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  • Writer's pictureGuylaine Richer de Lafleche

An Introduction to the Scientific Study of Dreams

J. A. Hobson's Activation-Synthesis Hypothesis

All of us, at one point in our lives, have been in awe by the perplexity of our dream content. How many of us though have stopped to think about how the activity in our brain, while we sleep, could be a result of why we dream? A well-known American psychiatrist, and a leading researcher in the scientific study of dreams, John Allan Hobson, has stopped and thought about

this for quite some time.

J. A. Hobson is widely known for his research on REM sleep, as well as his ‘Activation-Synthesis Hypothesis’ that he introduced to us in 1975 with his fellow Harvard graduate, Psychiatrist Robert McCarley. Hobson started his training in psychoanalysis paying close attention to Freud and Dostoyevsky, however, it wasn’t long before he grew frustrated by the lack of scientific material to support these theories; he feels even more firmly about this today. While acknowledging the brilliance and great writing that Freud brought to the table, Hobson states in a 2012 lecture at the Instituto Superior de Psicologia Aplicada in Portugal, “we are now living in the 21st century, Freud has been dead for over 70 years. There is absolutely nothing Freudian about any dream theory thats worth a grain of salt.” It was a bold move to target hundred-year-old theories, however, Hobson was not concerned; “I think that the work of psychology begins with the individuals mind, and you have, within your head, the laboratory to do the kind of research that really needs to be done.” That being said, Hobson has grown tired of his frivolous ways of bashing Freud and would like to clear the air so he can be properly understood. He sees himself as continuing Freud's original goals by providing a neurological explanation to measure the connections between mental activity and brain activity, with special reference to waking, sleeping, and dreaming.

To explain his theory, I would like to start at the very beginning of life and introduce to you Hobson’s idea of protoconsciousness. Protoconsciousness is “a primordial state of brain organization that is a building block for consciousness. In humans, protoconsciousness is proposed to develop as brain development proceeds in REM sleep in utero and in early life.” This idea of protoconsciousness transpired in 2008 when Hobson was asked to give a keynote address at the annual sleep meeting. Although difficult to prove, this theory has been established from scientific evidence based off of our REM sleep cycle.

Figure 1: “The relative proportions of each 24-hour day that are devoted to wake, REM sleep, and non-REM sleep change dramatically over our lifetime. Exactly how and when these states develop in early utero existence is not known (dotted lines), but data from premature infants suggests that REM sleep is almost all of life at 26 weeks of gestation age. After 26 weeks, waking increases progressively and inexorably until death.”

If we take a look at figure 1 we can see that it suggests REM sleep begins in utero, perhaps around the third trimester, and proves to continue in abundance for 2-3 years of an infants life. This tells us that REM sleep is a very prominent feature in the development of the brain and is absolutely crucial to our survival. Taking a look at the non-REM sleep state, we can see it matures relatively late and increases as REM decreases, therefore it doesn’t fully begin until you have enough brain to support it. It is in this manner that we can conclude REM sleep is a state of protoconsciousness, “it occurs before birth, is very prominent in early life, and declines as life goes on. It declines at the expense of waking, [thus] the dynamic between waking and REM sleep dreaming is continuous.”

Now that we know REM sleep is a state of protoconsciousness — and as we know is also the stage most ripe for dreaming — it is reasonable to say that “dream consciousness is a state of primary consciousness.” It is the ability to function in the present moment. It has been proven that all mammals have regulated states of REM sleep, therefore one can assume that animals too must be dreaming and experiencing primary consciousness much like us. But what do we have that animals do not? Well, we have more elaborate brains and with that we have higher states of consciousness, like secondary consciousness. Secondary consciousness grows as our brain does, and is proposed to function in the accessibility to ones history, self-reflective awareness, abstract thinking, and interpretations. It is clear that dreams are self evidently significant, however, it is in this light that we may ask ourselves, does waking consciousness need dream interpretations to proceed? Based off of evidence of animal models, it has been determined that “only mammals have thermoregulation and only mammals have REM sleep, so it is likely that these two functions — and dreaming — are tied together in some way.” Our brains cannot operate without temperature regulation, and we cannot thermoregulate our bodies without sleep. It is in this case that the study of sleep could be placed “on par with other very important aspects of biology.” It may even make you wonder if dreaming is perhaps a coincidence.

To further understand this, lets take a look at Hobson’s activation-synthesis hypothesis. It is based off the comparison of different neuronal activity that happens in our brainstem during waking and REM sleep, part of which was discovered by planting micro-electrodes on the brain stems of cats. During waking our aminergic modulation is very high; our aminergic system transmits monoamines (e.g. serotonin, norepinephrine) that are located in the locus coerules and raphe nucleus of the brain stem. In waking these neurones continuously fire at a steady beat, but as we fall into a period of REM sleep they stop firing almost completely and our brain is turned “offline.” At the same time our aminergic system gradually demodulates, our cholingeric system gradually increases. Our cholingeric system uses acetylcholine (e.g. muscle movement, and autonomic nervous system) as a neurotransmitter. The cholingeric system has relatively low levels of activity in waking, increased activity during non-REM, and reaches it’s peak in REM. Figure 2 shows this process quite nicely in the form of a three-dimensional state space plot known as the AIM model (‘A’ for Activation, ‘I’ for Input/Output Gating, ‘M’ for Modulation).

Figure 2: AIM model shown in a three-dimensional state space plot.

As you can see in figure 2, diagram ‘a’ (following the ‘A’ axis), both waking and REM are highly activated states, however, they're in very different spaces. Waking is at the top — where the aminergic modulation and external stimuli are very high — and REM is at the bottom — where the cholingeric modulation and internal stimuli are very high. Knowing this, we can reasonably theorize that the brain activation that is “associated with eye movements, is associated with aminergic demodulation of the brain,” as well as the hyper-modulation of the cholingeric neurons. Thus, supporting the theory that “dreaming and waking are two states of consciousness that are complementary to each other.” It is in this evidence that Hobson states; “dreaming is not an unconscious mental process, dreaming is an altered state of consciousness, to which I do not have access when I am awake! That doesn't mean, of course, that dreaming is repressed and that it is therefore the enemy of waking consciousness, quite the contrary, dreaming is very meaningful and that is in the service of waking consciousness.” The AIM model relates to all states of consciousness, not just the wake and sleep. The green cone in figure 2, diagram ‘b’, is “designed to show the locus of various altered states of consciousness that are associated with various brain injuries, e.g. brain stem damage. There are 4 or 5 different lowered states of consciousness that all exist in that part of the state space” and of course if you go out of that state space (where there is no brain activation) you would die.

The formal evidence that has come from MRI, PET, and SPECT scanning has completely revolutionized sleep research. Figure 3, diagram ‘a’, displays the different areas of activation and deactivation during REM sleep. The red zones are shown as the areas of the brain that are less active in REM than in waking, where the blue zones show the areas that are more active in REM than in waking. This indicates that “waking and REM are different states of the brain, with respect to not just the level of activation, but the distribution of activation” as well. This can help us to understand the emotional intensification we experience in dream. Dreaming, more often than not, has three major emotions (aggression, anxiety, and elation) and there is a reason for this. The amygdala is involved with the experiencing of emotions and as we can see, is highly active in our state of REM.

Figure 3

The PET imaging studies in figure 4, diagram ‘b’, show us that during REM our frontal lobe (more specifically the dorsolateral prefrontal cortex) is practically inactive, unlike waking where it is fully activated. “The dorsolateral prefrontal cortex is thought to be the seat of executive ego” — this can explain our lack of self-reflective awareness in dream. “The frontal lobe is the part of the brain that controls important cognitive skills in humans such as emotional expression, problem solving, memory, language, judgment, and sexual behaviour. It is, in essence, the “control panel” of our personality and our ability to communicate.”

Figure 4: PET imaging

Both figure 2 and 4 give us a look at the lucid dreaming state. “Lucid dreaming is very interesting, its a hybrid state with certain aspects of waking and certain aspects of dreaming.” If you compare the lucid dreaming state to the non-REM state you will see they are quite similar. Our brainstems are modulating both the aminergic and cholinergic systems, however, in lucidity our brain activation is at it’s peak. That being said, “the localization of the activation in the frontal lobe turns out to be extremely important in determining whether or not you are going to have lucid dreams.” This can explain why lucid dreamers sometimes complain about waking up from their state of lucidity. If that area becomes too active the dreamer will wake-up, but if its not active enough they will be pulled back into the dream. The main point to take away is that states of lucidity, dreaming, and waking are all differentiated from each other in quantifiable and measurable respects.

You may be wondering why a psychiatrist is so interested in the study of dreams. Well, dreaming is a psychosis by definition. It “is a state of mind in which one sees and hears things that do not exist in the real world, they exist inside the head and we are deluded about them.” They are visual hallucinatory, incongruous, discontinuous, aggressive, pleasant, and bizarre. They are caused by brain activation in sleep, and for this they are peculiar by a specified cause. “The psychosis with which dreaming is most identical to is organic psychosis. Organic psychosis is the kind of psychosis that occurs in people when they stop drinking or taking drugs,” or when they have a known physical abnormality in the functioning of their brain. Psychosis is still very much a mystery, however, if dreaming is a model of organic psychosis, by definition, then it can help us in beginning to understand the secondary symptoms of disorders like schizophrenia psychosis or psychotic depression. What’s even more interesting, because dreams are often hypomanic they can give us a pretty good picture of affective disorder. That being said, you can understand why “the study of dreaming is not only relevant to those of us that are interested in psychotherapy, but to those of us who are interested in psychiatry. Dreaming is a model for madness!”

In all the uproar many people wrongly believed Hobson has claimed dreaming has no meaning, but that is simply not true. Hobson’s theory displays the form of dreaming rather than the content of dreaming. He believes dreams do not conceal meaning, however, he is “not against the idea that dreams have meaning, or that dreaming is an important subject for psychology, and for clinical psychology in particular.” As a psychiatrist, Hobson wanted to “recreate a dream theory that was compatible with modern neuroscience.” He is after universals, “things that characterize your dreaming, my dreaming, everyones dreaming — regardless of whether you dream about your mother, or I dream about my father — it doesn't have to do with biographical content, it has to do with formal content.” By doing so, this meant he had to ask himself whether or not his hypotheses were compatible with science; “if its not compatible with science, then you either reject it and don't think about it anymore, or you go to church on Sunday… I mean, thats all there is to it!” With that in mind, Hobson is not suggesting all psychotherapy be scientific, but rather it can be scientific up to a point — and in your theory of dreams in particular.

Hobson is a true lover of the study of dreams. He has been keeping a dream journal for almost 40 years now and is still seduced by the mysteries of our nocturnal adventures. He has even remodelled part of his barn in Vermont into an interactive sleep museum for students! It has been an honour for me to research Dr. Hobson’s work, and I can genuinely say his theory has helped me to understand dreams as a whole. Dr. Hobson has taught me to not only respect the beauty of dreams but to cherish the human brain. I hope you too, feel the same way and choose to continue your dreamwork with his theory in mind.


“[Dreaming] is a psychedelic state that comes with a suit. You don't need to take drugs, you don't need to buy things, you just need to go to bed, and teach yourself to wake-up and remember these things. It’s a free theatre for you!” - J. A. Hobson



  • Hobson, J. A. (2003). Dreaming: A Very Short Introduction. New York: Oxford University Press.

  • Hobson, J. A. (2012). Dreaming as Virtual Reality [Vimeo Video]:

  • Healthline Editorial Team. (2015, March 2). Body Maps/Frontal Lobe:


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