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. 2021 May 5;109(9):1567–1581.e12. doi: 10.1016/j.neuron.2021.03.009
Parameters of the M1 circuit model
symbol value unit description
NE 160 - number of E units
NI 40 - number of I units
τ 150 ms time constant of M1 dynamics
τrise 50 ms rise time constant of h(t)
τdecay 500 ms decay time constant of h(t)
A implicit - set so that h(t) has a maximum of 5

Parameters of the arm mechanics and hand trajectories

symbol value unit description
L1 30 cm length of upper arm link
L2 33 cm length of lower arm link
M1 1.4 kg mass of upper arm link
M2 1.0 kg mass of lower arm link
D2 16 cm center of mass of lower link, away from elbow
I1 0.025 kg m-2 moment of inertia of upper link
I2 0.045 kg m-2 moment of inertia of lower link
θ1init 10. deg. value of θ1 at rest
θ2init 143.54 deg. value of θ2 at rest
θreach(i) 36×(i2) deg. reach angles (i=1,,8)
dreach 20 cm reach distance
τreach 120 ms time constant of reach velocity profile

Parameters of the LQR algorithm

symbol value unit description
λ 0.1 - input energy penalty in Equation 30

Parameters of the thalamo-cortical circuit model

symbol value unit description
λ 0.01 - input energy penalty in Equation 30
p 0.2 - density of random connections from M1 to thalamus
ME 100 - number of E units in M1 L4
MI 100 - number of I units in M1 L4
τy 10 ms neuronal time constant in thalamus
τz 10 ms neuronal time constant in M1 L4

Parameters of the photoinhibition model

symbol value unit description
Nph 100 - number of M1 I units perturbed (60%)
hph 3 - input to perturbed I units during photoinhibition
Tph 400 ms duration of photoinhibition