From: tychay@juliet.caltech.edu (Chay, Terrence Y.)
Subject: Canary Song (Re: Brain is READ ONLY)
Followup-To: alt.cyberpunk.tech
News-Software: VAX/VMS VNEWS 1.41    
Organization: California Institute of Technology
Date: Tue, 1 Sep 1992 08:09:00 GMT

In article <csmith-310892103253@cyrano.gmu.edu>
csmith@blackplague.gmu.edu (Blackplague) writes...

>On another note, scientists working with canaries have discovered a VERY
>interesting fact.  When a canary learns a new song (from being introduced
>to a new species of canary) not brain of the canary GROWS a new section to
>deal with the new song.  Yes, GROWS.  New brain cells are created.  This
>flies in the face of all previous experiences in brain developement.

Blackplague,
  i have heard the same thing so i looked it up in the meager resources i have.
i also seem to remember that this phenomenon was unique to songbirds.

-------
  i am wondering what implications you a.cp.tech'ers feel this as on a.cp.tech?
any viewpoints?
  btw, i noticed that the Sept 92 Scientific American has a whole issue on the
Mind and Brain... sorry i can't say more, i just got my copy.

does anyone know the original cites? this is all i could find (and it's probably
too old anyways)

MY REFERENCES
#1
  "Song-learing behavior: the interface with neuroethology" Peter Marler
  Trends in Neurosciences, May 1991.
  [i did not read this since i don't know what "neuroethology" is]

#2
  "Reassessing the mechanisms and origins of vocal learing in birds" Fernando
   Nottebohm.  TINS May 1991 again.
Abstract: The most widely accepted hypothesis of vocal imitation in birds pre-
  dates many recent studies on the behavior, anatomy, physiology, and cell
  biology of this phenomenon.  It states that vocal learining involves two
  steps: (1) an auditory memory is laid down, and (2) vocal output is modified
  until the auditory feedback it generates matches the model.  This black-
  box model of vocal imitation disregards circuitry.  We now know that
  the brain pathways for voclal learining in birds include a series of
  well defiend nuclei and projections [outputs].  some of these nuclei and
  projections develop late in ontogeny [??], at the time when auditory models
  are first acquired and imitated.  We also know that the pathways involved
  in song production respond to sond, an observation that blurs the demarcation
  between what is auditory and what is a motor circuit.  These and other recent
  discoveries call for a reassessment of mechanisms and origins of vocal learing
  in birds and mammals.
  [sounded rather boring so i read no farther]

#3
  Levitan and Kaczarek.  _The Neuron_:Cell and Molecular Biology. c.1991
  p 319-20
REGULATION OF NEURONS BY TESTOSTERONE IN SONGBIRDS:  One of the clearest
examples of the influence of steroid hormones on the properties of a neuron
is found in songbirds such as canaries.  In this case the hormones produce
profound plastic changes [redundancy] in the properties of adult neurons, 
emphasizing that there are commonalities in mechanisms of development and
adult plasticity.  During the breeding season, adult male canaries generate
a song made up of a fixed pattern of individual sounds, termed syllables.  This
sterotyped pattern of syllables is termed a _stable song_.  Although in any one
bird the dong pattern remains relaticely fixed during the spring reproductive
season, the specific pattern of syllables that comprises a stable song is lost
in the months that follow.  At this time the animals vocalize variable
patterns of syllables, termed _plastic song_, and may generate new syllables
that were not used in prior years.  In the next breeding season, the bird
acquires a brand new pattern of syllables in its stable song. [!!]

  [the next two paragraphs are about how testosterone level changes
  birdsong]

  One intersting aspect of the remodeling of neural form and connections in
song birds is that not only can preexisting connection be modified by hormones,
but new neurons may be added to a pathway [!!]...

#4
  Purves & Lichtman.  _Principle of Neural Development_ c. 1985. p338-341.
  DEVELOPMENT OF BIRDSONG
  These ethological studies of birds and monkeys are in accord with a growing
body of neurobiological evidence that confirms that experience can modify
innate behavior in a more or less permanent way.  Particularly instructive is a
series of studies on birdsong carried out over the last two to three decades...

  [Here is something interesting]
  In zebra finches, for example, song learning is restricted to about the first
80 days after hatching.  Canaries, on the other hand, learn new phrases of song
with each successive season and so exted their repertoire... Like chaffinches
and zebra finches, mail white-crowned sparrows learn song during a defined
period early in life. So keen is their preconception of what constitutes a
proper song that they will not learn the song of other sparrow species when 
exposed to it in the laboratory...; even more remarably, they can learn their
species song when it is spliced together on a tape with the song of a sympatric
[??] species.  Thus , these birds recognize the song they are supposed to learn
even under confusing and difficult conditions.  Evidently vocal learning
occurs by modifying vocal output until the auditory feedback generated by
the young bird mataches a model of the species song [hmm.. sounds like #2].
All told, these observation amply confirm that the neonatal [new born] nervous 
system already contains detailed information about what behaviors to learn and
when to learn them [!!]...
  [more stuff about canaries, but boring so i won't type it]

i am curious about how any of you feel about the conclusions marked with a [!!].

          -terrychay
                 TYCHAY@CITJULIE.BITNET
                 tychay@juliet.caltech.edu