Monkey Broca, Wernicke?

[Tom Givon]

Neuroscience advances somewhat fitfully. For every announced new 
discovery,  there is sooner or later (more often sooner) a finding 
pointing in another direction. This is because of the complexity & 
distributiveness of most higher cognitive system. Another instasnce, I 
suppose, of the three blind men describing the elephant. So first, we 
need to be cautious about evaluating 'radical new discoveries', 
particularly about language (which is the most complex & distributive 
capacity supported by the brain).

More to the point, the function-specific regions ("modules") of the 
cortex  ('periphery') are all  mamalian evolutionary projections from 
the *limbic-thalamic sub-cortex*. This is true of vision, audition, 
motor control, somatic-sensory areas, attention, episodic & semantic 
memories, etc. And for most of those 'higher' cortical capacities, the 
limbic-thalamic areas remain part of the functional system--in a a 
*distributive network* (see e.g. M-M. Mesulam's  "Principles of 
Behavioral & Cognitive Neurology", 2nd edition,  Oxford U. Press, 2000 
as a major source on this. But there is a vast  lit. on the subject).

Thus, because so many of the cognitive capacities that support human 
language are  the outgrowth of (functionally amenable) pre-linguistic 
capacities, the limbic-thalamic areas are implicated in almost all 
brain-activity related to language processing. And the pre-human primate 
brain is so close to ours in its general architecture, there's no reason 
to assume that the same core-periphery relation doesn't apply there.

So if at one time research implicates a cortical area ('periphery')  and 
at another a sub-cortical one ('core') in executing the same function, 
be it linguistic or pre-linguistic, it is because* both* are implicated. 
Keep on truckin'.  TG

=======================

Mark P. Line wrote:

>jess tauber wrote:
>  
>
>>Study hints language skills came early in
>>primates-http://news.yahoo.com/s/nm/20060725/sc_nm/science_language_dc
>>
>>I remember being told that lower primates only utilize lower (limbic)
>>brain centers for vocal communication. So what does all this mean??
>>    
>>
>
>I think this study is important precisely because it had been hypothesized
>that monkey vocalization does not involve the cortex. This rather
>seriously overgeneralized hypothesis came about because experiments
>(starting in the 1970's, I think) showed that vocalization was elicited by
>limbic but not by cortical stimulation.
>
>Apart from the obvious ramifications for our understanding of the
>phylogeny of primate communication, the study also suggests that the
>reason for those stimulation results in monkeys may be due to limbic
>control of vocalization even if there is cortical involvement in the
>actual behavior: limbic stimulation causes vocalization because it
>provides the control stimulus, while cortical stimulation does nothing
>because the limbic signal is absent. Note that monkeys don't want to
>vocalize willy-nilly except for good reason (since there might be an
>undetected predator within earshot), and that there would be solid
>inhibitory pathways preventing vocalization if only Broca is stimulated
>without the limbic input.
>
>Humans will have evolved past this limbic control -- most communication is
>consciously intended and neocortically controlled. (There's an obvious
>joke about throwbacks at a recent coffee klatsch.)
>
>I'm surprised that no such study was done before now and that the
>limbic-only hypothesis for monkey vocalization remained unfalsified until
>now, but I guess I'll take their word for it.
>
>-- Mark
>
>Mark P. Line
>Polymathix
>San Antonio, TX
>  
>