Neural circuitry underlying perception of duration depends on language experience

Thai, a language which exhibits a phonemic opposition in vowel length, allows us to compare temporal patterns in linguistic and nonlinguistic contexts. Functional MRI data were collected from Thai and English subjects in a speeded-response, selective attention paradigm as they performed same/different judgments of vowel duration and consonants (Thai speech) and hum duration (nonspeech). Activation occurred predominantly in left inferior prefrontal cortex in both speech tasks for the Thai group, but only in the consonant task for the English group. The Thai group exhibited activation in the left mid superior temporal gyrus in both speech tasks; the English group in the posterior superior temporal gyrus bilaterally. In the hum duration task, peak activation was observed bilaterally in prefrontal cortex for both groups. These crosslinguistic data demonstrate that encoding of complex auditory signals is influenced by their functional role in a particular language.