So let me talk about QAR (the Quasi-Penultimate Accent Rule) of Mid IE. I deduced based on the wandering accent seen in many of IE's nominal and verbal paradigms that Mid IE, the stage of PIE that I position before the event of Syncope (the loss of most unstressed vowels), must have had a regular accent placed mostly on the penultimate syllable (i.e. second-from-last syllable) of words. In a few instances however, the accent was antepenultimate (i.e. third-from-last syllable) but interestingly these exceptions seem to always show up like clockwork when a postclitic has been attached. These postclitics are things like *-sa, the nominative case ending derived from *sa "the" (> PIE *so); and *-ta, attached to the 3ps ending and derived from *ta "that" (> PIE *to-). I deduce that they've been attached within the Mid IE period (6000 to 5000 BCE), which means that before these additions Old IE had a perfectly regular accent on the penultimate syllable.
Proterodynamic and hysterodynamic are terms used to describe how the accent behaves in nouns when they're declined with case suffixes. In proterodynamic nouns, the accent wanders between the root and the suffix of the noun stem. In hysterodynamic nouns, the accent wanders between the suffix and the case ending. More basically however, we can just combine the patterns together and state simply that their accent shifts between one syllable and the immediately following syllable. I realized a long time ago now that these two paradigms must have once been one and the same paradigm and that they were the result of a loss of unaccented final vowels (Syncope) and the underlying penultimate accent before Syncope which obscured their relationship and the nature of the wandering accent.
But maybe none of this is sinking in as long as I talk all this linguistics babble so I'll illustrate what I'm talking about with a few paradigms of PIE nouns which exhibit typical alternations in the stem between fullgrade and zerograde because of an alternating accent, thereby showing you my thoughts on their earlier case forms:
"the dog" (subject)
"the dog" (object)
"of the dog"
"at, by the dog"
"the tree" (subject)
"of the tree"
"at, by the tree"
"the grandson" (subject)
"the grandson" (object)
"of the grandson"
"at, by the grandson"
"the water" (subject)
"of the water"
"at, by, in the water"
It's almost inevitable that there will be some changes that may seem irregular here. They're caused either by analogical leveling (i.e. the spread of a particular form or feature across a paradigm) or by sound changes that I've added to my QAR or Syncope rules. For example, some may be curious why the nominative ending *-s disappears in the paradigm for *kwon- "dog" but this omission happens after many PIE nouns whose stems end in resonants (*l, *r, *m, *n). A characteristic lengthening of the preceding vowel is the sign of a missing case ending that once was there (e.g. *ph₂tḗr "father" < *ph₂térs, *dʰǵʰōm "earth, ground" < *dʰǵʰoms). In my theory, I place this loss of the nominative ending of these nouns at the end of the Late IE period (around 4500-4000 BCE).
 Fortson, Indo-European Language and Culture: An Introduction (2004), pp.107-108 (see link). Proterodynamic and hysterodynamic are also known as proterokinetic and hysterokinetic.
 Fortson, Indo-European Language and Culture: An Introduction (2004), p.104 (see link).
(Jan 25 2008) I forgot the palatal diacritic on the *k of *ḱwon- "dog" and so I changed that and also added the Lindeman variant with intervening *-u- in the nominative. While I don't personally believe that Indo-European had palatal consonants at all and that they should be reinterpreted as plain stops, I am respecting traditional convention here to minimize confusion of readers who will be more familiar with the standard notation.