Cyclic alternating pattern in sleep and its relationship to creativity

Background/Objectives: Sleep has been shown to enhance creativity, but the reason for this enhancement is not entirely known. There are several different physiological states associated with sleep. In addition to rapid (REM) and non-rapid eye movement (NREM) sleep, NREM sleep can be broken down into Stages (1-4) that are characterized by the degree of EEG slow wave activity. In addition, during NREM sleep there are transient but cyclic alternating patterns (CAP) of EEG activity and these CAPs can also be divided into three subtypes (A1-A3) according to speed of the EEG waves. Differences in CAP ratios have been previously linked to cognitive performances. The purpose of this study was to learn the relationship CAP activity during sleep and creativity. Methods: The participants were 8 healthy young adults (4 women), who underwent 3 consecutive nights of polysomnographic recording and took the Abbreviated Torrance Test for Adults (ATTA) on the 2 and 3rd mornings after the recordings. Results: There were positive correlations between Stage 1 of NREM sleep and some measures of creativity such as fluency (R= .797; p=.029) and flexibility ( R=.43; p=.002), between Stage 4 of Non-REM sleep and originality (R= .779; p=.034) and a global measure of figural creativity (R= .758; p=.040). There was also a negative correlation between REM sleep and originality (R= -.827; p= .042) . During NREM sleep the CAP rate, which in young people is primarily the A1 subtype, also correlated with originality (R= .765; p =.038). Conclusions: NREM sleep is associated with low levels of cortical arousal and low cortical arousal may enhance the ability of people to access to the remote associations that are critical for creative innovations. In addition, A1 CAP activity reflects frontal activity and the frontal lobes are important for divergent thinking, also a critical aspect of creativity.

Cyclic alternating pattern in narcolepsy patients and healthy controls after partial and total sleep deprivation

To investigate the regulation NREM sleep at baseline and in morning recovery sleep after partial and total sleep deprivation (SD) in narcolepsy-cataplexy (NC) using cyclic alternating pattern (CAP).

Delta sleep instability in children with chronic arthritis

The objective of the present study was to evaluate the expression of a cyclic alternating pattern (CAP) in slow wave sleep (SWS) in children with the well-defined chronic syndrome juvenile idiopathic arthritis (JIA). Twelve patients (9-17 years of age), 7 girls, with JIA were compared to matched controls by age, pubertal stage and gender. After one night of habituation in the sleep laboratory, sleep measurements were obtained by standard polysomnography with conventional sleep scoring and additional CAP analyses. The sleep parameters of the JIA and control groups were similar for sleep efficiency (91.1 ± 6.7 vs 95.8 ± 4.0), sleep stage in minutes: stage 1 (16.8 ± 8.5 vs 17.8 ± 4.0), stage 2 (251.9 ± 41 vs 262.8 ± 38.1), stage 3 (17.0 ± 6.0 vs 15.1 ± 5.7), stage 4 (61.0 ± 21.7 vs 77.1 ± 20.4), and rapid eye movement sleep (82.0 ± 27.6 vs 99.0 ± 23.9), respectively. JIA patients presented nocturnal disrupted sleep, with an increase in short awakenings, but CAP analyses showed that sleep disruption was present even during SWS, showing an increase in the overall CAP rate (P < 0.01). Overall CAP rate during non-rapid eye movement sleep was significantly higher in pediatric patients who were in chronic pain. This is the first study of CAP in pediatric patients with chronic arthritis showing that CAP analyses can be a powerful tool for the investigation of disturbance of SWS in children, based on sleep EEG visual analysis.

Rhythmic Masticatory Muscle Activity during Sleep: Etiology and Clinical Perspectives

L’activité rythmique des muscles masticateurs (ARMM) pendant le sommeil se retrouve chez environ 60% de la population générale adulte. L'étiologie de ce mouvement n'est pas encore complètement élucidée. Il est cependant démontré que l’augmentation de la fréquence des ARMM peut avoir des conséquences négatives sur le système masticatoire. Dans ce cas, l'ARMM est considérée en tant que manifestation d'un trouble moteur du sommeil connue sous le nom de bruxisme. Selon la Classification Internationale des Troubles du Sommeil, le bruxisme est décrit comme le serrement et grincement des dents pendant le sommeil. La survenue des épisodes d’ARMM est associée à une augmentation du tonus du système nerveux sympathique, du rythme cardiaque, de la pression artérielle et elle est souvent en association avec une amplitude respiratoire accrue. Tous ces événements peuvent être décrits dans le contexte d’un micro-éveil du sommeil. Cette thèse comprend quatre articles de recherche visant à étudier i) l'étiologie de l’ARMM pendant le sommeil en relation aux micro-éveils, et à évaluer ii) les aspects cliniques du bruxisme du sommeil, du point de vue diagnostique et thérapeutique. Pour approfondir l'étiologie de l’ARMM et son association avec la fluctuation des micro-éveils, nous avons analysé le patron cyclique alternant (ou cyclic alternating pattern (CAP) en anglais), qui est une méthode d’analyse qui permet d’évaluer l'instabilité du sommeil et de décrire la puissance des micro-éveils. Le CAP a été étudié chez des sujets bruxeurs et des sujets contrôles qui ont participé à deux protocoles expérimentaux, dans lesquels la structure et la stabilité du sommeil ont été modifiées par l'administration d'un médicament (la clonidine), ou avec l'application de stimulations sensorielles (de type vibratoire/auditif) pendant le sommeil. Dans ces deux conditions expérimentales caractérisées par une instabilité accrue du sommeil, nous étions en mesure de démontrer que les micro-éveils ne sont pas la cause ou le déclencheur de l’ARMM, mais ils représentent plutôt la «fenêtre permissive» qui facilite l'apparition de ces mouvements rythmiques au cours du sommeil. Pour évaluer la pertinence clinique du bruxisme, la prévalence et les facteurs de risque, nous avons effectué une étude épidémiologique dans une population pédiatrique (7-17 ans) qui était vue en consultation en orthodontie. Nous avons constaté que le bruxisme est un trouble du sommeil très fréquent chez les enfants (avec une prévalence de 15%), et il est un facteur de risque pour l'usure des dents (risque relatif rapproché, RRR 8,8), la fatigue des muscles masticateurs (RRR 10,5), les maux de tête fréquents (RRR 4,3), la respiration bruyante pendant le sommeil (RRR 3,1), et divers symptômes liés au sommeil, tels que la somnolence diurne (RRR 7,4). Ces résultats nous ont amenés à développer une étude expérimentale pour évaluer l'efficacité d'un appareil d'avancement mandibulaire (AAM) chez un groupe d'adolescents qui présentaient à la fois du bruxisme, du ronflement et des maux de tête fréquents. L'hypothèse est que dans la pathogenèse de ces comorbidités, il y a un mécanisme commun, probablement lié à la respiration pendant le sommeil, et que l'utilisation d'un AAM peut donc agir sur plusieurs aspects liés. À court terme, le traitement avec un AAM semble diminuer l'ARMM (jusqu'à 60% de diminution), et améliorer le ronflement et les maux de tête chez les adolescents. Cependant, le mécanisme d'action exact des AAM demeure incertain; leur efficacité peut être liée à l'amélioration de la respiration pendant le sommeil, mais aussi à l'influence que ces appareils pourraient avoir sur le système masticatoire. Les interactions entre le bruxisme du sommeil, la respiration et les maux de tête, ainsi que l'efficacité et la sécurité à long terme des AAM chez les adolescents, nécessitent des études plus approfondies.

Sonno e funzioni cognitive: ruolo della microstruttura del sonno NREM

STUDY OBJECTIVE: Cyclic Alternating Pattern (CAP) is a fluctuation of the arousal level during NREM sleep and consists of the alternation between two phases: phase A (divided into three subtypes A1, A2, and A3) and phase B. A1 is thought to be generated by the frontal cortex and is characterized by the presence of K complexes or delta bursts; additionally, CAP A1 seems to have a role in the involvement of sleep slow wave activity in cognitive processing. Our hypothesis was that an overall CAP rate would have a negative influence on cognitive performance due to excessive fluctuation of the arousal level during NREM sleep. However, we also predicted that CAP A1 would be positively correlated with cognitive functions, especially those related to frontal lobe functioning. For this reason, the objective of our study was to correlate objective sleep parameters with cognitive behavioral measures in normal healthy adults. METHODS: 8 subjects (4 males; 4 females; mean age 27.75 years, range 2334) were recruited for this study. Two nocturnal polysomnography (night 2 and 3 = N2 and N3) were carried out after a night of adaptation. A series of neuropsychological tests were performed by the subjects in the morning and afternoon of the second day (D2am; D2pm) and in the morning of the third day (D3am). Raw scores from the neuropsychological tests were used as dependent variables in the statistical analysis of the results. RESULTS: We computed a series of partial correlations between sleep microstructure parameters (CAP, A1, A2 and A3 rate) and a number of indices of cognitive functioning. CAP rate was positively correlated with visuospatial working memory (Corsi block test), Trial Making Test Part A (planning and motor sequencing) and the retention of words from the Hopkins Verbal Learning Test (HVLT). Conversely, CAP was negatively correlated with visuospatial fluency (Ruff Figure Fluency Test). CAP A1 were correlated with many of the tests of neuropsychological functioning, such as verbal fluency (as measured by the COWAT), working memory (as measured by the Digit Span – Backward test), and both delay recall and retention of the words from the HVLT. The same parameters were found to be negatively correlated with CAP A2 subtypes. CAP 3 were negatively correlated with the Trial Making Test Parts A and B. DISCUSSION: To our knowledge this is the first study indicating a role of CAP A1 and A2 on behavioral cognitive performance of healthy adults. The results suggest that high rate of CAP A1 might be related to an improvement whereas high rate of CAP A2 to a decline of cognitive functions. Further studies need to be done to better determine the role of the overall CAP rate and CAP A3 on cognitive behavioral performances.

Attività autonomica cardiaca e funzioni neurocognitive nei pazienti affetti da sindrome delle gambe senza riposo (RLS): effetto dei farmaci dopamino agonisti in acuto e a lungo termine

Several studies showed that sleep loss/fragmentation may have a negative impact on cognitive performance, mood and autonomic activity. Specific neurocognitive domains, such as executive function (i.e.,prefrontal cortex), seems to be particularly vulnerable to sleep loss. Pearson et al.(2006) evaluated 16 RLS patients compared to controls by cognitive tests, including those particularly sensitive to prefrontal cortical (PFC) functioning and sleep loss. RLS patients showed significant deficits on two of the three PFC tests. It has been recently reported that RLS is associated with psychiatric manifestations. A high prevalence of depressive symptoms has been found in patients with RLS(Rothdach AJ et al., 2000). RLS could cause depression through its adverse influences on sleep and energy. On the other hand, symptoms of depression such as sleep deprivation, poor nutrition or lack of exercise may predispose an individual to the development of RLS. Moreover, depressed patients may amplify mild RLS, making occasional RLS symptoms appear to meet threshold criteria. The specific treatment of depression could be also implicated, since antidepressant compounds may worsen RLS and PLMD(Picchietti D et al., 2005; Damsa C et al., 2004). Interestingly, treatments used to relieve RLS symptoms (dopamine agonists) seem to have an antidepressant effects in RLS depressed patients(Saletu M et al., 2002&2003). During normal sleep there is a well-regulated pattern of the autonomic function, modulated by changes in sleep stages. It has been reported that chronic sleep deprivation is associated with cardiovascular events. In patients with sleep fragmentation increased number of arousals and increased cyclic alternating pattern rate is associated with an increase in sympathetic activity. It has been demonstrated that PLMS occurrence is associated with a shift to increased sympathetic activity without significant changes in cardiac parasympathetic activity (Sforza E et al., 2005). An increased association of RLS with hypertension and heart disease has been documented in several studies(Ulfberg J et al., 2001; Ohayon MM et al., 2002).

Analysis of cerebral and autonomic response to respiratory events in patients with Sleep Apnea Syndrome

The arousal scoring in Obstructive Sleep Apnea Syndrome (OSAS) is important to clarify the impact of the disease on sleep but the currently applied American Academy of Sleep Medicine (AASM) definition may underestimate the subtle alterations of sleep. The aims of the present study were to evaluate the impact of respiratory events on cortical and autonomic arousal response and to quantify the additional value of cyclic alternating pattern (CAP) and pulse wave amplitude (PWA) for a more accurate detection of respiratory events and sleep alterations in OSAS patients. A retrospective revision of 19 polysomnographic recordings of OSAS patients was carried out. Analysis was focused on quantification of apneas (AP), hypopneas (H) and flow limitation (FL) events, and on investigation of cerebral and autonomic activity. Only 41.1% of FL events analyzed in non rapid eye movement met the AASM rules for the definition of respiratory event-related arousal (RERA), while 75.5% of FL events ended with a CAP A phase. The dual response (EEG-PWA) was the most frequent response for all subtypes of respiratory event with a progressive reduction from AP to H and FL. 87.7% of respiratory events with EEG activation showed also a PWA drop and 53,4% of the respiratory events without EEG activation presented a PWA drop. The relationship between the respiratory events and the arousal response is more complex than that suggested by the international classification. In the estimation of the response to respiratory events, the CAP scoring and PWA analysis can offer more extensive information compared to the AASM rules. Our data confirm also that the application of PWA scoring improves the detection of respiratory events and could reduce the underestimation of OSAS severity compared to AASM arousal.

Sediment texture, carbonate content, and carbonate mineralogy of ODP Holes 182-1130A and 182-1132B

At Sites 1130 and 1132 of Ocean Drilling Program Leg 182 in the Great Australian Bight, we recovered an expanded Pleistocene section dominated by packstone and wackestone, deposited at unusually high rates of >20 cm/k.y. Shipboard observations detected an intermittent meter-scale alternation of light gray intervals with olive-gray intervals. Meter-scale samples were collected from the upper 250 m at both sites and decimeter-scale samples from four selected 2.5- to 4.0-m intervals in order to determine the texture and composition of sediments deposited along the upper slope throughout the Quaternary. Detailed textural and compositional data are presented from a total of 540 samples collected from both sites. Results indicate a general coarsening upward at both sites, with an accompanying upcore increase in high-Mg calcite (HMC) and aragonite and a decrease in low-Mg calcite (LMC). Samples collected at decimeter-scale intervals substantiate that the alternating light gray and olive-gray units detected on board ship are lithologically distinct. Light gray units consist of an LMC-rich silt, whereas olive-gray units consist of an aragonite and HMC-rich sand and silt. Sediment sources as well as timing and controls of this cyclic depositional pattern will be the subject of further investigations.

Changes in muscle recruitment patterns during skill acquisition

The control of movement is predicated upon a system of constraints of musculoskeletal and neural origin. The focus of the present study was upon the manner in which such constraints are adapted or superseded during the acquisition of motor skill. Individuals participated in five experimental sessions, ill which they attempted to produce abduction-adduction movements of the index finger in time with an auditory metronome. During each trial, the metronome frequency was increased in eight steps from an individually determined base frequency. Electromyographic (EMC) activity was recorded from first dorsal interosseous (FDI), first volar interosseous (FVI), flexor digitorum superficialis (FDS), and extensor digitorum communis (EDC) muscles. The movements produced on the final day of acquisition more accurately matched the required profile, and exhibited greater spatial and temporal stability, than those generated during initial performance. Tn the early stages of skill acquisition, an alternating pattern of activation in FDI and FVI was maintained, even at the highest frequencies. Tn contrast, as the frequency of movement was increased, activity in FDS and EDC was either tonic or intermittent. As learning proceeded, alterations in recruitment patterns were expressed primarily in the extrinsic muscles (EDC and FDS). These changes took the form of increases in the postural role of these muscles, shifts to phasic patterns of activation, or selective disengagement of these muscles. These findings suggest that there is considerable flexibility in the composition of muscle synergies, which is exploited by individuals during the acquisition of coordination.

Complementary and layered expression of Ephs and Ephrins in developing mouse inner ear

The distributions of the Eph-class receptors EphA4 and EphB 1, and their ligands ephrin-A2, ephrin-B1, and ephrin-B2, were analysed by immunostaining in the mouse inner ear. Complementary patterns of EphA4 and its potential ligand ephrin-A2 were found, with ephrin-A2 in many of the structures lining the cochlear duct and within the cochlear nerve cells, and EphA4 in the deeper structures underlying the cochlear duct and in the cells lining the nerve pathway. EphB1 and its potential ligands ephrin-B1 and ephrin-B2 showed a segregated layered expression in the lateral wall of the cochlear duct (the external sulcus), which together with EphA4 expressed in the area, form a four-layered structure with an alternating pattern of receptors and ligands in the different layers. This arrangement gives the potential for different bidirectional Eph-mediated interactions between each of the layers. The results suggest that the Eph system in the cochlea may have a role in maintaining cell segregation during phases of cochlear development. (C) 2002 Wiley-Liss, Inc.

Maintenance of the corneal epithelium is carried out by germinative cells of its basal stratum and not by presumed stem cells of the limbus

The purpose of this investigation was to analyze the proliferative behavior of rabbit corneal epithelium and establish if any particular region was preferentially involved in epithelial maintenance. [3H]-thymidine was injected intravitreally into both normal eyes and eyes with partially scraped corneal epithelium. Semithin sections of the anterior segment were evaluated by quantitative autoradiography. Segments with active replication (on) and those with no cell division (off) were intermingled in all regions of the tissue, suggesting that the renewal of the epithelial surface of the cornea followed an on/off alternating pattern. In the limbus, heavy labeling of the outermost layers was observed, coupled with a few or no labeled nuclei in the basal stratum. This suggests that this region is a site of rapid cell differentiation and does not contain many slow-cycling cells. The conspicuous and protracted labeling of the basal layer of the corneal epithelium suggests that its cells undergo repeated cycles of replication before being sent to the suprabasal strata. This replication model is prone to generate label-retaining cells. Thus, if these are adult stem cells, one must conclude that they reside in the corneal basal layer and not the limbal basal layer. One may also infer that the basal cells of the cornea and not of the limbus are the ones with the main burden of renewing the corneal epithelium. No particular role in this process could be assigned to the cells of the basal layer of the limbal epithelium.

Estudo do comportamento dos aços ferramentas soldados em fadiga

Sabendo-se que a fadiga é uma redução gradual da capacidade de carga do componente pela ruptura lenta e gradual do material. E que este defeito decorre do avanço infinitesimal de microtrincas, que se formam no interior do material, imperceptível a olho nu, como também é notório que a presença dos elementos de liga nos aços, propicia alterações nas propriedades metalurgias e mecânicas no material, aplicado à obra. Por outro lado, ao ser submetido a processamentos dos mais diversos, os mesmos, deformam nas zonas elásticas, plásticas e ao fim rompem-se. Ressaltando-se o objetivo deste estudo, destina se abordar as uniões soldadas, nos estágios em que ficam sujeitas a altas temperaturas e resfriam sem controle, até a temperatura ambiente. Ao fim, são solicitados por carregamentos cíclicos constantes ou alternados. Nesta particularidade, espera-se detectar mudanças estruturais profundas na Zona Termicamente Afetada – ZTA, em razão do superaquecimento sofrido, tanto na proximidade do ponto central da poça de fusão como na região localizada na vizinhança. Como não dispomos de parâmetros suficientes e necessários ao controle destas alterações, propomos analisar a ZTA da junta soldada, com a finalidade de avaliar o comportamento metalúrgico e suas implicações causadas pelas interações gás-metal. Analisar os efeitos resultantes do triangulo formado pelo material base aço AISI/SAE 4340, SAE 1020 chanfrados em V e o eletrodo revestido E-6013. A análise da estrutura será realizada pelas técnicas de ensaio metalográfico usando o método da microscopia óptica – MO o qual é de ampla difusão nas comunicações técnicas e cientificas, através das quais, distinguirão as transformações multifásicas. Transformações estas, distintas pelas transformações das austenitas diretas em martensitas sem passar pelas ferritas e perlitas. Com estas identidades, o metalógrafo pode caracterizar e predizer as reações futuras das estruturas mediante a análise das solicitações, a que possam estar submetidas. Para analisar o comportamento em fadiga dos materiais em questão, adota-se como parâmetro auxiliar, o ensaio do pêndulo de Charpy. Portanto, pelos resultados obtidos, conclui-se que as estruturas são comprometidas por tensões internas em conseqüência fragilizam, mas o procedimento de soldagem pode ser adotado, seguido de recozimento para alivio de tensões, se não fizer trincas.

Root-Growth Behavior of the Arabidopsis Mutant rgr11 : Roles of Gravitropism and Circumnutation in the Waving/Coiling Phenomenon

In this study we investigated the kinetics of the gravitropic response of the Arabidopsis mutant rgr1 (reduced root gravitropism). Although the rate of curvature in rgr1, which is allelic to axr4, was smaller than in the wild type (ecotype Wassilewskija), curvature was initiated in the same region of the root, the distal elongation zone. The time lag for the response was unaffected in the mutant; however, the gravitropic response of rgr1 contained a feature not found in the wild type: when roots growing along the surface of an agar plate were gravistimulated, there was often an upward curvature that initiated in the central elongation zone. Because this response was dependent on the tactile environment of the root, it most likely resulted from the superposition of the waving/coiling phenomenon onto the gravitropic response. We found that the frequency of the waving pattern and circumnutation, a cyclic endogenous pattern of root growth, was the same in rgr1 and in the wild type, so the waving/coiling phenomenon is likely governed by circumnutation patterns. The amplitudes of these oscillations may then be selectively amplified by tactile stimulation to provide a directional preference to the slanting.

The spatial patterns of β/A4 deposit subtypes in Down's syndrome

The spatial patterns of diffuse, primitive and classic β/A4 deposits were studied in coronal sections of the hippocampus and adjacent gyri in 11 cases of Down's syndrome (DS) varying in age from 38 to 67 years. The objectives of the study were first, to compare the spatial patterns of β/A4 deposits revealed in DS with those reported in cases of Alzheimer's disease (AD) and second, to study how the spatial patterns of β/A4 deposits may develop in the tissue. The spatial patterns revealed in DS exhibited a number of similarities with those reported in AD: (1) the range and frequency of the different types of spatial pattern revealed were similar, (2) β/A4 deposits occurred in clusters and in many cortical tissues, the clusters were distributed in a regular pattern parallel to the pia, (3) the clusters of diffuse and primitive β/A4 deposits occurred in an alternating pattern along the cortex, and (4) the clusters of classic β/A4 deposits were not correlated with the clusters of the diffuse and primitive deposits. Primitive deposits may develop from the diffuse deposits in regions of the cortex where extracellular paired helical filaments were formed. However, clusters of the classic β/A4 deposits, which are formed in older cases, appear to develop independently of the diffuse and primitive deposits. © 1994 Springer-Verlag.

An unusual axial–axial combination of alternating cyclic rings in the chair conformations of hexameric water and chlorine-water clusters

An alternating hexameric water (H2O)(6) cluster and a chlorine-water cluster [Cl-2(H2O)(4)](2-) in the chair forms combine axially to each other to form a 1D chain [{Cl-2(H2O)(6)}(2-)](n) in complex [FeL2]Cl center dot(H2O)(3) (L=2-[(2-methylaminoethylimino)-methyl]-phenol)]. The water molecules display extensive H-bonding interactions with monomeric iron-organic units to form a hydrogen-bonded 2D supramolecular assembly.