Why Are You Anonymous?

[Annotation in BOLD were made following comments on twitter, and below]

Many tweeters and bloggers are anonymous. [Several people have pointed out that what I really mean is pseudonymous, e.g., Acclimatrix below. This is correct! And I am not talking about, e.g., anonymous manuscript review.] An exchange today (18 November 2013) on twitter between @vinwalsh (who is Professor Vincent Walsh, UCL), and @neurobollocks (who is, erm, neurobollocks), regarding the appropriateness (or not) of anonymity, prompted me to write my 2 pence about the subject.

This is because I started thinking about this issue when one anonymous tweeter – whose tweets I admire – let out enough information for me to know that they were in my circle of friends – so they know me, and who I am on internet and in real life. But I cannot know who they are. Furthermore, they were planning to be at (at least) two parties/socials at the Society for Neuroscience conference, where I was planning to be — yet I didn’t know who they were! I guess felt a bit frustrated, or at the very least, that it was a lost opportunity.

The feeling was compounded when I went to the #SFNbanter party, and the first thing that happened was someone told me to take my name badge off. So, no real-name badges allowed, and no badges with twitter handles either. In other words, it was very difficult to meet any of the people who I know on twitter – anonymous or otherwise. [But importantly, it turns out there was actually NO official no-badge policy at #SFNbanter! And I want it to be clear: I did meet some people, and had great time.]

So I did what I always do when I have a question about the internet: I talked to Baxter (that’s Professor Mark Baxter, Mount Sinai, @markgbaxter). Profs like me, Baxter (and, I am guessing, Vince) are at a point where we care a lot less than we used to about what people think of us. It is one of the great joys of getting older. We’re at a stage at which we can afford to say what we think (well, more or less).

But undergrads, PhD students, even post-docs, are battling fierce competition for their next position every few years. They can’t afford to make enemies. So I can see why they might feel the need to be anonymous, in order to be healthily sceptical and constructively critical, as every scientist should be … but with (relative) impunity.

The downside to that approach, however, is this: I’ve encountered young (I presume) tweeters/bloggers in my area whose thoughts, writing and attitude impress me greatly. If I had a position going, or knew of someone with such a position going, I’d contact them/ recommend them immediately. Problem is … they’re anonymous. Another missed opportunity.

So in a way, with anonymity, something is definitely lost. I don’t have a wide-ranging solution for this problem, of course. And I can’t change people; all I can do is ask what I might be able to do differently. What I come up with is probably pie-in-the-sky, but maybe what us PIs need to do is work on our egos such that we don’t make it personal, and hold grudges, when someone merely disagrees with us. As long as they’re not rude about it. Then maybe young people won’t be so scared to be themselves.

I did say it was pie-in-the-sky.

So to summarise, I guess I understand why a young scientist might feel the need to be anonymous.

But, if you’re a Prof using a pseudonym – dude, sort yourself out. [By this I meant ‘Prof’ as it is used in the U.K., to mean the final career stage (i.e., not N.A. Assistant or Associate Prof). So this a mild jokey-poke at my Prof colleagues. It’s been pointed out, though, that there are very good reasons anyone might choose to be pseudonymous — see, e.g., Zen Faulkes’ comment below.]


The Appendix Theory of Neurogenesis

We’ve all had “theories”, haven’t we. That’s “theory”, not theory. You know what I mean by “theories”: those not-necessarily-at-all-well-formulated, probably untestable crap ideas that pass briefly through your mind when staring out the window of a bus, or repeat in your mind when you’re trying to sleep. Thankfully for the world, they usually end up going nowhere.

A “theory” of mine that I once considered for an appropriate time of about 2 seconds is The Appendix Theory of (Adult Hippocamal) Neurogenesis. If you don’t know, in the 90s an idea was confirmed, that — contrary to Cajal’s (somewhat disappointing) assumption that brain cells are never born but just die — new brain cells are born, and one of the places that happens is the dentate gyrus of the hippocampus, a structure neuroscientists automatically and immutably pair-associate with memory function. Once AHN was discovered, the critical question for those of us interested in function was what, specifically did these new neurons do for us? What is AHN for?

You’ve already guessed the idea behind Appendix Theory. It is that AHN is vestigial; the young neurons thus formed add nothing to our cognitive abilities. Indeed, these neurons are weird; they are over-responsive and highly plastic and may contribute little to the DG circuitry, other than maybe some noise.

Appendix Theory was immediately challenged and apparently proved predictably daft by experiments that found that knocking down AHN by irradiation or other methods led to impairments in spatial memory. But not everyone got this result: in some experiments knock-down had no effect, a finding consistent with Appendix Theory. A possible resolution to this ambiguity came when it was reported that AHN knock-down impaired the discrimination of similar locations – thought to require the formation of non-overlapping representations through a computational process called ‘pattern separation’ – without affecting other aspects of spatial cognition (Clelland et al., 2009). The previous inconsistencies could now be explained, because the load on pattern separation in these tasks was never controlled – in some studies it might have been high, and in some low (e.g., ambiguous cues in one water maze room, but not another). Appendix Theory received a number of subsequent coffin-nails from other groups reporting that AHN knock-down impairs the discrimination of similar locations/contexts, and indeed that increasing AHN can enhance this function. Support for this function of AHN has now come from several species, using a variety of behavioural paradigms, and from methods including lesions, patient populations, and neuroimaging. Appendix Theory seems to be dead, and right or wrong, a function for AHN in pattern separation has become the assumption.

A new paper, however, could yet breathe new life into Appendix Theory. Groves et al (2013) used a novel method to knock down AHN, and found no impairments on any spatial tasks. How could all of those studies from using all those species, paradigms and methodologies be wrong? It’s possible. For example, methods of knocking down AHN, like any lesion method, could have off-target effects. In Clelland et al, really what we should have done is include a group with selective lesions of the mature neurons in the DG — but I have no idea how that could be done! (Clever suggestions below the line please.)

The trouble is, most of the tests in this new paper – standard spatial tests like water maze and fear conditioning – are irrelevant because, as described above, plenty of people have shown little effect of AHN knock-down, and these past inconsistent results appear to have been resolved by reassessment of those old data in terms of pattern separation. However Groves et al did include a test of pattern separation that had been used previously, a radial maze task similar to that used in Clelland et al.. Unfortunately, for some reason the small separation condition wasn’t more difficult than the large. In another test, the condition that was meant to tax pattern separation elicited significantly fewer errors from the rats. So, it is hard to be convinced the rats in this study were really challenged appropriately. It’s worth noting that in some of the anti-Appendix experiments (including our own), the two conditions were equidifficult for controls. The difference is that those studies found impairments. When claiming no effect, however, it has to be clear the animals were adequately challenged.

Indeed, when claiming a negative a minimum requirement is to show that the behavioural tests used are sensitive to comparable manipulations. The authors argue their tests are sensitive because full hippocampal lesions have an effect. (But in mice, not rats.) I couldn’t find their pattern separation test in any of their other papers, but let’s assume it’s sensitive to hippocampus lesions. Trouble is, a hippocampus lesion is hardly comparable to a lesion of 10% of the cells in the dentate gyrus. Before deciding that all those studies described above are wrong, and embracing Appendix Theory, we need to see that their task is sensitive enough to pick up effects of a comparably sized lesion, ideally in the same species.

One can also reasonably ask whether this new knock-down method was functionally effective at all; after all, the point of the paper is that no impairments were found. There are indeed some effects on elevated plus maze but, as the authors very honestly pointed out, it wasn’t significant at an appropriate level of statistical rigour. To be honest though, that would be a bit of a picky criticism, for at least two reasons. First, if Appendix Theory is correct, there is no prospect of a ‘positive functional control’ because according to Appendix Theory AHN doesn’t have any function! And second, the knock-down of neurogenesis was 98%, which is huge! It seems to me this is the real strength of the study, a new method for creating a very substantial knock-down of AHN.

I should also mention that the authors add to their study a meta-analysis of studies of neurogenesis knock-down. That could be really useful. Trouble is, as far as I can tell the analysis included what appears to be only a random two papers testing pattern separation – and both of these were contextual fear conditioning, which is widely regarded as the most problematic paradigm (no manipulation of the load on pattern separation). Furthermore they failed to consider any study testing the effects of enhancement of neurogenesis, which provides particularly strong evidence for functional efficacy, especially in studies in which the increase in neurogenesis was apparently very selective. In any case such an analysis does not capture the persuasive power of the replication of the finding using very dissimilar methodologies and species, as is the case of AHN and pattern separation.

To conclude, this impressive new method for a achieving a very substantial knock-down of neurogenesis could prove very valuable for studies of the functional role of AHN, and the molecular events associated with it. (Although it should be noted that this method itself had known off-target effects, namely it affects not just neurons, but glia.) For now, though, it is clearly not quite time to embrace Appendix Theory.