sensorimotor experience and language

[Elizabeth Bates]

I'm not an expert in research on awake-behaving monkeys, let me stress, but
I understand that experiments like Rizzolati's involve a long training
period in which the animal is rewarded for (1) moving in the direction he
needs to move to get the reward, and then (2) waiting to make that movement
until a "go" signal is given.  After they are trained up, the single cell
recording is done.  So, the operational definition of "the animal is
planning an arm movement" would be performance on a trial in which a
movement in Direction A will be produced, but the animal is still waiting
for the "go" signal.  By the way, there is also human fMRI work on
covert motor activity, in which people are instructed to (1) covertly
copy a set of finger movements, (2) plan those movements but wait for
a "go" signal before they are 'covertly executed', and (3) plan those
movements but then inhibit them when a 'stop' signal is given.  Believe
it or not, distinct though related patterns of frontal/prefrontal
activation are seen in each of these three conditions, quite systematic!
Even more exciting (or disturbing, depending on your point of view), the
various areas involved in covert planning/execution/inhibition of hand
movements overlap markedly with the areas that show up in covert speech....

With regard to the question about whether these are movements that the
monkey is familiar with, the answer is definitely "yes": these are
relatively simple directed movements that the animal uses in everday
life, and hence do not represent animal homologues to imitation in the
strong sense of imitation of novel acts that the animal has never seen
before.  It is an empirical question whether imitation of known vs.
imitation of novel movements elicit similar patterns of activation in
humans (monkeys do so little of any interest in the latter domain that
the experiment really couldn't be done.....see research on this topic
by Elisabetta Visalberghi -- the term "monkey see/monkey do" is really
misleading, because humans are the only primates who perform reliably
in this domain!).

-liz bates



>> Elizabeth Bates wrote:
>> >....
>> >For example, Italian neurophysiologist Rizzolatti has studied
>> > neurons in premotor cortex that fire preferentially when the monkey is
>> > planning an arm movement in one particular direction (a kind of covert
>> > motor analogue to the line-orientation preference cells in visual cortex).
>> > The most interesting finding here for our purposes is that these cells
>> > also fire when the monkey observes someone else making an analogous
>> > arm movement!
>
>It is, of course, hard to sort through all of this. How did Rizzolatti
>know, for example, that their monkey was "planning" an arm movement?
>Actually, I suppose that Rizzolatti did have an experimental paradigm
>that isolates planning activity (though it'd still be interesting to
>know how it was done). But then comes the next question: When the monkey
>observes an analogous movement, is this a movement that the monkey is in
>some sense already familiar with? In other words, with monkey-see/
>monkey-do, are we talking about a see-do pairing that the monkey would
>have to -learn- to do? The question becomes relevant, I think, for
>concerns one might have about -acquisition- in humans.
>
>later,
>Lynn Eubank
>eubank at unt.edu