Sleep disturbances are common for children with attention-deficit/hyperactivity disorder (ADHD) and are of great clinical significance. Brain dopamine plays an important role for both ADHD symptoms and sleep-wake regulation. We therefore suggest that one basic aspect of integrative brain-behavior relationship such as the sleep-wakecycle may certainly be addressed in a dynamic developmental theory of ADHD.
The crying curve across early infancy may reflect the developing interaction between circadian and homeostatic processes of sleep-wake regulation. Excessive crying may be interpreted as a misalignment of the two processes. On the basis of the proposed mechanism, excessive crying may be an honest signal of need, namely, to elicit parental resources to modulate the behavioral state.
A new working hypothesis of sleep-wakecycle mechanisms is proposed, based on ontogeny and functional/anatomic compression of two stochastic neuronal models of information coding that complement each other in a key/lock fashion: the axonal arbor patterns (AAP – “hardware”) and the neuronal spike interval inequality patterns (SIIP – “software”). [Hobson et al.; Nielsen; Revonsuo; Solms; Vertes & Eastman].
Clinical and experimental evidence suggests that hippocampal damage causes more severe disruption of episodic memories if those memories were encoded in the recent rather than the more distant past. This decrease in sensitivity to damage over time might reflect the formation of multiple traces within the hippocampus itself, or the formation of additional associative links in entorhinal and association cortices. Physiological evidence also supports a two-stage model of the encoding process in which the initial encoding occurs during active waking and (...) deeper consolidation occurs via the formation of additional memory traces during quiet waking or slow-wave sleep. In this article I will describe the changes in cholinergic tone within the hippocampus in different stages of the sleep-wakecycle and will propose that these changes modulate different stages of memory formation. In particular, I will suggest that the high levels of acetylcholine that are present during active waking might set the appropriate dynamics for encoding new information in the hippocampus, by partially suppressing excitatory feedback connections and so facilitating encoding without interference from previously stored information. By contrast, the lower levels of acetylcholine that are present during quiet waking and slow-wave sleep might release this suppression and thereby allow a stronger spread of activity within the hippocampus itself and from the hippocampus to the entorhinal cortex, thus facilitating the process of consolidation of separate memory traces. (shrink)
Dreaming - a particular form of consciousness that occurs during sleep - undergoes major changes in the course of the night. We aimed to outline state-dependent features of consciousness using a paradigm with multiple serial awakenings/questionings that allowed for within as well as between subject comparisons. Seven healthy participants who spent 44 experimental study nights in the laboratory were awakened by a computerized sound at 15-30 minute intervals, regardless of sleep stage, and questioned for the presence or absence of sleep (...) consciousness. Recall without content (‘I was experiencing something but do not remember what’) was considered separately. Subjects had to indicate the content of the most recent conscious experience prior to the alarm sound and to estimate its duration and richness. We also assessed the degree of thinking and perceiving, self- and environment-relatedness and reflective consciousness of the experiences. Of the 778 questionings, 5% were performed during wakefulness, 2% in stage N1, 42% in N2, 33% in N3 and 17% in rapid eye movement (REM) sleep. Recall with content was reported in 34% of non-REM and in 77% of REM sleep awakenings. Sleep fragmentation inherent to the study design appeared to only minimally affect the recall of conscious experiences. Each stage displayed a unique combination of characteristic features of sleep consciousness. In conclusion, our serial awakening paradigm allowed us to collect a large and representative sample of conscious experiences across states of being. It represents a time-efficient method for the study of sleep consciousness that may prove particularly advantageous when combined with techniques such as functional MRI and high-density EEG. (shrink)
Although considerable attention has been paid to the possible involvement of sleep in memory processing, there is no substantial evidence for it. Walker describes a phenomenon of consolidation-based enhancement (CBE), whereby performance on select procedural tasks improves with overnight sleep; that is, without additional practice on the tasks. CBE, however, appears restricted to a few tasks, and even with these tasks CBE is not confined to sleep but also occurs during wakefulness. Sleep serves no unique role in this process. At (...) best, CBE is a slow, time-dependent process of consolidation that begins with task acquisition in waking and can under some circumstances extend to sleep. (shrink)
There are strong resemblances between the neurobiological characteristics of hallucinations occurring in the particular case of schizophrenia and the hallucinatory activity observed during the rapid-eye-movement (dreaming) sleep stage: the same prefrontal dorsolateral deactivation; forebrain disconnectivity and disinhibition; sensory deprivation; and acetylcholine, monoamine, and glutamate modifications.
This study investigated the relation between sleep and school performance in a large sample of 561 adolescents aged 11-18 years. Three subjective measures of sleep were used: sleepiness, sleep quality and sleep duration. They were compared to three measures of school performance: objective school grades, self-reported school performance, and parent-reported school performance. Sleepiness – ‘I feel sleepy during the first hours at school’ – appeared to predict both school grades and self-reported school performance. Sleep quality on the other hand – (...) as a measure of (un)interrupted sleep and/or problems falling asleep or waking up – predicted parent-reported school performance. Self- and parent-reported school performance correlated only moderately with school grades. So it turns out that the measures used to measure either sleep or school performance impacts whether or not a relation is found. Further research on sleep and school performance should take this into account. The findings do underscore the notion that sleep in adolescence can be important for learning. They are compatible with the hypothesis that a reduced sleep quality can give rise to sleepiness in the first hours at school which results in lower school performance. This notion could have applied value in counseling adolescents and their parents in changing adolescents’ sleep behavior. (shrink)
In January 1959, famous radio DJ Peter Tripp stayed awake for 200 hours in a glass booth on Times Square, exposing his weakening body and distracted sleepless mind to the public. Tripp's playing with the borderlines of consciousness was a media attraction, but the DJ also served as a guinea pig for scientific research. From the late 19th century on, several experts had tried to explore the world of wakefulness by observing stay-awake-men. With their help, researchers tested methods of measuring (...) alertness, validated and modified theories about sleep, and tried to answer the question of how long and under what circumstances human beings, above all workers and soldiers, were able to stay awake and remain efficient and accountable. By reconstructing the history of the stay-awake-men, this article shows how the perception of “being awake” changed over time and thereby points to the historicity of our very basic notions for describing the states of the human mind. (shrink)
Recent studies in sleep and dreaming have described an activation of emotional and reward systems, as well as the processing of internal information during these states. Specifically, increased activity in the amygdala and across mesolimbic dopaminergic regions during REM sleep is likely to promote the consolidation of memory traces with high emotional/motivational value. Moreover, coordinated hippocampal-striatal replay during NREM sleep may contribute to the selective strengthening of memories for important events. In this review, we suggest that, via the activation of (...) emotional/motivational circuits, sleep and dreaming may offer a neurobehavioral substrate for the offline reprocessing of emotions, associative learning, and exploratory behaviors, resulting in improved memory organization, waking emotion regulation, social skills, and creativity. Dysregulation of such motivational/emotional processes due to sleep disturbances (e.g. insomnia, sleep deprivation) would predispose to reward-related disorders, such as mood disorders, increased risk-taking and compulsive behaviors, and may have major health implications, especially in vulnerable populations. (shrink)
The nature and time course of sleep onset (hypnagogic) mentation was studied in the home environment using the Nightcap, a reliable, cost-effective, and relatively noninvasive sleep monitor. The Nightcap, linked to a personal computer, reliably identified sleep onset according to changes in perceived sleepiness and the appearance of hypnagogic dream features. Awakenings were performed by the computer after 15 s to 5 min of sleep as defined by eyelid quiescence. Awakenings from longer periods of sleep were associated with (1) an (...) increase in reported sleepiness, (2) a decrease in the length of mentation reports, (3) a decrease in the frequency of reports of normal, wake-like thoughts, (4) an increase in the frequency of ''unusual thoughts,'' and (5) increased frequencies of formal dream features, including visual hallucination, self-representation, fictive movement, narrative plot, and bizarreness. While sleep-onset reports can include all features of rapid eye movement (REM) dream reports, the number of such features is markedly reduced at sleep onset, suggesting that this mentation is a greatly diminished version of REM dreaming. (shrink)
The complexity and mysteriousness of mental processes during sleep rule out thinking only in term of generators. How could we know exactly what mental sleep experience (MSE) is produced and when? To refer to REM versus NREM as separate time windows for MSE seems insufficient. We propose that in each cycle NREM and REM interact to allow mentation to reach a certain degree of complexity and consolidation in memory. Each successive cycle within a sleep episode should contribute to (...) these processes with a different weight according to the time of night and distance from sleep onset. This view would avoid assuming too great a separation between REM and NREM functions and attributing psychological functions only to a single state. [Nielsen]. (shrink)
Organisms are self-producing and self-maintaining, or autopoietic systems. Therefore, the course of evolution and adaptation of an organism is strongly determined by its own internal properties, whatever role external selection may play. The internal properties may either act as constraints that preclude certain changes or they open new pathways: the organism canalizes its own evolution. As an example the evolution of feeding mechanisms in salamanders, especially in the lungless salamanders of the family Plethodontidae, is discussed. In this family a large (...) variety of different feeding mechanisms is found. The authors reconstruct this evolutionary process as a series of bifurcation points of either constraints or opportunities forming a sequence of preconditions for the formation of a high-speed projectile tongue characteristic of tropical salamanders. Furthermore, it is shown how parallel evolution of seemingly unrelated domains within an organism such as respiratory physiology, life history biology and pattern of ontogeny has rather direct relevance to the feeding biology, thus demonstrating that organisms always evolve as wholes. (shrink)
Studies in cognitive psychology showed that personality (openness to experience, thin boundaries, absorption), creativity, nocturnal awakenings, and attitude toward dreams are significantly related to dream recall frequency (DRF). These results suggest the possibility of neurophysiological trait differences between subjects with high and low DRF. To test this hypothesis we compared sleep characteristics and alpha reactivity to sounds in subjects with high and low DRF using polysomnographic recordings and electroencephalography (EEG). We acquired EEG from 21 channels in 36 healthy subjects while (...) they were presented with a passive auditory oddball paradigm (frequent standard tones, rare deviant tones and very rare first names) during wakefulness and sleep (intensity, 50 dB above the subject’s hearing level). Subjects were selected as High-recallers (HR, DRF = 4.4 ± 1.1 dream recalls per week) and Low-recallers (LR, DRF = 0.25 ± 0.1) using a questionnaire and an interview on sleep and dream habits. Despite the disturbing setup, the subjects’ quality of sleep was generally preserved. First names induced a more sustained decrease in alpha activity in HR than in LR at Pz (1000-1200ms) during wakefulness, but no group difference was found in REM sleep. The current dominant hypothesis proposes that alpha rhythms would be involved in the active inhibition of the brain regions not involved in the ongoing brain operation. According to this hypothesis, a more sustained alpha decrease in HR would reflect a longer release of inhibition, suggesting a deeper processing of complex sounds than in LR during wakefulness. A possibility to explain the absence of group difference during sleep is that increase in alpha power in HR may have resulted in awakenings. Our results support this hypothesis since HR experienced more intra sleep wakefulness than LR (30 ± 4 vs 14 ± 4 min). As a whole our results support the hypothesis of neurophysiological trait differences in high and low-recallers. (shrink)
Hegel argues that madness should not be understood as it had been traditionally, viz. ‘sleeping while awake,’ the intrusion of sleep or unconsciousness on waking, conscious life, but that rather madness must be understood as an inescapable possibility of waking life, and a constitutive part of consciousness itself.
What, if anything, do dreams tell us about ourselves? What is the relationship between types of sleep and types of dreams? Does dreaming serve any purpose? Or are dreams simply meaningless mental noise--"unmusical fingers wandering over the piano keys"? With expertise in philosophy, psychology, and neuroscience, Owen Flanagan is uniquely qualified to answer these questions. In this groundbreaking work, he provides both an accessible survey of the latest research on sleep and dreams and a compelling new theory about the nature (...) and function of dreaming. Flanagan argues that while sleep has a clear biological function and adaptive value, dreams are merely side effects, "free riders," irrelevant from an evolutionary point of view. But dreams are hardly unimportant. Flanagan argues that dreams are self-expressive, the result of our need to find or to create meaning, even when we're sleeping. Written with remarkable insight, Dreaming Souls offers a fascinating new way of apprehending one of the oldest mysteries of mental life. (shrink)
This note concerns a puzzle about probability which has recently caught the attention of a number of philosophers. According to the current philosophical consensus, the solution to the puzzle reveals that one can acquire new information, sufficient to change one's credences in certain events, just by having a certain experience, even though one knew all along that one would have an experience which felt exactly like this. I argue that the philosophical consensus is mistaken.
In this paper we claim that individual subjects do not have so much control over sleep that it is aptly characterized as a personal choice; and that normative implications related to public health and sleep hygiene do not necessarily follow from current findings. It should be true of any empirical study that normative implications do not necessarily follow, but we think that many public health sleep recommendations falsely infer these implications from a flawed explanatory account of the decision to sleep: (...) the consumer choice view. This view, which we criticize here, proposes that sleep duration and sleep quality be understood as one choice among many. (shrink)
Research in the neurosciences continues to provide evidence that sleep plays a role in the processes of learning and memory. There is less of a consensus, however, regarding the precise stages of memory development during which sleep is considered a requirement, simply favorable, or not important. This article begins with an overview of recent studies regarding sleep and learning, predominantly in the procedural memory domain, and is measured against our current understanding of the mechanisms that govern memory formation. Based on (...) these considerations, I offer a new neurocognitive framework of procedural learning, consisting first of acquisition, followed by two specific stages of consolidation, one involving a process of stabilization, the other involving enhancement, whereby delayed learning occurs. Psychophysiological evidence indicates that initial acquisition does not rely fundamentally on sleep. This also appears to be true for the stabilization phase of consolidation, with durable representations, resistant to interference, clearly developing in a successful manner during time awake (or just time, per se). In contrast, the consolidation stage, resulting in additional/enhanced learning in the absence of further rehearsal, does appear to rely on the process of sleep, with evidence for specific sleep-stage dependencies across the procedural domain. Evaluations at a molecular, cellular, and systems level currently offer several sleep specific candidates that could play a role in sleep-dependent learning. These include the upregulation of select plasticity-associated genes, increased protein synthesis, changes in neurotransmitter concentration, and specific electrical events in neuronal networks that modulate synaptic potentiation. Key Words: consolidation; enhancement; learning; memory; plasticity; sleep; stabilization. (shrink)
This papers attempts to bridge business ethics to corporate social responsibility including the social and environmental dimensions. The objective of the paper is to suggest an improvement of the most commonly used corporate environmental management tool, the Life Cycle Assessment (LCA). The method includes two stages. First, more phases are added to the life-cycle of a product. Second, social criteria that measure the social performance of a product are introduced. An application of this “extended” LCA tool is given.
In this paper, we present an argument strengthening the view of Norman Daniels, Bruce Kennedy and Ichiro Kawachi that justice is good for one's health. We argue that the pathways through which social factors produce inequalities in sleep more strongly imply a unidirectional and non-voluntary causality than with most other public health issues. Specifically, we argue against the 'voluntarism objection' – an objection that suggests that adverse public health outcomes can be traced back to the free and voluntary choices of (...) individual actors. Our argument proceeds along two lines: an empirical line and a conceptual line. We first show that much of the empirical research on sleep supports the view that those with fewer opportunities are those who have poorer sleep habits. We then argue that sleep-related decisions are not of the same nature as most other lifestyle choices, and therefore are not as easily susceptible to the voluntarism objection. (shrink)
This paper explores the meaning of dreamless sleep. First, I consider four reasons why we commonly pass over sleep's ontological significance. Second, I compare and contrast death and sleep to show how each is oriented to questions regarding the possibilities of "being-a-whole." In the third and final part, I explore the meaning and implications of "being-toward-sleep," arguing that human existence emerges atop naturally anonymous corporeality (i.e. living being). In sum, I try to show that we can recover an authentic — (...) if somewhat ambiguous — sense of "being-a-whole" only by recognizing the ontological significance of dreamless sleep. (shrink)
Sustainability informs the framework for a seminar that we teach for junior and senior undergraduates entitled "The Ethics and Economics of Sustainable Societies." One of the class requirements has each student research and write a life-cycle case study, an exercise in which they trace the full, or partial, life-cycle of some product with which they are familiar. Students are expected to examine the economic, ethical, and ecological implications along each step in the life-cycle of the product. We (...) believe that life-cycle cases in general are very helpful in revealing the full economic, ethical, and ecological consequences of product development, marketing, use, and disposal. We also believe that asking students to research the product themselves provides additional pedagogical benefits. After a brief review of the philosophical case for our alternative view of corporate social responsibility, we will describe the life-cycle case method, offer several examples from our own classes, and make the case for the pedagogical benefits of this approach. (shrink)
We present evidence disputing the hypothesis that memories are processed or consolidated in REM sleep. A review of REM deprivation (REMD) studies in animals shows these reports to be about equally divided in showing that REMD does, or does not, disrupt learning/memory. The studies supporting a relationship between REM sleep and memory have been strongly criticized for the confounding effects of very stressful REM deprivation techniques. The three major classes of antidepressant drugs, monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), and (...) selective serotonin reuptake inhibitors (SSRIs), profoundly suppress REM sleep. The MAOIs virtually abolish REM sleep, and the TCAs and SSRIs have been shown to produce immediate (40–85%) and sustained (30–50%) reductions in REM sleep. Despite marked suppression of REM sleep, these classes of antidepressants on the whole do not disrupt learning/memory. There have been a few reports of patients who have survived bilateral lesions of the pons with few lingering complications. Although these lesions essentially abolished REM sleep, the patients reportedly led normal lives. Recent functional imaging studies in humans have revealed patterns of brain activity in REM sleep that are consistent with dream processes but not with memory consolidation. We propose that the primary function of REM sleep is to provide periodic endogenous stimulation to the brain which serves to maintain requisite levels of central nervous system (CNS) activity throughout sleep. REM is the mechanism used by the brain to promote recovery from sleep. We believe that the cumulative evidence indicates that REM sleep serves no role in the processing or consolidation of memory. Key Words: antidepressant drugs; brain stem lesions; dreams; functional imaging; memory consolidation; REM deprivation; REM sleep; theta rhythm. (shrink)
During sleep, humans experience the offline images and sensations that we call dreams, which are typically emotional and lacking in rational judgment of their bizarreness. However, during lucid dreaming (LD), subjects know that they are dreaming, and may control oneiric content. Dreaming and LD features have been studied in North Americans, Europeans and Asians, but not among Brazilians, the largest population in Latin America. Here we investigated dreams and LD characteristics in a Brazilian sample (n=3,427; median age=25 years) through an (...) online survey. The subjects reported recalling dreams at least once a week (76%). Dreams typically depicted actions (93%), known people (92%), sounds/voices (78%), and colored images (76%). The oneiric content was associated with plans for the upcoming days (37%), memories of the previous day (13%), or unrelated to the dreamer (30%). Nightmares usually depicted anxiety/fear (65%), being stalked (48%), or other unpleasant sensations (47%). These data corroborate Freudian notion of day residue, and suggest that dreams are simulations of life situations that are related to our psychobiological integrity. Regarding LD, we observed that 77% of the subjects experienced LD at least once in life (44% up to 10 episodes ever), and for 48% LD subjectively lasted less than 1 minute. LD frequency correlated weakly with dream recall frequency (r=0.20, p<0.01), and LD control was rare (29%). LD occurrence was facilitated when subjects did not need to wake up early (38%), a situation that increases REMS duration, or when subjects were under stress (30%), which increases REMS transitions into waking. These results indicate that LD is a relatively ubiquitous but not frequent state, being unstable, difficult to control, and facilitated by increases in REMS duration and transitions to wake state. Together with LD incidence in USA, Europe and Asia, our data from Latin America strengthen the notion that LD is a general phenomenon of the human species. (shrink)
Dreams are used figuratively throughout Greek literature to refer to something fleeting and/or unreal. In Plato, this metaphorical language is specifically used to describe an epistemological distinction: the one who has false knowledge or opinion is said to be dreaming while the one who has true knowledge is said to be awake. These figures are also central to Philo of Alexandria's philosophical language in De somniis 1-2 and De Iosepho . Although scholars have documented these epistemological metaphors in Plato and (...) related treatments of the concept of sleep in Heraclitus, it has not been discussed in any detail in relation to Philo's treatment of Joseph in these two treatises. In De somniis 1-2, Philo primarily emphasizes his role as a dreamer and thus one incapable of true knowledge. In De Iosepho , Joseph is a dream interpreter who is not only awake but also capable of interpreting the figurative dream of life to which most people are subject. Although some scholars have considered these treatises contradictory in terms of their treatments of Joseph, an analysis of Philo's figurative use of sleep and dreaming reveals that they are a part of a coherent exegetical framework. (shrink)
Historians of science have attributed the emergence of ecology as a discipline in the late nineteenth century to the synthesis of Humboldtian botanical geography and Darwinian evolution. In this essay, I begin to explore another, largely neglected but very important dimension of this history. Using Sergei Vinogradskii’s career and scientific research trajectory as a point of entry, I illustrate the manner in which microbiologists, chemists, botanists, and plant physiologists inscribed the concept of a “cycle of life” into their investigations. (...) Their research transformed a longstanding notion into the fundamental approaches and concepts that underlay the new ecological disciplines that emerged in the 1920s. Pasteur thus joins Humboldt as a foundational figure in ecological thinking, and the broader picture that emerges of the history of ecology explains some otherwise puzzling features of that discipline – such as its fusion of experimental and natural historical methodologies. Vinogradskii’s personal “cycle of life” is also interesting as an example of the interplay between Russian and Western European scientific networks and intellectual traditions. Trained in Russia to investigate nature as a super-organism comprised of circulating energy, matter, and life; over the course of five decades – in contact with scientists and scientific discourses in France, Germany, and Switzerland – he developed a series of research methods that translated the concept of a “cycle of life” into an ecologically conceived soil science and microbiology in the 1920s and 1930s. These methods, bolstered by his authority as a founding father of microbiology, captured the attention of an international network of scientists. Vinogradskii’s conceptualization of the “cycle of life” as chemosynthesis, autotrophy, and global nutrient cycles attracted the attention of ecosystem ecologists; and his methods appealed to practitioners at agricultural experiment stations and microbiological institutes in the United States, Western Europe, and the Soviet Union. (shrink)
The interplay between top-down, bottom-up attention and consciousness is frequently tested in altered states of consciousness, including transitions between stages of sleep and sedation, and in pathological disorders of consciousness (the vegetative and minimally conscious states; VS and MCS). One of the most widely used tasks to assess cognitive processing in this context is the auditory oddball paradigm, where an infrequent change in a sequence of sounds elicits, in awake subjects, a characteristic EEG event-related potential (ERP) called the mismatch negativity (...) (MMN), followed by the classic P300 wave. The latter is further separable into the slightly earlier, anterior P3a and the later, posterior P3b, linked to bottom-up and top-down attention, respectively. We discuss here the putative dissociations between attention and awareness in disorders of consciousness, sedation and sleep, bearing in mind the recently emerging evidence from healthy volunteers and patients. These findings highlight the neurophysiological and cognitive parallels (and differences) across these three distinct variations in levels of consciousness, and inform the theoretical framework for interpreting the role of attention therein. (shrink)
This paper, using modern Darwinian theory, proposes an explanation for the increasingly high incidence of breast cancer found among pre-and post-menopausal women living today in westernized countries. A number of factors have been said to be responsible: genetic inheritance (BRCA-1), diet (specifically the increased consumption of dietary fat), exposure to carcinogenic agents, lifetime menstrual activity, and reproductive factors. The primary aim of this paper is to demonstrate the value of a perspective based on Darwinian theory. In this paper, Darwinian theory (...) is used to explore the possibility that the increased incidence of breast cancer is due primarily to the failure to complete in a timely manner the reproductive developmental cycle, beginning at menarche and continuing through a series of pregnancies and lactation. On the basis of comparative data, we assume that most women in ancestral populations began having children before age 20 or so and tended to remain either pregnant or nursing for most of their adult lives. If a woman did not have a child by age 25 or so, she probably would never have one. Therefore, selection would probably not have acted against deleterious traits, such as cancer, that appeared after that age, just as it does not act against such traits in old age. (shrink)