[6 Apr 2004]

Below are e-mail responses from researchers of bird brain to my message concerning their papers Haesler et al and Teramitsu et al. See also commentaries by the academic institutes of the researchers, based on talking with them, in university news release, press release by Max Planck Society and this university release. See the related texts for discussion of the issue.

All the responses seem to try to give "speech" a new meaning of "motor actions", rather than "coordination of motor actions to produce linguistic utterances". Obviously, if speech is "motor actions", then all animals have speech skills. So when people (including these researchers) say that only humans among mammals have speech, they don't mean "motor actions", they mean "production of linguistic utterances". This is certainly a cortical function, and hence has no homology in birds. Faced with this question, this researchers try to confuse the issue by extending the definition of speech. In the case of Jarvis, it may be that he genuinely believes that some non-cortical structures in the human brain have speech functionality, notwithstanding the contrary neuropsychological evidence.

It should be noted that the issue of cortex in humans vs. non-cortex in birds is not mentioned in all the commentaries above, even though these are for non-experts that would not be expected to know it.

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my message
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Dear Stephanie A. White,

In your recent paper "Parallel FoxP1 and FoxP2 Expression in Songbird and
Human Brain Predicts Functional Interaction" you  are referring to the
relation
between bird song  and human speech. However, according to current theories,
 human speech is controlled by some part of the cerebral cortex, which is
undeveloped in birds, and bird song is controlled by some nuclei that do not
have parallels in the mammalian brain. In other words, the control of human
speech and bird song is done by two  evolutionary unrelated systems.

Are you suggesting that the current theories wrong? Or that the unrelated
systems converged on using the same gene?

Thanks,

Yehouda Harpaz

 

From: "Dan Geschwind" 
To: "Yehouda Harpaz" ; 
Sent: Sunday, April 04, 2004 4:26 PM
Subject: Re: FoxP, birds song and human speech.


Dear Yehouda:

Human speech involved parallel distributed systems that are not fully
understood, t clearly involve subcortical structures in which fox
genes are expressed. Speech and all complex motor movements have
significant basal ganglia involvement, thalamic etc....

best,

DG

Dr. Daniel H. Geschwind
Associate Professor
Director, Neurogenetics Program
Department of Neurology
710 Westood Plaza, RNRC 1-145
UCLA School of Medicine
Los Angeles, CA 90095

----- Original Message -----
From: "Stephanie White" 
To: "Yehouda Harpaz" 
Sent: Friday, April 02, 2004 6:28 PM
Subject: Re: FoxP, birds song and human speech.


An upcoming paper in the Journal of Comparative Neurology clarifies
avian brain structures relative to mammalian brain.  It is now clear
that the avian brain contains much more pallium than previously
thought when it was named 100 years ago.  Pallium gave rise to cortex.
The first author is Reiner.  I'm not sure when it will make it to
print.  Meanwhile, I agree that LANGUAGE is clearly cortical, but the
actual control of the muscles used for speaking will have a
basal-ganglia component.  Interestingly, even strokes of the human
cerebellum sometimes end up disrupting speech.

From: "Erich D. Jarvis" 
To: "Yehouda Harpaz" ; ;

Sent: Friday, April 02, 2004 3:11 PM
Subject: Re: FoxP, birds song and human speech.


Dear Yehouda,

We are saying exactly what you state below. That the current
evolutionary theories of how avian and mammalian brains are related
are wrong. That there are similarities between a so far not well
characterized human language system with the well characterized song
bird vocal learning system. Some of the similarities for the
language/song specific behaviors are thought to be the result of
convergence. Others similarities outside the language/song systems
are the results of common ancestry with stem amniotes. Details on the
answers to the two questions you have below are coming out in two
papers that will be published within the next 1-3 months:
>
Revised Nomenclature for Avian Telencephalon and Some Related
Brainstem Nuclei. A Reiner, L Bruce, A Butler, A Csillag W Kuenzel, L
Medina, G Paxinos, D Perkel, T Shimizu, G Striedter, M Wild, G Ball,
S Durand, O Gunturkun, D Lee, CV Mello, A Powers, S White, G Hough, L
Kubikova, TV Smulders, K Wada, J Dugas-Ford, S Husband, K Yamamoto, J
Yu, C Siang, ED Jarvis (2004) J. Comp. Neurol. (in press, May 2004).

Learned Birdsong and the Neurobiology of Human Language. ED Jarvis,
In:  Behavioral Biology of Bird Song, HP Zeigler, P Marler (eds.)
(2004) Annals of the New York Academy of Sciences (in press, June
2004).

Sincerely,

Erich Jarvis

Erich D. Jarvis, Ph.D.
Assistant Professor
Department of Neurobiology, Box 3209
Duke University Medical Center
Durham, North Carolina 27710

(919) 681-1680 Phone
(919) 681-0877 Fax
http://www.jarvislab.net/