What's New in Neurofeedback

• With goggles, 'split-brain' theory comes into focus -www.boston.com/dailyglobe2/092/science/with_goggles_split_brain_theory_comes_into_focus+.shtm

• Brain Cells Killed During Binge Drinking Episodes -story.news.yahoo.com/news?u=/nm/20020417/hl_nm/brain_drinking_1

• Inducing Creativity with TMS -news.bbc.co.uk/hi/english/sci/tech/newsid_1932000/1932709.stm

[Last month I discussed Leonhard and Brugger’s model of dominance failure for schizophrenia and its relevancy to neurotherapy. This month I explore my own model of what dominates, or fails to dominate, normal brain function.]

Flight in bats and bees is the result of convergent evolution. Color vision in monkeys and humans is not. Flight evolved in bats, bees, and pterodactyls independently, in response to similar selective pressures. Color vision was more-or-less already available to our common ancestor, a primate whose descendents include present-day monkeys and humans. (This is known as divergent evolution, the more familiar kind.)

Hemispheric specialization is evident in species as diverse as birds, rodents, and dolphins (Glick, 1985), and thus it appears to be a product of convergent evolution (Corballis, 1983). Cerebral asymmetry arose at least twice -- birds and mammals, and perhaps many times in between. What was the common selective pressures that caused this unusual state? What split the rat brain, the bird brain, the whale brain, and the child brain into Mac and PC, two separate and distinct processors?

The left and right cerebral hemispheres are the primary focus of most laterality research. Here, the functional differences are pronounced and more comfortably evaluated. But functional and structural asymmetries are present in the basal ganglia, the thalamus (Speedie & Heilman, 1982, 1983) and probably our most ancient parts (brainstem). At birth an infant’s left brain is already attuned to speech sounds, her right brain sensitive to music (Entus, 1977; Best et al, 1982). Given the relative immaturity of an infant’s cerebrum, we are surely observing complementary specialization of subcortical structures when we uncover them in the neonate. So functional laterality may stretch from stem to stern, hindbrain to forebrain, and be common in all creatures with (bisymmetric) gray matter. Why is this so? Why are there no one-brain animals out there, no singular CNS designs? Could it be that structural and functional asymmetry is a necessary adaptation to our environment? Could it be that two brains in one animal addresses, quite successfully, a fundamental conundrum of survival?

Perhaps.

Evolution is the story of life adapting to environmental parameters. Fundamental to this adaptation process is the acquisition of rules. Acquiring rules, genetically and behaviorally, allows an animal to respond appropriately and quickly to its environment, to predict behavior, events, and their consequences (however briefly). An animal that fails to acquire the current rules in play will not be there the next day.

So what are these rules? Why did animal nervous systems evolve a PC and a Mac, two central processors (joined together by a commissure or two)? Because evolution had a hand in the current design, we know that, however expensive and nonsensical it may seem at first, this design is advantageous. In fact it is likely to be the best and ultimate design. Not one, but two brains are needed to thrive on our planet. But why two? The simple answer is... because the environment is two-fold as well. Confronted with a dual environment, animal nervous systems responded in kind.

So am I to believe that our world superimposes two distinct and disparate systems of rules on every animal on Earth? If so, what are these two systems of rules? Well, the first thing to realize is that Mother Earth, the larger world around us, and all the critters we see, flows along using only a single set of laws, however complex they may be. The second set of laws appear when we introduce an observer to Mother Earth, an observer with gray matter. Suddenly the environment has two distinct realms of being, of control: one inside the animal, the other outside the animal.

Sounds too simple, and unrelated to psychopathology. Let me explain. Or at least defend.

First, those who dally in cerebral hemisphericity are forced (daily) to defend functional dichotomization itself. (At least those few who continue to tilt at the task of dividing brain function into two bins.) The reasons for seeking out two central qualities of our 3-pound universe have already been outlined nicely by Bogen and Bogen (1983):

1. Conceptual tidiness is desirable
2. Capturing the "essence" (rather than all relevant facts) needs be no more predictive to be valuable than, say, the notion of natural selection
3. Dichotomization meets a specific need which arose outside of neuropsychology (e.g., two kinds of intelligence, etc); and finally
4. "We understand cerebral specialization better when we see all the activities of a hemisphere as reflections of the same underlying design" (Liberman, 1975).

Dozens of dichotomies have been proposed to describe the different information processing strategies of the two hemispheres. Verbal/nonverbal , serial/parallel processing, transformational/associative, historical/timeless -- I could go on and on (Bradshaw and Nettleton, 1981). However, no single dichotomy has satisfactorily explained all or even the majority of laterality findings. Bogen suggested a stopgap measure years ago (Bogen, 1969), a catch-basin for all hemisphere dichotomies: the left processes propositional information, the right processes appositional information. What is appositional information? Whatever isn’t covered by proposition. Whatever the right brain does. This may have some transient use, but it hardly illuminates the workings of the right mind.

I proposed a dichotomy (in 1989 and again today) which is simple yet neatly explains the fundamental behavioral differences of the asymmetric brain. The left side of the brain processes input according to rules by which the organism itself is organized, and the right side of the brain processes input according to the rules by which the environment is organized.

Not so simple, not so clear... Let me rephrase.

It comes down to a matter of control and relationship, as does most things in life. The left presumes there is nothing which is not an extension of itself, controlled by it, generated by it. The right assumes the opposite relationship: there is no IT in the world; the world, the environment, exists apart from right brain, beyond influence, generated by an other. Again, the world as a subset of the self (left) versus the world entirely independent of the mind perceiving it (right). Two modes of ideation: interior and exterior referencing, for short. The left mind treats all stimuli as interior to itself, the right mind treats all stimuli as exterior to itself.

Why would such a simple dichotomy be predictive or even helpful? Besides the outside chance of being correct, it dovetails nicely with the quintessential dilemmas of psychopathology:

Where does the self end and the world begin?

When one mode of ideation dominates behavior or inhibits the other mode’s contributions, the world is too much with us, or not enough with us (paranoid schizophrenia and depression, perhaps).

This dichotomy is relevant to cognition as much as it is to psychopathology. Although self and world distinctions may not appear relevant to hum-drum cognitive processes, they do indeed, when framed correctly. These modes of ideation at the level of cognition exist as two central tendencies (listed thrice): category and identity, reduction and individuation, same and different. Whenever possible, the left collapses to category, to sameness, to one state of likeness, in its attempt to attach meaning to percept. Stimuli readily fall victim to the black hole of categorical membership; no hair or features allowed once the left imposes its will. Yet on the other hand, or on the other side of the skull, the right brain has no will. It does not collapse representations, it preserves them; it individuates and suffers the differences. Unable to form categories, it associates between unique items to attain meaning. So on the left we have promiscuous, ruthless imposition countered on the right by sensual, willowy reception. This is the process by which meaning emerges in the mind: a stimuli stripped of differences while simultaneously (across commissures) distinguished.

(Evaluating this dichotomy in normal populations for tasks and stimulus types is beyond the scope of this article. See my personal website for past articles on this topic, http://home.onemain.com/~dk1008206/).

Many or perhaps most psychiatric illnesses occur when one mode of ideation is (over)activated at the expense of the other. Considerable research has been performed on the relation between psychopathology and cerebral laterality, beginning with Flor-Henry (1969) who noted how left and right-sided foci in temporal lobe epilepsy were associated with schizophrenia and manic-depression, respectively. Diagnostic heterogeneity is a given when it comes to large, encompassing syndromes such as schizophrenia and mood disorders, but when we examine the mentation and behavior of psychiatric subtypes, we often find ourselves faced with left or right hemispheric dysfunction. Psychopathology as a failure to sustain exteriorality or interiorality appropriately.

Schizophrenia is claimed by many to be a disorder of hemispheric overactivation and/or poor interhemispheric integration. The therapeutic effect of neuroleptics may be on account of this pharmocological agent's ability to interfere with interhemispheic communication, resulting in a "chemical callosotomy" (Myslobodsky, 1983) To summarize many reports, paranoid schizophrenic often suffer from overactivation of the left hemisphere (LH) while nonparanoids suffer from overactivation of the right hemisphere (RH) (e.g., Lerner et al, 1977). Persistent overactivation of the LH indicates greater reliance on interior reference -- all is self. The greater world exists as part of the schizophrenic, serving him. Peripheral events appear relevant to his interior states or thoughts.

Nasrallah (1985) argues that interhemispheric integration normally involves the inhibition of awareness by the LH that it is receiving information from the RH. Paranoia and positive (Schneiderian) symptoms, such as thought insertion and thought withdrawal, arise in a schizophrenic patient when there is a reduction of this inhibitory process. In effect, the LH becomes aware of a consciousness (RH) that is communicating with it, conveying relevant information about the world, but the LH ascribes the location of this source outside of the person. Failure to differentiate one’s self from objects or others can be viewed as a failure or reduction of exteriorality, to be associated with LH overaction or RH underactivation. A catatonic patient may neglect self-direction, positioning his body (and thoughts) according to rules he perceives dictated to him by the exterior. Catatonia is associated with RH dysfunction.

Right hemisphere deficit syndrome in children is characterized by impairment of the RH, particularly the parietal lobe (Voeller, 1986). These children suffer from an inability to develop relationships, personality disorders, socially inappropriate behavior, and an inability to perceive emotional states of other human beings. (Many also exhibit aprosodic speech.) According to the self/world dichotomy, a child with decreased RH functioning does not learn to exclude the world from himself during development and subsequently interacts with others as if they are part of him rather than separate entities with minds of their own. The world never gains status in the child. Self exists; but others and the world are merely unlikely postulates. Pronounced egocentrism and self-referentiality should be prominent in their behavior and this appears to be the case. For example, many show an unawareness and lack of concern about the consequences of antisocial acts. Such children usually do not play with other children, and when they do, only with younger children who can be "bossed" around. A mother of a child with RH deficit syndrome reported that when she was driving her son in a car with other boys: "they were talking about ball games and he was talking about the way train signals worked" (Voeller, 1986). One could interpret this as a manifestation of egocentrism. Right hemisphere dysfunction in attachment disorder continue this line of research (Schore, 2000; 2002).

Mania is all self, deep depression all world with no room for self; panic all suddenly world, anxiety a balancing problem between self and world. Etc. Etc. In the final analysis, the usefulness of any model is its ability to explain old data, predict new findings, and deepen our understanding of the phenomenon in question. And it should address as much of the range of the data as possible. For cerebral asymmetry, this range is the human mind. From behavior to development, from evolution to neurochemistry, from neuroanatomy to sociology. This is about as close to the infinite as one is likely to tread.

Selected References

Bradshaw, J.L. & Nettleton, N.C. (1981) The nature of hemispheric specialization in man. Behavioral and Brain Sciences, 4, 51-91.

Bogen, J. E. (1969) The other side of the brain, Bulletin of the Los Angeles Neurological Society, 34, 1179-1183.

Glick, S.D. (1985) Cerebral lateralization in nonhuman species, New York: Academic Press.

Lerner, J., Nachshon, I., & Carmon, A. (1977) Responses of paranoid and non-paranoid schizophrenics in a dichotic listening task. J Nervous Mental Diseases, 164, 247-252.

Myslobodsky, M.S., ed. (1983). Hemisydromes: Psychobiology, Neurology, Psychiatry. New York: Academic Press.

Voeller, K. (1986) Right-hemisphere deficit syndrome in children, Am J Psychiatry, 143, 1004-1009.

Wordsworth, W (1807). The world is too much with us.

News & Reviews NEW BOOKS

Cerebral Reorganization of Function After Brain Damage
by Harvey S. Levin, Jordan Grafman

Basic research on neuroplasticity and clinical research on reorganization of function after brain injury reviewed. -www.amazon.com/exec/obidos/ASIN/0195120264/top100

Clinical Guide to Depression in Children and Adolescents
by Mohammad Shafii, Sharon Lee Shafii

Review of recent research including sleep medicine, endocrinology, and biochemistry. -www.amazon.com/exec/obidos/ASIN/0880483563/top100

Chronic Fatigue Syndrome: A Biological Approach
by Patrick Englebienne

Summarizes advances and discusses insights that support CFS as a distinct and specific physical disease including protein biochemistry, virology, and pharmacology -www.amazon.com/exec/obidos/ASIN/0849310466/top100

Anxiety and Its Disorders, Second Edition
by David H. Barlow

A new model of panic and anxiety based on recent developments in emotion theory, cognitive science, and neuroscience. -www.amazon.com/exec/obidos/ASIN/1572304308/top100

Neuropsychology of Anxiety : An Enquiry into the Functions of the Septo-Hippocampal System
by Jeffrey A. Gray, Neil McNaughton

Very interesting model of anxiety based on hippocampal function. I suspect this will become the dominant model of anxiety as well as hippocampal function. -www.amazon.com/exec/obidos/ASIN/0198522703/top100

The Biology of the Autistic Syndromes
by Christopher Gillberg, Mary Coleman