Identification of a pathway for intelligible speech in the left temporal lobe.
It has been proposed that the identification of sounds, including species-specific vocalizations, by primates depends on anterior projections from the primary auditory cortex, an auditory pathway analogous to the ventral route proposed for the visual identification of objects. We have identified a similar route in the human for understanding intelligible speech. Using PET imaging to identify separable neural subsystems within the human auditory cortex, we used a variety of speech and speech-like stimuli with equivalent acoustic complexity but varying intelligibility. We have demonstrated that the left superior temporal sulcus responds to the presence of phonetic information, but its anterior part only responds if the stimulus is also intelligible. This novel observation demonstrates a left anterior temporal pathway for speech comprehension.
Scott
S K
SK
Institute of Cognitive Neuroscience and Department of Phonetics and Linguistics, University College London, MRC Clinical Sciences Centre, Cyclotron Unit, Hammersmith Hospital, London, UK. sophie.scott@ucl.ac.uk
Blank
C C
CC
Rosen
S
S
Wise
R J
RJ
D000161:Acoustic Stimulation; D001303:Auditory Cortex / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology; D001306:Auditory Pathways / Q000502:physiology*; D001931:Brain Mapping; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D012815:Signal Processing, Computer-Assisted; D013060:Speech / Q000502:physiology; D013065:Speech Intelligibility / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D014055:Tomography, Emission-Computed