Functional Anatomy of Spoken Input Note that the low-level auditory pathway is not specialized for speech sounds – Both speech and non-speech sounds activate primary auditory cortex (bilateral Heschl’s Gyrus) on the top of the superior temporal gyrus

Functional Anatomy of Spoken Input Which parts of the auditory pathway are specialized for speech? Binder et al. (2000) – fMRI – Presented several kinds of stimuli: white noise pure tones non-words reversed words real words These have non-word-like acoustical properties These have word-like acoustical properties but no lexical associations word-like acoustical properties and lexical associations

Functional Anatomy of Spoken Input Relative to “baseline” scanner noise – Widespread auditory cortex activation (bilaterally) for all stimuli – Why isn’t this surprising?

Functional Anatomy of Spoken Input Statistical contrasts reveal specialization for speech-like sounds – superior temporal gyrus – Somewhat more prominent on left side

Functional Anatomy of Spoken Input Further contrasts to identify specialization for words relative to other speech-like sounds revealed only a few small clusters of voxels Brodmann areas – Area 39 – 20, 21 and 37 – 46 and 10