Question about serdes receiver

Hi,
I have difficulties at understanding a part of serdes receiver. Please see the attached picture.

1. What is the function of that part labeled INA? It looks like an instrument amplifier. I remember that it amplifies the difference between its input. Then, its two output pins should be a pair of amplified difference signals. What is the wire labeled as FB above? It shows only one wire. It is the same as the INA OUT? I don't connect INA with the text description on the LPF, HPF feedback to compensate for the respective components yet.

2. The input LPF1 and HPF2 are separate two branches. I do not see the function and necessity of the separation. LPF1 and LPF2 should be the same frequency range? The same applies to LPF2 and HPF2?

Please explain it to me if you know that.

Thanks