Spatial processing in the auditory cortex of the macaque monkey

Abstract

The patterns of cortico-cortical and cortico-thalamic connections of auditory cortical areas in the rhesus monkey have led to the hypothesis that acoustic information is processed in series and in parallel in the primate auditory cortex. Recent physiological experiments in the behaving monkey indicate that the response properties of neurons in different cortical areas are both functionally distinct from each other, which is indicative of parallel processing, and functionally similar to each other, which is indicative of serial processing. Thus, auditory cortical processing may be similar to the serial and parallel ''what'' and ''where'' processing by the primate visual cortex. If ''where'' information is serially processed in the primate auditory cortex, neurons in cortical areas along this pathway should have progressively better spatial tuning properties. This prediction is supported by recent experiments that have shown that neurons in the caudomedial field have better spatial tuning properties than neurons in the primary auditory cortex. Neurons in the caudomedial field are also better than primary auditory cortex neurons at predicting the sound localization ability across different stimulus frequencies and bandwidths in both azimuth and elevation. These data support the hypothesis that the primate auditory cortex processes acoustic information in a serial and parallel manner and suggest that this may be a general cortical mechanism for sensory perception.

Representation of auditory motion directions and sound source locations in the human planum temporale

“…2C), MVP-classification results showed that beside the vertical axis (up versus down), sound source location information can be reliably decoded bilaterally in hPT (Figure 3). Our results are in line with previous studies showing that posterior regions in auditory cortex exhibit location sensitivity both in animals (Recanzone, 2000;Stecker et al, 2005;Tian et al, 2001) and humans (Ahveninen et al, 2006(Ahveninen et al, , 2013Brunetti et al, 2005;Deouell et al, 2007;Derey et al, 2016;Krumbholz et al, 2005;Warren and Griffiths, 2003;Zatorre et al, 2002).…”

“…Lesion studies have indeed demonstrated the critical role of the auditory cortex for spatial hearing in humans (Duffour-Nikolov et al, 2012;Sanchez-Longo and Forster, 1958;Zatorre and Belin, 2001). Similar to the visual cortex dual-stream processing model, partially distinct ventral "what" and dorsal "where" auditory processing streams have been proposed for auditory processing (Barrett and Hall, 2006;Lomber and Malhotra, 2008;Rauschecker and Tian, 2000;Recanzone, 2000;Romanski et al, 1999;Tian et al, 2001;Warren and Griffiths, 2003). However, it remains poorly understood how the human brain implements the processing of auditory motion and location, and how these two processes differ from each other.…”

“…hPT is located in the superior temporal gyrus, posterior to Helsch' gyrus, and is typically considered part of the dorsal auditory stream (Poirier et al, 2017;Rauschecker and Tian, 2000;Recanzone, 2000;Romanski et al, 1999;Tian et al, 2001). Some authors have suggested that hPT equally engages in the processing of moving sounds and the location of static sound-sources (Barrett and Hall, 2006;Derey et al, 2016;Krumbholz et al, 2005;Smith et al, 2004Smith et al, , 2007Smith et al, , 2010Zatorre et al, 2002).…”

A Rate Code for Sound Azimuth in Monkey Auditory Cortex: Implications for Human Neuroimaging Studies

“…PSTHs were constructed with 3 ms bins . The mean response latency of the neurons in our sample was 50.2 ms, which is on the long end of the range of latencies in previous reports involving tonal stimuli near the characteristic frequency (Recanzone et al, 1993(Recanzone et al, , 1999(Recanzone et al, , 2000Fu et al, 2004;Kajikawa et al, 2005).…”

“…Although the methods used here have not been previously used in auditory cortex, a number of previous studies in monkeys and other animals have evaluated the spatial sensitivity of auditory cortical neurons using other means (Middlebrooks and Pettigrew, 1981;Rajan et al, 1990a,b;Brugge et al, 1994Brugge et al, , 1996Brugge et al, , 1998Brugge et al, , 2001Clarey et al, 1994Clarey et al, , 1995Middlebrooks et al, 1994Middlebrooks et al, , 1998Barone et al, 1996;Eggermont and Mossop, 1998;Xu et al, 1998;Brugge and Reale, 2000;Furukawa et al, 2000;Recanzone, 2000;Furukawa and Middlebrooks, 2002;Stecker et al, , 2005aMrsic-Flogel et al, 2005;Woods et al, 2006). These studies have provided numerous clues about auditory cortical spatial sensitivity that are more consistent with a rate code than a place code: neurons tend to exhibit broad spatial tuning (Recanzone, 2000;Mickey and Middlebrooks, 2003;Woods et al, 2006); many neurons show "hemifield" sensitivity (Middlebrooks and Pettigrew, 1981); few neurons have circumscribed receptive fields in frontal space (Rajan et al, .…”