Relating Monosynaptic and Functional Connectivity - Complementary Perspectives on Neural Computation -

Information processing in the brain is thought to result from the coordination of large-scale neuronal activity, but this occurs on a fine neural circuit. Here, we investigate their relationship. First, we estimate monosynaptic connectivity by applying an advanced analysis method to spike trains recorded with high-density microelectrodes and confirm that the estimated neuronal wiring is largely consistent with neuroanatomical and neurophysiological evidence. Second, we simulate calcium imaging signals from the same dataset and confirm that the estimated functional connectivity is influenced by shared inputs and population synchronization on slower timescales. Notably, even with unrealistically fast calcium dynamics, the functional connectivity is only partially consistent with the monosynaptic connectivity. These findings suggest the complementary roles for monosynaptic and functional connectivity: the former provides circuit-level specificity, while the latter reflects emergent system-wide patterns of activity. We propose that an integrative approach combining both perspectives is essential for understanding circuit-level computation in the brain.