Visualizing visual areas: two ways to do it
April 3, 2014
We hosted a micro-conference today about mouse visual areas and how to understand them. It is an exciting time to be thinking about this because recent tools make it possible to visualize lots of visual areas at the same time: for example, using intrinsic optical imaging and the right stimulus, you can identify, in an awake animal, multiple visual areas and use this information to tell you where to place your electrode or where to point your microscope. A more traditional way of figuring that out is to go by the published coordinates that define an area, sometimes garnered by cytoarchitecture or inputs. The problem with this traditional approach is that there can be variability across animals; being able to pinpoint an area in the unique brain of an individual animal is a huge advantage. We wanted to take the classic literature, which often defines areas based on thalamic input, with the emerging literature, defining areas based on functional responses. And most of all, we wanted to get in register the literature about the posterior parietal cortex and the literature about secondary visual areas.
The functional approach generates beautiful maps that clearly show the existence of multiple areas (see figure above; it’s from a recent paper by Manavu Tohmi in Current Biology). The basic functional properties of these areas are beginning to be defined, but much is still mysterious about how they relate to primate visual areas, and how they guide behavior.
We were happy to be joined by two colleagues from Columbia: Mehdi Sanayei and Naomi Odean, both from Mike Shadlen’s lab. Like us, they are interested in thinking not just about the flow of information through cortical areas, but also in understanding the role of subcortical structures, especially the thalamus.