Existence and Control of Go/No-Go Decision Transition Threshold in the Striatum
Fig 7
Effect of Dopamine and GPe firing rates on the balance of D1 and D2 activity.
(A) Mean firing rates of D1 MSNs and D2 MSNs populations plotted for different levels of dopamine. Darker shades of blue (red) correspond to D1 (D2) MSN activity for higher levels of dopamine. For lower than normal levels of dopamine, the DTT shifts to the left (from ≈ 19 Hz to ≈ 9 Hz). This decreases the regime with a bias towards D1 MSNs. For higher than normal levels of dopamine, the DTT shifts to right (from ≈ 19 to ≈ 27Hz). This, in turns, increases the regime with a bias towards D1 MSNs. (B) Effect of GPe firing rates on the DTT. Solid lines refer to the normal state of the striatum. GPe inhibits the fast spiking interneurons, shifting the DTT to the right (from ≈ 9 to ≈ 14Hz) (dotted lines). Therefore, the regime with a D2 bias (10 < λCTX < 14, D2 solid red line) now has a bias towards D1 MSNs (blue dashed line) (C) In dopamine depleted conditions, inhibition of fast spiking interneurons via GPe is not able to switch the bias from D2 MSNs to D1 MSNs (compare dashed red and dashed blue lines).