Each synaptic input was modeled as a time-varying conductance fit to an alpha function: with a time constant 5 ms and an amplitude determined by the excitatory input parameter of the model (ranging from 0.3 to 6 n8).

Our model consisted of three parameters: 1) IE delay the temporal delay between inhibitory and excitatory inputs, 2) I/ E ratio the ratio between the magnitude of inhibitory and excitatory inputs, and 3) Excitatory input the magnitude of the excitatory input .

8, vector strength and IPI synchronization limit were calculated for all simulated neurons with excitatory inputs between 3—6 nS.

3), when either a synchronized neuron’s inhibitory input was reduced or a non-synchronized neuron’s excitatory input was increased, the neural coding regime changed to a mixed response (i.e.

While for simulated neurons with the same excitatory input strength, the stimulus synchronization limit of synchronized neurons decreased as the I/E ratio increased (P<0.001, Spearman correlation coefficient), we did not observe a statistically significant trend between the stimulus synchronization limit and I/ E ratio in mixed response neurons (P>0.05, Spearman correlation coefficient).

4b) between the excitatory input strength and the Rayleigh statistic, the criterion we used to measure the statistical significance of stimulus-synchronization.

In contrast to this, non-synchronized neurons were more common when the net excitation was weak, which occurred for I/E ratios close to one (balanced excitation and inhibition) or low I/E ratios in combination with a weak excitatory input (Fig.

5b) between the net excitatory input (excitation-inhibition) and the discharge rate ratio.

Our model consisted of three parameters: 1) LE delay the temporal delay between inhibitory and excitatory inputs, 2) I/E ratio the ratio between the magnitude of inhibitory and excitatory inputs, and 3) Excitatory input the magnitude of the excitatory input (Fig.

Classification of neuron-type [non-sync (o), sync (X), mixed (+), atypical (square)] across two parameters ( Excitatory input and I/E ratio), with a fixed IE delay of (b) 0 ms and (c) 5 ms using a criterion of the maximum discharge rate to a pure tone being less than 20 spk/s.

where 7%,le and 7%,:sz denote the total cortical drive to the D1 and D2 MSNs, respectively and ACTX denotes the extra excitatory input to the D1 MSNs.

Hence, in this transitional region with small differences in the excitatory inputs to both MSN types (OHZ < ACTX < 2H2), it was possible to have higher firing rate for either of D1 or D2 MSNs, depending on the size of the cortical input drive (Fig 2A, dashed line and 2B, set of points marked by the oval).

Where ACTX is again the extra excitatory input given to D1 MSNs.

These inequalities imply that if the two MSN subpopulations receive the same amount of excitatory input , D2 MSNs will always have a higher firing rate.

Despite this evidence, current data are not sufficient to determine the exact strength and rate of excitatory inputs to D1 and D2 MSNs.

This requires more coincident excitatory inputs (i.e.

The rise times for the excitatory inputs Tm was set to be identical for all neurons.

In addition to excitatory input from the cortex, D1 and D2 MSNs received (self and mutual) recurrent inhibition as well as feedforward inhibition from the FSIs.