Wernicke’s and Broca’s area in chimps – Supplementary Sunday

This weeks top rated post is “humans have giant chimp brains” with a grand total of 3 up-votes, making it the 3rd most popular post of all time. As such this weeks Supplementary Sunday seeks to expand on this well-liked topic by identifying yet another similarity between the human and chimp brain: Wernicke’s area.

This is a particularly famous section of the brain so apologies if you’ve heard this summary before. It’s a small region found in the left hemisphere of the brain and was first identified in the 19th century by Dr Wernicke (as the name indicates) who noted a link between brain damage to that part of the brain and an inability/impairment to comprehend language.

Based on this link it was claimed to be the region of the brain responsible for language comprehension, however this view has now evolved somewhat. Language comprehension is now understood to be more dispersed throughout the left side of the brain with Wernicke’s area being an “epicentre” of this ability, rather than the sole location it occurs.

As such it isn’t quite as important as once believed but still very crucial. This has obviously prompted several studies trying to find an analogues area in chimps and other great apes. Surprisingly (given their lack of vocal language) the area of the chimp brain which should be the Wernicke’s area is assymetrical, like in humans. In other words, that region of the brain is larger in both humans and chimps on the left side.

Broca’s area is another assymetrical feature in the human brain associated with language, again being larger on the left than the right. Rather than language comprehension this region is linked to language production, with it being first discovered (again) by identifying damage to this area in patients unable to speak. Once again, it is now believe to be just one part of this process and, again, this assymetry is also seen in ape brain.

All of this suggests that the foundation for our brain structure – even parts associated with seemingly unique human abilites – was already laid in our ape ancestors

Broca’s area in chimps. Note how the left side is larger than the right.

Cantalupo, Claudio, and William D. Hopkins. 2001. ‘Asymmetric Broca’s Area in Great Apes’. Nature 414(6863): 505–505. doi:10.1038/35107134.
Gannon, Patrick J., Ralph L. Holloway, Douglas C. Broadfield, and Allen R. Braun. 1998. ‘Asymmetry of Chimpanzee Planum Temporale: Humanlike Pattern of Wernicke’s Brain Language Area Homolog’. Science 279(5348): 220–222. doi:10.1126/science.279.5348.220.

Apologies for the short post. I would try and claim I’m trying a new format but in reality I’m just being distracted by the Wimbledon final. However, if you like this abridged version speak up. Suggestions are always welcome.

About these ads

4 thoughts on “Wernicke’s and Broca’s area in chimps – Supplementary Sunday

  1. Interesting. And unsurprising really, because animals do have language – ie they can communicate. And 70% of human communication is body language anyway.

    • Well I did (and many people probably still do) tend to automatically associated communication with language. Thus finding that chimps had a brain similar to us in regards to communication was quite surprising. But on reflection, you’re right, it probably isn’t.

      My, you’ve certainly been leaving a lot of comments haven’t you.

  2. So I recently read the Carl Sagan piece on apes using sign language to communicate. Could it be considered that these areas of the brain that resemble our own can instead develop sign language as opposed to oral language in apes?

    • The main reason they taught the chimps sign language was because they lacked the vocal skills necessary to speak. Beyond that though, there are many similarities between the two systems so it seems likely similar parts of the brain are involved.

You evolved too. Have a say.

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s