This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.

Contribute Thoughts | Search Serendip for Other Papers | Serendip Home Page

Biology 202
2000 Third Web Report
On Serendip

The Role of Corollary Discharge in Schizophrenia

Ann Mitchell

In my last paper, on the neurobiology of music, I tried to explore the role of automatic motor functioning when a person performs music. After several conversations with a friend who is a performer himself, I began to wonder about the role of automatic processing in singing versus playing an instrument that is not already a part of one's body. Singing may be distinct from performing on an instrument not part of your body for two reasons: 1)the degree of automacy in the motor functioning of the diaphragm and trachea must be different from motor function of the fingers and arms, and 2) singing involves language, which uses the hemisphere of language opposite that hemisphere used for listening to music. Previously investigated(to some extent) the interplay between automatic motor patterns and the I-function. In this paper, I chose instead to investigate language disorders, specifically those disorders related to schizophrenia. In a forum discussion, Melissa Wachterman raised the issue of whether or not words were independent of each other, because if they were, then speech could also be considered in the category of automatic processing. However, Wachterman also noted that in certain cases it seemed that the word choice of schizophrenics was based on association from one word to the next, and thus the words were dependent upon each other. (1). Finally, I read an article which revealed the "break down" of David Helfgott to be a mild form of schizophrenia that still persists. (2).Therefore, this paper explores the role of corollary discharge in various language and thought disorder deficits related to symptoms of Schizophrenia and possible theories as to why these particular deficits might occur.

Upon attending one of David Helgott's first American performances after Helfgott's reintroduction into the world of classical piano, musical critic Terry Teachout made these harsh, but most likely realistic, comments about Helfgott and his piano playing:

No one even slightly familiar with the symptoms of schizophrenia could have failed to see that Geoffry Rush's brilliant performance in Shine was--to put it mildly--a lie. The real David Helfgott, it turned out, still wore the mask of insanity: the tic-like mannerisms shown in softened romanticized form in Shine were in fact dismayingly pronounced. Moreover, his playing was far more disorganized than on disc, and his technique, though to some extent still intact, was divorced from any meaningful musicality. It was as if his hands remembered how to play the piano, but were doing so without the guidance of his mind...It seems to me that many people have been unwilling to grapple with the harsh truth about Helfgott, the subject of the movie Shine: he has been , and gives every indication of still being, profoundly mentally ill. He grunts, mutters, sings, and talks to himself--very loudly--as he plays. He seems not fully aware of where he is... (2)

Teachout's observations provide an excellent segue into a description of the classical symptoms of schizophrenia. These symptoms are divided into two categories: positive and negative symptoms. According to Shepard "positive symptoms are those that should not be present", and negative symptoms are "absences of characteristics that should normally be found." (3). Examples of positive characteristics include: hallucinations(usually auditory), delusions(paranoia), disorganized speech or thought disorders(neologisms and word salads), and disorganized behavior(inappropriate affect particularly in social situations). Examples of negative symptoms include: lack of motivation, flatness of affect, social withdrawal, apathy, alogia, psychomotor retardation, and anhedonia. (4).Negative symptoms tend to be associated more with sudden onset, whereas positive symptoms occur more gradually are easier to treat. Features of schizophrenia tend to be mix of positive and negative symptoms. So, from the list of symptoms it appears that David Helfgott has a mild form of schizophrenia with easily treatable, positive symptoms.

This paper will focus on the positive symptoms, specifically those having to do with disorganized speech or thought disorder. Dobson identifies two categories of thought disorder: form and content. (5).Schizophrenics speak the same language as everyone else, usually in correct grammatical form, but their problem is coherence. Although rare, one reason why incoherence occurs is due to use of neologisms and word salads. Neologisms are made up words, usually the result of a combination of two words. (3) Word salads have more to do with associations between sets or phrases of words. For instance, when asked "what color is your dress?" one patient responded: "red...Santa Claus...flying through the sky...God...??" (5).

One reason why both of these aspects of thought disorder are most likely rare is that they are language specific. In a study conducted at the University of Helsinki, researcher's found that the type of strategy used to create neologisms may depend upon the language the child or schizophrenic speaks. For example, it was found that whereas English children tended to use conversion frequently, Finnish children do not use this strategy often. (6).These language specific aspects of thought disorder are paradoxical in the same sense that Tourette's Syndrome is also a paradox-how is it that some aspect of ourselves that is partially learned and a product of culture so precisely affected by a disorder whose etiology is assumed to be mostly organic?

These aspects also raise some very interesting issues if we are to understand the brain and behavior in terms of central pattern generators and corollary discharge. As Melissa Wachterman hypothesized, at first glance, it would seem that because schizophrenic thoughts sound so unrelated and not semantically meanigful, this must be a disorder in which there is no corollary discharge from one thought or phrase of words to the next. However, upon close examination, it appears that it depends upon which aspect of thought disorders one examines. Neologisms appear to be a product of speech that perhaps are independent or automatic of one another and therefore do not require corollary discharge. Some schizophrenic patients say that part of the reason why they invent neologisms is because they are thinking too quickly to spit out one word and instead they spit out a combination of two words. This also happens to non-schizophrenics as well, but probably less frequently. This example is similar to typing or playing the piano in that the act of speaking itself is so automatic that words fly out of the mouth faster than the person can think about them. Thus, these words are independent of the first or last word because the speed with which they are talking is so fast. Clearly this example implies that there is a central pattern generator.

On the other hand, word salads do have real associations from one word phrase to the next, suggesting corollary discharge between each thought. This example suggests that even though speech seems to indicate a central pattern generator, what actually occurs at the level of neurons is different. That is, these thoughts or particularly words in phrases are dependent upon one another, and therefore opposite of the proposed theory for why neologisms might occur. Yet, the interesting fact is that not only are they both part of the same disorder, but they are also both part of the same type of schizophrenia.

Although treatment options tend to decide on type and severity of schizophrenia, it is obvious that thought disorders and their effects (such as neologisms and word salads), make cognitive therapy difficult. The problem is the difficulty determining the exact level of comprehension in a patient who does not speak in semantically meaningful phrases. If the phrases are the only measure used to indicate their level of comprehension, then it would appear that these Schizophrenic patients are hopeless, and therapy is a lost cause. A specific cognitive technique that therapists and members of the family do use, however, is to play along with a patients delusions as opposed to reprimanding their lack of ability to think rationally. (7).

In her Editor's Prize winning essay written in 1995, Lauren Slater describes how she had to adapt and evolve a new strategy to understand her group therapy patients at a home for schizophrenic men. (8).In this first person account Slater realizes that the men do not respond well to normal therapy techniques such as trying to rationally convince a patient 'Leroy' that they "don't speak code in this group.", and asking, "why don't you tell all of us what you actually mean?" Instead, Slater finally decides to give in and play along one day when another patient, George, insists that a spaceship has landed on his belly. "...why don't we go for a ride in it then? Let's go!" Slater declares. As opposed to restructuring their thoughts according to her standards of how they should act, the strategy instead becomes finding a method in their madness. What Slater does discover is that there is a pattern, but one that only surfaces when these men are encouraged to indulge the very thoughts that are normally dismissed by the hospital staff as "crazy" and "non-sensical."

After her experience with these men, Slater claims "I do know, now, that the schizophrenic, in his better moments, is capable of some sorts of connections." Slater searches for instances of higher processing and connections because so many people dismiss the ramblings of the men as products of beings who can not make even the simplest connections. Slater also makes the point that the ability of these men to make connections depends on whether or not they are in a stressed, or non-stressed environment. She comes to this conclusion after one of the patients in the group dies and the others in the group are again lost in their own world of unreachable, imaginary thoughts. So, perhaps the distinction between reachable, treatable schizophrenics depends upon the type of environment they live in.

Yet, what is the extent to which the schizophrenic can make connections? Do they require a central pattern generator? Does corollary discharge exist? The example of neologisms implies that they do not have the ability to make connections. On the other hand, the example of word salads implies that they do have the ability to make connections. If schizophrenics did not have any connections or corollary discharge, one possible explanation for their behavior is that they are always stuck in an automatic mode. They would be disconnected from their I-function, or even disconnected from one phrase or thought to the next.

The ability or inability of schizophrenics to make these connections is very important because if it is assumed that schizophrenics have a level of comprehension higher than they are able to demonstrate, this has profound implications for treatment and their quality of life. Indeed it seems that the only way treatment of this sort would work is if it was in fact the case that schizoprenics had a higher ability to comprehend language than to speak the language. This situation is analogous to the process of learning a foreign language-there is always a point when comprehension surpasses speaking ability. In addition, this scenario implies that corollary discharge must be functional.

The other form of major treatment for Schizophrenia is, of course, pharmacological. Antipsychotics like haloperidol and chlorpromazine have been used ever since their introduction in the early 1950's to treat the positive symptoms of not only schizophrenia, but various other dopamine related disorders like Tourette's. Both of these disorders are associated with excess dopamine in the brain, specifically the mesolimbic region. (3). The negative symptoms, on the other hand, are associated with an anatomical difference in ventricle size and hypofrontality (improper functioning of the frontal cortex). The hypofrontality hypothesis is supported by studies which test schizophrenics on the Wiconsin Card Sorting Test. Blood flow in schizophrenics while doing card sorting task is lower in schizophrenics than non-schizophrenics. In addition, there is a decrease in homovanillic acid when schizophrenics perform this task which indicates that schizophrenia should then be due to a deficit of dopamine in the frontal cortex as opposed to an excess of DA in the mesolimbic cortex. (9).

How might one account for these two conflicting accounts of schizophrenia? Weinburger proposed a model in which brain stem dopamine neurons in normal state individuals have connections to both the limbic system and the prefrontal cortex. (10).Dopamine to both these areas causes separate negative feedback stimulation form both structures to the dopamine brain stem neurons. Schizophrenic patients have damage between the dopmaine brain stem neurons and the prefrontal cortex so that there is no inhibition form the prefrontal cortex, but increased stimulation of dopamine to the limbic areas. If dopamine as a neurotransmitter provides corollary discharge, and then one possible interpretation of this model would be that there is no corollary discharge between the dopamine neurons in the brain stem and the prefrontal cortex. This would then suggest that schizophrenia is a problem of corollary discharge between dopamine neurons in the brain stem and the prefrontal cortex.

In conclusion, there is definitely evidence for a central pattern generator for schizophrenia. The existence of corollary discharge, however, depends upon the types of symptoms present. Cognitive therapy and word salads indicate functional corollary discharge, whereas certain pharmacological models and neologisms do not. Also imperative to keep in mind is that there are many different forms of schizophrenia. It is possible that one form may have functional corollary discharge, while dysfunctional corollary discharge is a typical characteristic of another type of Schizophrenia.

WWW Sources

1)Neurobio&Behavi or forum, Topic 7

2)The David Helfgott Show, commentary from music critic reporter for the New York Daily News, Terry Teachout

3)The Symptoms and Treatment of Schizophrenia, good general introduction to multiple issues about Schizophrenia

4)N egative Symptoms, general introduction to negative symtpoms of Schizophrenia

5)Schizophreni a & Psychotic Disorders, course outline of an Abnormal Psychology class

6) Neologisms in Child Language, Abstract from Finnish study about different neologisms made by children who speak English and Children who speak English

7)Symptoms of Schizophrenia, another good general page for information about Schizophrenia

8)Welcome To My Country, an account of a group therapist's time spent with a group of schizophrenic men

9)Abdel Selection of Biblio Refs: Prefrontal Cortex (1981-1999), Part 6, Abstracts about Schizophrenia and memory

10)>Bloom & Kupfer (ed.) Psychopharmacology: The Fourth Generation of Progress, Raven Press: New York, 1995

| Course Home Page | Back to Brain and Behavior | Back to Serendip |

Send us your comments at Serendip
© by Serendip '96 - Last Modified: Wednesday, 02-May-2018 10:52:54 CDT