Lots more to say :), but
@alxecker's work on this as well as that of
@cris_niell as wel. We have also been working on this recently to resolve foveal V1 (more there). Our earlier work suggests high-res tracking is also necessary outside of fovea too:
jneurosci.org/content/36/23/…
ALT from McFarland et al (2014): RF sizes can be small in parafovea too