[From Erling Jorgensen (2006.01.12 2100 EST)]
Dick, Bryan, Dag, Dan, et al. –
Somewhat belatedly, this is with reference to the New York Times
article, “Cells That Read Minds” by Sandra Blakeslee, published on
January 10, 2006. (Thank you, Dick, for pointing the article out.
And thank you, Dag, for making the article readable here.)
The article mentioned, “Every time the monkey grasped and moved
an object, some cells in that brain region would fire.”
When I read this, the first things that struck me – thinking from the
vantage point of Perceptual Control Theory – were the following.
To “grasp” is an Event perception. To “move” is a Transition perception.
An “object” is a Configuration perception.
The article continued, “when the student raised the cone to his lips, the
monitor sounded - brrrrrip, brrrrrip, brrrrrip - even though the monkey
had not moved but had simply observed the student grasping the cone
and moving it to his mouth.”
“Raised-the-cone-to-his-lips” sounds like a Sequence perception. “To”
is a Relationship perception. And so forth. It seems as though it might
be possible to deconstruct what the article is describing into corresponding
PCT concepts.
In other words, PCT is a kind of conceptual map, to be overlaid on top
of a descriptive territory, to see if any increment of understanding can
arise from comparing the two, (keeping in mind all the time that “the map
is not the territory.”) The most useful kind of understanding is what we
call “explanation,” where a complex territory of relationships can be
effectively mapped onto a much smaller set of relationships (called
tautologies) on the map, with minimal loss of richness.
So, I would start quite simplistically. Hierarchical Perceptual Control
Theory has a heuristic for a bare bones model, consisting of levels of
perception that would need to be brought to their respective reference
standards, in order to accomplish a coordinated set of goals. The
phenomenon being raised by this research (in the NYTimes) is the
apparent observation that similar neurons may be involved, whether
acting oneself or observing another doing something similar.
So then, one of the descriptions from the New York Times article
stated, “The same brain cells fired when the monkey watched humans
or other monkeys bring peanuts to their mouths as when the monkey
itself brought a peanut to its mouth.”
A first approximation at deconstructing some of this into an HPCT
formulation might be as follows:
Program perception (implied) of “Eating”
~ IF no peanut, Grasp
~ ELSE, next
~ IF not at mouth, Bring toward
~ ELSE, Eat
including >
Category referents of “Peanut” and “Hand” and “Mouth”
and enacted via >
Sequence perception of “Grasp, then Bring toward, then Eat”
Ref. = Event-A, Relationship, Event-B
enacted via >
Relationship perceptions of “Distance-from-peanut” and “Distance-
from-mouth”
Ref. = zero
alternating with >
Event perceptions of “Grasp” and “Eat”
Ref. = Start & Stop points
enacted via >
Transition perceptions of “Hand/arm movements” and “Mouth movements”
Ref. = coordinated opponent process muscles
enacted via >
Configuration perceptions of “Body positions” and “Joint angles”
enacted via >
Sensation perceptions of “Finger pressure” and “Tendon stretch”
etc.
Such a series of enacted goals and sub-goals involves a number of
different perceptions. Many of these perceptions could be held in
common, whether the monkey was observing another or doing the
acting itself. This is less likely (I believe), the lower in the hierarchy
the perceptions are occurring. But it is certainly conceivable that
similar Event perceptions, Relationship perceptions, Sequence
perceptions, or even Program perceptions could have been activated
in either the observation condition or the acting condition. So, one
candidate for the “mirror neurons” of the article would be cells
corresponding to the perception nodes of the HPCT model.
I initially thought that another candidate could be cells corresponding
to the reference nodes of the HPCT model. My reasoning was that
the proposed origin of reference signals within the HPCT model is
essentially remembered perceptions, replayed into the downward
channel of descending control loops. That’s one reason I tried to
specify some of the reference standards, in the simplified PCT
description above.
But having done that, it does not seem that such things could be
objects of perception of the monkey. We would have to propose -
(and maybe the article is doing exactly this) – that the monkey is
imagining its own enactment of the perceptual goals that would be
needed, were it to be doing what it is observing. That may be the
import of the statement in the article about the gross physiology being
studied; namely, “Thin wires had been implanted in the region of its
brain involved in planning and carrying out movements.” According
to an extended version of the HPCT proposal, “planning” would be
a function carried out by the so-called imagination connection.
At any rate, I know this is simply launching off of a popularized
treatment in the mainstream media of research that I have not read
in the original journals. And I know this doesn’t do justice to the
complexity of the neurophysiology involved. But what we are looking
for here is an initial mapping of the tautological relationships within a
simplified model (i.e., a hierarchical arrangement of PCT control loops),
onto the territory of some neurophysiological observations.
The PCT model (and its HPCT elaboration) has found it fruitful to
operate with a very limited number of conceptual nodes. The argument
has been that such a vast simplification shows something tremendously
important about the functional arrangement known as negative feedback
control. Perhaps the recording of “mirror neurons” is one way that the
fiction of perceptual nodes manifests itself in the brain.
I’ll have to leave it to others to determine whether searching in such
a direction, with such a map, leads to any increments of understanding
or not.
All the best,
Erling
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