Online research in philosophy

The target articles on sleep and dreaming are discussed in terms of the concept of search activity integrating different types of behavior, body resistance, REM sleep/dream functions, and the brain catecholamine system. REM sleep may be functionally sufficient or insufficient, depending on the dream scenario, the latter being more important than the physiological manifestation of REM sleep. REM sleep contributes to memory consolidation in the indirect way. [Nielsen; Revonsuo; Solms; Vertes & Eastman].

The phylogenetic data are inconsistent with the hypothesis that REM sleep duration is correlated with learning or learning ability. Humans do not have uniquely high amounts of REM sleep. The platypus, marsupials, and other mammals not generally thought to have extraordinary learning abilities have the largest amounts of REM sleep. The whales and dolphins (cetaceans) have the lowest amounts of REM sleep and may go without REM sleep for extended periods of time, despite their prodigious learning abilities. Vertes & Eastman].

Reinterpretation of our data concerning sleep onset, motivated by the desire to pay close attention to “intra-individual regularities,” suggests that the experience of control might be a key factor in determining the subjective sense that sleep has begun. This loss of control seems akin to what Frith and others have described as “passivity experiences,” which also occur in schizophrenia. Although clearly sleep onset is not a schizophrenic episode, this similarity might help to explain other features of sleep onset. We further speculate that we could build upon the discovery of various “intra-individual regularities” to construct a model of sleep onset and other forms of sleep mentation.

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.

There are obvious flaws in REM sleep suppression paradigms that do not allow any conclusion to be drawn either pro or contra the REM sleep-memory hypothesis. However, less intrusive investigations of REM sleep suggest that this sleep stage or its adjunct neuroendocrine characteristics exert a facilitating influence on certain aspects of ongoing memory formation during sleep. [Nielsen; Vertes & Eastman].

It has been widely demonstrated that dreaming occurs throughout human sleep. However, we once again are facing new variants of the equation “REM sleep = Dreaming.” Nielsen proposes a model that assumes covert REM processes in NREM sleep. I argue against this possibility, because dream research has shown that REM sleep is not a necessary condition for dreaming to occur. [Nielson].

The Walker model raises a number of questions, particularly about the nature of the sleep states involved in consolidation enhancement. While REM sleep, Stage 2 sleep, and Stage 3/4 sleep have been implicated in procedural learning, we still do not understand which types of learning are involved with specific sleep states. Several possible ideas for future research are suggested.

Cellular mechanisms hypothesized to underlie sleep-dependent memory consolidation are expressed throughout the brain during sleep. Use of sleep deprivation to evaluate the functional importance of these mechanisms is confounded by degradation in waking performance resulting from impaired vigilance. There is a need for methods that will permit disruption of specific mechanisms during sleep only in the neuronal circuits most critically involved in learning. This should be accomplished without global sleep disruption and with preservation of the restorative aspects of sleep.

The advent of functional imaging has reinforced the attempts to define dreaming as a sleep state-dependent phenomenon. PET scans revealed major differences between nonREM sleep and REM sleep. However, because dreaming occurs throughout sleep, the common features of the two sleep states, rather than the differences, could help define the prerequisite for the occurrence of dreams. [Hobson et al.; Nielsen; Solms; Revonsuo; Vertes & Eastman].

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.