Rehearsal Biological Motion In Working Memory

Biological motion(BM)refers to the continuous configuration movement of animate entities in space.BM is the most common visual stimulus in environment which containing plenty of social information.Moreover,multiple aspects of social information can be extracted from BM,including gender,identity,emotion,intention,even personality.To form coherent BM representation and guide our social behavior,we need to not only process the BM in perception but also retain the BM information in working memory(WM).The ability to retain BM in"WM is at the core of humans’capacity to engage in normal social interactions.However,previous studies only focus on WM maintenance of BM.The function of WM is not only storing representations.but also processing them.As the most basic processing in working memory,rehearsal plays a key role in the maintenance of information and subsequent processing.This study explored WM rehearsal mechanism of BM through two aspects:attentional mechanism and neural mechanism.Firstly,the present study explored the nature of attention underlies retaining BM in WM via a dual-task paradigm.In distinct blocks participants were required to memorize BM or controlled visual information(locations in Experiments 1,3,and 5,and shapes in Experiments 2,4,and 6).Critically,during the WM maintenance phase,I inserted a visual search task(Experiment 1),a transparent motion task(Experiment 2),a backward digit counting task(Experiment 3 and 4),or a multiple object tracking task(Experiments 5 and 6)to consume spatial,object-based,domain-general,or dynamic attention,respectively.Results showed that comparing with location,memory performance of BM did not be selective impaired by the visual search task and the backward digit counting task.Comparing with shape,memory performance of BM did not be selective impaired by the transparent motion task and the backward digit counting task.However,the multi-object tracking task led to a selective impairment for BM memory performance comparing with location and shape.Secondly,the present study explored the neural substrates underlying the WM rehearsal of BM.Employing the functional magnetic resonance imaging(fMRI)technique,I defined a set of potential brain regions devoted to the BM processing in WM.Then a time-course analysis was performed over the pre-defined regions,which allowed us to differentiate the encoding and maintenance phases of WM.Finally,I examined the function of these brain regions in a dual-task behavioral experiment.It was found that mirror neuron system,which contained ventral premotor cortex,posterior frontal inferior gyrus,and rostral inferior parietal lobuler,was involved in BM WM rehearsal.All these regions exhibited larger activation for load 4 than for load 2 in WM maintenance phase.However,posterior superior temporal sulcus only involved in BM WM encoding.Conversely,if the limb movement task was added during BM WM maintenance phase,memory performance for BM was selective impaired comparing with control group.This study draws the following main conclusions:(1)Dynamic attention is critical for retaining BM in WM.(2)The activity of mirror neuron system is the neural basis of rehearsal BM in WM.