Brain Activation during Anticipation of Sound Sequences

Abstract

Music consists of sound sequences that require integration over time. As we become familiar with music, associations between notes, melodies, and entire symphonic movements become stronger and more complex. These associations can become so tight that, for example, hearing the end of one album track can elicit a robust image of the upcoming track while anticipating it in total silence. Here, we study this predictive "anticipatory imagery" at various stages throughout learning and investigate activity changes in corresponding neural structures using functional magnetic resonance imaging. Anticipatory imagery (in silence) for highly familiar naturalistic music was accompanied by pronounced activity in rostral prefrontal cortex (PFC) and premotor areas. Examining changes in the neural bases of anticipatory imagery during two stages of learning conditional associations between simple melodies, however, demonstrates the importance of fronto-striatal connections, consistent with a role of the basal ganglia in "training" frontal cortex (Pasupathy and Miller, 2005). Another striking change in neural resources during learning was a shift between caudal PFC earlier to rostral PFC later in learning. Our findings regarding musical anticipation and sound sequence learning are highly compatible with studies of motor sequence learning, suggesting common predictive mechanisms in both domains.

Selectivity for space and time in early areas of the auditory dorsal stream in the rhesus monkey

“…The traditional model of the auditory dorsal stream emphasizes its role in processing spatial information (Rauschecker 1998;Rauschecker and Tian 2000;Recanzone 2000), which is supported by many studies in monkeys and humans (Deouell et al 2007;Miller and Recanzone 2009;Warren et al 2002;Zimmer and Macaluso 2005). Nonspatial functions have been mapped to the dorsal stream as well (Belin and Zatorre 2000;Dhanjal et al 2008;Geschwind 1965;Hickok et al 2009;Leaver et al 2009;Lewis et al 2005;Perry et al 1999;Rauschecker 2011;Rauschecker and Scott 2009;Wernicke 1874;Wise et al 2001), especially in its extension to premotor and prefrontal cortices (see also introduction). This raises the possibility of a division of labor within the dorsal stream, with different subregions or substreams performing different functions.…”

“…However, other studies in humans have provided evidence for various nonspatial auditory functions to be represented in areas currently assumed to belong to the dorsal stream as well. These have included speech processing (Dhanjal et al 2008;Geschwind 1965;Hickok et al 2009;Wernicke 1874;Wise et al 2001;see, however, DeWitt and Rauschecker 2012), tracking of spectral motion (Belin and Zatorre 2000), timing of acoustic rhythm (Schubotz et al 2003), singing (Perry et al 1999), imagery of music (Leaver et al 2009), and representation of tool sounds (Lewis et al 2005). It has been argued that these functions are specific manifestations of a more general function of audio-motor control, which includes the processing of space and motion in space (Rauschecker 2011;Rauschecker and Scott 2009).…”

Analogues of simple and complex cells in rhesus monkey auditory cortex

“…Indeed, evidence for perceptual stream segregation at the neural level has previously been reported for rhesus monkey primary auditory cortex (48,49). In a subsequent step, temporal integration of acoustic information is necessary to accomplish the encoding of sound sequences, e.g., in the form of musical melodies (50,51) or auditory "objects" (52-54). Type-C cells in the auditory cortex may form the beginning of this integration.…”

Predictability of what or where reduces brain activity, but a bottleneck occurs when both are predictable

“…The putamen has been traditionally linked to motor-sequence learning and execution via a cortico-striatal loop that connects the SMA, putamen, pallidum and thalamic nuclei (Graybiel, 1998). However, it has also been linked to artificial grammar learning absent of motor execution (Lieberman, Chang, Chiao, Bookheimer, & Knowlton, 2004;McNealy, Mazziotta, & Dapretto, 2006) as well as to auditory anticipation for known materials (Leaver, Van Lare, Zielinski, Halpern, & Rauschecker, 2009). Thus, we take the involvement of these regions in the current study to reflect the coding of overall uncertainty, or successful learning of input contingencies.…”