Neurology Center

A team of Japanese scientists have found the most sarcastic part of the brain known to date. They also found the metaphor centre of the brain and, well, it's kind of like a pair of glasses.

The paper is Distinction between the literal and intended meanings of sentences and it's brought to you by Uchiyama et al. They took 20 people and used fMRI to record neural activity while the volunteers read 4 kinds of statements:

• Literally true
• Nonsensical
• Sarcastic
• Metaphorical

The neat thing was that the statements themselves were the same in each case. The preceding context determined how they were to be interpreted. So for example, the statement "It was bone-breaking" was literally true when it formed part of a story about someone in hospital describing an accident; it was metaphorical in the context of someone describing how hard it was to do something difficult; and it was nonsensical if the context was completely unrelated ("He went to the bar and ordered:...").

Here's what they found. Compared to the literally-true and the nonsensical statements, which were a control condition, metaphorical statements activated the head of the caudate nucleus, the thalamus, and an area of the medial PFC they dub the "arMPFC" but which other people might call the pgACC or something even more exotic; names get a bit vague in the frontal lobe.


The caudate nucleus, as I said, looks like a pair of glasses. Except without the nose bit. The area activated by metaphors was the "lenses". Kind of.

Sarcasm however activated the same mPFC region, but not the caudate:

Sarcasm also activated the amygdala.


That's as plausible an account as any but the problem is that we have no way of knowing, at least not from imaging studies, if it's true or not. As I said this is not the fault of this study but rather an inherent challenge for the whole enterprise. The problem is - switch on your caudate, metaphor coming up - a lot like the challenge facing biology in the aftermath of the Human Genome Project.

The HGP mapped the human genome, and like any map it told us where stuff is, in this case where genes are on chromosomes. You can browse it here. But by itself this didn't tell us anything about biology. We still have to work out what most of these genes actually do; and then we have to work out how they interact; and they we have to work out how those interactions interact with other genes and the environment...

Genomics people call this, broadly speaking, "annotating" the genome, although this is not perhaps an ideal term because it's not merely scribbling notes in the margins, it's the key to understanding. Without annotation, the genome's just a big list.

fMRI is building up a kind of human localization map, a blobome if you will, but by itself this doesn't really tell us much; other tools are required.

Uchiyama HT, Saito DN, Tanabe HC, Harada T, Seki A, Ohno K, Koeda T, & Sadato N (2011). Distinction between the literal and intended meanings of sentences: A functional magnetic resonance imaging study of metaphor and sarcasm. Cortex; a journal devoted to the study of the nervous system and behavior PMID: 21333979