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Significance of Input Correlations in Striatal Function

Figure 3

Signal representation in the striatum network when stimulated neurons received correlated inputs.

(A) Scheme of stimulus configuration-II (0; 0) presented to a fraction of striatum neurons, on top of the background excitatory input from the cortex and background inhibitory input from other striatal neurons. (B,C) Examples of MSNs spiking responses for two different stimuli to 30% of striatal neurons, with identical input firing rate ( = 400 Hz) and internal correlation ( = 0.02), but different shared correlations across stimulated neurons: low ( = 0.2; B) or high ( = 1.0; C), respectively. (D,E) Firing rate of the stimulated MSNs (D) and the unstimulated MSNs (E), averaged over the stimulation epoch, as a function of input correlation , for three different values of shared correlation . (F) Synchrony index of the stimulated MSNs (F) and the unstimulated MSNs (G) as a function of input correlation , for three different values of shared input correlation . Observe that the synchrony index of the stimulated MSNs increased both with increasing and increasing , due to the fact that larger led to more shared inputs among stimulated neurons, while larger resulted in more reliable spiking. In the unstimulated MSNs, (low values of did not influence synchrony, whereas high increased synchrony, due to the synchronized inhibition, induced by the synchronized spiking of the stimulated population. (H) Signal-to-noise ratio (SNR) of the striatum network as a function of both input correlation and shared correlation at = 0.3. Observe that maximal SNR was obtained for weakly correlated () input to individual striatal neurons and uncorrelated ( = 0) inputs to different striatal neurons. (I) Signal-to-noise ratio (SNR) of the striatum network as a function of both input correlation and stimulated fraction at = 0.2. Observe that maximal SNR was obtained for weakly correlated () input to a larger fraction of stimulated MSNs (larger ).

doi: https://doi.org/10.1371/journal.pcbi.1002254.g003