How do mammals estimate the speed of moving objects? Has there been any research on how mammals predict the speed of moving objects? In particular, how do they integrate top-down information? For instance, do they have greater difficulty estimating the speed of a fast-moving sloth more than a moving mouse?
@AliceD gave a great answer on the bottom up pathway. Let me add some top-down processing bits into the picture, since that's what you are asking.

First of all, at a perceptual level, motion perception is biased by prior expectations and strength of motion signal. E.g., see:


Stocker, A. A. and Simoncelli, E. P. (2006). Noise characteristics and prior expectations in human visual speed perception. Nature Neuroscience, 9(4):578-585. http://dx.doi.org/10.1038/nn1669


The neural activity of MT (and behavior) is known to be modulated by attention. E.g., see:


Monkey Area MT Latencies to Speed Changes Depend on Attention and Correlate with Behavioral Reaction Times. Neuron. 78(4):740–750. http://doi.org/10.1016/j.neuron.2013.03.014