求翻译，以及如何理解红字部分？

We also attempt to draw a more unifying picture of how, when, and where canonical signaling pathways crosstalk to facilitate a dynamic modulation of neurogenesis. Signal convergence may occur at several levels within, and in close proximity to, the signal-receiving cell. The surrounding niche provides the environment for a first level of signal integration. Here, local or temporal morphogen gradients could have opposing or cumulative effects on the signaling outcome.