Spoken word perception

Previous neuroimaging research (Binder et al., 2000; Scott & Johnsrude, 2003) showed that listening to spoken words activates auditory regions within the anterolateral STG and STS, which are linked to belt and parabelt areas. This observation corresponds to findings of research that compared the perception of consonant-vowel syllables and vowels to that of white noise and pure tones, indicating that activations responsive to phonetic perception occur in the STS (Jӓncke, Wüstenberg, Scheich, & Heinze, 2002).

While the passive presentation of words activates the STG bilaterally (Binder, Swanson, Hammeke, & Sabsevitz, 2008a; Petersen, Fox, Posner, Mintun, & Raichle, 1988; Wise et al., 1991), the comparison of the perception of spoken words to that of silence results in activation associated with speech within the posterior part of the STS/STG together with the left inferior frontal gyrus (lIFG) (e.g. Binder et al., 1994b; Petersen et al., 1988; Wise et al., 2001). For instance, both the perception and the recovery of individual words through memory have been linked to the left posterior superior temporal sulcus (pSTS) within the left superior temporal cortex (Wise et al., 2001). It has therefore been implied that the pSTS might link the perception of words with the long-standing representations of known words stored in memory (Wise et al., 2001). The pSTS/STG and lIFG have also been implicated with speech-related activations in studies that compared syllables to noise (Zatorre et al., 1992), words with reversed speech (Price et al., 1996a) and in research, which involved participants’ completion of phonological monitoring tasks (Demonet et al., 1992).

The left inferior frontal gyrus (lIFG)  (in orange) encompassing the pars orbitalis, pars triangualris, and the pars opercularis, with the last two constituting Broca's area (Brodmann areas 44 and 45).

More recently, speech processing was observed to elicit a premotor response that was correlated with improved perceptual performance (Callan, Callan, Gamez, Sato, & Kawato, 2010; Osnes, Hugdahl, & Specht, 2011). Nonetheless, a lack of activity in the left premotor cortex in response to articulatory complexity during perceptual processing of speech was concluded to imply that during speech perception, the left premotor cortex might be active only to a certain degree (Tremblay & Small, 2011a). Therefore it can be said that together with the IFG, left posterior temporal areas might be part of a network for phonological processing of perceived speech (Zatorre et al., 1992), which is contributed to by premotor and frontoparietal areas for articulatory processing (Tremblay & Small, 2011a).

References:

Binder, J.R., Frost, J. A., Hammeke, T.A., Bellgowan, P.S.F., Springer, J.A., Kaufman, J.N. &Posing, E.T. (2000). Human temporal lobe activation by speech sounds and non-speech sounds. Cerebral Cortex, 10, 512-28.

Binder, J.R., Rao, S.M., Hammeke, T.A., Frost, J.A., Bandettini, P.A., & Hyde, J.S. (1994b). Effects of stimulus rate on signal response during functional magnetic resonance imaging of auditory cortex. Brain Research Cognitive Brain Research, 2, 31-38.

Binder, J.R., Swanson, S.J., Hammeke, T.A., & Sabsevitz, D.S. (2008a). A comparison of five fMRI protocols for mapping speech comprehension systems, Epilepsia, 49, 1980-1997.

Callan, D., Callan, A., Gamez, M., Sato, M.A., &Kawato, M. (2010). Premotor cortex mediates perceptual performance. Neuroimage, 51, 844-858.

Demonet, J.-F., Chollet, F., Ramsay, A., Cardebat, D., Nespoulous, J.-L., Wise, R., Rascol, A., & Frackowiak, R. (1992). The anatomy of phonological and semantic processing in normal subjects. Brain, 115, 1753-1768. 

Jӓncke, L., Wüstenberg, T., Scheich, H., & Heinze, H.-J. (2002). Phonetic perception and the temporal cortex. NeuroImage, 15, 733-746.

Osnes, B., Hugdahl, K., Specht, K. (2011). Effective connectivity analysis demonstrates involvement of premotor cortex during speech perception. Neuroimage, 54, 2437-2445.

Petersen, S.E., Fox, P.T., Posner, M.I., Mintun, M, Raichle, M.E. (1988). Positron emission tomographic studies of the cortical anatomy of single-word processing. Nature, London, 331, 585-589.

Price, C. J., Wise, R., Warburton, E.A., Moore, C.J., Howard, D., Patterson, K., Frackowiak, R.S., &Friston, K.J. (1996a). Hearing and saying. The functional neuroanatomy of auditory word processing, Brain, 119 (Pt3), 919-931.

Scott, S.K., & Johnsrude, I.S. (2003). The neuroanatomical and functional organization of speech perception. Trends in Neuroscience, 26, 100-107.

Tremblay, P., Small, V.L. (2011a). On the context dependent nature of the contribution of the ventral premotor cortex to speech perception. Neuroimage, 57, 1561-1571.

Wise, R.J., Chollet, F., Hadar, U., Friston, K., Hoffner, E., & Frackowiak, R. (1991). Distribution of cortical neural networks involved in word comprehension and word retrieval. Brain, 114, 1803-1817.

Wise, R.J., Scott, S.K., Blank, S.C., Mummery, C.J., Murphy, K., & Warburton, E.A. (2001). Separate neural subsystems within 'Wernicke's area. Brain, 124, 83-95.

Zatorre, R.J., Evans, A.C., Meyer, E., & Giede, A. (1992). Lateralization of phonetic and pitch discrimination in speech processing. Science, 256, 846-849.