Population receptive field estimates of human auditory cortex

Abstract

Here we describe a method for measuring tonotopic maps and estimating bandwidth for voxels in human primary auditory cortex (PAC) using a modification of the population Receptive Field (pRF) model, developed for retinotopic mapping in visual cortex by Dumoulin and Wandell (2008). The pRF method reliably estimates tonotopic maps in the presence of acoustic scanner noise, and has two advantages over phase-encoding techniques. First, the stimulus design is flexible and need not be a frequency progression, thereby reducing biases due to habituation, expectation, and estimation artifacts, as well as reducing the effects of spatio-temporal BOLD nonlinearities. Second, the pRF method can provide estimates of bandwidth as a function of frequency. We find that bandwidth estimates are narrower for voxels within the PAC than in surrounding auditory responsive regions (non-PAC).

Extensive tonotopic mapping across auditory cortex is recapitulated by spectrally-directed attention, and systematically related to cortical myeloarchitecture

“…Stimulus-and attentionally-driven tonotopic organization outside of auditory core. In line with results from previous fMRI studies Woods et al, 2009;Humphries et al, 2010;Barton et al, 2012;Dick et al, 2012;Moerel et al, 2012;Saenz and Langers, 2014;Thomas et al, 2015;De Martino et al, 2015b;Ahveninen et al, 2016;Leaver and Rauschecker, 2016;Riecke et al, 2016), there is stimulus-driven tonotopic mapping extending well beyond auditory core, spanning the temporal plane and continuing into the superior temporal sulcus (STS). As shown in Fig.…”

“…In future research it will be informative to examine interactions with several frontal regions whose potential analogues are known to have direct feedforward and feedback connections in macaque monkeys (Romanski and Goldman-Rakic, 2002), and where in ferret there are clear modulatory influences on primary and non-primary auditory cortex during learning (Atiani et al, 2014;Shamma and Fritz, 2014). Similar to recent work in vision (Klein et al, 2014;Puckett and DeYoe, 2015), it will also be useful to establish the shape of the attentional population receptive field, and how this varies across auditory areas and relates to stimulus-driven auditory population receptive field size (Thomas et al, 2015). Finally, following on our own pilot work, it will be exciting to explore whether higher-level auditory regionalization may follow along some of the 'fault lines' revealed by shared local tonotopic and myelin gradients, and whether or not more sophisticated and finegrained spectral attentional manipulations may reveal a relationship between the degree of attentional malleability and underlying cortical architecture and circuitry.…”

Mapping sequences can bias population receptive field estimates

“…Results suggest that the spatiotemporal regularities in the mapping protocol significantly affected 112 pRF size (tuning width) estimates in agreement with what was previously observed for pRF size 113 in the visual (Binda et al, 2013) and the auditory domain (Thomas et al, 2015). Moreover, we 114 observed that the direction of the effect depended on the duration of the mapping cycle.…”

A Primer on Pattern-Based Approaches to fMRI: Principles, Pitfalls, and Perspectives

“…The receptive fields of voxels in early visual cortex have been characterized as simple two-dimensional Gaussian filters (Dumoulin and Wandell, 2008;Thirion et al, 2006), difference of Gaussians (Zuiderbaan et al, 2012), or as standard multi-parameter Gabor filter banks (Kay et al, 2008). Voxel-wise encoding models have been extended to effects of color (Brouwer and Heeger, 2009), facial identity (Gratton et al, 2013), attention (Sprague and Serences, 2013), working memory (Sprague et al, 2014), numerosity (Harvey et al, 2013), semantics (Huth et al, 2012), and even to other modalities (Schö nwiesner and Zatorre, 2009;Thomas et al, 2015). Encoding models also can incorporate nonlinear processing stages .…”