Auditory Spatial Coding Flexibly Recruits Anterior, but Not Posterior, Visuotopic Parietal Cortex

Abstract

Audition and vision both convey spatial information about the environment, but much less is known about mechanisms of auditory spatial cognition than visual spatial cognition. Human cortex contains >20 visuospatial map representations but no reported auditory spatial maps. The intraparietal sulcus (IPS) contains several of these visuospatial maps, which support visuospatial attention and short-term memory (STM). Neuroimaging studies also demonstrate that parietal cortex is activated during auditory spatial attention and working memory tasks, but prior work has not demonstrated that auditory activation occurs within visual spatial maps in parietal cortex. Here, we report both cognitive and anatomical distinctions in the auditory recruitment of visuotopically mapped regions within the superior parietal lobule. An auditory spatial STM task recruited anterior visuotopic maps (IPS2–4, SPL1), but an auditory temporal STM task with equivalent stimuli failed to drive these regions significantly. Behavioral and eye-tracking measures rule out task difficulty and eye movement explanations. Neither auditory task recruited posterior regions IPS0 or IPS1, which appear to be exclusively visual. These findings support the hypothesis of multisensory spatial processing in the anterior, but not posterior, superior parietal lobule and demonstrate that recruitment of these maps depends on auditory task demands.

Cortical and Sensory Causes of Individual Differences in Selective Attention Ability Among Listeners With Normal Hearing Thresholds

“…In contrast, when listeners focus their auditory selective attention on nonspatial, spectrotemporal acoustic features of a sound source, the visuospatial attentional network is less active (Braga, Wilson, Sharp, Wise, & Leech, 2013;Michalka et al, 2015Michalka et al, , 2016. Instead, regions of the brain closely associated with auditory processing show enhanced activation (Hill & Miller, 2010;Larson & Lee, 2014;Lee et al, 2013;Michalka et al, 2015Michalka et al, , 2016.…”

“…Instead, regions of the brain closely associated with auditory processing show enhanced activation (Hill & Miller, 2010;Larson & Lee, 2014;Lee et al, 2013;Michalka et al, 2015Michalka et al, , 2016. Thus, topdown attention to nonspatial auditory features differentially engages areas associated with auditory-specific processing and causes less activity in the visuospatial orienting network.…”

“…Converging evidence shows that, when listeners focus their auditory selective attention on a particular spatial location, areas in this well-known visuospatial attention network are more active compared with when not performing a task (Kong et al, 2014;Michalka, Rosen, Kong, Shinn-Cunningham, & Somers, 2016;Shomstein & Yantis, 2004, 2006Tark & Curtis, 2009). These regions are also more active when listeners solve the same cocktail party problem by using spatial cues (e.g., "listen to the talker on the left") than when they use spectrotemporal acoustic features (e.g., "listen to the female talker"; Bharadwaj, Lee, & Shinn-Cunningham, 2014;Hill & Miller, 2010;Lee et al, 2013;Michalka, Kong, Rosen, Shinn-Cunningham, & Somers, 2015).…”

A brief comparative review of primate posterior parietal cortex: A novel hypothesis on the human toolmaker

“…A recent fMRI study suggests that, depending on auditory task demands (spatial vs. temporal processing), auditory stimulation may recruit visuotopic regions within the PPC (Fig. 3D; Michalka, Rosen, Kong, Shinn-Cunningham, & Somers, 2016). Furthermore, transcranial magnetic stimulation (TMS) of PPC near the junction of the anterior intraparietal sulcus and the postcentral sulcus eliminates the facilitatory influence of vision (Pasalar, Ro, & Beauchamp, 2010) or audition (Serino, Canzoneri, & Avenanti, 2011) on tactile perception near the hand, suggesting a causal role of these parts of human PPC in multisensory integration.…”

“…(D) Activation in the human parietal lobule during spatial and temporal auditory processing. Reproduced with permission from Michalka, et al (2016).…”