Metrical Rhythm Implicitly Orients Attention in Time as Indexed by Improved Target Detection and Left Inferior Parietal Activation

Abstract

When we direct attentional resources to a certain point in time, expectation and preparedness is heightened and behavior is, as a result, more efficient. This future-oriented attending can be guided either voluntarily, by externally defined cues, or implicitly, by perceived temporal regularities. Inspired by dynamic attending theory, our aim was to study the extent to which metrical structure, with its beats of greater or lesser relative strength, modulates attention implicitly over time and to uncover the neural circuits underlying this process of dynamic attending. We used fMRI to investigate whether auditory meter generated temporal expectancies and, consequently, how it affected processing of auditory and visual targets. Participants listened to a continuous auditory metrical sequence and pressed a button whenever an auditory or visual target was presented. The independent variable was the time of target presentation with respect to the metrical structure of the sequence. Participants' RTs to targets occurring on strong metrical positions were significantly faster than responses to events falling on weak metrical positions. Events falling on strong beats were accompanied by increased activation of the left inferior parietal cortex, a region crucial for orienting attention in time, and, by greater functional connectivity between the left inferior parietal cortex and the visual and auditory cortices, the SMA and the cerebellum. These results support the predictions of the dynamic attending theory that metrical structure with its relative strong and weak beats modulates attentional resources over time and, in turn, affects the functioning of both perceptual and motor preparatory systems.

Neural dissociation of automatic and controlled temporal preparation by transcranial magnetic stimulation

“…Nevertheless, the current null result should be taken with caution as it is based on a small sample (N ¼12). In any case, the finding that rhythmic preparation was not affected by frontal TMS in our specific experimental setting it is not surprising according to neuroimaging studies pointing to subcortical rather than cortical structures, such as the putamen (Geiser et al, 2012;Marchant and Driver, 2013), and to more posterior rather than frontal areas, such as the premotor (Schubotz et al, 2003;Schubotz and von Cramon, 2001) or parietal cortex (Bolger et al, 2014;Marchant and Driver, 2013) in the ability to anticipate events unfolding in a rhythmic structure.…”

“…In these studies, the role of DLPFC in temporal orienting and rhythms has received less attention with respect to parietal areas, probably because the available evidence is contradictory so far. In particular, both left and right DLPFC were shown to be active in some temporal orienting studies (Coull et al, 2013;Coull and Nobre, 1998-when comparing temporal orienting vs. rest conditions), while only the left DLPFC was active in a rhythm experiment (Marchant and Driver, 2013); Bolger et al (2014) and Davranche et al (2011) did not report any involvement of the DLPFC in rhythm and temporal orienting tasks.…”

“…Other studies using temporally regular, isochronous sequences of stimuli (hereafter referred to as "rhythms") have also reported changes in performance and brain activity as a function of the matching between the inter-onset interval (interval between the onset of two stimuli forming the rhythmic sequence) and the foreperiod (Barnes and Jones, 2000;Bolger et al, 2014;Breska and Deouell, 2014;Correa and Nobre, 2008;Cravo et al, 2013;Doherty et al, 2005;Jones et al, 2002;Lange, 2009Lange, , 2010Sanabria et al, 2011;Sanabria and Correa, 2013;Schmidt-Kassow et al, 2009;Schwartze et al, 2011). The dynamic attending theory (Large and Jones, 1999) can explain these findings by assuming that regularity provided by rhythmic stimulation entrains attention to focus on points in time matching the structure of the rhythm.…”

Spoken Word Recognition Enhancement Due to Preceding Synchronized Beats Compared to Unsynchronized or Unrhythmic Beats

“…It would thus be expected that recognition of syllables that coincide with the high excitability phase will be enhanced. Effects of differencial processing in the presence of rhythm explained in terms of DAT include visual processing (Escoffier and Tillmann, 2008; Escoffier et al, 2010; Bolger et al, 2013, 2014; Miller et al, 2013) auditory processing (Bolger et al, 2013, 2014) and linguistic-semantic processing (Poulin-Charronnat et al, 2005). …”

Comparing the effects of implicit and explicit temporal expectation on choice response time and response conflict

“…A simple case would be experiencing rhythmically repeating events that generate an expectation that events will continue to occur on the beat. It has been shown that whether people are aware or unaware of the rhythmicity of the preceding stimulus sequence, they tend to respond faster to an event that occurs on the anticipated beat (e.g., Bolger, Coull, & Schön, 2014; Praamstra, Kourtis, Kwok & Oostenveld, 2006; Praamstra, Kourtis, Kwok & Oostenveld, 2006; Rohenkohl, Coull, & Nobre, 2011), suggesting that periodic rhythms automatically establish temporal expectations.…”