Brain Evolution

Forgive this long delayed update, I've been engrossed by recent discussion and growing interest in this most important aspect of human evolution. Recently, I finished an interview on the subject of Evolution and the Dreaming Brain. For that interview, I was furnished with a list of 18 questions, which we did not cover completely. Here are those answers completed:

Q: Kenneth - as an executive in the medical profession, how did you become interested in dreams and in particular the evolutionary aspects of dreaming?

Actually, my interest in dreaming began several years before my work profession—with a dream I had about a muddy shoe. What made this dream so affecting was my encounter with that exact shoe the follow day when I found it on the floor in the basement of the home where I was living at the time. My sister had just stepped in mud and left that shoe rather than track mud through the house. I was fascinated by the possibility this experience suggested—that dreaming can open a widow on future experiences.

By the time I joined the medical center I managed, my interest had evolved into wanting to understand the language of dreams much better than I did. In my efforts, I took a non-conventional approach that didn’t include any of the established ideas or conclusions of people like Sigmund Freud or Carl Yung. For me, their ideas represented the end of a journey and I didn’t want to reach that end without taking the journey myself. So I began by study my dreams and what they seemed to suggest. Then I compared my findings to the dreams of other people and what they believe their dreams suggested. To make a very long story short, what I believed I found was a type of universal language, which led to my first book on dream translation. Afterwards, I began to wonder what made that universal language possible. That led me to brain study and eventually evolution and the dreaming brain.

Q: Is the evolution of the brain relevant to studying or trying to understand dreams?

Whenever I’m asked that question, invariably the discussion becomes one about spirituality or reductionism vs. science—as though explaining dreams through science and evolution deprives dreaming of something profound. What I try to explain is how the science of dreaming doesn’t deprive us of our beliefs about dreaming; the science merely offers a perspective that could enhance what we believe. So, when I’m asked the question, “Is brain evolution relevant?”, I often answer by asking, “would we be able to dream without a brain.” If the brain is that important to dreaming, then the more we learn about the brain, the more we learn about dreams and dreaming.

We share the experience of dreaming with other animals. Therefore. I believe the ideas we form about dreaming may also apply to those animals. If they don’t, then our ideas may be invalid. So, to determine the validity of our ideas, we have to better understand what we share with other animals and why. Doing that, I believe, requires that we research the history of our physiological and behavioral commonalities—and that is what studying evolution provides—a history that explains the adaptations we share with other animals and why.

Q: So how does one study brain evolution relative to dreaming?

I think one has to have a clear perspective of what evolution is and how that perspective may apply to brain structure and those brain functions associated with dreaming. In the book, AN ANATOMY OF THOUGHT (Ian Glynn), evolution is concisely described as survival of the fittest through a process of natural selection. I think the general view of that process is one where stronger animals replace weaker animals. What isn’t stated in that view is that evolution creates these stronger or succeeding animals by building on the successful designs of weaker or prior species; in other words, evolution create stronger more adaptive species from what works with prior species. In terms of brain structure, I think this is shown by a succession of recent or refined neural structures rising from a base of less refined or primitive structures, by comparison. For example, in the mam-malian divisions of the brainstem we have the metencephalon (across-brain) arising contiguously after the myelencephalon (spinal brain). The MYEL is more primitive than the MET by comparison because of its less refined sensory systems. (An example of which is the vagus nerves [CX] of the MYEL that is associated with tactile ear sensory and the vestibulocochlear nerve [CVIII] of the MET that is associated with sound sensory.)

Relative to dreaming, each brain division contributes some neurologically induced distinction to the dreaming process. If we accept the con-tiguous design of brain structure as evidence of its path through evolution, I believe we have a blueprint for studying how each component of the brain and its dreaming process evolved.

Q: What is the current thinking on how the brain evolved? For example is the brain stem the most primitive, the midbrain and limbic regions the next and finally the cortical regions the most current?

Well, I think the predominant theory is that of neurologist, Paul Maclean, who actually coined the term limbic system back in 1952. In 1970 Dr. Maclean proposed that the human brain evolved in 3 stages: Rep-tilian, Limbic, and Neocortex. Known as the Triune Brain Theory, the 1st stage (reptilian) consist of the brainstem and cerebellum as suggested by the rep-tilian and amp-hibious forms of early life about 500 million years ago. The second stage consist of the limbic system, which Maclean associated with the shrew-like mammals that evolved at the feet of dinosaurs some 150 million years ago. The final stage, stage 3, Maclean associates with the neocortical developments of primates and large mammals, 2-3 million year ago.

In general, this theory follows the overall progression of brain structure from dinosaur to humanity but it doesn’t, in my opinion, clearly provide an explanation for that progression. For example, it doesn’t sufficiently explain how the components of the brainstem evolved. I believe that this kind of detailed explanation is essential to our precise understanding of the distinctions each brainstem component contributes to the dreaming process and why.

The theory that has become the basis from my investigation of evolution and the dreaming brain is what I refer to as “The Big Bang Brain Theory” or “3B Theory.” This theory suggests that our central nervous system began as a consequence of the sensory adaptations that early photo-synthetic life required to adjust to energy sources other than sun light. It’s based on the idea that we can track our brain’s evolution through its sensory systems as we might track evidence from the Big Bang back to the creation of the universe. This theory relies on evidence that our central nervous system reflects the con-tiguous nature of its evolution and that the succession of each sensory component within our central nervous system suggests the stage in evolution where our brain began receiving and processing such sensory information. Support for this theory is suggested by the increasing sophistication of brain function from spinal cord to cortex and by the bottom-up model of brain activation, which is consistent with Hobson’s activation synthesis hypothesis.

The increasing sophistication of brain function is suggested by the increasing complexity and enhancement of that function by succeeding neural developments from spinal cord to cortex. For example, we find tactile sensory nerves from our outer ear in the first segment of our brainstem (myelencephalon-spinal brain), while the sound sensory nerve from our inner ear arrives in the succeeding segment of brainstem (metencephalon).

The bottom-up model of brain activation suggest that the function of succeeding brain structures is dependent on the function of preceding brain structures. A perfect example of this are experiments that show the cortex as incapable of auto-activation without a neural connection to subcortical brain structures—such as Jouvet and Jouvet, “A Study of the Neurophysiological Mechanisms of Dreaming” (1963).

Q: Can you describe this evolution as it relates to the dreaming brain and dreaming?

The Triune Theory doesn’t specifically explain the origin of the dreaming brain. However, it does support the idea that our brain structure, from spinal cord to cortex, contiguously suggests the path the human brain traveled from a primitive state to its evolved form. Using the 3B theory and what we know of brain structure and those functions that govern the processes of sleep and dreaming, the path of our brain to dreaming began with the rhombencephalic phase of brain evolution. The rhombencephalon combines the first and second segment of our brainstem beginning at the spinal cord. These segments (Myelencephalon and Metencephalon) produced the first components of the sleep and dreaming process. Those components were spindles and atonia. Spindles are a type of brainwave pattern commonly associated with non-REM sleep and atonia is the relaxed state of muscle tone we associate with REM sleep. As some of our listeners may know, REM is an acronym for the rapid eye movements in sleep that we have associated with dreaming. The production of spindles concurrent with atonia during the first and second stages of our neural evolution suggests how these components of sleep probably began as a means to conserve energy between cycles of activity most likely associated with feeding—because at this development stage in the contemporary brainstem we find sensory-motor neural developments primarily related to feeding.

The next phase of our dreaming brain’s evolution arrived with the third and forth segment of the brainstem. Respectively, those segments were the mesencephalon and the diencephalon. The mesencephalon gave our animal, ancestors the sensory attribute that likely led to the distinctive brainwave activity we have associated with dream sleep.

At the mesencephalic stage of our neural evolution we find sensory developments associated with sight. Sight was perhaps the most important sensory development because before sight, our animals ancestor’s behaviors were likely governed by what they heard or felt. We know this was likely because below the level of sight related structures in the brainstem we only find sensory systems related to sound and tactile perception. With the addition of sight perception, early animals were probably capable of mediating their behaviors more efficiently than they could with just sound or tactile perception alone. This efficient mediation, inspired by sight perception, could have led to behaviors that were more proactive than reactive, which somewhat explains the distinctive brainwave activity associated with dreaming that the third and forth segment of the brainstem produce.

Some of our listeners may know that the stage of sleep commonly associated with dreaming is called paradoxical or D-sleep. This sleep stage produces a pattern of low amplitude, high frequency brainwaves, which is also the pattern conscious brain function creates. So at the MES and diencephalic stage of brain evolution we find the emergence of brain activity related to consciousness and dreaming that is concurrent with sight perception. Although this stage in the contemporary brain may suggests we have found the point in evolution where the brain began to dream, we don’t find the brain structures capable of constructing dream content at this point.

Dream construction is memory dependent, and the memory function related to dreaming evolved with the neocortex, which likely arose as an extension of the memory function begun by limbic evolution. Therefore, the dreaming we experience in present-day arrived with the evolution of the neocortex.

Q: From the perspective of evolution, what role does dreaming play? How did the brain evolve to dream and why?

From a perspective of evolution, dreaming is a recent development; it is the arousal in the brain that vestigial brainstem activity causes.

To be brief, sleep atonia, as a vestigial activity, likely evolved as a means to conserve energy during periods of rest or between feeding cycles. As these periods or cycles lengthened, animals adapted atonia as a way to extend their tolerance of prolonged periods of inactivity without feeding.

Dreaming, briefly again, appears to be a type of wakefulness in the brain during the sleep process. It probably evolved from the vigilance or wakefulness ancestral animals required to survive during periods of rest. That wakefulness became dreaming as those animals developed secure resting routines that no longer required constant vigilance. Therefore, the entirety of dream sleep seems to have evolved from a combination of the energy conserving process of atonia adaptation and the vigilance early animals required while resting.

The form of dreaming we experience today normally occurs at the onset of atonia. This suggests that the initiate of present-day dreaming is more closely associated with the energy conserving process atonia involves. Essentially, atonia results in diminished muscle readiness and increased energy uptake by the vital systems of the body. This is consistent with the efficient use of energy reserves for those bodily systems essential to survival during periods of rest. Specifically, dreaming initiates as a consequence of energy uptake by our resting brain. This vestigial process causes the arousal in the brain that leads to dreaming. When the brain arouses during this process, it begin to do what it was evolved to do and that is interpret influence.

Q: REM Research on animals indicates that almost all mammals go through REM cycles which we as humans associate with visual dreaming. How does evolution explain dreaming in these other animals?

Well, species that share common traits fall under the “common descent” model of evolution. Essentially, this model suggests that animals with like traits inherited those traits from a common ancestor. Accordingly, other animals dream probably for the same reason we do because we inherited that trait from a common ancestor. And, as I described earlier, the evolutional evidence appears to suggest that we dream as a consequence of the arousal in the brain that is caused by vestigial brainstem processes.

Q: In the work that Hobson and many others have done we have found that the midbrain with its limbic region and amygdala is very active in dreaming. The limbic region and amygdala are also very active in processing emotion and stress reaction - essentially the amygdala is our alarm system which readies us for fight or flight - a very primitive and basic safety function. This midbrain activity in dreaming has lead many scientists to conclude that dreams are processing emotion - perhaps unresolved emotional residue from events of the day. Revonsuo goes further to theorize that dreams are dealing with threats - which this portion of the brain indeed does. What is your thinking on why this very primitive part of the brain is so active in dreaming?

First, I must say that the work of Dr. Hobson and others on the neurological and neurochemical nature of sleep and dreaming has been extraordinary. Dr. Hobson, in particular, has a rich body of work that has profoundly influenced my thoughts on the nature of dreams and brain function. I think, however, that Revonsuo’s use of evolutionary psychology was inspired. Essentially, he suggests that if our ideas about dreaming are valid, they will be supported by what we know of evolution and its relationship to dreaming. So when we talk about the contribution of the limbic system to dreaming and dream content, we have to ask if the evolutional history of the limbic system supports our ideas about its function.

If we believe that the structure of our central nervous system reflects the contiguous nature of its evolution, then the limbic system evolved either after or concurrent with the thalamus. So, to understand the evolved function of the limbic, we have to first understand how thalamic function might have contributed to limbic development.

In studying the thalamus, we have to ask “what does its contemporary function and order in our central nervous system suggest about its evolution?” Well, we know that the thalamus is the first destination in our nervous system for all sensory information before entering the cortex, with the exception of olfactory sensory. This suggests that the very first thalamus, before the development of superior brain structures, was likely the final destination for all sensory information that entered the brains of early animals. If this is true, then the thalamus would have been to these animals what we believe the neocortex is to us: it would have been the place where multiple types of sensory information was processed to produce an appropriate behavioral response. When we examine the order in which the thalamus arises, we find its emergence after the hypothalamus and sight sensory neural systems. This suggests that these systems may have contributed to the emergence of thalamus.

If you are still following me, sight sensory systems brought with them desynchronous brain activity, which had been synchronous throughout the evolution of taste, touch, and sound sensory systems—as suggested by the sensory systems of the lower brainstem (MET and myelencephalon). What made sight perception so distinct was probably its independence from tactile forms of perception: what early animals perceived by sight was not dependent on what they felt. For those who might be wondering, even sound sensory is a tactile form of perception caused by our inner ear’s detection of minute changes in air pressure.

The integration and coordination of sight with tactile forms of perception, as I mentioned earlier, probably allow for better mediation in the behavioral responses of early animals. The contemporary thalamus suggests this early stage of behavioral mediation by virtue of being the sensory gatekeeper to our cortex.

As early animals became more sight dependent, the ability to recognize survival affecting influences by sight probably made the difference between those animals who survived and those who did not. Evolution of the limbic system suggests how the path to such recognition began. What the evidence in brain study appears to suggest is that the limbic system caused the persistence of affective mental influences: evolution of the amygdala intensified the emotional content of experience and hippocampal development intensified the spatial significance of experience—spatial significant memory is memory associated with the recall of our prior locations and actions because much of what we remember is dependent on where we were and what we were doing when we acquired those memories.

As the limbic development relates to dreaming, its evolved function does not appear to suggest any distinction between its activation in dream sleep and its conscious activation. In dream sleep, the limbic system appears to do what it was evolved to do for the conscious mind—and that is to intensify or assign some emotional significance to the content of experience. To suggest otherwise is to suggest that limbic function in sleep is unique from its function during the brain’s wakeful state—mere activation in dream sleep does not make limbic function unique, in my opinion.

Q: Does our lack of dream recall have an evolutionary basis?

Yes, it does in my opinion. And that lack of recall is tied to a probable basis in the evolution of memory overall. Evolution suggests that humanity evolved from less sophisticated animals. If memory evolved with those animals, that memory likely focused on experiences that had a palpable or physical impact on their survival: these animals likely remembered only those experiences that had a real or material affect on their physical well-being. As a result, our modern brain is predispose to remembering only those experiences that accompany physical experience. So, the question becomes, “How do we proved that assertion?”

Interestingly, the part of the brainstem where material/physical experience initially enters our central nervous center is also the same part that controls atonia. The rhombencephalon, if you recall from my earlier comments, appears to comprise the first and second stages of initial brain evolution that also controls atonia.

In brain experiments in the early 60’s by the preeminent sleep researcher, Dr. Michel Jouvet, the rhombencephalon was shown to engage and disengage atonia in the absence of a neural link to superior REM producing brain structures. Through atonia, Jouvet’s experiments demonstrated at least a partial cessation of rhombencephalic neural function. This partial suspension of neural function also suggest that physical experience has a diminished affect on brain function during atonia because material/physical information must pass through the rhombencephalon before entering superior brain structures. In short, the dreaming brain does not perceive dream experience as true physical experience and, therefore, does not generally attach dreams with the significance essential to memory.

Given the perspective I have gained through brain evolution, what we remember and the length of our memory is determined by how the brain processes experience. How the brain processes conscious experience and how it processes dream experience is not the same. This is suggested by low activation of the prefrontal cortex and atonic neural activity that only occurs when the brain is engaged in functional activity suggestive of REM sleep. These functional assessments of the dreaming brain suggest that the dreaming brain does not perceive its dream experience the same as those experiences occurring in physical reality. In an intact and healthy brain, the tonic activity of the rhombencephalon appears to activate prefrontal cortical function. Without prefrontal activation, we do not give our experiences the kind of attention that promotes sustained memories. Dreaming occurs without prefrontal activation; therefore, our dreams do not normally receive the kind of concurrent attention that promotes sustained memory like our conscious experience. When we awake with memories of having dreamed, those memories are due to the activation in our prefrontal cortex preceding our fully aroused state of consciousness. Our prefrontal cortex becomes active as we awake when the primitive components of our brainstem function begins to reengage their tonic activity. When our prefrontal becomes active, we are able to give the experience of dreaming the kind of attention that creates recall when we are fully awake. Because this attention comes after the experience of dreaming, our recall of what we dreamed is very often difficult to remember. We remember our conscious experiences better than dream experiences because the physical perceptions that accompany conscious experience stimulate the attention and the associative data network that make our conscious experiences memorable. Our memory of dreaming is dependent on our awakening brain’s ability to capture and retain the experience before it fades.

Q: What are the attributes of dreaming in the sleeping brain and what does the science suggests about their evolution?

Unfortunately, I do not subscribe to the continual activation theory of dreaming, which suggests that proper brain function is dependent on continual activation to through all phases of sleep. So, from my perspective, dreaming only occurs in paradoxical sleep and the primary components of that sleep stage are atonia, REM, and the desynchronous brainwave activity uniquely associated with REM and conscious brain function.

The evidence suggested by the brainstem and the earliest forms of complex life in the fossil record is that atonia evolved concurrent with the level of brain activity we associate with NREM sleep. NREM involves a pattern of progressively high amplitude, low frequency brainwave activity. The neural developments and behavioral responses that we find at this stage in the contemporary brain suggest that the behaviors of early life at this stage were more reactive that proactive. Contemporary studies show that animals with low-decerebrate brains remain in a continuous state of muscle atonia when left undisturbed. Animals with this type of brain preparation do not have intact brains beyond the rhom-ben-cephalon. The behavior of these experimental animals suggests that the ancestral animals who gave us the rhom-ben-cephalon were not very active.

In mid-brain experiments, where brain structure remains intact through the mesencephalic stage, we observe behaviors suggestive of contemporary REM sleep. In his experiments, Jouvet perceive this observation as evidence of REM’s neural origin. Movement of the eye is a response to the neural commands that the muscles of the eyes receive from superior brain structures. In those structures we find the evidence that our animal ancestor had became more active and had began to engage in more complex behaviors. The neural convergence these behaviors required likely produced the desynchronous brain activity and subsequent eye movement we now experience in dream sleep.

Q: There are a lot of theories of dreaming. What ideas about dreaming does brain evolution appear to support?

I think the most important ideas evolution supports are that our dreams are information and that they are meaningful. When we look at the evidence, we find brain function was evolved to perceive and respond to the information it receives both internal and external to the body. Essentially, dreaming is arousal in the brain amid sleep and there is nothing about this process suggesting that the brain does something different than what it was evolved to do when consciously awake. If the brain was evolved to perceive and respond to information, then that is exactly what it does when it arouses amid sleep—perceive and respond to the information resonant in brain structure. One might ask, “how so?”

Dreams are information in the sense that they describe something our brain believes it experienced during sleep. So, when we awake with dream about a house or food for example, that house and food describes information about something our brain believes it experienced while sleeping. Empirically, we know that our dreams are not concurrent with our actual experiences in physical reality; in other words, driving a car in a dream is not concurrent with our physical experiences while dreaming—that is unless we’re asleep behind the wheel of car. So the experiences in our dreams do not originate from our direct physical experiences outside the dream state. Therefore, the information our dreams convey likely originate from influences internal to what we experience physically.

Experiments by researchers like Jouvet and Jaime Villablanca suggest that our cortex does not become active without neural input from lower brain structure. Their experiments suggest that if the cortex produces dreaming, it cannot without the sensory input of lower brain structures.

Now, we know that dreams do not directly originate from our physical senses nor do they originate from the auto-activation of the cortex; therefore, this suggests that dreams most likely arise from resonant or latent brainstem influence; in other words, mental influence.

There is a growing belief among some dream researchers that limbic activation is the likely source of dream content. That belief appears to be based, in my view, on the assumption that limbic function in sleep is different from its wakeful function—that the limbic does something different during dream sleep than it does when we are awake. Such beliefs, again in my opinion, seem to ignore the research and evolutional evidence suggesting that the function of the limbic is more reactive than proactive; in other words, rather than inspire dream content, the limbic merely reacts to that content and those influences that cause dreaming. Rather than create our dream content, the limbic system merely interprets and tags those influence that do.

So, if we are looking for the source of dream content, I believe we should look at the likely source of our psychology, which appears to be the hypothalamus—in my opinion.

The hypothalamus has well researched associations with everyone of our instinctive drives: Hunger, sexuality, and sleep all appear to be mediated in someway by hypothalamic function. In terms of evolution, the hypothalamus appears in brain structure after the emergence of those neural systems that suggest early animals had become more active and had begun to engage in more complex behaviors. The hypothalamus appearance after these developments and its mediation of our drives suggest it probably evolved to enhance the mediation or management of the energy early animals were increasingly requiring.

I don’t think anyone can make a cogent argument against how much our instinctive drives influence our thoughts, emotions, and behavior. Animal experiments by Drs. Walter Cannon and Sidney Brittion in the 1920’s, and subsequent experiments by Dr. Philip Bard suggest that early animals at the stage of hypothalamic evolution had began to experience affective conditions of mind. These researchers were able to produce rage behavior in cats with only hypothalamic brain developments. In my opinion, this research suggests the stage at which our animal ancestors were beginning to experience a psychology. If our dreams are products of our psychology, I believe our hypothalamus is that source.

Q: What ideas about dreaming does brain evolution seem to contradict?

Well, one idea it contradicts is the limbic system as the source of dream content and another is that atonia evolved to serve the dream state. When we look at the mid-brain experiments of Dr. Jouvet, involving animals with intact brainstem structures through the mid-brain (mesencephalon), he believed he had found the neural seat of REM sleep. Jouvet observed animals that appeared to experience both the eye movements and atonia associated with REM sleep. The eye movements Jouvet observed were particularly slower and weaker than normal REM. Unfortunately, Jouvet didn’t consider that such eye movements could have been the residual effect of neural impulses from the severed motor nerves to the eye that remain in the mid-brain after transection. In this case, slower and weaker eye movements are like the twitching of a severed limb after its amputation. This kind of twitching in the eye would only surface in mid-brain experiments after the suspension of neural function by the rhombencephalon. If you’ll recall, this portion of our brainstem controls atonia and atonia suggests the partial cessation of neural function associated muscle readiness and a cessation of the neural function associated with the perception of true physical experience.

Mid-brain experiments do not produce eye movements when the lower brainstem is tonic or active because eye movement is subservient to forebrain function and that function is subservient to rhom-ben-cephalic activation. Again, this is consistent with the bottom-up or ascending activation model of brain function. The eyes don’t move during the these tonic state/mid-brain experiments because their movement becomes subservient in that state. During atonia, the lower brainstem releases it subservient command thus permitting independent movement of the eyes.

If we accept the contiguous design of contemporary brain structure as evidence of its evolution, then we must accept that the atonia producing structures evolved before REM and before dream producing brain structure. This alone suggests that atonia was not evolved to prevent movement in dream sleep. The body doesn’t move while dreaming because the dream activity of the brain doesn’t produce the type of neural commands that activate the muscle systems of the body. Our body, in atonia, does not move when we dream because that part of our brainstem that controls atonia doesn’t recognize the content of dreams as requiring movement. Our eyes move in dream sleep because:

1) Our eye movement evolved concurrently with the desynchronous activity of the upper-brain structures that produce dreaming and…

2) Because the muscle systems of our eyes are not govern the system that execute body movement.

The neural systems that execute our eye movements reside in the mesencephalon, while those of the body are found in the rhombencephalon—and, as I mentioned earlier, the rhom-ben-cephalon controls atonia.

Q: What does evolution of the dreaming brain suggest about the nature of mind and consciousness?

For me, studying the evolution of the dreaming brain has given me a perspective on how to define the mind and the nature of consciousness. As I now understand, a mind is an environment of cognitive activity that arises from brain function within brain structure. In terms of brain function, a mind is quantified by the capacity to integrate multiple sensory information in a way that produces behaviors independent of instinct. In terms of evolution, our brain began to function as a mind at the thalamic stage of development; its right and left hemisphere and interthalamic adhesion resembles contemporary cortical configuration.

Regarding the nature of consciousness, evolution of the brain—and the mind that brain creates—suggest to me that consciousness is the awareness brain function constructs within the mind. As a dream visual, the mind is represented by our environment within a dream and our consciousness is represented by our presences in that dream. Although I don’t think brain evolution explains the precise nature of consciousness, I believe it does suggests how consciousness manifests in the physical—and in the physical consciousness is a con-struct of brain function.

Q: Lets talk a bit about the content of our dreams. To the waking mind dream content seems illogical and bizarre, but based on our discussions with David Kahn, to the dreaming mind dream content seems to be a self-organizing sequence of fairly logical visual associations with whatever emotional issues the midbrain is processing at the time. Bob Van de Castle in his show on Content Analysis illustrated how closely the content aligns with issues in our waking lives. So how does evolution explain dream content?

I think it supports both Dr. Kahn and Dr. Van deCastle’s views. The functional evidence suggests that dreaming is a type of wakefulness in brain function. Nothing in the this evidence suggest the dreaming changes what the brain was evolved to do and that is perceive, interpret, and respond to sensory information. The likely source of the sensory information that causes dreaming are influences that the brain does not perceive as true physical experience, which explains why we do not normally leap from our beds and start running when we have dreams of being chased.

The part of the brainstem that responds to motor commands from the cortex does not recognize the commands of the dreaming brain as requiring gross body movement. Therefore, the influences that cause dreaming are those that the brain perceives as having a mental rather than physical significance. What this tells us about dream content is that its imagery most likely interprets mental influences. Emotional issues and day-to-day concerns often linger in our thoughts as we enter sleep. Those issues and concerns that continue to resonate after the NREM portion of our sleep become the influences I believe our sleeping brain interprets with dream imagery. I believe the evidence suggests that our dreams are interpretations of mental influences.

Q: We know from listening to Dr Stanley Krippner (who will again join us next week) that many dreams contain spiritual or extraordinary experiences. How does the evolution of the dreaming brain account for the spiritual significance of some dream experiences?

I think our beliefs and faiths have a powerful impact on our thoughts and feelings. If our dreams are interpretations of mental influences, then spiritual dreams interpret the resonant mental affects of our spiritual beliefs. In this way dreams tell us what we believe rather that offer judgments on the validity of our beliefs.

Q: Furthermore how does evolution account for what Dr Krippner calls extraordinary experiences, the metaphysical (precognitive, telepathic, etc.) dream experiences?

When I investigated this aspects of dream evolution for my book, I began with the assumption that if such experiences are possible brain evolution and function must support that possibility—and it seems that cortical evolution might.

The functional and structural evidence suggests that the cortex evolved as an extension of thalamic and limbic development; it evolved to extend the sensory integration function of the thalamus and the memory function associated with the limbic system. The early cortex gave early animals the ability to integrate their current sensory experiences with memories of past experiences in a way that allowed them to make better behavioral choices. As human ancestry became more dependent on the thought processing advantages of the cortex rather than its sensory processing advantages, our ancestors began to engage in more efficient anticipatory behaviors.

Beyond their responses to sensory experiences in the moment, the cortex gave our ancestry the ability to devise behaviors that anticipated such moments. Essentially, the cortex gave our ancestry an ability to engage in anticipatory thoughts and behaviors. With regards to precognitive dreaming, cortical function is unencumbered by the sensory experiences of the conscious mind. In this unencumbered state, the brain is theoretically able to interpret mental influences in a way that anticipates their outcome—and that, in essence, is the nature of precognition dreams—imagery that anticipate the outcome of some experience.

In terms of other types of metaphysical dreams, I frequently reference the extraordinary mental abilities we find in autistic savants. In my book, I described the case of Daniel Tammet, a highly functional savant. I described how his brain perceives and interprets common information in a way that produces uncommon results. For this type of evidence and what we know of cortical function in isolation from sensory experience, I believe that the dreaming brain is theoretically capable of extraordinary fetes of perception.

Q: Since evolution is still going on - what probable future does brain evolution and dreaming suggest?

I believe that the dreaming brain has a lot more to tell us about its evolution and future. We know that experience influences brain development and that dreaming is indeed an experience, which could explain why newborns appear to spend much of their sleep time dreaming. The experience and study of dreaming could potentially change our way of thinking and alter our mental canvass. In one conversation I had about the distinction between modern humans and the Neanderthals, I described how our brain function probably allowed us to anticipate our needs better, which gave us a survival advantage. Therefore, I think the next stage in our evolution will probably center around the brain and brain function. I think experiences like dream telepathy, precognition, and OBE—and the abilities of savants like Daniel Tammet and Kim Peeks—gives us a glimpse of our brain’s future evolution.

Q: Do you think that there is a consciousness evolution that parallels this brain evolution and if so where do you think our consciousness evolution might lead us?

Personally, I perceive the brain as a cup and consciousness as fluid within the cup. In my view, evolution affects only the cup and not the fluid within. As our brain evolves, I think humanity will be able to manifest consciousness in far greater quantities. When we talk about the savant ability of the mind, in my view this is example of the extraordinary way our brain is capable of evolving and manifesting consciousness.