However, the ability to plan was considerably worse in lucid dreams compared to wakefulness. Lucid and non-lucid dreams certainly feel subjectively different and this might suggest that they are associated with different patterns of brain activity. But confirming this is not as easy as it might seem. Participants have to be in a brain scanner overnight and researchers have to decipher when a lucid dream is happening so that they can compare brain activity during the lucid dream with that of non-lucid dreaming.
Ingenious studies examining this have devised a communication code between lucid dreamer participants and researchers during Rapid Eye Movement REM sleep, when dreaming typically takes place. Before going to sleep, the participant and the researcher agree on a specific eye movement for example two movements left then two movements right that participants make to signal that they are lucid. By using this approach, studies have found that the shift from non-lucid to lucid REM sleep is associated with an increased activity of the frontal areas of the brain.
A follow-up study found that electrically stimulating these areas caused an increase in the degree of lucidity experienced during a dream. Another study more accurately specified the brain regions involved in lucid dreams, and found increased activity in regions such as the pre-frontal cortex and the precuneus. Maybe I am unconscious while slumbering and confabulate my dreams when I awaken. This is unlikely for many reasons. Additionally, the length of dream reports correlates well with time elapsed in REM dreams.
More evidence comes from people with REM sleep behavior disorder, who lack the muscle paralysis, known as atonia, typical of REM sleep. They act out their dreams, sometimes even harming themselves or bed partners, and their actions match their dream reports. They might, for instance, move their legs while asleep and later report that they dreamed of walking. Dreams are of great interest to the student of the mind-body problem, because they bear witness that the brain alone is sufficient to generate consciousness.
We dream with eyes shut in the dark, disconnected from the outside world. The brain regions responsible for basic sensory perception are deactivated. Nor is behavior necessary, as we are motionless except for our breathing and eye movements. Thus, dreaming supports the old philosophical brain-in-the-vat idea that saw its modern renaissance in The Matrix. Cognitive neuroscientists have recently learned to decode some simple mental states—in essence, a primitive form of mind reading. When scientists ask people to view one of two images—a portrait or a photograph of a house—or to imagine either a face or a house, they can tell from brain analyses which of the two the person is seeing or imagining.
Once such techniques become more sophisticated, they could be put to use in dream work, so that in addition to studying the physiology of the dreaming brain, investigators will be able to read out the content of the dream itself. Then neuroscience will be in a much better position to answer the age-old questions that have fascinated everyone from oracles and shamans to Freud and, more recently, science-fiction enthusiasts: Why do we dream, and what do dreams mean?
Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. Get smart. Sign up for our email newsletter. Sign Up. He proposed that a part of our mind is made up of thoughts, desires, emotions, and knowledge that we are not aware of, but that nevertheless profoundly influence and guide our behaviors. In his books e. Its expression, however, is coded within dreams the work of dream , and unconscious thoughts are distorted before they emerge in the conscious mind of the sleeping subject manifest content of the dream.
As a consequence, the dreamer is not disturbed by repressed and unacceptable thoughts latent content of the dream and can continue sleeping this is the reason why Freud considered dreams the guardians of sleep.
As a consequence, Freud developed techniques to decode dreams and provide a way for an analyst to look inside the words and unconscious images of the patient, and to free them through patient insight. One of these techniques is called free association, and is regarded as an essential part of the psychoanalytic therapy process.
Free association is the principle that the patient is to say anything and everything that comes to mind. Over time, the therapist or analyst will draw associations between the many trains of uncensored speech the patient shares during each session. Hence, Freud considered that dreams, as well as slips, have a meaning and can be interpreted, so that one is justified in inferring from them the presence of restrained or repressed intentions Freud, , A psychic process is nothing more than the purpose which it serves and the position which it holds in a psychic sequence.
It gives access to an unknown dimension of ourselves that is fundamental in understanding who we are. It provides access to personal meaning. However, this situation may change as the relationship between psychoanalysis and neuroscience evolves.
The starting point was the creation of the International Society for Neuropsychoanalysis in It was founded by neuropsychologist and psychoanalyst Mark Solms with the intention to promote interactions and collaborations between psychoanalysis and neuroscience.
Finally, he presented his model of dreaming, the activation-synthesis hypothesis Hobson and McCarley, ; Hobson et al. In doing so, these chaotically generated signals arising from the brain stem acted as a physiological Rorschach test, initiating a process of image and narrative synthesis involving associative and language regions of the brain and resulting in the construction of the dream scenarios.
He argued that it is generally accepted that brain stem activation is necessary, but not sufficient, to explain the particular characteristics of dream consciousness. What does explain the particular characteristics of dream consciousness, according to Solms, are the following features of brain activity during REM sleep Braun et al. He further argued that his lesion studies Solms, are congruent with neuroimaging results because they showed that a total cessation of dreaming results from lesions in the medial part of the frontal lobe and in the temporoparietal junction whereas no cessation of dreaming was observed for core brainstem lesions or for dorsolateral prefrontal lesions.
Finally he emphasized that the activation of motivational mechanisms such as drives and basic emotions and of posterior perceptual system associated with deactivation of the executive control i.
Note that experimental results demonstrating the existence of unconscious representations that guide behavior e. This debate was a success for Mark Solms and neuropsychoanalysis. He proposes that dreaming and REM sleep are controlled by different brain mechanisms. According to Solms, REM sleep is controlled by cholinergic brain stem mechanisms, whereas dreaming is mediated by forebrain mechanisms that are probably dopaminergic.
This implies that dreaming can be activated by a variety of NREM triggers. Several experimental results support this hypothesis. First, behavioral studies have demonstrated that the link between REM sleep and dream reports is lax. Second, as Solms argued, the amount of dream recall can be modulated by dopamine agonists Scharf et al. Dream recall can be suppressed by focal brain lesions at the temporo-parieto-occipital junction and ventromedial prefrontal cortex; Solms, , These lesions do not have any appreciable effects on REM frequency, duration, or density Kerr et al.
Finally, some clinical studies suggest that a dream can be triggered by nocturnal seizures in NREM sleep, i. Some cases of recurring nightmares caused by epileptiform activity in the temporal lobe have indeed been reported Solms, Considering the issues that remain unresolved e.
Thus, both psychology and neuroscience have provided results and hypotheses that validate the possibility that dreaming has something to do with personal and meaningful issues. On the other hand, Freud argued that the unconscious, which guides behaviors and desires, express itself during dreams.
Note that some experimental studies in psychology have considered the psychoanalytic perspective. For example, Greenberg et al.
They showed that problems occurred very frequently in the manifest dream content and that these problems were nearly systematically related to the problems noted during pre-sleep wakefulness.
In addition, they observed that effective dreams i. This study thus confirmed that personal concerns influence dream content. In addition it provided new results suggesting that dreaming may have some psychological problem-solving function this result recalls the neuroscientific findings that sleep has a cognitive problem-solving function associated with brain reorganization; e.
Greenberg et al. To proceed further, approaches integrating psychoanalysis and neuroscience must now be developed. This limitation hampers the understanding of psychological and neurophysiological functioning in humans. These issues must be addressed, and the expertise of psychoanalysts in singularity and personal meaning is needed to do so in neuroscience and to further the understanding of dreaming and of the psyche. The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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