I believe our 1999 Nature Neuroscience paper is being cited for two reasons. First, there has been a resurgence of interest in higher order auditory processing over the last several years. So much research has been aimed at elucidating the neurobiology of the visual system that we now have to "catch-up" with the auditory system. Secondly, this paper poses the theory that the auditory and visual systems are more alike than previously thought and this is an interesting and controversial theory.

I think our paper brings several discoveries together to support a new theory that can be used to further our understanding of auditory processing. In this study we have demonstrated that parallel streams of auditory information, which originate in different subregions of auditory association cortex project to functionally distinct areas of the frontal lobe. Although the methodologies used (anatomical tract tracing and single unit electrophysiology) are not new, their combined use here resulted in unequivocal demonstration of auditory projections to prefrontal cortical targets, which had never been done previously.

Our work suggests that our brains may process auditory information the same way that visual information is processed - using distinct, but parallel systems to determining "what" something is and "where" it came from. The auditory stream for deciding "what" something is emanates from rostral auditory cortex and projects to several sites in rostral and ventral prefrontal cortex, which in the human brain, is involved in language processing (i.e. Broca's area). Another stream originates in caudal auditory cortex and targets caudal, dorsolateral prefrontal cortex, and is involved in spatial processing, for example, remembering "where" an object is.

I have been interested in how we make sense of what we hear since I was an undergraduate working with autistic children. During my postdoctoral work in Patricia Goldman-Rakic's lab I began to investigate auditory processing in the frontal lobe. Knowing that the human brain has sites within the frontal lobe that are specifically involved in language processing and in auditory working memory we theorized that non-human primates may have similar sites in the prefrontal cortex for the processing of communication-relevant auditory information.