MEG correlates of categorical perception of a voice onset time continuum in humans.
Event-related magnetic fields (ERFs) were recorded from the left hemisphere in nine normal volunteers in response to four consonant-vowel (CV) syllables varying in voice-onset time (VOT). CVs with VOT values of 0 and +20 ms were perceived as /ga/ and those with VOT values of +40 and +60 ms as /ka/. Results showed: (1) a displacement of the N1m peak equivalent current dipole toward more medial locations; and (2) an abrupt reduction in peak magnetic flux strength, as VOT values increased from +20 to +40 ms. No systematic differences were noted between the 0 and +20 ms stimuli or between the +40 and +60 ms CVs. The findings are in agreement with the results of multiunit invasive recordings in non-human primates regarding the spatial and temporal pattern of neuronal population responses in the human auditory cortex which could serve as neural cues for the perception of voicing contrasts.
Simos
P G
PG
Department of Neurosurgery, The University of Texas-Houston Medical School, 6431 Fannin Suite 7.148, Houston, 77030, TX, USA. asimos@heart.med.uth.tmc.edu
Diehl
R L
RL
Breier
J I
JI
Molis
M R
MR
Zouridakis
G
G
Papanicolaou
A C
AC
D000328:Adult; D001303:Auditory Cortex / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D011930:Reaction Time / Q000502:physiology*; D013060:Speech; D014831:Voice