Amygdala and orbitofrontal engagement in breach and resolution of expectancy: A case study.

Abstract

Constant prediction is a process of future-directed information processing (Rohrmeier & Koelsch, 2012). It is a major factor of the interaction with the complexity of the human environment and contributes to updating of the so-called cognitive world model (Brown & Brune, 2012; Bubic, von Cramon, Jacobsen, Schroger, & Schubotz, 2009; Bubic, von Cramon, & Schubotz, 2010; Friston, 2012). The top-down prediction of what is likely to come next is advantageous, for example, for the preparation of fast adequate responses to incoming stimuli (Friston, 2009). In audition it enables the identification of incomplete, noisy, or ambiguous stimuli, the reduction of the orienting response (Huron, 2001; Summerfield & Egner, 2009), and the preparation of more accurate responses (Schultz, Dayan, & Montague, 1997). Predictions are essential for the organism, often resulting in punishment as a result of failures, and rewards for success. Reward and punishment is reflected in negative and positive affective reactions (Grossberg, 2009; Pearce & Wiggins, 2012).Several music studies have examined emotions associated with expectancy (e.g., Koelsch, Kilches, Steinbeis, & Schelinski, 2008; Salimpoor, Benovoy, Larcher, Dagher, & Zatorre, 2011; Steinbeis, Koelsch, & Sloboda, 2005). One central principle underlying the evocation of emotions with music relies in part on expectancy and prediction (Huron, 2006; Koelsch, 2014; Meyer, 1956). Using EEG, Flores-Gutierrez et al. (2007) found a lateralized frontal alpha suppression during listening to unpredictable music, perhaps originating in limbic/paralimbic structures. Using fMRI, it was found that breaches of expectancy evoke blood-oxygen level dependent (BOLD) changes in the amygdala (Koelsch, Fritz, & Schlaug, 2008) and the orbitofrontal cortex (OFC; Tillmann, Janata, & Bharucha, 2003; Koelsch, Fritz, Schulze, Alsop, & Schlaug, 2005). The emotional reaction to unexpected musical information was found to be reflected in increased electrodermal activity (Koelsch et al., 2008; Steinbeis et al., 2005). These regions play an important role in various emotional processes, including breaches of expectancy (Nobre, Coull, Frith, & Mesulam, 1999). Notably, the OFC is, in addition to numerous other affective functions, associated with the evaluation of the emotional significance of sensory stimuli (Rolls, 2000).In summary, limbic/paralimbic circuits including the OFC and the amygdala appear to be important for emotional reactions to expectancy violations in music. Psychologically, breaches of expectancy in music create not only surprise (Koelsch et al., 2008), but also modulate tension (Lehne, Rohrmeier, & Koelsch, 2014). In tonal music, a structural breach is usually followed by a transitory phase, which leads to the resolution of the breach; this transitory phase represents a delay of the expected resolution and relaxation (Koelsch, 2014). Note that the studies mentioned above only explored the breach of expectancy, and not the effects of the resolution of the resulting tension.Expectancy in music and its resulting tension is a process that occurs over time, and usually involves several discrete events. Koelsch (2014) proposed that the different factors giving rise to tension and resolution contribute to a tension arc, with the different factors underlying tension including the build-up of expectancy, its breach, anticipation of resolution, and resolution (with maximum tension during breaches of expectancies and the subsequent transitory phase).The cognitive processing of unexpected chords (i.e., cognitive aspects of irregularity detection) is neurophysiologically reflected in an early right anterior negativity (ERAN), which is mainly generated in inferior fronto-lateral (neo-)cortex (Lehne et al., 2014; Sammler et al., 2013). Thus, unexpected chords elicit both cognitive and emotional processes. As mentioned above, the emotion reactions to unexpected chords appear to be reflected, for example, in an increased activation of the amygdala (Koelsch et al. …