Sunday, January 30, 2011

How I Read Papers

Last year I blogged about how I write blog posts. I don't really have anything to add to that, so here's some advice on how I read scientific papers - both the ones I read for my day job, and the ones I blog about.


Software:
If you read papers you need PubCrawler. It's free, and it's the best thing since PubMed, because it automatically searches PubMed for you and emails you the results. Second, you need a reference manager program. I use EndNote, but there are others, including various free ones. They're indispensable.

PubCrawler sends you lists of new papers you might want to read. A reference manager lets you to keep track of what you've read, and what you need to read in future; it lets you make notes on papers (see below), search them etc. and best of all it lets you insert them into Word or whatever and automatically generates a References list. If you're not using these tools, you're making life much harder than it should be.

Deciding What To Read: There are a lot of papers out there. My PubCrawler includes a search term for "antidepressants", which nets about 10 per day; one for "autism", about 5 per day; one for various brain regions I'm interested in, up to 50 per day, another for neurotransmitters I'm into, also 50...

So you need a triage system. I mentally put papers into 3 categories, based purely on the titles:
  1. Irrelevant - don't even click on it. I'd say about 80% of PubCrawler hits fall into this category.
  2. Somewhat interesting - read the abstract. 15%.
  3. Very interesting - read the whole thing. 5%.
Reading papers: Start with the abstract. Then read the Introduction, as it's usually a pretty good summary of previous work. I'll skip this only if I know all the existing literature (very rare). Then, head to the first paragraph of the Discussion: this typically contains a summary of the main results in non-technical language.

Finally, I'll skim the Methods and the Results. If something seems unusual, dodgy, or especially interesting, I'll go back and read these fully, but most of the time I don't bother. The remainder of the Discussion is generally just speculation, and rarely worth reading.

All that applies to original experimental articles. For review papers, if I read them at all I read them straight through; a well-written review should all be useful. A bad review is no use at all. If you start reading a review, and by the end of the first page you're wondering "But what's the point of all this?", it's probably the latter.

Making notes: This is the key to memory, for me at least. If I just read something, I barely remember it the next day let alone next month. Making notes forces you to actually understand it, and then it sticks. I make notes in EndNote for every paper, and even every abstract, I read. Once you get into the swing of it it's a natural part of reading and doesn't take much time.

Here's my notes on one recent paper:
Abstract. NRG1 --> ErbB4 promotes the formation of glutamatergic --> GABA interneuron synapses via stabilizing the PSD-95 at these synapses, but NOT at other synapses i.e. glut --> glut. Therefore, NRG1 contributes to the development of inhibitory signalling. The authors say this is interesting re: SCZ [but I think it's interesting re: autism as well!]
This makes sense, if you're me. Actually, though, I rarely ever read these notes. The point is to make them. You could scribble them on toilet paper and flush them once you're finished and they'd still do their job of boosting your memory.

Here's an uncensored extract from my notes on a paper I didn't like:
Less "medication resistant" patients did better [well that's AWESOME for a treatment that's meant to be an alternative to meds isn't it, you fuck]. They admit that the actual performance was crap NNT=12, but say it would be better if concomitant meds allowed [....well yeah either that or the effect would DISAPPEAR] and that it is equivalent to what would be expected if you gave a new drug or augmentation to this population [but you DIDN'T did you, you are referring to the literature, which is shit]. There's so many conflicts of interest it's almost tragic.
It deserved it, seriously. My comments are [in brackets], obviously.

Again - when I wrote these, I didn't expect to ever read them. The point is that by writing down my comments, I forced myself to make them coherent, and hence made myself remember them. This is crucial: if you only remember what the paper said, and not the fact that when you read it, you burst out laughing in disbelief, you'll go away thinking that the paper must have been fine.

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