Table A1.

Summary of model variables and parameters.

Quantity	Description
x i (t)	Transient localization signal at time t after array onset to FEF visual neurons with RF centered on region i (Equation 2).
v i (t)	Level of activity for an FEF visual neuron with RF centered on region i at time t, reflecting the probability that the neuron will generate a spike in the next millisecond (Equation 3).
z i (t)	Level of activity for a identification unit centered on region i at time t (Equation 4).
m i (t)	Level of activity at time t for an FEF movement unit corresponding to a saccade targeted at region i (Equation 10).
${\tilde{v}}_i(t)$	Input signal at time t to an FEF movement unit corresponding to a saccade targeted at region i (Equation 15).
b	Baseline excitatory input to an FEF visual neuron.
ι	Total amount of excitation provided by the localization signal.
μ T	Maximum level of identification activity for a search target.
μ D	Maximum level of identification activity for a distractor.
s	Shape parameter of gamma distribution describing transient localization signal.
r	Rate parameter of gamma distribution describing transient localization signal.
λ v	Rate at which FEF visual neuron activity decays over time.
λ z	Rate at which identification unit activity decays over time.
χ i,A	Strength of localization signal in location i of search array A, which equals 1 if a stimulus is present at that location of that array and zero if not.
η i,A	Strength of match between search target and the object in region i of search array A, which may be MT if the object is a target, MD if it is a distractor, or zero if there is no object at location i of array A.
$ℝ$	Indicator variable reflecting whether the growth of identification unit activity is multiplicatively gated by FEF activity ($ℝ=1$) or not ($ℝ=0$).
α x	Strength of feedforward inhibition of FEF visual neurons due to localization.
α z	Strength of feedforward inhibition of FEF visual neurons due to identification.
β v	Strength of lateral inhibition between FEF visual neurons.
β z	Strength of lateral inhibition between identification units.
ρ v	Range parameter describing spatial extent of lateral inhibition between FEF visual neurons (in standard units where the search array has a radius of one unit; see Equation 5).
ρ z	Range parameter describing spatial extent of lateral inhibition between identification units (in standard units where the search array has a radius of one unit; see Equation 6).
κ	Relative delay in conveying identity information to FEF visual neurons.
L	Number of FEF visual spike trains used to generate input signals to FEF movement units.
ρ m	Strength of lateral inhibition between FEF movement units.
λ m	Rate at which FEF movement unit activity decays over time.
ρ m	Range parameter describing spatial extent of lateral inhibition between FEF movement units (in standard units where the search array has a radius of one unit; see Equation 11).
g	“Gate” representing the minimum input activity needed to excite an FEF movement unit.
V	Standard deviation of momentary Gaussian noise in FEF movement units.
θ	Threshold level of activity at which an FEF movement unit initiates a saccade.