Posted on August 9, 2011 at 8:42 PM
The employment of basic neuroscientific research (what are known in government parlance as “6.1 Level” studies) in translational development (so-called “6.2 Level” work) and test and evaluation applications (“6.3 Level” uses) is not always a straightforward sequence of events. There are some well-done and very interesting basic neuroscientific findings that sniff of translational and applied utility, and recent demonstration that rats do not have neurological mechanism to allow finely tuned vertical orientation may be an example of such a study. Recent research by Robin Hayman, Madeleine Verriotis, Aleksandar Jovalekie, Andre Fenton, and Kathryn Jeffery, (Anisotropic encoding of three-dimensional space by place cells and grid cells) suggests that the rat brain does not process vertical-space information as efficiently or adeptly as horizontal and lateral field information, and this may have a number of implications – both for an understanding of brain-environmental interactions, and for future research.
At face value, there are a number of important big-picture “take-home” messages that can be gleaned from this study’s findings. The first is that brains are embodied in organisms that are embedded in environments (a phrase that I’m rather fond of using). The second is that this is probably a reciprocal interaction – brains may be structured to optimize function in a particular environment or set of environmental niches, and the niches in which an organism lives may strongly contribute to the ways that its brain structure and function(s) develop. The third, while seemingly a blinding flash of the obvious, is often a tripping point when interpreting or trying to speculate on the meaning of such studies’ results – namely, not all species live in the same environments, and not all brains are structured and function the same ways (both between species, and even within individual organisms and groups of organisms within a species). And finally, and perhaps, the most important of these “take-home” messages is that it’s not wise to try to directly “connect the dots” between both basic research and translational applications, and between model species and target species. Hyman, Verriotis et al. do a fine job of presenting their methods and results, and keeping the implications of, and inferences based upon these outcomes in appropriate scope, scale and contexts, and it’s perfectly OK (and, in fact, expected) to make inferences that support the need for additional more-applied research, or to address and compensate for differences between the model and the target species (what is sometimes referred to as “the extrapolators’ dilemma”).
But things get all gummed-up when research outcomes are taken out of context and used to make big jumps from premise to conclusions across broad expanses of methodological and phylogenetic real estate. Thus, in the case of rats’ neurological capacities for vertical orientation, in order to draw meaningful conclusions that are more broadly applicable, it would be necessary to conduct similar studies to assess the neural mechanisms for, and sensitivities to horizontal versus vertical orientation in other species, say, for the most obvious example, birds, or if you’d prefer to stick to mammals, squirrels, bats, arboreal and non-arboreal primates, and even, humans (ideally, not using invasive means, although using neuroimaging then raises a host of questions about actual utility and limitations of such methods).
In other words, without some type of human studies in particular, it’s difficult if not frankly problematic to infer what these results (using the rat model) mean for applications in “real-world” human scenarios. For example, I’ve seen some “spin” that the Hayman et al findings of rats’ horizontal sensitivity could be used to explain pilot disorientation and by extension, cases of pilot error and aviation mishaps). I’ve got a problem with this. In a “previous life,” I was an Aerospace Physiologist and Aviation Safety Investigator, and I’m aware of a large body of evidence to support that most cases of pilot disorientation are due to either (1) loss of situational awareness, (2) distraction, or (3) some form of spatial/sensory uncoupling and/or vertigo. Could movement in the vertical plane be contributory to this? Of Course. Is it possible that human brains do not efficiently process vertical orientation? Sure. Do we directly know this from the work of Hayman et al.? No. In some ways, that might be tantamount to claiming, “human pilot disorientation is due to rats’ diminished neurological sensitivity to vertical space.”
Rats have been, and may continue to be, a fine model for human neural function (although there is an issue here that relates back to what we do with the knowledge we gain relative to our regard for, and treatment of the model itself – I’ll be writing more about this in my forthcoming blog). True, both rats and humans are terrestrial animals and this may confer some similarities in the ways that ground-dwelling has affected neural evolution, development and capacities. But humans and rats do not have an identical evolutionary history, nor do we occupy the same environments in the same ways. Simply put, while our brains are similar to those of rats in many ways, we are not rats. So, while rats are wonderful, sophisticated creatures, humans are sophisticated in myriad other ways, and an understanding of the rat’s neural mechanisms should not be used to try to explain human cognitions and actions (and here I might add that it would be equally prudent to be cautious in drawing reductive conclusions about the basis of human cognition and actions from studies of human brains!).
It may very well be that the results of the study by Hayman and co-workers hold true for squirrels, bats, apes and humans (including aviators and non-aviators), but until we conduct such studies and know that for sure, it is important not to take findings about neural mechanisms of vertical orientation in the rat to a higher level than they were intended, or are applicable. Sure, it’s tempting to speculate upon what findings about rats’ neurological orientation to vertical space could mean for primates in a tree or humans bringing a 757 into LaGuardia. But, while I hate to pop anyone’s bubble, it really just means that rats don’t have a strong neurological orientation to vertical space. That’s it; that’s what Hayman et al. have shown, and that’s important, as it provides an understanding of the rat’s nervous system, and lays the groundwork for some exciting future studies. Models and findings that establish and fortify premises, and open possibilities for ongoing research with basic, translational and applied potential are valuable and useful. Making misappropriated comparisons and ampliative conclusions are not – particularly when such conclusions over-simplify the complexities of human cognition and behavior, and their social, legal and ethical consequences.
As neuroscientists, there’s a risk we run whenever our research findings are let out of the ivory tower and into the public sphere, and sometimes that’s hard to control. The very technology that allows me to publish my work in open access journals, and even shoot this blog across the ether of the Internet certainly plays a role in that, as information from the lab gets picked up, used and interpreted by a variety of sources. I’ve rallied against neurolalia, and Ray Tallis’ new book, The Aping of Man, Neuromania, Darwinitis, and the Misrepresentation of Humanity is equally strong in its condemnation of inapt neuromania, and I applaud Dr. Tallis in his call for more stringent consideration and use of neuroscientific studies, tools, and information. Indeed, there’s great power in such information – and with this power comes an increasing responsibility to shepherd it appropriately and wisely, lest we fall victim to Icarus’ folly of hubris and self-deceit: to fly too high on wings of weak evidence and misinformation that melt under the light and heat of scrutiny.