Emacs-like <up> and <down> key behaviour in index

[Neil Woods]

Is there a way to emulate Emacs's behaviour with the <up> and <down> keys in
the Index? E.g. pressing the <down> key moves the menu selection down until it 
reaches the bottom, then on the next <down> key-press the menu selection moves 
to the centre of the index. And the same in reverse for the <up> key.

Is there any key binding, variable or macro available which could enable
this behaviour?

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|   Neil Woods   |  Computational linguist & OpenBSD sysadm  |  C/C++/Lisp   |
| echo '[q]sa[ln0=aln256%Pln256/snlbx]sb12247225403800449909543746snlbxq'|dc |
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