Norm Cook's Topographic Callosal Inhibition?

Bill Park park at netcom.com
Sun Dec 12 19:14:36 EST 1993


NOTE: I wrote "bionet.neuroscience" TWICE in the Newsgroups: header in
      my original message, resulting in a double posting there.
      Sorry.  It's fixed above, please check if you follow up on this thread.

In article <2ec5l4$269 at news.bu.edu> jna at bu.edu (John Adams) writes:
> 
> Bill Park (park at netcom.com) wrote:
> : I have just enjoyed reading
> 
> : Norman D. Cook, _The Brain Code.  Mechanisms of Information Transfer
> :         and the Role of the Corpus Callosum_, London and New York,
> :         Methuen & Co., ISBN-N-0-416-40840-0 (1986).
> 
> : and was quite impressed with Cook's seven-year-old theory.
> 
> : 		-------  SUMMARY  -------
> 
> : Very briefly, Cook proposed that an important function of the corpus
> : callosum is to activate, on the cortex of the right hemisphere, those
> : concepts that constitute the "context" of (i.e., the concepts most
> : closely-associated with) any concept that is currently activated on
> : the left hemisphere.  His explanation posits the presence of several
> 
> Does Cook's theory (I'm unfamiliar with it) explain language parsing
> in split-brain patients? 

Cook says that usually the left hemisphere has the speech center, and
that that usually includes both the parsing functions and control of
the midline organs of speech.  Since we have only one set of lungs/
larynx/jaw/toungue/lips to speak with, we can't afford to have our two
hemispheres fighting over what they are to say!  Cook notes that the
right hemisphere by itself seems to have the verbal abilities of an
11-year old, according to Zaidel's studies of split-brain patients
(Zaidel 1979).  He also notes that about 1.5 degrees of the central
visual field go to both hemispheres, and auditory nerves don't all go
to the opposite hemisphere; a large portion go to the hemisphere on
the same side.  So, the left hemisphere has everything it needs to
parse what it reads and hears all by itself, except for the ability to
place information in context and to extract larger meanings.  Cook
interprets seven of eight characteristics of the "confusional state"
described by Geschwind (1982) and widely observed in neurological
clinics as just what one would expect from loss of context in language
processing.

> If not, it seems that split-brain patients parsing of language would
> be incredibly lethargic, when it is not...

Right.  In fact, in a discussion of the effects of right-hemisphere
damage in patients, Cook mentions (p. 135) their typical
"garrulousnous and punning," and predicts (in 1986) that these will
also be found in split-brain patients if looked for.  He notes that
neurosurgeons have a vested interest in the "normality" of patients
whose brains they have split, so that they may not have looked too
hard for these (admittedly subtle) deficits.  One may speculate as to
how much this candid observation advanced Cook's career! ;^/  He quotes
Sperry (1968): "Their intellect is ... handicapped in ways that are
probably not revealed in the ordinary tests." And (Sperry, 1974): "[he
notes] 'deficits in the ability to grasp broad, long-term or distant
implications of a situation,'" and " (Sperry, 1974): '... their
conversation tends to be restricted mainly to what is immediate and
simple."

Cook also places in the context of his brain model several other
classic clinically-observed conditions, such as attention deficits,
serial killers (maybe, can't find the page), and confabulation
(creative and bizzare explanations for or denials of neurological
problems).  For some amazing examples of confabulation, see Oliver
Sacks' highly-readable book, The Man Who Mistook His Wife for a Hat
and Other Clinical Tales (reference #11 in the bibliography below).

Cook notes that right-hemisphere damage can have a surprising effect
on a patient's sense of humor: Cook says (p. 24), "Gardner and Denes
(1973) and Gardner et al. (1975) reported that right-hemisphere damage
results in anomalous affect and an inability to understand non-verbal
cartoons. ... they concluded that 'the left hemisphere[-damaged]
patient tends to exhibit those preferences and reactions of a normal
individual deprived of linguistic output ...; the right
hemisphere[-damaged] patient resembles a 'sophisticated language
machine' responding appropriately to linguistic messages, but with a
tendency to extrapolate illegitimately on the basis of fragmentary
data.' ... Although fully capable of describing in words the elements
of the cartoon, frequently those elements could not be pieced together
into the coherent humorous whole."

"Related findings were obtained by Brownell et al. (1983).  They
tested twelve patients with right-hemisphere dmage on their ability to
choose a humorous ending to a verbal joke from among four
alternatives.  For example, the body of one such joke was as follows

	The neighborhood borrower approached Mr. Smith on Sunday
	afternnoon and inquired: 'Say Smith, are you using your
	lawnmower this afternoon?'

	'Yes, I am,' Smith replied warily.

	The neighborhood borrower then answered: ...

And the patients had to choose the most appropriate ending:

	1) (correct): 'Fine, then you won't be needing your golf
	   clubs, I'll just borrow them.'

	2) (non-sequitur): 'You know, the grass is greener on the
	   other side.'

	3) (straightforward, neutral): 'Do you think I could use it
	   when you are done?'

	4) (straightforward, sad): 'Gee, if only I had enough money, I
	   could buy my own.'

"Not surprisingly they found that (i) the right-hemisphere-damaged
patients simply could not choose the humorous ending as often as a
control subject.  More interestingly, however, they also found that
(ii) the right-hemisphere-damaged patients preferred the non-sequitur
ending more than the controls.  Brownell et al. interpreted the latter
finding as indicating a normal predilection for the surprise element
in humor, but a clearly abnormal inability in 'integrating the content
across parts of the narrative.'"

> : Among other predictions, Cook suggested that his model would help to
> : explain the extreme speed and accuracy with which people can
> : disambiguate language as they listen to speech or read: The right
> (see above)
> 
> : 5) Cook never seems to get around to explaining the mechanism by which
> : the right hemisphere aids the left.
> 
> could it be possible that one hemisphere can take over both jobs?

Yes, such "plasticity" has been noted for several different functions
including language, though often patients regain only partial
function.  Not surprisingly, children seem to be more capable of such
massive neural reorganizations than adults.  I also recall some
stories (perhaps in one of Sacks' books) about seemingly normal people
who were found at autopsy to have a completely missing hemisphere, or
brains consisting only of a thin shell of cortex (the white matter
having been mostly lost due to hydrocephaly) and an outlaw biker who
had enough organizational skills to lead a motorcycly gang but was
found at autopsy to have a smooth brain like a sheep's.  Others can
probably cite references.

> : The question of the stability of such an iterative process is
> : interesting.  So that the reader can investigate it, Cook gives a
> : MicroSoft BASIC program to simulate it and even to compute the
> : resulting artificial EEG signal produced by the simplified artificial
> : brain as it "thinks."  Unfortunately, he doesn't show any results of
> : running this program, only refers to some earlier papers.
> 
> Can someone type this in and get it to the net?
> I'd love to examine it....

There might be some copyright violation problems in doing that.
Perhaps someone who knows where Cook is now could contact him and see
if he wants to post it, or allow someone to post it.

There are two programs: The static simulation is about 180 lines long,
while the dynamic simulation (the one that produces an EEG) is about
100 lines long.  Both are pretty dense; I'd scan them in with optical
character recognition software if I had the facilities, rather than
try to retype them and comb out my typing errors.

The static program seems to print an ASCII grid representation of the
activation patterns in the left and right simulated cortexes.  The
dynamic one prints out a table of values of a left and right simulated
EEG electrode vs. time.

A rewrite with a modern interactive graphics interface for Macs and
PCs might be a useful teaching aid.  If anyone undertakes this, please
isolate the simulation code from the user interface code so it can be
more easily ported across Macs, DOS, Windows, and Unix systems.

It would be interesting to encode a simple semantic net on each side,
hook up the simulation to input and output streams of simulated
language units (e.g. words or concepts), and see it if did the right
thing.  Might be a lot of work, even for a pretty sketchy domain of
discourse.

> : If it doesn't terminate, does that suggest a mechanism for the "monkey
> : chatter" of thoughts that Eastern meditation attempts to suppress?
> ---------------------------------------------------------------------------
> John Adams        jna at acs.bu.edu	         jna at silver.lcs.mit.edu
> Boston University +========================================================
> 458 Beacon St     | CS / Cognitive Neural Systems hopeful...
> Boston, MA 02115  | :)
> 617.765.0818      | 
> ------------------+--------------------------------------------------------

References (from Cook):

Brownell, H.H., Michel, D. Powelson, J. and Gardner, H. (1983)
     'Surprise but not coherence: sensitivity to verbal humor in
     right-hemisphere patients,' Brain and Language, 18, 20-7.

Gardner, H. and Denes, G. (1973) 'Connotative judgments by aphasic
     patients on a pictorial adaptation of the semantic differential,'
     Cortex, 9, 183-96.

Gardner, H., Ling, K., Flamm, L. and Silverman, J. (1975)
    'Comprehension and appreciation of humor in brain-damaged
     patients,' Brain, 98, 399-412.

Geschwind, N. and Levitsky, W. (1968) 'Human brain: left-right
    asymmetries in temproal speech region,' Science, 161, 186-7.

Geschwind, N. (1982) 'Disorders of attention: a frontier in
     neuropsychology,' Philosophical Transactions of the Royal Society
     (London), B298, 173-85.

Sperry, R. W. (1968) 'Hemisphere deconnection and unity in conscious
     awareness,' American Psychologist, 23, 723-33.

Sperry, R. W. (1974) 'Lateral specialization in the surgically
     separated hemispheres,' in Milner, B. (ed.) Hemispheric
     Specialization and Interaction, Cambridge, mass., MIT Prress.

Zaidel, E. (1979) 'Performance on the TTPA following cerebral
     comissurotomy and hemispherectomy,' Neuropsychologia, 17, 259-80.

Here's a bibliography of Sacks' writings that I pulled off the Library
of Congress mainframe via the unix command

	telnet locis.loc.gov

Tried to do a search for Cook's later works, but the L.O.C. just went down.

1. 92-162036: Sacks, Oliver W.  Seeing voices : a journey into the world of
     the deaf /  New rev. ed., Picador ed.  London : Picador, published by Pan
     Books, 1991.  xvi, 189 p. : ill. ; 20 cm.
     NOT IN LC COLLECTION
2. 92-407: Sacks, Oliver W.  Migraine /  Rev. and expanded [ed.]  Berkeley :
     University of California Press, c1992.  xxiii, 338 p., [8] p. of plates :
     ill. (some col.) ; 24 cm.
     LC CALL NUMBER: RC392 .S33 1992
3. 90-4914: Sacks, Oliver W.  Awakenings /  1st HarperPerennial ed.  New York :
     HarperPerennial, 1990.  xxxix, 408 p., [8] p. of plates : ill. ; 21 cm.
     NOT IN LC COLLECTION
4. 89-46487: Sacks, Oliver W.  Seeing voices : a journey into the world of the
     deaf /  1st Harper Perennial ed.  New York : HarperCollins, 1990.  xvi,
     186 p. : ill. ; 20 cm.
     NOT IN LC COLLECTION
5. 89-4817: Sacks, Oliver W.  Seeing voices : a journey into the world of the
     deaf /  Berkeley : University of California Press, c1989.  xv, 180 p. :
     ill. ; 24 cm.
     LC CALL NUMBER: HV2370 .S23 1989
6. 87-30462: Sacks, Oliver W.  A leg to stand on /  South Yarmouth, Ma. : J.
     Curley, [1988], c1984.  xvi, 284 p. (large print) ; 22 cm.
     NOT IN LC COLLECTION
7. 87-7130: Sacks, Oliver W.  Awakenings /  New York : Summit Books, c1987.
     xxx, 339 p., [6] p. of plates : ill. ; 23 cm.
     LC CALL NUMBER: RC382 .S23 1987
8. 86-45686: Sacks, Oliver W.  The man who mistook his wife for a hat and
     other clinical tales /  1st Perennial Library ed.  New York : Perennial
     Library, 1987, c1985.  x, 243 p. ; 22 cm.
     NOT IN LC COLLECTION
9. 86-45685: Sacks, Oliver W.  A leg to stand on /  1st Perennial Library ed.
     New York : Perennial Library, 1987, c1984.  222 p. ; 20 cm.
     NOT IN LC COLLECTION
10. 86-24305: Sacks, Oliver W.  The man who mistook his wife for a hat /
     South Yarmouth, Ma. : J. Curley, c1986.  xvii, 398 p. : ill. ; 23 cm.
     LC CALL NUMBER: RC351 .S195 1986
11. 85-17220: Sacks, Oliver W.  The man who mistook his wife for a hat and
     other clinical tales /  New York : Summit Books, c1985.  xvi, 233 p. :
     ill. ; 25 cm.
     LC CALL NUMBER: RC351 .S195 1985
12. 84-16352: Sacks, Oliver W.  Migraine : understanding a common disorder /
     Berkeley : University of California Press, c1985.  xx, 270 p. : ill. ; 22
     cm.
     LC CALL NUMBER: RC392 .S33 1985
13. 84-8497: Sacks, Oliver W.  A leg to stand on /  New York : Summit Books,
     c1984.  222 p. ; 23 cm.
     LC CALL NUMBER: RC339.52.S23 A35 1984
14. 82-74563: Sacks, Oliver W.  Awakenings /  New York : E.P. Dutton, c1983.
     338 p., [8] p. of plates : ill. ; 20 cm.
     LC CALL NUMBER: RC382 .S23 1983
15. 78-570647: Sacks, Oliver W.  Migraine: the evolution of a common disorder
     London, Faber, 1970.  3-298 p. illus. 23 cm.
     LC CALL NUMBER: RC392 .S33 1970
16. 78-128584: Sacks, Oliver W.  Migraine: the evolution of a common disorder
     Berkeley, University of California Press [1970]  298 p. illus. 23 cm.
     LC CALL NUMBER: RC392 .S33 1970b
17. 76-675733: Sacks, Oliver W.  Awakenings /  Rev. ed.  Harmondsworth, Eng. :
     Penguin Books, 1976.  344 p., [4] leaves of plates : ill. ; 19 cm.
     NOT IN LC COLLECTION
18. 75-30600: Sacks, Oliver W.  Awakenings /  New, rev. ed.  New York :
     Vintage Books, 1976.  344 p., [4] leaves of plates : ill. ; 19 cm.
     NOT IN LC COLLECTION
19. 74-163507: Sacks, Oliver W.  Migraine; the evolution of a common disorder,
     A new and abridged ed.  Berkeley, University of California Press [1973]
     220 p. illus. 21 cm.
     LC CALL NUMBER: RC392 .S33 1973
20. 73-176168: Sacks, Oliver W.  Awakenings  London, Duckworth [1973]  xiii,
     255 p. illus. 22 cm.
     LC CALL NUMBER: RC141.E6 S22 1973
21. 73-15363: Sacks, Oliver W.  Awakenings,  [1st. ed. in the U.S.]  Garden
     City, N.Y., Doubleday, 1974 [c1973]  xiv, 249 p. 22 cm.
     LC CALL NUMBER: RC382 .S23 1974

Bill Park
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