When the user clicks a structure and the Videodisc Controls window is open,
the Atlas program must determine which animations are appropriate for
illustrating that structure. This is done by searching a previously-loaded 
list of entries called a "videodisc map", which associates each structure
with one or more videodisc segments under appropriate titles.

The content of the file is a single two-level list containing the following:
((structure title start-frame stop-frame)<BR>
...
...
(structure title start-frame stop-frame))

The <start-frame> and <stop-frame> items are integer frame numbers enclosed
in quotes.  These specify the range of disc frames to be played when the user
selects one of the titles and clicks "PLAY". If a single frame is all that is
needed, the starting and stopping frame numbers should be made equal.

A specific example from the Human Brain Animations map:

   (("amygdala" "Dissections" "37284" "37379")
   ("amygdala" "Peel Surface" "552" "783")
   ("amygdala" "Translucent Cortex" "7491" "7853")
   ("amygdala" "With Ventricles" "32217" "32581")
   ("caudate nucleus" "Dissections" "37901" "38088")
   ("caudate nucleus" "Peel Surface" "1305" "1560"))

If this map were in use at a time when the user clicked a structure named
"amygdala", the Videodisc Controls window would display a list of 3 titles:
"Dissections", "Peel Surface", and "Translucent Cortex". Initially, the
first of these would be shown as the default animation in case the user
just clicked the "PLAY" button.


Historical note: it might seem unusual to impose a Lisp syntax onto a
data file format which is clearly not Lisp code. The source of the format
was a server in use with a previous version of the client which was built
to fetch this kind of data from a database over the network. The server
program was built in Lisp, and returned results in its convenient native
format which has continued to work well.