludo. Aunque la incidencia de pediculosis de la cabeza está disminuyendo, sigue siendo un problema de salud pública prevalente en la población infantil de Uberlândia, MG. La pediculosis puede estar asociada con el sexo, la edad y las características del cabello. Las variaciones en el grado de estos factores de influencia dependen del perfil de la población estudiada. Se requieren estudios adicionales en grupos de población a lo largo del tiempo, particularmente en aquellos que reciben asistencia inadecuada o carecen de educación y asistencia sanitaria estatal.

O objetivo deste estudo foi verificar a ocorrência de piolhos de cabeça em crianças de um hospital público de Uberlândia, MG e fatores associados à pediculose como sexo, idade, características do cabelo e condições socioeconômicas, além de obter informações dos pais / responsáveis. quanto à epidemiologia, sua transmissão, prevenção e controle. Para a obtenção dos dados foram utilizados inspeção direta dos cabelos e ficha de caracterização e questionário. Uma taxa de ocorrência de 6,1% foi encontrada em 230 crianças examinadas em um hospital público, 111 mulheres e 119 homens com as taxas mais altas observadas em crianças do sexo feminino de 4 a 8 anos com cabelo médio a longo. Renda, escolaridade, lavagem dos cabelos, tipo, cor e espessura do cabelo não parecem influenciar na distribuição da pediculose nas crianças atendidas no hospital de Uberlândia. O questionário respondido pelos pais / responsáveis ​​indicou que as crianças tiveram pelo menos uma infestação na vida. O uso de pente fino e pesticidas foram os métodos de controle mais comumente adotados. O sintoma mais frequente foi coceira intensa no couro cabeludo. Embora a ocorrência de pediculose cefálica esteja em declínio, ainda é um problema de saúde pública prevalente na população infantil de Uberlândia, MG. A pediculose pode estar associada ao sexo, idade e características do cabelo. As variações no grau desses fatores influenciadores dependem do perfil da população estudada. Estudos adicionais são necessários em grupos populacionais ao longo do tempo, principalmente naqueles que são inadequadamente assistidos ou carecem de educação e assistência à saúde do Estado.

The Spatiotemporal Pattern of the Human Electroencephalogram at Sleep Onset After a Period of Prolonged Wakefulness.

During the sleep onset (SO) process, the human electroencephalogram (EEG) is characterized by an orchestrated pattern of spatiotemporal changes. Sleep deprivation (SD) strongly affects both wake and sleep EEG, but a description of the topographical EEG power spectra and oscillatory activity during the wake-sleep transition after a period of prolonged wakefulness is still missing. The increased homeostatic sleep pressure should induce an earlier onset of sleep-related EEG oscillations. The aim of the present study was to assess the spatiotemporal EEG pattern at SO following SD. A dataset of a previous study was analyzed. We assessed the spatiotemporal EEG changes (19 cortical derivations) during the SO (5 min before vs. 5 min after the first epoch of Stage 2) of a recovery night after 40 h of SD in 39 healthy subjects, analyzing the EEG power spectra (fast Fourier transform) and the oscillatory activity [better oscillation (BOSC) detection method]. The spatiotemporal pattern of the EEG power spectra mostly confirmed the changes previously observed during the wake-sleep transition at baseline. The comparison between baseline and recovery showed a wide increase of the post- vs. pre-SO ratio during the recovery night in the frequency bins ≤10 Hz. We found a predominant alpha oscillatory rhythm in the pre-SO period, while after SO the theta oscillatory activity was prevalent. The oscillatory peaks showed a generalized increase in all frequency bands from delta to sigma with different predominance, while beta activity increased only in the fronto-central midline derivations. Overall, the analysis of the EEG power replicated the topographical pattern observed during a baseline night of sleep but with a stronger intensity of the SO-induced changes in the frequencies ≤10 Hz, and the detection of the rhythmic activity showed the rise of several oscillations at SO after SD that was not observed during the wake-sleep transition at baseline (e.g., alpha and frontal theta in correspondence of their frequency peaks). Beyond confirming the local nature of the EEG pattern at SO, our results show that SD has an impact on the spatiotemporal modulation of cortical activity during the falling-asleep process, inducing the earlier emergence of sleep-related EEG oscillations.

Occurrence and awareness of head lice among elderly residents in long-term care facilities in Uberlandia, MG, Brazil

The purpose of this investigation was to determine the occurrence of head lice in long-term care facilities (LTCFs) in Uberlandia, MG, Brazil, analyze associations with sex, ethnicity, age and hair characteristics, and verify awareness among elderly adults. Head inspections were performed and infestation was characterized on individual forms. A questionnaire on the biology, epidemiology and control of head lice was applied. Overall occurrence was 1.4%, being highest in elderly women with medium-length curly hair. Questionnaire responses indicated that the majority had no general knowledge on head lice. More than 40% reported infestation at some point in their lives and most knew how to control it. Overall occurrence was considered low and is related to measures adopted by the LTCFs, which controlled infestation by minimizing the influence of factors normally associated with its occurrence. The study was pioneer in analyzing associations between head lice and the degree of autonomy of elderly adults.

Epidemiological aspects of head lice in children attended to at a public hospital in Uberlândia, Minas Gerais state, Brazil

Pediculosis capitis is a public health problem not only in Brazil, but also in many countries worldwide. Children are the most likely population group to be infested. The purpose of this study was to verify the prevalence of head lice in children seen at the public hospital in Uberlândia, Minas Gerais State, and factors associated with ectoparasitosis in this group. In addition, data about the transmission, prevention and control were obtained from the children's parents or guardians. The scalp and hair of every child aged 2 to 12, attended to at the hospital pediatric outpatient clinic from 2015 to 2017, were examined. Questionnaires and characterization sheets were also used to obtain and record the information. The overall prevalence rate observed was 2.8%. The highest prevalence rates were observed in girls with medium length hair. Children presented a relatively low prevalence of head lice in the parasitological examinations. However, the answers to the questionnaires indicated that this ectoparasitosis is common in this population group. All the children examined were of school age, and their parents or guardians indicated the school environment as the main source of infestations. The responses to the questionnaires also highlighted evidence of negligence on the part of guardians of positive children regarding the occurrence of this ectoparasitosis. The information obtained indicates that authorities should design/improve their plans of action regarding guidelines for parents or guardians for adequate prevention and control of this ectoparasitosis

Symptom severity and mindreading in narcissistic personality disorder.

BACKGROUND: Grandiose narcissism has been associated with poor ability to understand one's own mental states and the mental states of others. In particular, two manifestations of Narcissistic Personality Disorder (NPD) can be explained by poor mindreading abilities: absence of symptomatic subjective distress and lack of empathy. METHODS: We conducted two studies to investigate the relationships between mindreading capacity, symptomatic subjective distress and narcissistic personality. In the first study (N = 246), we compared mindreading capacities and symptomatic distress in three outpatient samples: narcissistic patients (NPD); patients with other Personality Disorders (PD); patients without PD. In the second study (N = 1357), we explored the relationships between symptomatic distress, mindreading and specific NPD criteria. RESULTS: In the first study, the NPD patients showed poorer mindreading than the patients without PD and comparable to patients with other PDs. Symptomatic subjective distress in the narcissistic group was less severe than in the other PDs group and comparable to the group without PDs. However, no relationship emerged between mindreading and symptomatic subjective distress. In the second study, taking the clinical sample as a whole, symptomatic distress appeared negatively linked to grandiosity traits, while mindreading scores were negatively linked to empathy. CONCLUSIONS: NPD showed specific mindreading impairments. However, mindreading capacity did not appear to be directly connected with subjective distress, but did appear to be connected with specific aspects of narcissistic pathology.

Avoidant personality disorder and social phobia: Does mindreading make the difference?

OBJECTIVE: Avoidant personality disorder (AvPD) is closely related to and partially overlaps with social phobia (SP). There is an ongoing debate as to whether AvPD and SP can be classified as separate and distinct disorders or whether these diagnoses rather reflect different degrees of severity of social anxiety. The hypothesis of this study is that in patients with AvPD and in those with AvPD and comorbid SP both interpersonal functioning and metacognitive abilities (the ability to understand mental states) are more severely impaired than they are in patients with SP only. We also hypothesise that the interpersonal and metacognitive functioning of these patients (both AvPD and AvPD+SP) is comparable to that of patients with other PD diagnoses. METHODS: To test this hypothesis, we compared four groups (22 patients with SP, 32 patients with AvPD, 43 patients with both AvPD and SP and 50 patients with other personality disorders without SP and AvPD criteria) on metacognitive abilities, interpersonal functioning and global symptomatic distress. RESULTS: Metacognitive ability showed significant variation among the four groups, with the lowest score observed in the AvPD group. As far as the interpersonal functioning is concerned, the lack of sociability was more severe in the AvPD group compared with the SP group. These differences were maintained even after controlling for global symptomatic distress. CONCLUSION: Results are in line with the alternative model of PD, proposed in the DSM-5, as dysfunction of the self and relationships. They suggest that specific impairments in critical areas of self domains and interpersonal domains of personality functioning may serve as markers distinguishing AvPD from SP.

Levels of Social Sharing and Clinical Implications for Severe Social Withdrawal in Patients with Personality Disorders.

Social sharing capacities have attracted attention from a number of fields of social cognition and have been variously defined and analyzed in numerous studies. Social sharing consists in the subjective awareness that aspects of the self's experience are held in common with other individuals. The definition of social sharing must take a variety of elements into consideration: the motivational element, the contents of the social sharing experience, the emotional responses it evokes, the behavioral outcomes, and finally, the circumstances and the skills which enable social sharing. The primary objective of this study is to explore some of the diverse forms of human social sharing and to classify them according to levels of complexity. We identify four different types of social sharing, categorized according to the nature of the content being shared and the complexity of the mindreading skills required. The second objective of this study is to consider possible applications of this graded model of social sharing experience in clinical settings. Specifically, this model may support the development of graded, focused clinical interventions for patients with personality disorders characterized by severe social withdrawal.

Head lice in school children in Uberlandia, Minas Gerais state, Brazil

School-aged children have shown to be the group most susceptible to Pediculus capitis infestation, possibly due to their habits and behaviors. The purpose of the study was to verify the prevalence of head pediculosis in preschool children from Uberlândia, MG, and factors associated with infestation. The children's parents or guardians were also evaluated regarding socioeconomic status, knowledge of symptomatology and control of this ectoparasitosis. Data were obtained by direct examination of each child's head and a questionnaire answered by parents/guardians. The overall prevalence rate was 7.5% among the 372 children examined, and 4 to 5-year-old girls with long hair presented significantly higher prevalence rates. Information from the questionnaires indicated that 45% of the children had already been infested at least once and the main symptom mentioned was intense itching on the scalp. Those responsible mostly used natural control measures to control infestations. The results indicated that children under the age of six should also be included in head pediculosis control programs

Mindreading Dysfunction in Avoidant Personality Disorder Compared With Other Personality Disorders.

The ability to reflect on one's own states of mind and those of others (metacognition or mindreading) is strongly implicated in personality disorders (PDs). Metacognition involves different abilities, and there is evidence that specific abilities can be selectively impaired in different PDs. The purposes of this study were to compare metacognitive competence in avoidant PD (AvPD) with that in other PDs and to investigate whether there is a specific profile for AvPD. Sixty-three patients with AvPD and 224 patients with other PDs were assessed using the Metacognitive Assessment Interview. AvPD patients showed difficulties with two metacognitive functions: monitoring and decentration, even when the severity of psychopathology was controlled for. These results support the hypothesis of specific profiles of metacognitive dysfunction in different PDs and highlight a close link between impaired monitoring and decentration functions and the inhibited and withdrawn personality style typical of AvPD.

Personality Disorders and Mindreading: Specific Impairments in Patients With Borderline Personality Disorder Compared to Other PDs.

The capacity of understanding mental states is a complex function which involves several components. Single components can be selectively impaired in specific clinical populations. It has been suggested that impairments in mindreading are central for borderline personality disorder (BPD). However, empirical findings are inconsistent, and it is debatable whether BPD presents a specific profile of mindreading impairments. The aim of this study is to compare BPD and other PDs in mindreading. Seventy-two patients with BPD and 125 patients with other PD diagnoses were assessed using the Metacognition Assessment Interview. BPD showed difficulties in two mindreading functions, differentiation and integration, even when the severity of psychopathology was controlled. These results suggest a specific mindreading impairment in BPD and a strong relationship between these impairments and the severity of psychopathology.

HEAD LICE IN HAIR SAMPLES FROM YOUTHS, ADULTS AND THE ELDERLY IN MANAUS, AMAZONAS STATE, BRAZIL.

A study of head lice infestations among young people, adults and elderly individuals was conducted from August 2010 to July 2013 in Manaus, AM, Northern Brazil. Hair samples collected from 1,860 individuals in 18 barber shops and beauty parlors were examined for the ectoparasite. The occurrence of pediculosis and its association with factors, such as sex, age, ethnicity, hair characteristics and the socioeconomic profile of salon customers, salon location and seasonal variation were determined. The overall occurrence rate was 2.84%. Occurrence was higher in hair samples from non-blacks and the elderly. Higher occurrence was also observed during kindergarten, elementary and junior education school holidays. The results indicate that the occurrence of head lice among young people, adults and the elderly in Manaus is relatively low compared to that determined in children and in other regions of the country. After children, the elderly were the most affected. The study also indicated the need to adopt additional procedures to improve surveys among the population with low or no purchasing power, which is usually the most affected by this ectoparasitic disease.

Head lice in harr samples from youths, adults ad the elderly in manaus, amazonnas state, Brazil / Pediculose da cabeça em amostras de cabelos de jovens, adultos e idosos em Manaus, Estado do Amazonas, Brasil

A study of head lice infestations among young people, adults and elderly individuals was conducted from August 2010 to July 2013 in Manaus, AM, Northern Brazil. Hair samples collected from 1,860 individuals in 18 barber shops and beauty parlors were examined for the ectoparasite. The occurrence of pediculosis and its association with factors, such as sex, age, ethnicity, hair characteristics and the socioeconomic profile of salon customers, salon location and seasonal variation were determined. The overall occurrence rate was 2.84%. Occurrence was higher in hair samples from non-blacks and the elderly. Higher occurrence was also observed during kindergarten, elementary and junior education school holidays. The results indicate that the occurrence of head lice among young people, adults and the elderly in Manaus is relatively low compared to that determined in children and in other regions of the country. After children, the elderly were the most affected. The study also indicated the need to adopt additional procedures to improve surveys among the population with low or no purchasing power, which is usually the most affected by this ectoparasitic disease.

Estudo sobre a pediculose do couro cabeludo em jovens, adultos e idosos foi realizado de agosto de 2010 a julho de 2013 em Manaus - AM, região norte do Brasil. Amostras de cabelos obtidas de 1.860 indivíduos em 18 barbearias e salões de beleza foram examinadas à procura do parasito. Procurou-se verificar a ocorrência da pediculose e sua associação com fatores tais como: sexo, idade, etnia, características dos cabelos e perfil socioeconômico dos clientes dos salões, localização dos salões e variação sazonal. A taxa de ocorrência encontrada foi 2,84%. Ela foi maior em amostras de cabelos de não negros e dos idosos. Também se observou maior prevalência no período de férias escolares do ensino fundamental e médio. Os resultados indicam que a ocorrência da pediculose em jovens, adultos e idosos em Manaus é relativamente baixa em comparação com as encontradas em crianças e as encontradas em outras regiões do país. Depois das crianças, os idosos seriam os mais acometidos. O estudo também indica a necessidade de adotar procedimentos adicionais para melhor amostrar a faixa da população com menor ou com nenhum poder aquisitivo, a qual geralmente é a mais acometida por esta ectoparasitose.

Pediculose em crianças e jovens atendidos em orfanatos e ambulatório público de Manaus, AM, Brasil / Pediculosis capitis on children and young people attended in orphanages and outpatient clinics in Manaus, AM, Brazil

A pediculose do couro cabeludo é um problema de saúde pública não somente no Brasil, mastambém em vários países do mundo. Crianças em idade escolar têm demonstrado ser o grupomais susceptível à infestação por seus hábitos e comportamentos. Estudos recentes encontraram baixas taxas de ocorrência em crianças e jovens de creches e escolas de Manaus-AM. Foramobjetivos deste estudo verificar a prevalência da pediculose do couro cabeludo em crianças e jovens atendidos em abrigos/orfanatos e no setor de pediatria de um ambulatório público na cidade de Manaus e também analisar possíveis associações com idade, sexo, etnia e tamanho dos cabelos dos parasitados. O diagnóstico da parasitose foi feito com base no exame direto das cabeças das crianças e jovens e, em seguida, foi preenchida uma ficha com informações sobre cada um dos 437 indivíduos examinados. Observou-se uma prevalência total de 44,8 por cento. Houve maior ocorrênciaem indivíduos do sexo feminino (57,7 por cento) e nas faixas etárias acima de 5 anos de idade. Indivíduos com cabelos longos exibiram a maior prevalência (62,3 por cento). Os resultados apresentados neste trabalho mostram a necessidade de investigação desta ectoparasitose em grupos que apresentem características epidemiológicas como as descritas aqui e outras que os predisponham a esta e outras ectoparasitoses, mesmo em áreas/cidades onde esta dermatite parasitária apresente baixas taxas deocorrência na população.

Pediculosis capitis is a public health problem not only in Brazil but in many countries worldwide.School children have been shown to be the most likely group to be infested due to their habits andbehaviors. Recent studies have encountered low prevalences of this infestation on children attendedin nurseries and schools in Manaus, Amazon State. The study objectives were to verify the prevalenceof pediculosis on children and young people assisted in shelters / orphanages and the pediatricdepartment of a public clinic in the city of Manaus, as well as to analyze possible associations withage, sex, ethnicity and length of hair of those infested. The diagnosis of parasites was made from thedirect examination of the heads of children and young people and then a form with information was completed, for each of the 437 individuals examined. There was an overall occurrence rate of 44.8 percent.The parasite was more frequent on females (57.7 percent) and in the age groups older than five years old. Subjects with long hair had the highest prevalence (62.3 percent). The results presented in this work show theneed to investigate this parasitic skin disease in groups that have the characteristics / epidemiological factors studied here and others that may predispose them to this and other ectoparasites, even in areas/ cities where this parasitic dermatitis has shown low occurrence rates in the population.

Topographic electroencephalogram changes associated with psychomotor vigilance task performance after sleep deprivation.

OBJECTIVES: The psychomotor vigilance task (PVT) is a widely used method for the assessment of vigilance after sleep deprivation (SDEP). However, the neural basis of PVT performance during SDEP has not been fully understood. In particular, no studies have investigated the possible relation between EEG topographical changes after sleep loss and PVT performance. The aim of the present study is to assess the EEG topographic correlates of PVT performance after SDEP. METHODS: During 40 h of SDEP, 16 healthy male subjects were evaluated in four sessions performed at the same time (11:00 a.m. and 11:00 p.m.) of the first and second day with: (a) subjective sleepiness recordings by means of the Karolinska Sleepiness Scale (KSS); (b) EEG recordings (5 min eyes-open condition); and (c) PVT. RESULTS: SDEP induced a slowing of PVT reaction times (RTs), higher level of subjective sleepiness and an increase of delta, theta, alpha and beta 1 EEG activity. Only slowest PVT RTs were influenced by circadian factors, with longer RTs in the morning. Both fastest PVT RTs and KSS scores were positively correlated with post-SDEP changes in EEG theta activity, mainly in centro-posterior areas, but not with other EEG frequencies. KSS scores and PVT measures were also positively correlated. CONCLUSIONS: These findings suggest that SDEP differently affects PVT variables, and that an increase in theta activity may be the principal EEG basis of the post-SDEP slowing of fastest PVT RTs. Similar neural mechanisms seem to underlie both performance deterioration to PVT and the increase of subjective sleepiness.

Sleep deprivation affects somatosensory cortex excitability as tested through median nerve stimulation.

BACKGROUND: Changes of cortical excitability after sleep deprivation (SD) in humans have been investigated mostly in motor cortex, while there is little empirical evidence concerning somatosensory cortex, and its plastic changes across SD. OBJECTIVE: To assess excitability of primary somatosensory cortex (S1) and EEG voltage topographical characteristics associated with somatosensory evoked potentials (SEPs) during SD. METHODS: Across 41 h of SD, 16 healthy subjects participated in 4 experimental sessions (11.00 a.m. and 11.00 p.m. of the 1st and 2nd day) with: a) subjective sleepiness ratings; b) EEG recordings; c) SEPs recordings; d) behavioral vigilance responses. RESULTS: A clear enhancement of cortical excitability after SD was indexed by: (a) an amplitude increase of different SEPs component in S1; (b) higher voltage in occipital (around 35-43 ms) and fronto-central areas (around 47-62 ms). Circadian fluctuations did not affect cortical excitability. Voltage changes in S1 were strongly related with post-SD fluctuations of subjective and behavioral sleepiness. CONCLUSIONS: Sleep may have a role in keeping cortical excitability at optimal (namely below potentially dangerous) levels for the human brain, rebalancing progressive changes in cortical responsiveness to incoming inputs occurred during time spent awake. On the other hand, higher level of cortical responsiveness after sleep loss may be one of the mechanisms accounting for post-SD alterations in vigilance and behavior.

Hippocampal slow EEG frequencies during NREM sleep are involved in spatial memory consolidation in humans.

The hypothesis that sleep is instrumental in the process of memory consolidation is currently largely accepted. Hippocampal formation is involved in the acquisition of declarative memories and particularly of spatial memories. Nevertheless, although largely investigated in rodents, the relations between spatial memory and hippocampal EEG activity have been scarcely studied in humans. Aimed to evaluate the effects of spatial learning on human hippocampal sleep EEG activity, we recorded hippocampal Stereo-EEG (SEEG) in a group of refractory epilepsy patients undergoing presurgical clinical evaluation, after a training on a spatial navigation task. We observed that hippocampal high-delta (2-4 Hz range) activity increases during the first NREM episode after learning compared to the baseline night. Moreover, the amount of hippocampal NREM high-delta power was correlated with task performance at retest. The effect involved only the hippocampal EEG frequencies inasmuch no differences were observed at the neocortical electrodes and in the traditional polysomnographic measures. The present findings support the crucial role of hippocampal slow EEG frequencies during sleep in the memory consolidation processes. More generally, together with previous results, they suggest that slow frequency rhythms are a fundamental characteristic of human hippocampal EEG during both sleep and wakefulness, and are related to the consolidation of different types of memories.

Systemic rhabdomyolysis induced by venom of freshwater stingrays Plesiotrygon iwamae and Potamotrygon motoro (Chondrichthyes-Potamotrygonidae) from the Amazon Basin.

Injuries caused by freshwater stingrays are characterized by intense pain and pathological changes at the lesion site, including oedema, erythema and, in most cases, necrosis. In this study, the systemic myotoxic activity induced by mucus extracts from the dorsal region and stinger of the stingrays Plesiotrygon iwamae and Potamotrygon motoro was described, analysed and quantified. Twenty-four hours after injection of 400 µg of the extracts into the gastrocnemius muscle of mice, the following effects were observed: coagulative necrosis of the muscle tissue, muscle fibre regeneration and the presence of inflammatory infiltrates, including neutrophils, macrophages, and a reduced number of eosinophils and lymphocytes. These changes were also observed, although to a lesser extent, in the gastrocnemius muscles of the contralateral limbs, demonstrating that the extracts from the two species could induce systemic rhabdomyolysis. Based on morphometric analysis, it was observed that the stinger extract of P. motoro was more potent in inducing local and systemic myotoxic activity, followed by the dorsal extract from P. motoro and stinger and dorsal extracts from P. iwamae, which induced similar effects.

How we fall asleep: regional and temporal differences in electroencephalographic synchronization at sleep onset.

OBJECTIVES: We hypothesized that the brain shows specific and predictable patterns of spatial and temporal differences during sleep onset (SO) reflecting a temporal uncoupling of electrical activity between different cortical regions and a dissociated wakelike and sleeplike electrocortical activity in different cortical areas. METHODS: We analyzed full-scalp electroencephalographic (EEG) recordings of 40 healthy subjects to investigate spatial and temporal changes of EEG activity across the wake-sleep transition. We quantified EEG sleep recordings by a fast Fourier transform (FFT) algorithm and by a better oscillation (BOSC) detection method to the EEG signals, which measured oscillatory activity within a signal containing a nonrhythmic portion. RESULTS: The most representative spatial change at SO is the frontalization of slow-wave activity (SWA), while the θ activity, which mostly shares a similar temporal and spatial pattern with SWA, exhibits a temporo-occipital diffusion. The time course of these oscillations confirms that the changes of the dominant waves coexist with topographic changes. The waking occipital prevalence of α oscillations is progressively replaced by an occipital prevalence of θ oscillations. On the other hand, more anterior areas show a wide synchronization pattern mainly expressed by slow waves just below 4 Hz and by spindle oscillations. CONCLUSIONS: The whole pattern of results confirms that the centrofrontal areas showed an earlier synchronization (i.e., they fall asleep first). This finding implies a coexistence of wakelike and sleeplike electrical activity during sleep in different cortical areas. It also implies that the process of progressive brain disconnection from the external world as we fall asleep does not necessarily affect primary and higher-order cortices at the same time.

Validity of the Italian version of the Pittsburgh Sleep Quality Index (PSQI).

The aim of this study is to validate the Italian version of the Pittsburgh Sleep Quality Index (PSQI), comparing five different groups of individuals (healthy young and elderly, sleep apnoea syndrome patients, depressed patients, individuals with dementia) by both questionnaire scores and polysomnographic measures. Fifty individuals (10 for each group) participated in the study. Each of them filled in the PSQI and slept for two consecutive nights in the sleep laboratory. The PSQI showed an overall reliability coefficient (Cronbach's α) of 0.835, indicating a high degree of internal consistency. The mean PSQI global score showed significant differences between groups, with an impaired overall quality of sleep in patients' groups with respect to both the healthy groups. Results also indicated that the best cut-off score (differentiating "good" from "bad" sleepers) is 5. Pittsburgh Sleep Quality Index is a useful, valid and reliable tool for the assessment of sleep quality, with an overall efficiency comparable to the mother language version and differentiate "good" from "bad" sleepers. The Italian version of the questionnaire provides a good and reliable differentiation between normal and pathological groups, with higher scores reported by people characterized by impaired objectively evaluated sleep quality.