In Search of Memory: The Emergence of a New Science of Mind

by Eric R. Kandel

As we have seen, short-term psychotherapy now comes in at least four different forms, and brain imaging may provide a scientific means of distinguishing among them. If so, it may reveal that all effective psychotherapies work through the same anatomical and molecular mechanisms. Alternatively, and more likely, imaging may show that psychotherapies achieve their goals through distinctly different mechanisms in the brain. Psychotherapies are also likely to have adverse side effects, as drugs do. Empirical testing of psychotherapies could help us maximize the safety and effectiveness of these important treatments, much as it does for drugs. It could also help predict the outcome of particular types of psychotherapy and would direct patients to the ones most appropriate for them.

In her book An Unquiet Mind, Kay Jamison describes the benefits of both modes of treatment for even a serious illness—in her case, bipolar disorder. Lithium treatment for the disorder prevented her disastrous highs, kept her out of the hospital, saved her life by preventing her from committing suicide, and made long-term psychotherapy possible. “But, ineffably,” she writes, “psychotherapy heals. It makes some sense of the confusion, reins in the terrifying thoughts and feelings, returns some control and hope and possibility of learning from it all. Pills cannot, do not, ease one back into reality.”

Thus, in monkeys, as in humans, there is a critical period for social development.

The work of Anna Freud, Spitz, and Harlow was expanded by John Bowlby, who formulated the idea that the defenseless infant maintains a closeness to its caretaker by means of a system of emotive and behavioral response patterns that he called the “attachment system.” Bowlby conceived of the attachment system as an inborn instinctual or motivational system, much like hunger or thirst, that organizes the memory processes of the infant and directs it to seek proximity to and communication with its mother. From an evolutionary point of view, the attachment system clearly enhances the infant’s chances of survival by allowing its immature brain to use the parent’s mature functions to organize its own life processes. The infant’s attachment mechanism is mirrored in the parent’s emotionally sensitive responses to the infant’s signals. Parental responses serve both to amplify and reinforce an infant’s positive emotional states and to attenuate the infant’s negative emotional states. These repeated experiences become encoded in

Biological approaches to psychoanalytic theory could, in principle, explore all three types of unconscious processes. One way of doing so—which I will explain in the next chapter—is to compare images of activity generated by unconscious and conscious perceptual states and to identify the regions of the brain recruited by each. Most aspects of our cognitive processes are based on unconscious inferences, on processes that occur without our awareness. We see the world effortlessly and as a unified whole—the foreground of a landscape and the horizon beyond it—because visual perception, the binding of the various elements of the visual image with one another, occurs without our being aware of it. As a result, most students of the brain believe, as Freud did, that we are not conscious of most cognitive processes, only of the end result of those processes. A similar principle seems to apply to our conscious sense of free will.

develop productive insights into consciousness, the new science of mind first had to settle on a working definition of consciousness as a state of perceptual awareness, or selective attention writ large. At its core, consciousness in people, is an awareness of self, an awareness of being aware. Consciousness thus refers to our ability not simply to experience pleasure and pain but to attend to and reflect upon those experiences, and to do so in the context of our immediate lives and our life history. Conscious attention allows us to shut out extraneous experiences and focus on the critical event that confronts us, be it pleasure or pain, the blue of the sky, the cool northern light of a Vermeer painting, or the beauty and calm we experience at the seashore.

How are we to find this small population of nerve cells that could mediate the unity of consciousness? What criteria must they meet? In Crick and Koch’s last paper (which Crick was still correcting on his way to the hospital a few hours before he died, on July 28, 2004), they focused on the claustrum, a sheet of brain tissue that is located below the cerebral cortex, as the site that mediates unity of experience. Little is known about the claustrum except that it connects to and exchanges information with almost all of the sensory and motor regions of the cortex as well as the amygdala, which plays an important role in emotion. Crick and Koch compare the claustrum to the conductor of an orchestra. Indeed, the neuroanatomical connections of the claustrum meet the requirements of a conductor; it can bind together and coordinate the various brain regions necessary for the unity of conscious awareness.

Ekman, who has cataloged more than 100,000 human expressions, was able to show, as did Charles Darwin before him, that irrespective of sex or culture, conscious perceptions of seven facial expressions—happiness, fear, disgust, contempt, anger, surprise, and sadness—have virtually the same meaning to

everyone (figure 28–1).

faces with fearful expressions, we found prominent activity in the amygdala, the structure deep in the brain that mediates fear. What was surprising was that conscious and unconscious stimuli affected different regions of the amygdala, and they did so to differing degrees in different people, depending on their baseline anxiety.

Unconscious perception of fearful faces activated the basolateral nucleus. In people, as in mice, this area of the amygdala receives most of the incoming sensory information and is the primary means by which the amygdala communicates with the cortex. Activation of the basolateral nucleus by unconscious perception of fearful faces occurred in direct proportion to a person’s background anxiety: the higher the measure of background anxiety, the greater the person’s response. People with low background anxiety had no response at all. Conscious perception of fearful faces, in contrast, activated the dorsal region of the amygdala, which contains the central nucleus, and it did so regardless of a person’s background anxiety. The central nucleus of the amygdala sends information to regions of the brain that are part of the autonomic nervous system—concerned with arousal and defensive responses. In sum, unconsciously perceived threats disproportionately affect people with high background anxiety, whereas consciously perceived threats activate the fight-or-flight response in all volunteers.

Una ubicacion del subconciente

Here again, the networks activated by unconsciously perceived threats were recruited only by the anxious volunteers. Surprisingly, even unconscious perception recruits participation

These are fascinating results. First, they show that in the realm of emotion, as in the realm of perception, a stimulus can be perceived both unconsciously and consciously. They also support Crick and Koch’s idea that in perception, distinct areas of the brain are correlated with conscious and unconscious awareness of a stimulus. Second, these studies confirm biologically the importance of the psychoanalytic idea of unconscious emotion. They suggest that the effects of anxiety are exerted most dramatically in the brain when the stimulus is left to the imagination rather than when it is perceived consciously. Once the image of a frightened face is confronted consciously, even anxious people can accurately appraise whether it truly poses a threat. A century after Freud suggested that psychopathology arises from conflict occurring on an unconscious level and that it can be regulated if the source of the conflict is confronted consciously, our imaging studies suggest ways in which such conflicting processes may be mediated in the brain. Moreover, the discovery of a correlation between volunteers’ background anxiety and their unconscious neural processes validates biologically the Freudian idea that unconscious mental processes are part of the brain’s system of information processing. While Freud’s ideas have existed for more than one hundred years, no previous

Bases de la psicopatología

brain-imaging study had tried to account for how differences in people’s behavior and interpretations of the world arise from differences in how they unconsciously process emotion. The finding that unconscious perception of fear lights up the basolateral nucleus of the amygdala in direct proportion to a person’s baseline anxiety provides a biological marker for diagnosing an anxiety state and for evaluating the efficacy of various drugs and forms of psychotherapy.

Pa mandarselo a la gracia

In discerning a correlation between the activity of a neural circuit and the unconscious and conscious perception of a threat, we are beginning to delineate the neural correlate of an emotion—fear. That description might well lead us to a scientific explanation of consciously perceived fear. It might give us an approximation of how neural events give rise to a mental event that enters our awareness. Thus, a half century after I left psychoanalysis for the biology of mind, the new biology of mind is getting ready to tackle some of the issues central to psychoanalysis and consciousness.

such issue is the nature of free will. Given Freud’s discovery of psychic determinism—the fact that much of our cognitive and affective life is unconscious—what is le...

A critical set of experiments on this question was carried out in 1983 by Benjamin Libet at the University of California, San Francisco. Libet used as his starting point a discovery made by the German neuroscientist Hans Kornhuber. In his study, Kornhuber asked volunteers to move their right index finger. He then measured this voluntary mo...

brain by means of an electrode on the skull. After hundreds of trials, Kornhuber found that, invariably, each movement was preceded by a little blip in the electrical record from the brain, a spark of free will! He called this potential in the brain the “readiness poten...

Libet followed up on Kornhuber’s finding with an experiment in which he asked volunteers to lift a finger whenever they felt the urge to do so. He placed an electrode on a volunteer’s skull and confirmed a readiness potential about 1 second before the person lifted his or her finger. He then compared the time it took for the person to will the movement with the time of the readiness potential. Amazingly, Libet found that the readiness potential appeared not after, but 200 milliseconds before a person felt the urge to move his or her finger! Thus by merely observin...

Libet proposes that the process of initiating a voluntary action occurs in an unconscious part of the brain, but that just before the action is initiated, consciousness is recruited to approve or veto the action. In the 200 milliseconds before a finger is lifted, consciousness determines whether it

Guau!,

The psychologists Richard Gregory and Vilayanur Ramachandran have drawn strict limits on that argument. They point out that “our conscious mind may not have free will, but it does have free won’t.” Michael Gazzaniga, one of the pioneers in the development of cognitive neuroscience and a member of the American Council of Bioethics, has added, “Brains are automatic, but people are free.” One cannot infer the sum total of neural activity simply by looking at a few neural circuits in the brain.

Freud: A Life for Our Time (New York: W. W. Norton, 1988);

Freud