Holding Biological Motion in Working Memory: An fMRI Study

Abstract

Holding biological motion (BM), the movements of animate entities, in working memory (WM) is important to our daily life activities. However, the neural substrates underlying the WM processing of BM remain largely unknown. Employing the functional magnetic resonance imaging (fMRI) technique, the current study directly investigated this issue. We used point-light BM animations as the tested stimuli, and explored the neural substrates involved in encoding and retaining BM information in WM. Participants were required to remember two or four BM stimuli in a change-detection task. We first defined a set of potential brain regions devoted to the BM processing in WM in one experiment. We then conducted the second fMRI experiment, and performed time-course analysis over the pre-defined regions, which allowed us to differentiate the encoding and maintenance phases of WM. The results showed that a set of brain regions were involved in encoding BM into WM, including the middle frontal gyrus, inferior frontal gyrus, superior parietal lobule, inferior parietal lobule, superior temporal sulcus, fusiform gyrus, and middle occipital gyrus. However, only the middle frontal gyrus, inferior frontal gyrus, superior parietal lobule, and inferior parietal lobule were involved in retaining BM into WM. These results suggest that an overlapped network exists between the WM encoding and maintenance for BM; however, retaining BM in WM predominately relies on the mirror neuron system.

Development of Social Working Memory in Preschoolers and Its Relation to Theory of Mind

“…Additionally, it is important to note that researchers have suggested that there might be two distinct types of social WM (Lieberman, ; Xin & Lei, ): One requires participants to internally focus their attention on friends' internal traits and rank them according to a specific dimension (i.e., internally orientated social WM; e.g., Meyer & Lieberman, , ; Meyer et al., , ); the other requires participants to focus their attention on the external world and their friends' faces or actions (externally orientated social WM; e.g., Gao et al., , ; Lu et al., ; Shen et al., ; Thornton & Conway, ; Xin & Lei, ). Xin and Lei () elegantly showed that there are certain differences in the neural substrates of these two types of social WM.…”

“…If the child could not focus on a trial because of unexpected issues, experimenter presented the same trial again by pressing the space bar on the keyboard. Note that previous studies added a digit rehearsal task to the memory task to prevent participants from verbally encoding BM stimuli (e.g., Gao et al., ; Lu et al., ; Shen et al., ). However, we did not do this because children do not develop verbal rehearsal strategies until around 7 years old (Hitch et al., ).…”

“…So far, researchers have explored the capacity (Gao, Bentin, & Shen, ; Shen, Gao, Ding, Zhou, & Huang, ), storage manner (Thornton & Conway, ), function (Gao et al., ; Meyer et al., , ; Xin & Lei, ), and neural substrates of social WM (Lieberman, ; Lu et al., ; Meyer & Lieberman, , ; Meyer et al., , ; Thornton & Conway, ; Xin & Lei, ). However, no study, to the best of our knowledge, has yet explored the development of social WM.…”

“…Moreover, two lines of evidence imply that social information is indeed processed when retaining BM in WM. First, neuroimaging studies have shown that the neural substrates for WM storage of BM include the mirror neuron system (Gao et al, 2015;Lu et al, 2016), which is suggested to have a close link with social cognition (e.g., Rizzolatti & Fabbri-Destro, 2008; but see Cook, Bird, Catmur, Press, & Heyes, 2014 for a different view). Second, Gao et al (2016) found that the WM capacity of BM, but not canonical WM capacity (e.g., color), is a predictor of empathy, which is a key aspect of social functioning.…”

Distinct neural substrates for visual short‐term memory of actions

“…Other studies using multivariate pattern analysis (MVPA) have successfully decoded the specific motion direction during the delay period in MT areas (Emrich, Riggall, LaRocque, & Postle, ; LaRocque, Riggall, Emrich, & Postle, ). Nevertheless, in another study of action VSTM using point‐light motion animations, it has been found that the frontal and parietal lobules were involved in maintaining action during the delay (Lu et al, ). As this study did not include the VSTM task for objects and spatial locations, it remains unclear if these regions are specific to VSTM of actions or they are shared by VSTM of other stimuli (or aspects of stimuli) such as objects/agents or spatial locations.…”