This Season’s Hottest Brain Regions

By Neuroskeptic | May 5, 2010 3:17 pm

Are you a budding neuroscientist who’s not sure which part of the brain to specialize in? Or perhaps you’re a purveyor of media neuro-nonsense who’s wondering which area to namedrop as being the key to sex / intelligence / politics next?

Well, wonder no more, because Neuroskeptic can now exclusively reveal which parts of the brain are hot, and which are not, right now (thanks to the high-tech method of searching PubMed and counting the papers published referring to eight major brain regions, each year from 1985 to 2009.)

The hippocampus stands out as an extremely hot region with both a huge number of papers and rapid growth over 25 years. So it’s probably a good place to build a career… but on the other hand, the market may be saturated already, and it shows some signs of flatlining in the past few years. The cerebellum has long been popular, but growth has been extremely slow lately.

To better highlight the growth curves here’s the same data but normalized to the year 2000 (so “2” means twice as many papers as in 2000, etc.)

This shows major differences. The orbitofrontal cortex and cingulate cortex are both undergoing massive growth at the moment. The amygdala and parietal cortex are pretty hot too. By contrast, the cerebellum and the caudate are stuck in the scientific doldrums.

Why are the patterns so different for different parts of the brain? That’s a big question which hopefully will get discussed in the Comments. I suspect that the recent rise of the cingulate cortex and the orbitofrontal cortex, however, has much to do with the rise of fMRI (i.e. within the last 10 years, mostly), which allows them to be easily studied in humans for the first time.

Both of these areas are quite difficult to study with older technologies like EEG, because of their location within the head. That said, the same problem applies to plenty of other regions, but the orbitofrontal and cingulate cortex are also difficult to study in lab rats and mice, because it’s not clear which parts of the rodent brain map onto which parts of the human brain in these regions. By contrast, things like the cerebellum and caudate nucleus have exact rodent equivalents, perhaps making them more attractive to early researchers.

CATEGORIZED UNDER: amygdala, graphs, history, science
  • http://www.blogger.com/profile/06984866295985152765 JRQ

    There are many of us who define our area of study not by brain regions, but by cognitive function….thus, the regions about which we publish tend to be those that show the greatest response when some function or another is manipulated.

    That is, it is the function that gets hot, gets scanned, and the areas that pop out most readily are the ones that get studied further.

    I would expect the recent upsurge in cingulate interest is probably driven by the curernt hotness of decision-making, reward and emotion.

    Also, how much of the recent boost in parietal interest is attributable to episodic memory studies? massive long-standing interest in episodic memory has been a major driver of research on the hippocampus, because of the well-known and long-ago-established role of the hippocampus and medial-temporal lobes in memory formation. Before fMRI, there was little reason to consider parietal regions in episodic memory. But put someone in the scanner and ask them to remember things, and you typically got a big blast of lateral parietal activity. So there has been a recent surge of memory studies focusing lateral parietal regions in attempt to figure out what role(s) those regions are playing in episodic memory function.

    so, I would say the “hotness” of the brain area is in a large part a consequence of the “hotness” of the functions to which it responds when you scan those functions.

  • http://www.blogger.com/profile/06984866295985152765 JRQ

    er… meant to say “recent surge in orbitofrontal and cingulate interest”

  • http://www.blogger.com/profile/07047660504672048110 Will

    The cingulate gyrus is studied in mice. A lot. I would agree that it may not be a perfect analog for the human cingulate, but I think it's a little misleading to suggest that it's not an extremely active area of study.

  • http://www.blogger.com/profile/07238602721399083531 Bronson

    No mention of ventral temporal lobes or occipital lobes! The pubmed search technique probably wouldn't pick up on the large amount of studies done in these regions because they are often sub-divided (V1, V2, V3, MT etc) or given different names (ventral temporal lobes, occipital-temporal junction etc). The hippocampus is a small, anatomically defined (i.e., not functionally defined) region, so will be more consistently labelled across studies in the abstracts surveyed.

    It would be interesting to also compare these publication rates against how much a given brain region is subject to susceptibility effects. If a region (i.e., amygdala, OFC) suffers from signal drop out then this will reduce the likelihood that a study will be sensitive to detecting changes in brain activity.

  • http://www.blogger.com/profile/08010555869208208621 The Neurocritic

    For sheer volume you have to include the insula. From 1985-2009 there was a total of 197,256 articles (compare to 82,438 for the hippocampus). The number of PubMed hits for insula in 1985 was 3,906; in 2008 it was 13,375.

  • http://www.blogger.com/profile/06647064768789308157 Neuroskeptic

    JRQ: That's a good point. Although it's a bit of a chicken and egg question… How much of the recent interest in reward etc. comes from the availability of fMRI, which for the first time made it easy to measure activity in the basal ganglia / OFC in humans? :)

  • http://www.blogger.com/profile/06647064768789308157 Neuroskeptic

    Will: You're right…oops. But I think this is another case of fMRI making it feasible to study in humans – my understanding is you can measure cingulate activity with EEG (midline) but that only picks up from the dorsal bits. Whereas the more “emotional” bits, like the subgenual ACC which seems to be important in mood, needs fMRI or PET.

  • Anonymous

    I just wanted to let you know that I really appreciate this blog and it's content. Great way to start of next years' neuroscience class:D

  • http://www.blogger.com/profile/06647064768789308157 Neuroskeptic

    Thanks!

  • Anonymous

    OK so just where does the “id” reside in the brain? And where does the “superego” call home? I want to use rTMS to stimulate the former and eliminate the later. This may help me feel better. Especially in light of the recent Archives of General Psychiatry NIH-funded (and not Big Pharma)report of a study indicating that rTMS is, basically, a sham. Any hope for me in the near term using this treatment to unleash my lashing libido without guilt and self-reproach?

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Neuroskeptic

No brain. No gain.

About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.

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