The sequential encoding of competing action goals involves dynamic restructuring of motor plans in working memory

Abstract

Gallivan JP, Bowman NA, Chapman CS, Wolpert DM, Flanagan JR. The sequential encoding of competing action goals involves dynamic restructuring of motor plans in working memory. J Neurophysiol 115: 3113-3122, 2016. First published March 30, 2016 doi:10.1152/jn.00951.2015.-Recent neural and behavioral findings provide support for the influential idea that in situations in which multiple action options are presented simultaneously, we prepare action plans for each competing option before deciding between and executing one of those plans. However, in natural, everyday environments, our available action options frequently change from one moment to the next, and there is often uncertainty as to whether additional options will become available before having to select a particular course of action. Here, with the use of a target-directed reaching task, we show that in this situation, the brain specifies a competing action for each new, sequentially presented potential target and that recently formed action plans can be revisited and updated so as to conform with separate, more newly developed, plans. These findings indicate that the brain forms labile motor plans for sequentially arising target options that can be flexibly restructured to accommodate new motor plans. action; perception; decision-making; motor planning; working memory

Prospective task knowledge improves working memory-guided behaviour

“…A recent EEG study showed that in situations where different WM contents are associated with specific actions, the selection of taskrelevant sensory representations and appropriate motor plans may occur in parallel and not serially as would be expected if the WM code was primarily sensory in nature 13 . Instead, these results are consistent with a model of WM in which the brain, when possible, will link sensory representations to their motor plan to guide future behaviour, further integrating the WM literature to literature on motor planning 14,15 . However, many WM tasks, such as continuous report tasks 16 or change-detection tasks 7 , do not allow for motor preparation at encoding, but instead require a comparison between a WM stimulus and an unpredictable post-delay target.…”

The role of working memory for bridging the gap between perception and goal-directed actions: Evidence by mu and beta oscillations in sensorimotor cortex

“…Further support for this notion comes from prior investigations showing that it is possible to simultaneously plan reaching movements towards multiple target objects and to subsequently only select one out of the already planned movements 7,42,43 . Referred to the current experiment, the S-R mapping following a one-item retro-cue toward a red item would contain the following information: 'If the memory probe is red, press the left button, if not, press the right button'.…”

“…Importantly, Hommel, Müsseler, Aschersleben and Prinz 2 highlighted that a motor plan is a code of the perceptual consequences of a motor action rather than a conscious plan of a complex sequence of muscle tension and relaxation. Important for this account, working memory can not only actively store stimulus representations in different sensory stores 4,5 , but also higher-level representations of to-be-executed actions [6][7][8][9] . It is therefore reasonable to assume that the transition from purely sensory information to higher-level sensorimotor representations for guiding future actions proceeds in working memory.…”

Memory Based Decision Making: A Spiking Neural Circuit Model

“…Machens's study [35] shows that decision-making is controlled by memory signals, and that action control is achieved by mutual restraint between decision-making patterns. Gallivan's [36] research indicates that brain sequential decision-making is achieved through competition among decision-making patterns, which is accomplished by local inhibition between patterns. The experiments of Kuo's work [1] shows that there is a game relationship between controlled decision-making (memory-based decision-making) and stimulus response.…”