The mind can be observed from two perspectives: first as a material object, or the brain, and second as subjective awareness. This duality leads to two modes of inquiry: psychological and neuropsychological. To quote Mark Solms and Oliver Turnbull1, “there is everything to gain and nothing to lose from integrating our two modes of inquiry.”
What Does Neuroscience Tell Us About Dreaming?
Neuroscience has come to understand a great deal about the neurobiological basis of dreaming. The discovery of REM sleep in 19532 initiated the neuroscientific understanding of sleep and dreaming. Initial dream research was based on EEG studies in sleep labs.
EEG revolutionized dream research and neurology in general because it provided a non-invasive mechanism for assessing the activity of the brain. Early EEG studies revealed that sleep was not a single state, but multiphasic consisting of five stages repeated several times during the night. Early sleep research posited that dreaming was exclusively associated with REM sleep, also called paradoxical sleep since its brain waves resemble the waking brain.
Do Dreams Have Meaning?
Believing that the brainstem was responsible for REM led to the Activation Synthesis Model of Dreaming developed by Hobson and McCarley3. This stated that the brainstem activated dreaming in the forebrain, and that dreams synthesized the ”meaningless” images and “feelings that are randomly produced by brainstem cell firings.” This theory contradicted most psychological theories about dreaming as well as the intuitive understanding possessed in many early cultures. This hypothesis was refuted by subsequent research that discovered the presence of non-REM dreaming located in other regions of the cortex.
What Is the Mechanism of Dreaming?
The development of advanced brain imaging techniques5 such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) made it possible to visualize regional activation patterns associated with changes in brain activity. Rosalind Cartwright6 in her book The Twenty-Four Hour Mind summarizes this research. The findings are exciting and informative. From brain imaging studies, scientists have discovered that specific areas of the cortex are activated in dreaming. During REM dreaming, brain activation changes in a systematic manner. Activation of the limbic system of the brain stimulates the beginning of the dream process. The second area of the brain that is active is located in the occipital-temporal-parietal junction. This area receives, analyzes and stores information and is associated with the generation of visual-spatial imagery. While these two areas are active during dreaming, the dorsolateral pre-frontal cortex right behind the forehead is deactivated. This part of the brain is the logical area responsible for executive cognitive functions such as planning and evaluating.
These findings provide a neuroscientific understanding for why dreams are so visual, sometimes bizarre and intensely emotional. The brain centers that are activated in the limbic system and the zone between, occipital-temporal-parietal junction, account for the hyper-emotionality, hyper-associativity and intense visual imagery that characterizes dreams, while the frontal lobe structures, aka Freud’s censor, that mediate analytic problem solving and self-reflection are shut down.
Why Do We Dream?
We know that we have a need for REM, but researchers don’t know precisely what we need REM for. Deprive individuals of REM, and they become more anxious, irritable and have difficulties concentrating. The importance of REM is also evident in the developmental changes that occur with REM. Individuals spend increasingly less time in REM as they grow older; children need more REM than adults. The implication is that REM is significant for the development of cognitive activity and emotional regulation.
The emerging view in neuroscience is that dreams are related to memory consolidation and emotional regulation that occur in the brain during sleep. This may include re-organizing and re-coding memories in relation to emotional drives, as well as transferring memories between brain regions. Optimally, during sleep, the individual is actively reviewing, processing and sorting previous experiences with new information. These findings support the notion that dreams have a healing and self-regulating function.
Neuroscience can explain the mechanisms of dreaming but can’t answer the question of why we dream. If there is a biological significance to REM, at the very least it is associated with dreaming and the significance that dreaming holds for our psyches.
As we try to understand this relationship, neuroscientists find themselves struggling with their subjective perspective noted by Solms and Turnbull, that moves into speculation. The mystery of dreaming remains alongside that other great mystery, what is consciousness.
The Brain—is wider than the Sky—
For—put them side by side—
The one the other will contain
With ease—and you—beside
The Brain is deeper than the sea—
For—hold them—Blue to Blue—
The one the other will absorb—
The Brain is just the weight of God—
For Heft them—Pound for Pound—
And they will differ—if they do—
As Syllable from Sound—
Emily Dickinson (1862)
Written by Larry Brooks
Larry Brooks, Ph.D. is a Licensed Clinical Psychologist who has been in full-time private practice in Glendale for 25+ years. In addition to his psychotherapy practice, he provides consultation to post licensed mental health professionals and has written for the Cultural Weekly, an online publication critically examining cultural issues of the day.
- Solms, M., & Turnbull. (2002). The Brain and The Inner World. Other Press.
- Dement, W., E., & Kleitman, N. (1957). Cyclic variations in EEG during sleep and their relations to eye movements, body motility, and dreaming. EEG and Clinical Neurophysiology, 9:673-690.
- Hobson, J.A., & McCarley, R. (1977). The brain as a dream state generator: An activation-synthesis hypothesis of the dream process. American Journal of Psychiatry, 134:1335-1348.
- Cartwright, R.,D. (2010). The Twenty-Four Hour Mind. Oxford University Press.