Brain maps

Brain mapping is heralded as a promising dimension of contemporary neuroscience. It offers to provide a basis for understanding how the brain functions; how organic brain damage or disease can affect brain and behaviours. It can also offer a perspective on neural correlates of consciousness, and so provide a voice in discussions over the very nature of the mind in nature. It is important, given this potential, to understand what brain mapping can’t readily do, or at least some of the risks of overconfidence in it. A good starting point is the metaphor of ‘map’ in the first place.

Reading into maps

Maps have come to be considered as scientific instruments for representing physical geographies in objective ways. This has been so since at least the scientific revolution of the C17th, through the enlightenment, to today. The emphasis in this paradigm is upon surveying the land and accurately recording it, where ‘accuracy’ refers to mathematical notions of precision and relation. This slant in cartography is fascinating and ingenious. It’s also very useful when one wants to get from A to B. But there is a hidden story in mapping, and there are tacit metaphors and values within it:
In the map itself, social structures are often disguised beneath an abstract, instrumental space, or incarcerated in the coordinates of computer mapping. And in the technical literature of cartography they are also ignored, notwithstanding the fact that they may be as important as surveying, compilation, or design in producing the statements that cartography makes about the world and its landscapes. Such an interplay of social and technical rules is a universal feature of cartographic knowledge. In maps it produces the “order” of its features and the “hierarchies of its practices.”
Harley, J. B., Deconstructing the Map in Cartographica, v. 26, n. 2 (Spring 1989), 1-20

The notion here is that a visual representation precisely (in a mathematical sense) mirroring a scene, looked at in a peculiar way, produces a good map. Maps can be isomorphic with the territory they represent, and in this sense be good maps. But, as is well known, the map is not the territory [1]. The idea of survey as source obscures the peculiar kind of looking that that discipline takes on; mathematical accuracy is just one kind available; the objective nature of the truthfulness of the map is a chosen ideal, not a given. So much for what the map shows, but what does this say? [2]

The cartographers are talking about their maps and not landscapes. That is why what they say frequently becomes so paradoxical when translated into ordinary language. When they forget the difference between map and landscape—and when they permit or persuade us to forget that difference—all sorts of liabilities ensue.
Theodore Roszak, Where the Wasteland Ends: Politics and Transcendence in Postindustrial Society. New York: Doubleday, 1972, 410

Liabilities include at least the normalisation of the strange ways of seeing that cartography requires, and the marginalisation of other ways of seeing (even though they may be valuable); the steering of activities onto a presumed path-dependency that is nevertheless contingent. It’s very easy to get mired in a contingent and embedded social vision, brought with the very presence of the map.

This can be important politically, culturally, and in terms of travelling, where maps of the territory are in play. If we think about maps of the brain, and the promises they bring, maybe the stakes are as high or higher: where we want to make discoveries about the mind’s place in nature, we want to be sure our maps are accurate in the right ways.

‘Right’ in the right ways

We don’t learn more from the mathematically precise map than we do from another type. There isn’t an objective scale of knowledge that we ascend upon reading the precise map. We get different things from different maps. Any map is as much an expression of an embedded social vision as is another, be it an artistic, technical, consumer, or cultural artefact. The danger is the liability to conflate this or that expression as closer to truth; to imagine a group or a discipline has the rights ‘to inspecting, repairing, and polishing the mirror of nature’ that is the mind (Rorty, R., Philosophy and the Mirror of Nature, ch. 8).

europa_polyglotta
Europa Polyglotta: Is this a good map?

The map represents more than the area it depicts, however precisely it does that. It is an icon of the land, just as a diagram of a circuit is its icon. In this case, the diagrammatic similarity is where the meaningfulness of the icon comes from.  Following Hume’s terminology, this relation can be called ‘resemblance’. But resemblance between the map and the mapped is itself contingent.

We know that maps exist that don’t want or try to be mathematically precise. The London tube map, presented in the header image above, is one famous example. Its meaningfulness doesn’t come from the visual similarity between the map and the mapped, but through presenting the continuities of the rail system’s internal relations. This relation can be called ‘contiguity’, again from Hume. That’s what matters when you need to decide how to get to Mornington Crescent.

We have at least these two possible ways for maps to have meaning, and these have appeared following a general reflection on mapping. What does this mean for the enterprise of brain mapping?

Go left at the hippocampus

What kind of a map is a brain map? Is it an icon that resembles its source? Is it a symbol with a contiguous relation? How we approach these questions will serve to feed reflection on what we ought to learn from brain maps, and from the venture of brain mapping as a whole. This nature video suggests some of this complexity, but still takes mathematical precision and resemblance as an overarching value. It appears that new maps of the brain are presented in terms of the resemblance model. The boons from this clarity are hoped to be great:

The 97 [previously un-mapped] sections (per hemisphere) that were previously not known will allow scientists to delve much deeper into the brain’s functions. The new map can help surgeons and lead to cures for diseases like Alzheimer’s and autism as well a fresh understanding of how our most important organ develops and ages.

Stunning New Map of the Brain Shakes Up Neuroscience

Nevertheless, the critique of cartography that asks for reflection upon the cultural and societal content of maps comes into play here too. The forgetting of valuable difference, the obscuring of these methods as very strange ways of seeing; these risk prompting us to hand over the rights to the polishing of the mirror.

The brain map, in coming from sophisticated imaging sources, is certainly an icon resembling its source. But it also harbours ambitions about function, and the proper function, of the territory it represents. In this, there is something like the contiguity of the tube map. It is an icon, resembling its source, with contiguity as an animating ideal. This makes it a moving target, in terms of how we ought to assess it.

Imagine we had a map of the London tube that could somehow morph between an icon based in resemblance, and an artefact animated by contiguity. The luck we might have in our travels would be out of our hands, in this case. If it happened to show a resemblance image today, we might see it’s better to walk from Covent Garden to Leicester Square, for example. But in the same mode, we’d not know that the Piccadilly Line was faster, going west from central London, than the District.

Likewise, if it flipped into contiguity mode we might think walking from South Kensington to Knightsbridge would be similar to walking from Knightsbridge to High Street Kensington, being similarly spaced on this kind of map. But the former journey is more than twice as long as the latter.

And anyway there is the question of what kind of journey we’re trying to have: speed isn’t always the master motivator for a journey. Here, the point is that there are more decisions about the trip than are provided for simply by having the map. Decisions, values, ideals colour the use and assessment of the map in brain science as much as they do in travel.

Are we sure that mapping brain regions with the same rationale as the Ordnance Survey is the most valuable way to approach ‘diseases like Alzheimer’s and autism’? A beautiful picture, a dynamic image accurate to the nanoscale, isomorphic to the brain region it represents; this will correlate well with the changing state of a brain region over time. Does this mean it correlates with disease? Such a hope would mean that disease was reducible to organic dysfunction, and was discoverable by a particular way of seeing.

neurons
Neurons: Is this a good map? [3]

The internal relations among parts would seem as important here, that is, the contiguity relation between map and mapped. But then we know that there are dimensions of illness that are socially constructed, and so this contiguity would somehow anyway have to extend to relations beyond the skull.

To begin diagnosing disease on the basis of dysfunction relative to the map, is no small move. Dysfunction in terms of a breakdown in resemblance with the map, or contiguity among all the relevant elements, becomes a seriously complicated proposition. The description above of autism as a disease, for example, will likely sound odd to many. That is surely a socio-political claim, as much as one of brain science.

Getting a brain map right in the right ways for representing the organ, understanding its functions, diagnosing its problems is a very valuable aim. Getting a brain map right in the wrong ways to diagnose disease, to conceptualise consciousness, to advance self-understanding is a serious risk.

What’s missing from a brain map, as many other maps, is the meaning of what is mapped. The interpretation is not in the map, and the map does not present its contents neutrally. Most generally, the idea of scientific ways of seeing as good ways of seeing is as present here as in the cartographic ideal of isomorphism with the land.

The clarity presented in detail can obscure the epistemological content of the map. Luis Borges captures this well in his (very) short story On Exactitude in Science. It is as if the scientific image has as its ideal a 1:1 recreation of its source — this would be a good brain map. But what it meant would remain obscure. Neuroscience might end up discussing and treating disorders of the map, rather than remembering a brain is represented there.

We might not need go as far as Lewis Carroll’s Sylvie and Bruno, who decide to “…use the country itself, as its own map, … I assure you it does nearly as well.” But it’s very likely worth treating polishing the mirror as a group activity.

[1] Alfred Korzybski, Science and Sanity: An Introduction to Non-Aristotelian Systems and General Semantics, 3rd ed. with new pref. Lakeville, Connecticut: The International Non-Aristotelian Pub. Co., 1948: 58, 247, 498, 750-51

[2] It would be interesting to pursue a Wittgensteinian reading of maps, following the Tractatus, especially with respect to, “4.115 [philosophy] will signify what cannot be said, by presenting clearly what can be said.”

[3] From Plebe, A., De La Cruz, V. M., Neurosemantics
Neural Processes and the Construction of Linguistic Meaning, Springer, 2016, p.30

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