Without going for total golf (tempting, but I can resist) I'd still write something like:

my $n = 8;
my $i = 1;
my @array;
push @array, $n--, $i++, $i++, $n-- while $n > $i;
print "@array";
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This breaks the rule of not increasing/decreasing the same variable twice in the same statement, but in practise this will work in all versions of perl5. Notice that in fact it wouldn't work if pre-increment/pre-decrement had been used instead of post-increment/post-decrement