nature neurOSCIenCe advance online publication a r t I C l e S A fundamental property of speech perception is that listeners map continuously variable acoustic speech signals onto discrete phonetic sound categories A number of studies support the notion that the posterior superior temporal gyrus (pSTG) in Wernicke's area is important for higher order auditory processing of speech sounds To answer these questions, we recorded cortical local field poten tials from the pSTG in four human subjects undergoing awake crani otomy with speech mapping as part of their epilepsy 14 or brain tumor surgery RESULTS We employed a classic procedure first described in 1957 (ref. 6) to investigate the perceptual and neural organization of stop conso nant phonemes. Consonantvowel syllables were synthesized with 14 equal and parametric changes in the starting frequency of the F2 transition (second vocal tract resonance) that ranged perceptually across three initial consonants /ba/ to /da/ to /ga
