Norman Allan
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Motor Integration in the Central Nervous System

My doctoral research was a study of the vocal behaviour of baby chicks, how they twitter and peep as they run around together and with their mother hen. I would put electrodes into their brains, send a little current that would make them call (while they were anesthetized), and this work lent some interesting insight into how motor behaviours are integrated in the nervous system. This work, conducted from 1965 through 1970, is still fresh and cutting edge (I believe). There is an introduction to it below, and/or you can consult the thesis itself at Sussex University: "The Central Control of Vocalization in the Chick (of the domestic fowl)"; the doctoral thesis of Norman Allan, 1971:


the cheeping of a chick:
             an example of information and action
              emerging out of the nervous system
ccevoked.jpg (4539 bytes)

I first encounter the concept of non-linear oscillation
in the 1960s during research into the neural organization
of an expressive behaviour -
to wit, the cherpings of the chick.

         cctwitwit.jpg (1089 bytes) cctwitwit.jpg (1089 bytes)
for my sins I tortured baby chicks
to see what makes them tick
to see how they make their noises
I jolted their brains with electricity
and took them apart.
Physically, for the chick,

three things are involved in making a sound.

1 ~ it has to blow (expire forcefully) air
over a membrane which then vibrates.
this membrane is called the syrinx;
ccsyrinx4.gif (991 bytes)
2 ~ it has to maintain air-pressure
in the thoracic air-sac in which the syrinx sits.
It does this by opening and closing a valve; and
3 ~ it modulates the tension of the syrinx and hence
the pitch/tone of the called note
by the contraction on a pair of muscles
(the extrinsic syringeal muscles).

The chick has the following repertoire of calls:

If you startle it it trills
cctrill.jpg (2597 bytes)
if you grab it, it trills (because it's startled)
and then it "shrieks"and then it peeps.
cctrill.jpg (2597 bytes)ccshreek.jpg (3056 bytes)
If it is (happily) interested in something
it does calls an excited ascending tweet-tweet
cctwitwit.jpg (1089 bytes) cctwitwit.jpg (1089 bytes)
and if it is just tootleing along
it does another sort of twittering
cctwitter.jpg (1795 bytes)
if it is distressed it peeps
ccpepep.jpg (1788 bytes)
In its twittering
cctwitter.jpg (1795 bytes)        cctrill.jpg (2597 bytes)
we see that it is calling portions of its trill,
and we see that when it is happily interested
it calls the ascending portions of the trill,
cctwitwit.jpg (1089 bytes)cctwitter.jpg (1795 bytes) ccd.jpg (2004 bytes)
but when it is distressed it calls the descending portion.
To do this the oscillating motor out put to
the syringeal muscles and to the air-sac valve
must be more or less matched for frequency
but must vary/shift in phase.
There are occasions on which we can see
these two forms/signals manifest in the calls
            ccshift.jpg (2200 bytes)
It appears as if the air-valve.signal on occasion can
spill over into the syringeal muscle signal.
this spill over is quite regularly seen
in the excited tweet-tweet

cctwitwit.jpg (1089 bytes) cctwitwit.jpg (1089 bytes)
So a continuum from approach/interest/(pleasure?)
through to avoidance/distress
is manifest in the chicks calls
as a shift in relative phase
between the two cycles,
one driving the syringeal muscles
and another driving the air-valve.
cctrill.jpg (2597 bytes)   ccshreek.jpg (3056 bytes)
     ccevoked.jpg (4539 bytes)
We see a second continuum in the chick vocal repertoire.
When we evoke calls by electrically stimulating
a particular area of the brain
(the Call Motor Area of the Optic Tectum overlaps,
but is not confined to, the Lateral Mesencephalic Nucleus)

we get a series of calls that segregates into bouts
    ccevoked.jpg (4539 bytes)
                              (this is in the anaesthetised animal)
and we see the peep emerge
the same peep we see in the unhappy chick
cctrill.jpg (2597 bytes)ccshreek.jpg (3056 bytes)
       ccpepep.jpg (1788 bytes)    ccpepep.jpg (1788 bytes)  
so here we see breath and we see "quenching"
(as breath grows large the trill modulation is blown out)

the repertoire maps out in two dimensions
(plus a single step seen in the startle:trill)
y) force of expiration / exertion
x) approach / avoid,  pleasure / distress,  nice / nasty
z) rate of arousal
(the single step seen in the startle:trill)

ccmap2.jpg (3438 bytes)

when I brought my data, the sound graphs,
to the mathematician biologist Brian Goodwin
he said, "this looks like non-linear system."

Phase shifts: there aren't many central nervous system phase shifts
in the literature.  The only one I'm familiar with originates around
the same era as my chick call work, late 1960s:
Adey reports that when you are teaching a cat a task
during the learning a part of the hippocampus leads
(is phased in front of) activity in the adjacent cortex
but after the task is learned it lags.

Judgement: does approach / avoid,  pleasure / distress
imply, represent, reflect
a judgement?
Is judgement (here in our baby chick) manifest in a phase shift?
(Is judgement a  quality solely of mind?
don't machines make judgements and decisions?)

In approach (pleasure) we see a lifting, a rising tone
with avoidance, distress we see a falling, a descent

I am reminded of What's His Name, "the baby watcher",
who speaks of "energy envelopes" (sic)
and how these give a qualitive tone to an event
is it building, bursting, fading -
part of happening emotional tone come from its
temporal/energetic envelope

I'm also reminded of Madame Blavatsky.
In my doctoral thesis I ventured (in a footnote)
that the chick's repertoire smacked of Madame B.
and her good and bad vibrations

see: Norman Allan's doctoral dissertation
"The Central Control of Vocalization
in the chick of the Domestic Fowl."
Sussex University: 1971


Chapter 4: neural nets


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