Language - anatomy

Golestani, N., Paus, T., and Zatorre, R.J. (2002) Anatomical correlates of learning novel speech sounds. Neuron, 35, 997-1010.

We examined the relationship between brain anatomy and the ability to learn non-native speech sounds, as well as rapidly changing and steady-state non-linguistic sounds, using voxel-based morphometry in 59 healthy adults. Faster phonetic learners appeared to have more white matter in parietal regions, especially in the left hemisphere. The pattern of results was similar for the rapidly changing but not for the steady-state non-linguistic stimuli, suggesting that morphological correlates of phonetic learning are related to the ability to process rapid temporal variation. Greater asymmetry in the amount of white matter in faster learners may be related to greater myelination allowing more efficient neural processing, which is critical for the ability to process certain speech sounds.

Stimuli

Hindi consonant-vowel syllables

Schematized frequency versus time diagrams of the (left) dental and (right) retroflex synthetic consonant-vowel (CV) syllables. Each line represents the center frequency of a formant. The black dot indicates a noise burst.
Diagram of CV1 (dental) Diagram of CV7 (retroflex)
Spectrogram of CV1 Spectrogram of CV7
CV1 CV2 CV3 CV4 CV5 CV6 CV7




Non-linguistic stimuli

Schematized frequency versus time diagrams of (left) sound 1 and (right) sound 7 from the rapidly changing nonlinguistic (NL) stimulus continuum. Each line represents the center frequency of a formant.
Diagram of NL1 Diagram of NL7
Spectrogram of NL1 Spectrogram of NL7
NL1 NL2 NL3 NL4 NL5 NL6 NL7




Tonal stimuli

TS TS2 TS3 TS4 TS5 TS6 TS7




Note: All sounds on this page are MP3 files encoded at 96 Kbps and are of lower audio quality than the stimuli used in the actual experiments.  If your browser is not configured to launch an MP3 player automatically, right click on the link and choose "Save link as..." in Netscape Navigator or "Save Target As..." in Microsoft Internet Explorer to save the file to disk.  You can then play the sample with any MP3 capable media player such as the one below.  It has recently been verified that, for reasons still unknown, some versions of Netscape Navigator 4.x can sometimes save MP3 data incorrectly.  Mozilla, Opera, Netscape Navigator 6.x and Internet Explorer do not have this difficulty.