Cortical Correlates of Attention to Auditory Features

Abstract

Pitch and timbre are two primary features of auditory perception that are generally considered independent. However, an increase in pitch (produced by a change in fundamental frequency) can be confused with an increase in brightness (an attribute of timbre related to spectral centroid) and vice versa. Previous work indicates that pitch and timbre are processed in overlapping regions of the auditory cortex, but are separable to some extent via multivoxel pattern analysis. Here, we tested whether attention to one or other feature increases the spatial separation of their cortical representations and if attention can enhance the cortical representation of these features in the absence of any physical change in the stimulus. Ten human subjects (four female, six male) listened to pairs of tone triplets varying in pitch, timbre, or both and judged which tone triplet had the higher pitch or brighter timbre. Variations in each feature engaged common auditory regions with no clear distinctions at a univariate level. Attending to one did not improve the separability of the neural representations of pitch and timbre at the univariate level. At the multivariate level, the classifier performed above chance in distinguishing between conditions in which pitch or timbre was discriminated. The results confirm that the computations underlying pitch and timbre perception are subserved by strongly overlapping cortical regions, but reveal that attention to one or other feature leads to distinguishable activation patterns even in the absence of physical differences in the stimuli.Although pitch and timbre are generally thought of as independent auditory features of a sound, pitch height and timbral brightness can be confused for one another. This study shows that pitch and timbre variations are represented in overlapping regions of auditory cortex, but that they produce distinguishable patterns of activation. Most importantly, the patterns of activation can be distinguished based on whether subjects attended to pitch or timbre even when the stimuli remained physically identical. The results therefore show that variations in pitch and timbre are represented by overlapping neural networks, but that attention to different features of the same sound can lead to distinguishable patterns of activation.

Short- and long-term memory for pitch and non-pitch contours: Insights from congenital amusia

“…Under another interpretation, however, this effect could be seen as further evidence that brightness and pitch are closely related; in fact, pitch and timbre cues are known to interact perceptually (Allen & Oxenham, 2014;Marozeau & de Cheveigné, 2007;Melara & Marks, 1990;Warrier & Zatorre, 2002), and they may activate overlapping brain regions (Allen et al, 2019(Allen et al, , 2017Bizley et al, 2009;Warren et al, 2005). Given these similarities, a deficit in pitch processing should lead to an impairment in brightness processing to the extent that these dimensions are perceived by shared mechanisms.…”

“…All three of these dimensions are known to interact perceptually (Allen & Oxenham, 2014;Marozeau & de Cheveigné, 2007;Melara & Marks, 1990;Verschuure & van Meeteren, 1975;Warrier & Zatorre, 2002), with pitch and brightness perception perhaps relying on overlapping neural mechanisms (Allen, Burton, Mesik, Olman, & Oxenham, 2019;Allen, Burton, Olman, & Oxenham, 2017;Bizley, Walker, Silverman, King, & Schnupp, 2009;Warren, Jennings, & Griffiths, 2005). Specifically, changes in pitch and brightness seem to activate strongly overlapping regions of auditory cortex, but produce patterns of activation within those regions that can be statistically distinguished (Allen et al, 2019(Allen et al, , 2017.…”

“…All three of these dimensions are known to interact perceptually (Allen & Oxenham, 2014;Marozeau & de Cheveigné, 2007;Melara & Marks, 1990;Verschuure & van Meeteren, 1975;Warrier & Zatorre, 2002), with pitch and brightness perception perhaps relying on overlapping neural mechanisms (Allen, Burton, Mesik, Olman, & Oxenham, 2019;Allen, Burton, Olman, & Oxenham, 2017;Bizley, Walker, Silverman, King, & Schnupp, 2009;Warren, Jennings, & Griffiths, 2005). Specifically, changes in pitch and brightness seem to activate strongly overlapping regions of auditory cortex, but produce patterns of activation within those regions that can be statistically distinguished (Allen et al, 2019(Allen et al, , 2017. When studied separately, fundamental frequency (F0) and pitch seem most strongly represented in anterolateral primary auditory cortex (Bendor & Wang, 2005;Norman-Haignere, Kanwisher, & McDermott, 2013), whereas spectral shape (resulting in brightness variations) may be more strongly represented in the superior temporal sulcus (Warren et al, 2005).…”

Infants can outperform adults in pitch and timbre perception

“…Adults often have difficulty distinguishing between pitch and the aspect of timbre known as brightness, describing increases in both as being "higher." In studies of discrimination, interference between the two dimensions is common (Allen & Oxenham, 2014;Borchert, Micheyl, & Oxenham, 2011;Lau & Werner, 2014), and in functional imaging studies, substantial overlap between representations of pitch and brightness has been reported (Allen, Burton, Mesik, Olman, & Oxenham, 2019). Musical training typically leads to be better pitch discrimination prior to explicit training (Madsen, Marschall, Dau, & Oxenham, 2019;Micheyl et al, 2006), but does not eliminate such interference (Allen & Oxenham, 2014).…”

A unitary model of auditory frequency change perception

“…However, in spite of centuries of intense scrutiny, the precise nature of the auditory cues determining pitch in the general case has remained elusive, with many additional candidates beyond periodicity [3][4][5]. Moreover, in the perceptual domain, the independence of pitch from other perceptual attributes such as timbre has been recently challenged [6][7][8][9][10]. Here, we explore a unifying hypothesis, suggesting that a salient perceptual dimension on which sounds can be ordered from "low" to "high" is in fact a compound construct, seamlessly derived by listeners from the combination of distinct auditory cues, each adaptively weighted in a manner that can be sound-dependent and listener-specific.…”