Brain Maps, Icons & Indices

There are certain things we take for granted about science, that paradigm of objectivity. For one, there's its objectivity; that science is not objective seems a vague and fundamental contention whose proof seems as obvious and elusive as the horizon. There's another thing we take for granted: that models mirror the causal structure they depict. It's easy to forget that images generated by apparatuses such as MRI and electron microscopy are still essentially maps, and it's easy to construe the image with the thing generating the image--a tool that's the product of another tool (the scientific method) that's the product of The Human Brain, a popular subject of so many models and images.

First a few concessions: these images are for teaching and learning; the people who drew the amygdala in early issues of Brain knew very well that it wasn't perfectly congruent with the original. It was The Amygdala, a representation, not an amygdala functioning as part of a system filled with idiosyncracies and undocumentable anomalies. Really someone just wanted to convey the idea of the amygdala, enough said.



But these icons can become a little more connected to the real thing: they can become indeces. Comparing a representation of the brain to an actual brain, certain variations become noticeable. A representation that records this variation is an index: basically, a repository for information storage and retrieval. Now the diagram is a little more implicated in the system it represents.

There are other examples of images that are both icon and index: for instance, a map drawn by someone who, nevermind the circumstances, is quite without significant parts of his left brain. For this person, the map is an icon--it's a familiar, sorta gestalt representation suggestive of the represented (the actual content of which is often not experienced, or not able to be experienced, entirely and simultaneously). So, working from a map, this person draws, say, the U.S's West Coast, sees that he's copied what the map shows, and calls it complete. For a psychologist, this map isn't an icon, but an index of the guy's brain injury. The guy was his own diagnostic tool. The diagram is an important part of the system at work in this guy's brain.

To be continued...