The Dream in Contemporary Psychiatry

Does the dream have a place in contemporary psychiatry? It is not entirely clear how most psychiatrists would, or should, answer this question at present. If it had been asked in the 1950s, a “modal” psychiatrist of the time might well have answered, “Yes, a central place,” adding perhaps, “Why do you ask?” At that time clinical thinking in psychiatry had been strongly influenced by Freud’s psychological theory of mind, the theory he formulated to account for observations on dreams and dreaming that he reported in his classic study The Interpretation of Dreams(1). In it, free associations to dream images were used as guides to the discovery of forgotten memories of traumatic experiences of early life. Freud regarded these as playing a major role in the pathogenesis of neurotic symptoms and related clinical disorders. Recovery of these (repressed) memories into consciousness was considered as playing an important role in treatment. By the 1950s the main outlines of the theory had been incorporated into general psychiatry. Psychoanalytic theory and training in psychoanalytic psychotherapy constituted major parts of many, if not most, psychiatric residency curricula. It is not difficult to understand why, at that time, serious interest in the dream held a place of central importance in psychiatry.

But at present a satisfactory answer to the (now) controversial question implicitly posed in the title of this article needs to be more complex and multifaceted than a simple “yes” or “no.” Note that the important place of the dream in the 1950s was a reflection of an interest that was centered—in fact, anchored—in the psychoanalytic psychology of the dream and the dream process. But the question must now be reframed because our information base has become so much larger and more complex. And it encompasses a wide range of sectors (e.g., clinical, theoretical, therapeutic, and research), each with its subspecialties and programmatic interests. The relative importance of the dream obviously varies according to the specific issues under consideration and the context in which the question is considered.

This article begins with selective discursive reviews of cogent sectors of research: 1) relatively recent research (1953–1999) on the neurobiology and clinical psychophysiology of dreaming sleep; 2) experimental cognitive neuroscientific studies of perception, emotion, and memory (2, 3) and the putative interrelationships among them in generating dream imagery (4, 5); and 3) psychoanalytic studies (1900–1999) on related aspects of dreams and the dream process. A discussion of possible relationships among ideas from these three areas follows. All of this entails discussion of the mind/brain problem, which introduces logical dilemmas into debates about Freud’s theory of the dream, a theory burdened by a long history of vulnerability to interpretive bias. Finally, the article considers the question of assigning, in light of the foregoing considerations, a realistic approach to contemporary dream research and a perspective concerning the proper place of the dream and, by implication, of psychoanalysis in contemporary psychiatry.

The Neurobiology and Psychophysiology of REM Sleep

REM Sleep in Animals

Aserinsky and Kleitman’s discovery in 1953 of REM sleep (6) inaugurated an exciting and highly important epoch of research on this newly identified state of the brain in both animals and man. In a relatively short period of time (enabled by advanced neurobiological, computer science, and instrumental techniques), experimental programs to study this special brain state were carried out in animals (7–15). This work generated vast amounts of important information and concepts about the neurobiology (electrophysiology and neurochemistry) of REM sleep. Neurosurgical techniques aided in the specification of brain areas and structures in which functional changes associated with REM sleep were located. It was demonstrated in the cat that the biological mechanism (decrease in the ratio of aminergic to cholinergic activity) that instigated REM sleep was located in the pons. During REM sleep, repetitive excitatory bursts of electrical activity originating in the pons (pontogeniculo-occipital waves) ascend to stimulate higher brain structures, including those associated with vision and control of saccadic eye movements as well as the association cortex, with its storehouse of memory traces and memories (16, 17). We can surmise from eye movements and muscle twitches that cats and other animals may have experiences similar to dreaming during REM sleep, but since they cannot talk, we cannot study the mental aspects of dreaming (e.g., imagery, plot, and relationship to waking emotional life). These rich neurobiological data about REM sleep in animals provide a wealth of information about their dreaming brains but nothing about their dreaming minds.

Dreaming in Man

Scientists assume that the physiology of REM sleep in humans must be much the same as it is in the cat. Noninvasive studies of the dreaming human brain support this assumption. But what about the dreaming mind of humans? This is a critical consideration when we come to assess the place of the dream in psychiatry.

Data concerning the nature of both the dreaming mind and the dreaming brain in humans are important, particularly for understanding the relationship of mind to brain. This issue in turn involves exploring the relationships between two different data sets: one from “the bottom up” (neurobiology) and the other from “the top down” (psychoanalysis and clinical psychology). Are the models of the dreaming mind that the two approaches generate irreconcilable (one right and the other wrong), or can they be viewed as complementary? It is this relationship that must ultimately be understood in order to solve the problem of defining the nature of the dreaming mind/brain and of assessing the importance of the dream in general psychiatry.

One promising approach to the mind/brain problem is attempting to map mind onto brain, i.e., to search for neural correlates of mental function. In regard to dreaming, the search is for correlations between 1) the content and process of the dreaming mind and 2) the neurobiology (physiology and clinical anatomy) of the dreaming brain. This approach may sound relatively straightforward, but the philosophical complexities of the mind/brain problem, and the enduring shadow of Freud’s controversial theory, complicate the task. The logical problem stems from the fact that the study of mind deals with a domain of immaterial phenomena (meanings and motives), whereas the study of brain deals with a domain of material phenomena (matter and energy). Mental and brain sciences, pertaining as they do to two different domains, use different languages and techniques; their concepts are framed at different levels of abstraction; and their units are not interchangeable. For example, a one-unit change in a subjectively scored intensity rating of a patient’s suicidal fantasy cannot be regarded as equivalent to a quantified one-unit difference in serum 3-methoxy-4-hydroxyphenylglycol. Nor is a relatively friendly divorce necessarily associated in a quantitatively linear way with less REM density than that associated with a relatively unfriendly one. For these reasons, simultaneous or parallel study of mind and brain reveal covariances or correspondences rather than cause-and-effect sequences. Debates about interpretation of the empirical data begin, as will be discussed, with Freud’s postulate that “the dream is instigated by a wish.”

To achieve a more complete and balanced psychobiologic concept of mind/brain function in dreams and dreaming, top-down data from psychoanalytic and related clinical psychological studies should be evaluated and taken into account along with data from the bottom-up neurobiologic sciences. This is because psychoanalysis gains access to unique, often hidden, personal aspects of human experience that are not accessible to biologic methods of investigation. For example, psychoanalytic studies elicit information about the dreamers’ past and current life experiences and about the functional interrelationships among memory, emotion, and dream imagery, e.g., the observation that memory and emotion in combination participate in generating dream imagery and, in this way, participate in the mental work of the dream (explanation to follow). Surely it is not unreasonable to expect this kind of information to supplement and complement, rather than conflict with, neurobiologic information.

REM Sleep and the Dreaming Mind

Perhaps this area can be best introduced by a brief review of research on human subjects in the sleep laboratories that sprang up after the discovery of REM sleep. In these laboratories, subjects slept all night while polygraphic recordings of EEGs, extraocular muscle movements, and various autonomically innervated physiologic systems were recorded. This permitted experimenters to awaken subjects from REM sleep and study their reports of the dreams they had immediately before arousal. This kind of experimentation generated an extensive and valuable literature concerning the nature of REM sleep in humans and about the formal characteristics and content of REM dreams (18–33). Aspects of that literature that are well known and are not of central relevance to the main (mind/brain) issues under discussion here will not be included in this review. What will be emphasized here is that many of these studies originally sought correlations between concomitant REM sleep physiology and the details of dream content. Since the laboratory dreams were formed at the same time that the polygraph was recording changes in underlying brain state and function, this seemed like a golden opportunity to discover precise relationships between dream content and brain function, that is, to map mind directly onto brain. Gardner et al. (33), using double-blind methodology, demonstrated a biological-psychological correlation during dreaming. Their data showed a statistically significant correlation between dreamed movements of upper and lower girdle limbs and small twitches measured by electromyography in limb muscles corresponding to the limbs used in the dreamed movements. But most studies of this kind were disappointing in the sense that they failed to discover reliable or convincing point-to-point relationships between specified elements (e.g., images or plot aspects) of verbally reported subjective dream experience and concomitant objectively demonstrated biological brain events. In other words, the subjective psychological dream reports for the most part were not in synch with the physiological records, nor were the dream experiences accessible to direct observation by physiological techniques or instruments.

But many clinical psychophysiologic experiments (26, 27, 34–37) were highly productive in a different way, one that is of relevance here. They found correspondences between qualitative and cognitive aspects of dream content and the emotional problems that confronted the dreamer in a wider time frame than that of the experimental night. That is, the time span considered in their correlational studies encompassed current, as well as past, stressful life problems. These correspondences, as will be discussed shortly, illuminate the role of memory and emotion in the dream process. It is worth noting here that emotion occupies both domains (mind and brain) and may, when sufficiently understood, provide a key for understanding the mechanisms that link covariant, as well as corresponding, mind and brain data. This constitutes an exciting frontier for future research as new investigative tools and techniques develop.

In 1977 Hobson and McCarley (38), citing animal data showing that REM sleep is instigated by physiologic changes in the pons, advanced the (now) well-known “activation-synthesis” hypothesis of dreaming, which they asserted refutes Freud’s theory that the dream is instigated by a wish. In REM sleep, they said, the brain is in a highly activated state, during which ascending excitatory pontogeniculo-occipital waves stimulate higher midbrain and forebrain cortical centers, producing rapid eye movements and randomly spreading activation over the association cortex, in which memory traces are stored (activation: the first half of the theory). According to their theory, the dream images and experiences, having been randomly generated, do not in and of themselves have or convey any meaning. To make sense of the experience, the dreamer, on awakening, “edits” the story line to make at least a modicum of sense of it (synthesis: the second half of the theory). Affect in a dream is regarded as a secondary response to the content of the dream experience. (The part of the theory dealing with affect has subsequently been modified by Hobson [39]. In light of recent imaging data, he now regards the affect as primary in shaping content.) According to the second part of the theory, the dream report is regarded merely as a work sample, reflecting the dreamer’s way of dealing with affect and disturbing ideas. Regarded in this way, the dream can be secondarily useful to the clinician in his or her attempts to understand the working of a patient’s mind (cognitive style, defenses, and the like) but has no relevance to unconscious mental events or meanings.

Wait a minute! There are problems to confront here. First, there are logical philosophical problems in the interpretation of the data. It is clear (and has been demonstrated in animals) that an altered balance in the relative levels of aminergic and cholinergic activity in the pons instigates the onset of REM sleep, a brain state. But it is not clear how those same changes in the pons can be solely responsible for the complex dreams experienced subjectively by humans during sleep. After all, REM sleep is not the dream. Two sets of data derived from study of the same phenomena but using the different methods of two different disciplines are not identical or interchangeable. The neurophysiologic pontine findings cited by Hobson (17, 39) support the activation-synthesis hypothesis in respect to the instigation of REM sleep, which is an activated brain state. But coming from a different domain, they cannot be considered directly relevant to the dream as a mental experience and, similarly, cannot disprove Freud’s hypothesis that a wish is the instigator of the dream. As will be discussed shortly, this is a more complicated issue.

Second, there are problems raised by recent neurophysiological and neuroanatomical data (and by somewhat older, but still relevant, psychoanalytic and cognitive neuroscientific findings) that are not satisfactorily accounted for by the activation-synthesis hypothesis. These data have given rise to competing hypotheses and have generated vigorous debate. The controversy seems to arise mainly from differences in the interpretation of data rather than from the data themselves, which do not, with one exception to be discussed, seem to be in question. These interpretive differences, which do not yet seem amenable to full satisfactory resolution, occasioned a recent open debate between J. Allan Hobson and Mark Solms at a meeting of the neuropsychoanalysis group of the New York Psychoanalytic Institute in Nov. 1998 (39). The problematic issues raised at that meeting are not inconsequential. They lie at the center of the question addressed in this article (the place of the dream in contemporary psychiatry) and therefore warrant discussion here. In addressing them, we should keep in mind that emotion is a prominent part of the dream experience and that it plays a role in generating and shaping both the process and the content of dreaming. Since emotion, as previously noted, belongs to both domains (having both mental and physiologic bodily manifestations), it can be studied by both methods. Consequently, attention to the role of emotion in dreaming should provide an opportunity for constructing empirical and conceptual bridges that can facilitate resolution of at least some of these controversial issues.

Addressing the Controversy

There are several areas of research to consider in addressing these controversial issues, including the following:

1. Clinicoanatomical research on the neuropathology underlying cogent clinical disturbances of sleep and dreaming (40).

2. Behavioral studies of affective neurobiology in animals (41, 42).

3. Neuroimaging (positron emission tomography [PET]) studies of human subjects during REM sleep (43–45).

4. Cognitive neuroscientific experimental programs on nonhuman primates (2, 3) that bear implications for understanding relationships between perception, cognition, and memory, as they may play a role in generating dream imagery.

5. Psychoanalytic observations on dream imagery (1, 4, 5) and their implications for memory.

6. Clinical observations relevant to the putative role of REM sleep in relation to the problem-solving functions of REM sleep (26, 27, 32, 34–37).

Instigation of the Dream

Mark Solms (40), a neuropsychologist and Freud scholar, has conducted extensive clinicoanatomical research on the neuropathology of clinical disturbances of sleep and dreaming. He reminded us that Freud’s definition of “wish” designates it as a psychobiologic phenomenon, the expression of an instinctual need whose source is somatic (46):

Freud, in designating the wish as the instigator of the dream, did not think of the wish as an immaterial mental phenomenon but rather as a motivational (material or energy) source arising from within the body (as part of the metabolic life process) and creating a bodily need that requires work on the part of the mental apparatus (mind) to meet that need. For example, tissue dehydration gives rise to thirst, which requires intake of water. This a job for the mind that requires cognition (recognizing the sensation of thirst as a need for water, remembering where water is found, and, by means of its connection with the brain, energizing the motor systems that govern the body movements needed to reach the water source and drink). Because the muscles are paralyzed in dreaming sleep, Freud postulated that the consummatory path in the mental apparatus must flow in a reverse direction from that in the waking state, i.e., toward the sensory end rather than the motor end, producing a hallucinatory fulfillment of the wish to drink. The familiar example is “the dream of convenience,” the thirsty dreamer dreams of going to get a glass of water and drinking it rather than waking up and going to get a glass of water. Is it likely that the pontine instigator of REM sleep acting alone could activate the circuitry and mechanisms needed to accomplish all of the mental and neural work that is required? One would think not. On its face, it seems unlikely that random excitation of higher brain centers could enable the dreamer to hallucinate the whole sequence and imagine satisfying his thirst.

Could there be other brain loci and mechanisms involved in this complex task? Solms (47) pointed out that dreams, indistinguishable from the dreams of REM sleep, can occur in the absence of REM sleep (48, 49) and that REM sleep can occur in the absence of dreaming (50–55)! He reported on 26 patients in whom there were extensive destructive lesions of the pons and an absence of REM sleep. Only one of the 26 reported a cessation of dreaming. The other 25 were conscious enough to report that they were experiencing dreams, although they were not having REM sleep (47). (Hobson [39] expressed doubt that patients with pontine lesions extensive enough to eliminate REM sleep could be conscious enough to report dreaming.)

In Solms’s clinicoanatomical studies (which included 332 patients with cerebral lesions), there were only two forebrain lesion sites that he found to be associated with a cessation of dreaming. One was located in the occipitotemperoparietal junction. The other site was the bilateral ventromesial quadrant of the frontal lobes involving interruption of the mesocortical-mesolimbic dopaminergic system of the ventromedial forebrain. This system of fiber tracts is the one identified by Panksepp (42) as the “curiosity-interest-expectancy” command system of the ventromedial forebrain, the system associated with instinctual appetitive craving states. It is interesting to speculate that this may well be the brain system that provides the putative psychobiologic substrate for “search activity,” a mechanism proposed by Rotenberg (56) in his theory that REM sleep and dreams provide a psychobiologic mechanism for dealing with conflictual life problems. In any event, the “curiosity-interest-expectancy” command system identified by Panksepp lies in the area of greater activity during REM sleep, as has been revealed by PET imaging studies (43–45). Solms points out that it is the same fiber tract that was interrupted surgically in the psychosurgical treatment (leukotomy) of schizophrenia and other severe intractable psychiatric syndromes in the 1940s. The operation was performed thousands of times. A review of the published reports (50–55) reveals that these patients became anhedonic and lacked initiative. And in all cases, the patients stopped dreaming, although they continued to experience REM sleep.

Solms (47) convincingly argued that the “curiosity-interest-expectancy” command system of the ventromedial forebrain is a second system capable of instigating the activated dreaming state of the brain and of subserving the generation of emotionally meaningful dream experience. He considered this ventromedial system of fiber tracts to be more directly responsible for the actual dream, postulating that the appetitive dopaminergic stimuli could well act as “demands upon the mind for work” during dreaming sleep. He stated that it is not yet entirely clear how these two putative instigator mechanisms (i.e., the pontine and forebrain) may be linked in producing dreaming. But he considered that all of these findings, taken together, bring us much closer to Freud’s postulate that the wish is the instigator of the dream and makes a cogent case against Hobson’s assertion that such a statement has been proven wrong.

Dream Imagery and Its Relation to Memory

A considerable body of evidence (to be discussed) indicates that dreaming sleep plays a significant role in memory function and that manifest dream content, particularly imagery, reflects that function. Both experimental studies on nonhuman primates, using the methods of cognitive neuroscience (2, 3), and clinical psychoanalytic studies of the dream (1, 4, 5) shed light on this (memory) aspect of dreaming. Although the methods are quite different, the results are surprisingly convergent in that data from both domains (to be discussed) strongly suggest that emotionally meaningful life experiences are encoded in memory by sensory percepts that were registered during the life experiences that they encode. It is thought that such percepts may appear later as images in dreams and, when they do, serve as mnemonic references to those meaningful experiences.

Beginning in the 1970s, an extensive program of experimental cognitive neuroscientific studies was carried out in subhuman primates by Mishkin and coworkers (2, 3). These experiments are of particular interest here because they identify the neural (corticolimbic) circuitry that is involved in matching newly registered (strange) patterns of sensory stimuli to previously registered emotionally meaningful patterns that have been retained in memory. Using the “delayed nonmatching to sample test,” Mishkin and Appenzeller reported that a perceptual pattern (which initially registers in the primary visual cortex and, by means of processing in the prestriate cortex, reaches area TE of the inferior temporal cortex) is not yet available in (declarative-type) memory for matching until it has been linked, by limbic and paralimbic structures, to the memory circuits of the prefrontal and association cortices. The important point is that in passing through the limbic structures that generate and regulate emotion, the encoding perceptual trace is inextricably linked to the affect that accompanied its processing into memory. These findings support the idea of enduring neural networks of memory organized by emotion. This is an idea that can be regarded as isomorphic with the psychoanalytically derived concept of enduring nodal memory networks organized by emotion (to be discussed). It is interesting to note parenthetically that in these experiments it was found that information routed from area TE directly to the basal ganglia without passing through the limbic system is available for activating instrumental conditioned responses.

Kandel (57) recently suggested that this instrumental memory system may constitute “another unconscious system” that is capable of initiating or guiding behavior, as does information in the repressed dynamic unconscious. But he added that it is a system that does not seem to be available for recovery in consciousness by undoing repression. He urged psychoanalysis to take it under consideration in its studies of unconsciously motivated behavior. (I wonder if it might be preferable for clarity to refer to this other system as “not conscious” to distinguish it from the psychoanalytic concept of the “repressed dynamic unconscious.”) Perhaps it is related to Freud’s concept of “primal repression” (58).

Psychoanalytic Studies

In Freud’s analysis of his “Dream of the Botanical Monograph,” recounted in The Interpretation of Dreams(1, pp. 169–176, 282–285), he observed that the ideas and memories represented in that dream were arranged in nodal networks. All ideas produced in his free associations to the dream elements connected to one or the other of the nodal points of “botanical” or “monograph.” Recent clinical studies have extended the concept to include multiple nodal points and to apply beyond the single dream, i.e., to a concept that applies to long-term memory networks that are organized by affect, the principle of affective organization of memory (4, 5), which can be summarized as follows:

Each of us carries within our mind/brain an enduring network of stored memories encoded by images that were perceived during significant emotional life experiences. Such images and the memories they encode are associationally linked by a shared potential to evoke identical or highly similar complexes of emotion. Such networks are organized around a core of perceptual images or part images that encode memories of early events that have been experienced as highly emotional, some even cataclysmic, by the child. As development proceeds, the networks branch out, as later events evoke similar conflicts and emotional states. Encoded images that connect strongly and closely with several others in the network (and through them with still others) can be thought of as nodal points in the enduring memory networks of the mind/brain. An illustrative example of a nodal image would be “the dried plant, as if from an herbarium” in Freud’s “Dream of the Botanical Monograph” (1, p. 169). Freud’s free associations to this particular dream image matched that image, by means of shame and guilt, to his current feelings about failing to be considerate of his wife’s wishes for him to bring home her favorite flower. And, similarly, it matched feelings from the past incident, when he had failed to identify a dried plant from an herbarium on a botany examination. In this incident he had failed to meet his father’s expectations of him as a student. And, ultimately, at a later time he recalled a much earlier memory of an incident in which (as a small boy) he had failed to meet his father’s expectations about behavioral decorum. On that occasion his father had reacted by saying to his wife, “That boy will never amount to anything.” The image of the dried plant was also connected to his studies of the coca plant, which also were associated with failed ambition; he had narrowly missed discovering the local anesthetic properties of cocaine. At the time of this dream Freud was preoccupied with his writing and research into dreams and neurosis. He felt guilty and ashamed, open to criticism for neglecting his practice and his financial obligations to his wife and growing family. Free associations to this particular dream image (“the dried plant, as if from an herbarium”) led back through a network of memories of failures that had been accompanied by the emotions of shame and guilt. These affects can be regarded then as organizers of the memory network, spinning associative threads as connecting links between images that encoded earlier and earlier painful memories.

Detailed examples of memory networks from other patients have been reported previously (4, 5, 59). In these reports it was observed that current life conflicts were matched with relevant memories of past problem situations that had been encoded in the patients’ memories by images registered during the stressful experiences. It has been postulated that these dream images could have been recruited from memory by affects that connected them to the current conflict. In other words, the images could have been sensitized to pontogeniculo-occipital wave stimulation by relevant affects, rather than by having appeared in the dream as the result of random stimulation during REM sleep (5).

The Memory-Processing Function of REM Sleep

It is indeed impressive that the idea of enduring neural networks of memories in the brain is isomorphic with the psychoanalytic concept of enduring nodal memory networks in the mind. The corticolimbic brain circuits underlying neural memory networks might well be regarded as the neural substrate for the mental mechanisms that underlie the formation of nodal memory networks in the mind. And it is important to note again that the corticolimbic circuits that linked percepts to affect in Mishkin’s experiments did so by enabling the experimental animals to match new patterns of perceptual stimulation to previously registered and stored perceptual experience that was meaningful. The same matching function is now considered to operate “off line” during REM sleep. This hypothesis was first offered by Dewan (60) and later elaborated by Winson (61) to constitute an “off-line processing” function of REM sleep, a process that serves a crucial adaptive survival function in evolution by making it possible during sleep (when external sensory input circuits are inactive) to store important information and discard that which is not. In this way, over the course of mammalian evolution, space for memory storage in the brain was conserved without undue expansion of the rapidly enlarging forebrain.

The Evolutionary Biology of REM Sleep

Panksepp (42) noted that the executive mechanisms of REM sleep are situated far down in the brain, mainly caudal to the ascending reticular activating system, and suggested that REM sleep mechanisms might be older than waking ones. He stated:

Further Comment

Note that the same limbic and paralimbic areas that are involved in the matching function just mentioned (in regard to Mishkin and coworker’s experiments and REM sleep) have been demonstrated by PET to be highly activated during REM sleep (43–45). They, too, must be major participants in generating the affect that is such a prominent component of dreams. In respect to theory, affect surely can be considered a likely candidate for instigator of the dream, perhaps instead of, in combination with, or as a component of the wish, as postulated by French and Fromm (62). Its theoretical importance, along with that of memory, in dream process and formation is further underlined by data from clinical psychophysiologic sleep laboratory studies, which demonstrate that the manifest content of dreams is related to current conflictual situations and problems in the dreamer’s life (28, 32, 34–37). The matching function just discussed could (by means of shared affect) link current problems to memories of similar problems from the past that have been stored in the dreamer’s nodal memory network. How could such insights have been formulated without knowing details of the dreamer’s current life problems and his or her personal history? As noted earlier, this top-down information clearly adds an additional, i.e., psychological, dimension and, in so doing, facilitates formulation of a more comprehensive and balanced view of the dream and the dream process.

Discussion

The place of the dream in psychiatry is shifting toward a more interesting and prominent position than it occupied in recent years, when we were being urged to regard it as a byproduct of brain stem physiology without intrinsic psychological significance. The latter attitude, which tended to diminish clinical interest, could have evolved in part as a reaction to the earlier, almost exclusive interest attached to Freud’s theory as the only available basis for theoretical and clinical approaches to study of the dream. Now the availability of new brain imaging techniques, along with the increasing sophistication and sensitivity of cognitive psychological techniques, make the dream an ideal subject for experimental exploration of the relationship between mind and brain, which has always been an issue of central importance in psychiatry. And, as we become increasingly appreciative of the dream as an integrated product of adaptive mind/brain functions, the therapeutic potential for working with the dream clinically should become increasingly clear.

As the foregoing discussion shows, there is now an abundance of new data and competing theoretical interpretations to justify a reappraisal of older views. But many unanswered questions remain, and research in both domains, mind and brain, is required. But if data from these domains are out of synch much of the time, and if concepts are incompatible in the minds of some investigators, how and when (if ever) will integrated heuristic concepts emerge? Perhaps slowly and in stages. How far might we go at present? A first step, which takes currently available information from each realm into consideration and examines it in parallel makes it possible to formulate a preliminary psychobiological concept of the dream process:

Put another way, it can be said that the mind exploits (for memory and cognitive functions) the special physiologic state of the activated dreaming brain. The latter, as PET data reveal, could well provide neural mechanisms for mental operations, such as the mnemonic matching function (discussed previously), a function that could be helpful to the dreamer as he or she confronts current life problems. This is a psychobiologic concept that contains the rationale for promising technical approaches to working with dreams in psychotherapy and psychoanalysis (59, 62–64).

Such a contemporary psychobiologic view of the dream process conforms to both psychoanalytic and neuroscientific empirical findings and is heuristic in serving as a staging concept for developing corollary hypotheses in either or both domains. Data from both contribute unique information; the concept could not have been constructed from either side alone, illustrating how thoughtful dialogue between clinical psychoanalytic and cognitive neuroscience data and concepts can be reciprocally enriching. For example, Braun and co-workers (43) observed the selective activation of extrastriate visual cortices and attenuation of activity in the primary visual cortex, along with decreases in activity in the frontal association areas, including the lateral orbital and dorsolateral prefrontal cortices. They suggested that “REM sleep may represent a state in which the brain engineers selective activation of an interoceptive network, which is dissociated from primary sensory and heteromodal association areas at either end of the visual hierarchy that mediate interactions with the external world” (43, p. 94). This is an idea that certainly seems compatible with, perhaps complementary to, the preliminary psychobiologic concept of the dream process just offered.

But that concept is offered as a preliminary, certainly not final or complete, understanding of the dream process. Although the data reviewed earlier account for much of dream imagery and process, they do not, for example, explain how, or for what purpose, the affectively organized memory information processed in the mind/brain is arranged in the episodic, story-like format of the manifest dream. Nor do they explain how the imagery and plot activity are actually transduced into dream consciousness. And many questions about repetitive dreams, nightmares, and posttraumatic dreams remain unanswered. The information about dreaming and dreaming sleep now available takes us far into understanding questions about the dream that Freud raised in 1900 but do not bring us to closure in addressing all of his hypotheses. For example, his concepts of the wish as instigator of the dream and of the dream censor, both of which I, as well as many others, consider to be quite prescient, are not directly validated or disproved by the empirical data reviewed here. In this connection, I wonder whether it might not be good to avoid preoccupation with concerns as to whether neuroscience data either refute or confirm various of Freud’s original formulations and theories. This issue can, and often has been, counterproductive by introducing bias into the evaluation of data and theory, perhaps even unwittingly into research design. Might it not be more productive to regard Freud’s rich theoretical legacy as a source of generative hypotheses? Unanswered or incompletely resolved questions such as those just mentioned and additional ones that may be suggested by the material reviewed can be regarded as challenges for further research to both psychoanalysis and cognitive neuroscience. It is hoped that the disciplines can eventually find comfortable ways to collaborate in addressing them. If, as, and when they succeed in doing so, the dream should find its proper place in psychiatry.

Received Dec. 10, 1999; revisions received April 19 and Sept. 1, 2000; accepted Sept. 6, 2000. From the Department of Psychiatry, Yale University School of Medicine. Address reprint requests to Dr. Reiser, 255 Bradley St., New Haven, CT 06510; [email protected] (e-mail).