Differences in fMRI intersubject correlation while viewing unedited and edited videos of dance performance

Abstract

Intersubject correlation (ISC) analysis of functional magnetic resonance imaging (fMRI) data provides insight into how continuous streams of sensory stimulation are processed by groups of observers. Although edited movies are frequently used as stimuli in ISC studies, there has been little direct examination of the effect of edits on the resulting ISC maps. In this study we showed 16 observers two audiovisual movie versions of the same dance. In one experimental condition there was a continuous view from a single camera (Unedited condition) and in the other condition there were views from different cameras (Edited condition) that provided close up views of the feet or face and upper body. We computed ISC maps for each condition, as well as created a map that showed the difference between the conditions. The results from the Unedited and Edited maps largely overlapped in the occipital and temporal cortices, although more voxels were found for the Edited map. The difference map revealed greater ISC for the Edited condition in the Postcentral Gyrus, Lingual Gyrus, Precentral Gyrus and Medial Frontal Gyrus, while the Unedited condition showed greater ISC in only the Superior Temporal Gyrus. These findings suggest that the visual changes associated with editing provide a source of correlation in maps obtained from edited film, and highlight the utility of using maps to evaluate the difference in ISC between conditions.

Untangling the relatedness among correlations, part I: Nonparametric approaches to inter-subject correlation analysis at the group level

“…For example, one popular approach for one condition was to acquire a null distribution for the whole brain by randomizing the time series across voxels and time points (e.g., circularly shifting each subject’s time series by a random lag so that they were no longer aligned in time across the subjects) (Kauppi et al, 2010; Nummenmaa et al, 2012; Abrams et al, 2013; Kauppi et al, 2014; Pajula and Tohka, 2014; Trost et al, 2015; Herbec et al, 2015; Bridwell et al, 2015). For comparing two conditions, a different permutation test was used on the N elements { z ij , i < j } through element-wise sign flipping (Kauppi et al, 2014).…”

“…One common practice in the literature is to obtain the group mean directly by averaging the ISC values across N subject pairs { r ij , i > j } (Kauppi et al, 2010; Nummenmaa et al, 2012; Honey et al, 2012; Pajula and Tohka, 2014; Kauppi et al, 2014; Bridwell et al, 2015; Lillywhite et al, 2015; Herbec et al, 2015). However, mathematically, the averaging as implemented in the ISC Toolbox (Kauppi et al, 2014) is problematic for the following reason.…”

“…The differences in synchronization can be further explored across groups or conditions. Such a methodology with natural stimulus presentations has flourished and been applied to wide variety of FMRI experiments, such as visuoauditory movie stimuli (Hasson et al, 2004, 2008; Golland et al, 2007; Jääskeläinen et al, 2008; Kauppi et al, 2010; Nummenmaa et al, 2012), the synchronization of emotion (Nummenmaa et al, 2012), the impact of mass media coverage on various perceptions of the H1N1 pandemic (Schmälzle et al, 2013), real-world thought processing (e.g., educational television viewing of Sesame Street) between children and adults (Cantlon and Li, 2013), videos of dance performance (Herbec et al, 2015), narratives (Wilson et al, 2008), music (Abrams et al, 2013; Alluri et al, 2013; Thiede, 2014; Trost et al, 2015, Lillywhite et al, 2015), aesthetic performance (Jola et al, 2013), neural responses shared across languages (Honey et al, 2012), and political speeches (Schmälzle et al, 2015). In addition, applications have been seen in other neuroimaging modalities, such as MEG (Thiede, 2014), EEG (Bridwell et al, 2015), and ECoG (Potes et al, 2014).…”

Neural mechanisms for integrating consecutive and interleaved natural events

“…In line with this, shuffling a movie using discontinuity edits markedly lowers ISC in higher‐order associative and frontal cortices across observers [Hasson et al, ; Lerner et al, ]. In contrast, adding continuity edits to depiction of continuous action actually increases ISC in the occipital, ventral temporal, and parietal cortices [Herbec et al, ] leaving ISCs in the posterior temporal regions unaffected. Indeed, we did not observe significant differences in the event‐related responses to scene onsets when the clips were preceded by the previous clip of the same movie (Consecutive condition) versus a clip from a different movie (Interleaved condition; Fig.…”

Neural correlates of experience with CCTV surveillance of naturalistic prosocial and antisocial interactions: a reverse correlation analysis

“…It is also relevant to note that the occurrence of camera devices at times also 21 corresponded to times with very little activity occurring within the scene, which in 22 some instances may have contributed to the decrease in activation. However, recent 23 results (Herbec et al, 2015) using unedited and edited videos of the same dance 24 performance revealed that editing activates a wide network of brain areas including 25 frontal cortex and possibly interactions within these brain networks might interact with 1 pSTS and FFA activity. 2 3 Differences between the groups of observers were apparent in the results of 4 the chi-squared analysis revealing a greater frequency of significantly activated 5 timeframes for novices viewing the prosocial CCTV footage only compared to CCTV 6 operators.…”