Why do people go on and on so about the fusiform gyrus and face recognition? What's the deal? I think they carry on because ... well, because they can! As it turns out, the neuronal activity in the fusiform face area (FFA; see e.g. Kanwisher N, McDermott J, Chun MM. 1997. The fusiform face area: a module in human extrastriate cortex specialized for face perception. J Neurosci. 17(11):4302-11) really does have a tight link to face recognition processes. Evidently, the holistic aspects of face processing are 'elementary' or 'primitive' (in a computational-representational sense) such that a circumscribed cortical area forms the basis for the functional process. That does not mean that other areas are not involved, but apparently the FFA plays a privileged role. Who would have thunk it - face recognition has a place.
Anyway, I am jealous. I would like for us speech-types to have an area like that, too. The fusiform face area and the parahippocampal place area are practically household names (well ... in pretty nerdy households). What do we have? Why don't we have something like the 'superior speech field' SSF, or the 'middle speech gyrus' MSG? Can we have that please?
Well, it's not so clear that that would make sense. What we have is an increasingly articulated functional and anatomic boxology -- for example in the way Greg and I presented in in our 2007 Nature Reviews Neuroscience paper (see earlier blog entry). I think this does make sense, because 'speech perception' or 'spoken word recognition' are in my view not monolithic; rather, a number of subroutines are necessary parts of successful speech perception. No single area is responsible for a sufficient number of processes to by itself deserve the name 'speech area.' So, although we often continue to search for the speech area, I think this is wrong-headed. We should be radical decompositionalists instead, and identify (cognitively, computationally) all the subroutines implicated in speech processing. And find a neurobiologically plausible implementation (a la Marr) for the computational subroutines.
Of course, I could be wrong about that ... Reasonable people can disagree, so maybe there is an area 'specialized for speech'. I'd certainly like to hear the arguments.