Functional Anatomy of Spoken Input

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