On Constructing a Reality - Understanding Understanding: Essays on Cybernetics and Cognition - page 222

FIGURE 14.
that they touch; and in this way drawing the little thread, c, that you see to be
attached at base of toes and on the nerve, at the same instant they open the entrance
of the pore, d,e, at which this little thread terminates, just as by pulling one end of
a cord, at the same time one causes the bell to sound that hangs at the other end.
Now the entrance of the pore or little conduit, d,e, being thus opened, the animal
spirits of the cavity F, enter within and are carried by it, partly into the muscles that
serve to withdraw this foot from the fire, partly into those that serve to turn the eyes
and the head to look at it, and partly into those that serve to advance the hands and
to bend the whole body to protect it.
Note, however, that some behaviorists of today still cling to the same
view, 8 with one difference only, namely, that in the meantime Descartes'
“animal spirit” has gone into oblivion.
Computation
The retina of vertebrates, with its associated nervous tissue, is a typical case
of neural computation. Figure 15 is a schematic representation of a mam-
malian retina and its postretinal network. The layer labeled 1 represents
the array of rods and cones, and layer 2 the bodies and nuclei of these cells.
Layer 3 identifies the general region where the axons of the receptors
synapse with the dendritic ramifications of the “bipolar cells” (4) which, in
turn, synapse in layer 5 with the dendrites of the ganglion cells” (6), whose