Dunno about credible, but here’s one rat study with a lot of citations, and I think it’s where I first read about it: http://jneurosci.org/content/25/38/8593.fu

Dunno about credible, but here’s one rat study with a lot of citations, and I think it’s where I first read about it: http://jneurosci.org/content/25/38/8593.full http://jneurosci.org/content/25/38/8593.full