Do you have two of those super-deluxe probe things? Maybe you could redo the experiment with more precision than any of the rest of us.
My guess is that if warm pitching initially the edge would be cooler and the core warmer. As the yeast get going there won't be any difference. As the yeast slow down the core will lag slightly behind the edge.
Although it would be academically interesting, I suspect the yeast don't care *that* much.

