Unveiling sleep mysteries: neurobiology of dreaming / Revelando mistérios do sono: neurobiologia dos sonhos

Dreaming is the result of the mental activity of rapid eye movement (REM) sleep stage, and less commonly of non-REM sleep. Dreams offer unique insights into the patients' brains, minds, and emotions. Based on neurophysiological and neuroimaging studies, the biological core of dreaming stands on some brain areas activated or inactivated. Dream abnormalities in neurological disorders include a reduction / cessation of dreaming, an increase in dream frequency, changes in dream contents and accompaniments, and the occurrence of dreamlike experiences (hallucinations) mainly during the wake-sleep/sleep-wake transitions. Dream changes can be associated with several neurological conditions, and the unfolding of biological knowledge about dream experiences can also have significance in clinical practice. Regarding the dream importance in clinical neurological management, the aim of this paper encompasses a summary of sleep stages, dreams neurobiology including brain areas involved in the dreams, memory, and dreams, besides Dreams in the aging people and neurodegenerative disorders.

Sonhar é o resultado da atividade mental do estágio do sono de movimento rápido dos olhos (REM) e, menos comumente, do sono não-REM. Os sonhos oferecem informações únicas sobre o cérebro, a mente e as emoções dos pacientes. Com base em estudos neurofisiológicos e de neuroimagem, o núcleo biológico do sonho está em algumas áreas do cérebro ativadas ou inativadas. As anormalidades do sonho nos distúrbios neurológicos incluem uma redução / cessação do sonho, um aumento na frequência do sonho, alterações nos conteúdos e acompanhamentos do sonho e a ocorrência de experiências semelhantes ao sonho (alucinações), principalmente durante as transições de vigília-sono / sono-vigília. As mudanças do sonho podem estar associadas a várias condições neurológicas, e o desenvolvimento do conhecimento biológico sobre as experiências do sonho também pode ter significado na prática clínica. Com relação à importância do sonho no manejo neurológico clínico, o objetivo deste artigo é resumir os estágios do sono, a neurobiologia dos sonhos, incluindo as áreas do cérebro envolvidas nos sonhos, a memória e os sonhos, além dos sonhos nos idosos e nos distúrbios neurodegenerativos.

Comparative analysis of multiple sleep latency tests (MSLT) parameters and occurrence of dreaming in patients with daytime sleepiness of narcoleptic and non-narcoleptic origin / Estudo comparativo de parâmetros de testes de latências múltiplas do sono (TLMS) e ocorrência de sonhos em pacientes hipersones narcolépticos e não-narcolépticos

OBJECTIVE: To compare MSLT parameters in two groups of patients with daytime sleepiness, correlated to the occurrence and onset of dreams. METHOD: Patients were submitted to the MSLT between January/1999 and June/2002. Sleep onset latency, REM sleep latency and total sleep time were determined. The occurrence of dreams was inquired following each MSLT series. Patients were classified as narcoleptic (N) or non-narcoleptic (NN). RESULTS: Thirty patients were studied, 12 were classified as narcoleptics (N group; 40 percent), while the remaining 18 as non-narcoleptic (NN group; 60 percent). Thirty MSLT were performed, resulting in 146 series. Sleep was detected in 126 series (86 percent) and dreams in 56 series (44.44 percent). Mean sleep time in the N group was 16.0±6.3 min, while 10.5±7.5 min in the NN group (p<0.0001). Mean sleep latency was 2.0±2.2 min and 7.2±6.0 min in the N and NN group, respectively (p<0.001). Mean REM sleep latency in the N group was 3.2±3.1min and 6.9±3.7 min in the NN group (p=0.021). Dreams occurred in 56.9 percent of the N group series and 28.4 percent in that of the NN group (p=0.0009). Dream frequency was detected in 29.8 percent and 75 percent of the NREM series of the N and NN groups, respectively (p=0.0001). CONCLUSION: Patients from the N group, compared to the NN group, slept longer and earlier, demonstrated a shorter REM sleep onset and greater dream frequency. NN patients had a greater dream frequency in NREM series. Thus, the occurrence of dreams during NREM in the MSLT may contribute to differentially diagnose narcolepsy and daytime sleepiness.

OBJETIVO: Comparar variáveis do TLMS em dois grupos de pacientes hipersones e correlacionar presença e momento de ocorrência de sonhos. MÉTODO: Os pacientes foram submetidos a TLMS entre janeiro de 1999 e junho de 2002. Analisou-se a média das latências de sono, latências de sono REM e tempo total de sono. A presença de sonhos foi inquirida após cada série. Classificou-se os pacientes em narcolépticos (N) e não-narcolépticos (NN). RESULTADOS: Do total de 30 pacientes, 12 foram classificados no grupo N (40 por cento) e 18 no NN (60 por cento). Dos 30 TLMS foram obtidas 146 séries. Houve sono em126 (86 por cento) e sonho em 56 (44,44 por cento). O tempo médio de sono no grupo N foi 16,0±6,3min e no NN 10,5±7,5min (p<0,0001). A latência média de sono no grupo N foi 2,0±2,2min e no NN 7,2±6,0min (p<0,001). A latência média do sono REM no N foi 3,2±3,1min e no NN 6,9±3,7min (p=0,021). Houve sonhos em 56,9 por cento das séries do grupo N e 28,4 por cento do NN (p=0,0009). A freqüência de sonhos em séries NREM no N foi 29,8 por cento e no NN 75 por cento (p= 0,0001). CONCLUSÃO: Os pacientes do grupo N dormiram mais e mais rapidamente, apresentaram REM mais precocemente e maior freqüência de sonhos que os NN. Estes apresentaram maior freqüência de sonhos em séries NREM. A presença de sonhos em NREM no TLMS pode contribuir no diagnóstico diferencial entre narcolepsia e hipersonia diurna.

Sonho, memória e o reencontro de Freud com o cérebro / Dream, memory and Freud's reconciliation with the brain

Para que serve sonhar? A vasta contribuiçäo sobre a funçäo dos sonhos dada por Freud e Jung foi em grande parte ignorada pela ciência, pela falta de um método quantitativo e de hipóteses testáveis. Näo obstante, vários resultados experimentais corroboram dois importantes "insights" psicanalíticos: 1) que os sonhos freqüentemente contêm elementos da experiência do dia anterior, denominados de "restos do dia", e 2) que estes "restos" incluem atividades mnemônicas, levando portanto a uma facilitaçäo do aprendizado. Em particular, dados recentes sugerem que os sonhos podem desempenhar um papel essencial na consolidaçäo das memórias, levando aquelas recentemente adquiridas a migrar do hipocampo para o neocórtex. Tomados em conjunto, estes resultados indicam a necessidade de reavaliar cientificamente o legado psicanalítico

Rapid eye movements during paradoxical sleep in patients with cerebrovascular disease

Rapid eye movements that occur during paradoxical sleep are generated from the brainstem and are modulated by cerebral hemispheres. In an attempt to establish the participation of cerebral hemispheres on rapid eye movements, we carried out a quantitative study of eye movements density in patients bearing hemispheres vascular lesions. The polysomnographic recordings of 24 patients were compared to those of 24 healthy volunteers. Density of rapid eye movements was defined as the porcentage of eye movements during the respective time of paradoxical sleep. Based on the present results, we concluded that: stroke patients with hemispheric lesions displayed increased density of rapid eye movements; there was no difference on the density of rapid eye movements according to the hemispheric lesion; higher density of rapid eye movements was observed in patients with anterior hemispheric lesion.

Correlation between concomitant theta waves in nucleus reticularis pontis oralis and in hippocampus, thalamus and neocortex during dreaming in rats

Theta waves, which are the main electrophysiological expression of dreaming activity in many brain structures of rats, often undergo specific changes in voltage and frequency according to the oniric patterns. Much is known about their mechanisms but little is known regarding their origin, which has been ascribed to a specific activation of either the reticular formation or the septal nuclei or nucleus reticularis pontis oralis. In the present study, rats were prepared for chronic recording of the electro-oscillograms of cortical areas 10, 3 and 17, of hippocampal CA1 and CA3 fields, of nucleus reticularis thalami, nucleus reticularis pontis oralis and occasionally of nucleus reticularis caudalis. Head, rostrum, eye and forelimb movements were also recorded, so that the oniric behaviors could be precisely identified. The scatter diagrams and the corresponding correlation coefficients (r) of the voltage of concomitant waves were determined for each possible pair of leads. The potentials were analyzed at a frequency of 256 Hz over a period of 1 to 3 sec. A very high degree of correlation was observed between theta waves in nucleus reticularis pontis oralis, hippocampal fields and nucleus reticularis pontis caudalis; sometimes r approached unity. Although these data cannot be taken as proof of nucleus reticularis pontis oralis being the source of theta waves, they are at least compatible with this hypothesis.

Psicobiología de los sueños

Dreams, as a brain product are in the same status as thinking, memory and crativity, and are domain of neuroscience and neuropsicology. This review compiles a fascinating, new, and broad field of neuroscience that deals with biological and psicological aspects of what is known today about dreams

Sueño, sueños y aprendizaje. Hacia una neurofisiología de la cognición

In this paper the author summarizes different pathways of reaserch around biological functions os sleeping, and particularly of the REM sleep. It is clear that there is a significant direct relationship between duration and amount os REM sleep and the degree of learning during wakefulness and, at the end, with the degree of consolidation of such learning. Interesting too is the controversy around learning durin sleeping. Finally, the findings around hemispheric asymmetry in the generation of dreaming is another field of active investigation.

Insônia do lactente / Insonnia of infant

A insônia do lactente consiste na dificuldade de adormecer ou em despertares durante a noite, iniciando no primeiro ano de vida. Neste artigo será relatada uma pesquisa feita com crianças que apresentam insônia, dando ênfase à dinâmica familiar da criança

Rostrum movements in desynchronized sleep as a prevalent manifestation of dreaming activity in wistar rats

Considering that eye movements express visual dreams in humans and are prominent during desynchronized sleep in cats, monkeys and birds, rostrum movements were investigated in a macrosmatic species, the rat, to the hypothesis that, expressisng olfactory and tactile (involving the vibrissae) dreams, they would prevail over eye movements. Desynchronized sleep episodes lasted 148.8 ñ 12.4 s, rostrum movements lasted 80.7 ñ 6.9 s and eye movements occurred during 40.4 ñ 3.9 s, all in accordance with the original hypothesis