Spike Correlations in a Songbird Agree with a Simple Markov Population Model
Figure 5
Burst Epochs and Pairwise Correlations
(A) Instantaneous firing rates of a recorded HVCI neuron (top), a simulated HVCI neuron without burst epochs (middle), and a simulated HVCI neuron with burst epochs (bottom). Burst epochs are indicated by arrows.
(B) A sample raster plot of a simultaneously recorded HVCRA–HVCI pair (top) and a comparable plot from model simulations (bottom). The inclusion of burst epochs gives rise to rows with very sparse HVCI bursting (top arrow) and rows with dense HVCI bursting (bottom arrow), as is seen in real data.
(C–F) Average CSP functions in different neuron types. The functions are plotted in reference to a spike in the first pair, i.e., with respect to RA spikes in (D) and with respect to HVCRA spikes in (E).
(C) RA–RA neuron pairs (from n = 29 recorded pairs). p = 6/7, and q = 39/40.
(D) RA–HVCI pairs (n = 50 pairs). The arrow indicates an asymmetry that is reproduced by the model. p = 9/11, and q = 49/50.
(E) HVCRA–HVCI (n = 26). p = 7/8, and q = 59/60.
(F) HVCI–HVCI pairs (n = 19). HVCI neurons randomly link to 56 of the 100 HVCRA groups. p = 7/8, and q = 32/33.
In (C–F) LI = 50, pI = 0.63, DR = 240 ms, pR = 0.92, and LR = 13.