Clarifying the auditory dorsal stream, again: a comment on Rauschecker 2014

Josef Rauschecker has a new paper out in Frontiers titled, "Is there a tape recorder in your head? How the brain stores and retrieves melodies." It's worth a look.  The problem of coding sequences of information is an important, and poorly understood one.

But that's not I want to highlight here.  Instead I want to put some comments of Rauschecker's in their proper context, i.e., the context of the neuroscience of hearing that exists outside of his laboratory. He writes,  

The dorsal stream was originally defined by its involvement in auditory spatial processing (Rauschecker and Tian, 2000) and movement in space (Warren et al., 2002). This is still believed to be correct (Rauschecker, 2012), but the role of the dorsal stream has been expanded to include sensorimotor integration and control in more general terms (Rauschecker and Scott, 2009; Rauschecker, 2011), including the representation of sequences.

As I pointed out in this post, the idea of dual streams in auditory processing pre-date Rauschecker and Tian by at least a half a century, and can trace their route back even farther to Carl Wernicke who argued for the existence of two auditory pathways, one that projects to the motor system and on that projects to the conceptual system.

Secondly, the idea that the dorsal auditory stream processes spatial information has been questioned and re-questioned by the likes of Robert Zatorre, John Middlebrooks, as well as by work in my own lab headed by former grad student Kevin Smith.  A discussion of why, from a purely conceptual standpoint, "spatial processing" cannot possibly be a "stream" can be found in this review by Hickok & Saberi.  To summarize our point, streams are organized around computational tasks (what you do with information) not around information types.  So "This is still believed to be correct" is better stated as, "This is still believed to be correct, by Rauschecker."

Good to see, though, that Rauschecker has correctly acknowledged the "expansion" of the role of the dorsal stream to include sensorimotor integration.  I'm sure his omission of Hickok & Poeppel, 2000, 2004, 2007, Wise et al. 2001, Buchsbaum et al. 2001, Hickok et al. 2003, 2009, 2011, Pa & Hickok, 2008, Isenberg et al. 2012, to name few, was a merely a proofing error.

The rest of the references for Rauschecker 2014:

Buchsbaum, B., Hickok, G., & Humphries, C. (2001). Role of Left Posterior Superior Temporal Gyrus in Phonological Processing for Speech Perception and Production. Cognitive Science, 25, 663-678. 

Hickok, G., & Poeppel, D. (2000). Towards a functional neuroanatomy of speech perception. Trends Cogn Sci, 4, 131-138. 

Hickok, G., & Poeppel, D. (2004). Dorsal and ventral streams: A framework for understanding aspects of the functional anatomy of language. Cognition, 92, 67-99. 

Hickok, G., & Poeppel, D. (2007). The cortical organization of speech processing. Nature Reviews Neuroscience, 8(5), 393-402. 

Hickok, G., Buchsbaum, B., Humphries, C., & Muftuler, T. (2003). Auditory-motor interaction revealed by fMRI: Speech, music, and working memory in area Spt. Journal of Cognitive Neuroscience, 15, 673-682. 

Hickok, G., Okada, K., & Serences, J. T. (2009). Area Spt in the human planum temporale supports sensory-motor integration for speech processing. J Neurophysiol, 101(5), 2725-2732. doi: 91099.2008 [pii]

10.1152/jn.91099.2008

Hickok, G., Houde, J., & Rong, F. (2011). Sensorimotor integration in speech processing: computational basis and neural organization. Neuron, 69(3), 407-422. doi: S0896-6273(11)00067-5 [pii]10.1016/j.neuron.2011.01.019

Isenberg, A. L., Vaden, K. I., Jr., Saberi, K., Muftuler, L. T., & Hickok, G. (2012). Functionally distinct regions for spatial processing and sensory motor integration in the planum temporale. Hum Brain Mapp, 33(10), 2453-2463. doi: 10.1002/hbm.21373

Middlebrooks, J. C. (2002). Auditory space processing: here, there or everywhere? Nat Neurosci, 5(9), 824-826.

Pa, J., & Hickok, G. (2008). A parietal-temporal sensory-motor integration area for the human vocal tract: Evidence from an fMRI study of skilled musicians. Neuropsychologia, 46, 362-368. 

Smith, K. R., Okada, K., Saberi, K., & Hickok, G. (2004). Human cortical motion areas are not motion selective. Neuroreport, 9, 1523-1526.

Smith, K. R., Saberi, K., & Hickok, G. (2007). An event-related fMRI study of auditory motion perception: no evidence for a specialized cortical system. Brain Res, 1150, 94-99. 

Smith, K. R., Hsieh, I. H., Saberi, K., & Hickok, G. (2010). Auditory spatial and object processing in the human planum temporale: no evidence for selectivity. Journal of Cognitive Neuroscience, 22(4), 632-639. doi: 10.1162/jocn.2009.21196

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

Zatorre, R. J., Bouffard, M., Ahad, P., & Belin, P. (2002). Where is 'where' in the human auditory cortex? Nat Neurosci, 5(9), 905-909.