REM sleep and dreaming: towards a theory of protoconsciousness
Nature Reviews| Neuroscience volume 10 | November 2009 | 803
J. Allan Hobson
Dreaming has fascinated and mystified humankind for ages: the bizarre and evanescent qualities of dreams have invited boundless speculation about their origin, meaning and purpose. For most of the twentieth century, scientific dream theories were mainly psychological. Since the discovery of rapid eye movement (REM) sleep, the neural underpinnings of dreaming have become increasingly well understood, and it is now possible to complement the details of these brain mechanisms with a theory of consciousness that is derived from the study of dreaming. The theory advanced here emphasizes data that suggest that REM sleep may constitute a protoconscious state, providing a virtual reality model of the world that is of functional use to the development and maintenance of waking consciousness.
True or False?
How to Tell If a Particular Memory Is True or False
Daniel M. Bernstein and Elizabeth F. Loftus
Association for Psychological Science Volume 4—Number 4
How can you tell if a particular memory belonging to you or someone else is true or false? Cognitive scientists use a variety of techniques to measure groups of memories, whereas police, lawyers, and other researchers use procedures to determine whether an individual can be believed or not. We discuss evidence from behavioral and neuroimaging studies and research on lying that have attempted to distinguish true from false memories.
We remember events, people, and places all the time, but how accurate are those memories? More specifically, how can we identify true memories from false ones? A majority of studies trying to answer this question have tended to focus on one of several possible methods of analysis, concentrating on either groups of memories being reported (e.g., studying word lists and then remembering related words that were not included in the original lists) or the person who is reporting the memories (for example, using a battery of self-report questionnaires and behavioral assessments to predict who may be susceptible to forming false memories). In a new report, Daniel M. Bernstein and Elizabeth F. Loftus suggest that a combined approach — focusing on groups of memories, on the person who is remembering, and on the individual memory — along with taking advantage of a variety of research tools available (such as imaging devices, mathematical models, analysis techniques, and statistical methods) may be the best way to determine if a memory is truth or fiction.
Join the discussion here on APS.
Daniel M. Bernstein and Elizabeth F. Loftus
Association for Psychological Science Volume 4—Number 4
How can you tell if a particular memory belonging to you or someone else is true or false? Cognitive scientists use a variety of techniques to measure groups of memories, whereas police, lawyers, and other researchers use procedures to determine whether an individual can be believed or not. We discuss evidence from behavioral and neuroimaging studies and research on lying that have attempted to distinguish true from false memories.
We remember events, people, and places all the time, but how accurate are those memories? More specifically, how can we identify true memories from false ones? A majority of studies trying to answer this question have tended to focus on one of several possible methods of analysis, concentrating on either groups of memories being reported (e.g., studying word lists and then remembering related words that were not included in the original lists) or the person who is reporting the memories (for example, using a battery of self-report questionnaires and behavioral assessments to predict who may be susceptible to forming false memories). In a new report, Daniel M. Bernstein and Elizabeth F. Loftus suggest that a combined approach — focusing on groups of memories, on the person who is remembering, and on the individual memory — along with taking advantage of a variety of research tools available (such as imaging devices, mathematical models, analysis techniques, and statistical methods) may be the best way to determine if a memory is truth or fiction.
Join the discussion here on APS.
Transform Your Mind, Change Your Brain
In this talk, Richard J. Davidson explores recent scientific research on the neuroscience of positive human qualities and how they can be cultivated through contemplative practice. Distinctions among different forms of contemplative practices are introduced and shown to have different neural and behavioral consequences, as well as important consequences for physical health in both long-term and novice practitioners. New research also shows that meditation-based interventions delivered online can produce behavioral and neural changes. Collectively, this body of research indicates that we can cultivate adaptive neural changes and strengthen positive human qualities through systematic mental practice.
The Role of Sleep in Emotional Brain Processing
Cognitive neuroscience continues to build meaningful connections between affective behavior and human brain function. Within the biological sciences, a similar renaissance has taken place, focusing on the role of sleep in various neurocognitive processes and, most recently, on the interaction between sleep and emotional regulation. This review surveys an array of diverse findings across basic and clinical research domains, resulting in a convergent view of sleep-dependent emotional brain processing. On the basis of the unique neurobiology of sleep, the authors outline a model describing the overnight modulation of affective neural systems and the (re)processing of recent emotional experiences, both of which appear to redress the appropriate next-day reactivity of limbic and associated autonomic networks. Furthermore, a rapid eye movement (REM) sleep hypothesis of emotional-memory processing is proposed, the implications of which may provide brain-based insights into the association between sleep abnormalities and the initiation and maintenance of mood disturbances.
How we read each other's minds?
Sensing the motives and feelings of others is a natural talent for humans. But how do we do it? Here, Rebecca Saxe shares fascinating lab work that uncovers how the brain thinks about other peoples' thoughts -- and judges their actions.
Consolidation of Associative Memory
Hippocampal sharp wave/ripples during sleep for consolidation of associative memory.
Ramadan W, Eschenko O, Sara SJ.
PLoS One. 2009 Aug 20;4(8):e6697.
The beneficial effect of sleep on memory has been well-established by extensive research on humans, but the neurophysiological mechanisms remain a matter of speculation. This study addresses the hypothesis that the fast oscillations known as ripples recorded in the CA1 region of the hippocampus during slow wave sleep (SWS) may provide a physiological substrate for long term memory consolidation. We trained rats in a spatial discrimination task to retrieve palatable reward in three fixed locations. Hippocampal local field potentials and cortical EEG were recorded for 2 h after each daily training session. There was an increase in ripple density during SWS after early training sessions, in both trained rats and in rats randomly rewarded for exploring the maze. In rats learning the place -reward association, there was a striking further significant increase in ripple density correlated with subsequent improvements in behavioral performance as the rat learned the spatial discrimination aspect of the task. The results corroborate others showing an experience-dependent increase in ripple activity and associated ensemble replay after exploratory activity, but in addition, for the first time, reveal a clear further increase in ripple activity related to associative learning based on spatial discrimination.
Ramadan W, Eschenko O, Sara SJ.
PLoS One. 2009 Aug 20;4(8):e6697.
The beneficial effect of sleep on memory has been well-established by extensive research on humans, but the neurophysiological mechanisms remain a matter of speculation. This study addresses the hypothesis that the fast oscillations known as ripples recorded in the CA1 region of the hippocampus during slow wave sleep (SWS) may provide a physiological substrate for long term memory consolidation. We trained rats in a spatial discrimination task to retrieve palatable reward in three fixed locations. Hippocampal local field potentials and cortical EEG were recorded for 2 h after each daily training session. There was an increase in ripple density during SWS after early training sessions, in both trained rats and in rats randomly rewarded for exploring the maze. In rats learning the place -reward association, there was a striking further significant increase in ripple density correlated with subsequent improvements in behavioral performance as the rat learned the spatial discrimination aspect of the task. The results corroborate others showing an experience-dependent increase in ripple activity and associated ensemble replay after exploratory activity, but in addition, for the first time, reveal a clear further increase in ripple activity related to associative learning based on spatial discrimination.
Secrets of the Sleeping Brain
Why do we sleep? Although science has yet to explain the reason we spend one-third of our lives in this bizarre state, an exciting theory suggests that sleep can solidify newly learned memories by rewiring the architecture of brain.
Emerging neuroscience evidence also indicates that sleep can intelligently associate and integrate new memories together, performing a kind of "sleep-dependent alchemy." This phenomenon may fuel creative human insights, often reflected in dream content.
In addition to memory benefits, recent findings also suggest that sleep can "refresh" emotional brain reactivity, smoothing away the rough edges from our prior waking concerns, thereby allowing rational next-day decisions.
Emerging neuroscience evidence also indicates that sleep can intelligently associate and integrate new memories together, performing a kind of "sleep-dependent alchemy." This phenomenon may fuel creative human insights, often reflected in dream content.
In addition to memory benefits, recent findings also suggest that sleep can "refresh" emotional brain reactivity, smoothing away the rough edges from our prior waking concerns, thereby allowing rational next-day decisions.
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