  In this paper, we present a multi--layer, activity--dependent model for the
joint development of ocular dominance (OD) columns and cytochrome oxidase (CO)
blobs in primate primary visual cortex (V1). For simplicity, we focus on layers
4C and 2/3 with both layers receiving direct thalamic inputs and layer 4C
sending vertical projections to layer 2/3. Both the thalamic and the vertical
connections are taken to be modifiable by activity. Using a correlation--based
Hebbian learning rule with subtractive normalization, we show how the formation
of an OD map in layer 4C is inherited by layer 2/3 via the vertical
projections. Competition between these feedforward projections and the direct
thalamic input to layer 2/3 then results in the formation of CO blobs
superimposed upon the ocular dominance map. The spacing of the OD columns is
determined by the spatial profile of the intralaminar connections within layer
4, while the spacing of CO blobs depends both on the width of the OD columns
inherited from layer 4 and the spatial distribution of intralaminar connections
within the superficial layer. The resulting CO blob distribution is shown to be
consistent with experimental data. In addition, we numerically simulate
monocular deprivation and find that while the CO blob distribution is
unaltered, the OD pattern undergoes modification. The OD stripes of the
deprived eye narrow, whereas the OD stripes for the remaining open eye widen.
