Neural mechanisms for integrating consecutive and interleaved natural events

Abstract

To understand temporally extended events, the human brain needs to accumulate information continuously across time. Interruptions that require switching of attention to other event sequences disrupt this process. To reveal neural mechanisms supporting integration of event information, we measured brain activity with functional magnetic resonance imaging (fMRI) from 18 participants while they viewed 6.5-minute excerpts from three movies (i) consecutively and (ii) as interleaved segments of approximately 50-s in duration. We measured inter-subject reliability of brain activity by calculating inter-subject correlations (ISC) of fMRI signals and analyzed activation timecourses with a general linear model (GLM). Interleaving decreased the ISC in posterior temporal lobes, medial prefrontal cortex, superior precuneus, medial occipital cortex, and cerebellum. In the GLM analyses, posterior temporal lobes were activated more consistently by instances of speech when the movies were viewed consecutively than as interleaved segments. By contrast, low-level auditory and visual stimulus features and editing boundaries caused similar activity patterns in both conditions. In the medial occipital cortex, decreases in ISC were seen in short bursts throughout the movie clips. By contrast, the other areas showed longer-lasting differences in ISC during isolated scenes depicting socially-relevant and suspenseful content, such as deception or inter-subject conflict. The areas in the posterior temporal lobes also showed sustained activity during continuous actions and were deactivated when actions ended at scene boundaries. Our results suggest that the posterior temporal and dorsomedial prefrontal cortices, as well as the cerebellum and dorsal precuneus, support integration of events into coherent event sequences. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

Exploring the neural substrates of misinformation processing

“…The region has repeatedly been shown to support the integration of continuous pieces of verbal information in a coherent mental model (Silbert et al, 2014;Whitney et al, 2009;Wilson et al, 2008;Xu et al, 2005). In addition, reductions in PrC activity have recently been linked to integration difficulties (e.g., Lahnakoski et al, 2017). In light of these findings, our data suggest that basic integrative and coherence-building mechanisms are less engaged whenever new pieces of information that challenge a person's prior understanding of an event require encoding.…”

Topology of Functional Connectivity and Hub Dynamics in the Beta Band As Temporal Prior for Natural Vision in the Human Brain

“…1A). This has been shown to affect activity in higher-level visual regions that have longer temporal integration and much less activity in early visual cortex (Hasson et al, 2008). This procedure was repeated for each movie clip to generate three different scrambled movie clips.…”

“…An alternative hypothesis is that intrinsic connectivity reflects "idling" cortical circuits that are suppressed to facilitate taskspecific synchronization. For instance, recent fMRI work indicates that behavioral tasks cause robust reorganization of the spatial patterns of functional connections (Krienen et al, 2014;Spadone et al, 2015;Kim et al, 2017), including hubs (Gratton et al, 2016). In addition, the observation of movie scenes reduces MEG band-limited power (BLP) connectivity in the ␣ band between regions of the same network while increasing ␤-, -, and ␥-band correlation between regions of different networks .…”

“…Second, we compared two viewing conditions: one in which the sequence of scenes was played normally (natural vision) and another in which the scenes were temporally scrambled (scrambled vision). In the visual cortex, the statistics of intrinsic brain activity are more similar to natural than artificial or synthetic stimuli (Fiser et al, 2004;Berkes et al, 2011) and the slow-varying timescale of natural stimuli resembles that of neural fluctuations in associative cortex (Hasson et al, 2008;Honey et al, 2012;Boly et al, 2015). Accordingly, the prior hypothesis predicts that the topology and hub dynamics would be more similar between rest and natural vision than between rest and scrambled vision.…”

No evidence for functional distinctions across fronto-temporal language regions in their temporal receptive windows

“…For instance, such distinct networks may reliably track respectively independent aspects of a given stimulus, resulting in low ISCs that do not adequately characterize either network. This issue pertains not only to studies of linguistic processing (e.g., Lerner et al, 2014), but to any study based on voxel-wise ISCs including, e.g., the many studies characterizing the episodic network (Honey et al, 2012b;Regev et al, 2013;Silbert et al, 2014;Simony et al, 2016;Baldassano et al, 2017;Lahnakoski et al, 2017;Yeshurun et al, 2017a;Yeshurun et al, 2017b;Regev et al, 2018), whose location is highly variable across individuals (Braga and Buckner, 2017).…”