Catch the star! Spatial information activates the manual motor system

Abstract

Previous research demonstrated a close bidirectional relationship between spatial attention and the manual motor system. However, it is unclear whether an explicit hand movement is necessary for this relationship to appear. A novel method with high temporal resolution–bimanual grip force registration–sheds light on this issue. Participants held two grip force sensors while being presented with lateralized stimuli (exogenous attentional shifts, Experiment 1), left- or right-pointing central arrows (endogenous attentional shifts, Experiment 2), or the words "left" or "right" (endogenous attentional shifts, Experiment 3). There was an early interaction between the presentation side or arrow direction and grip force: lateralized objects and central arrows led to a larger increase of the ipsilateral force and a smaller increase of the contralateral force. Surprisingly, words led to the opposite pattern: larger force increase in the contralateral hand and smaller force increase in the ipsilateral hand. The effect was stronger and appeared earlier for lateralized objects (60 ms after stimulus presentation) than for arrows (100 ms) or words (250 ms). Thus, processing visuospatial information automatically activates the manual motor system, but the timing and direction of this effect vary depending on the type of stimulus.

Spatial-numerical associations without a motor response? Grip force says ‘Yes’

“…The study by Miklashevsky et al (2021) mentioned above examined a more extended period of 1000 ms and found a complex multiphasic pattern of activity in both hands regardless of number magnitude (see also our Fig. 1, an adapted image from da Silva et al, 2018, where a beginning of this pattern appears for lexical stimuli; see also Miklashevsky, 2022, for an identical pattern with visually presented objects). This pattern likely reflects unspecific cognitive processes that are not directly related to number magnitude but instead to perception of the stimulus, preparation, or execution of the verbal response (or response inhibition, in no-go trials), and memory-related processes.…”

How to not induce SNAs: The insufficiency of directional force

“…Therefore, we focused our analysis on time-windows prior to speech production, which began on average 576 ms after stimulus onset. We have utilized a cluster permutation analysis (with 5000 permutations and a correction for multiple comparisons) to identify the time-windows of interest during which number magnitude (in operand 1, operand 2, and the result) and the operation (plus, minus) affects force magnitude ([ 71 ]; for details see S3 File ). In the case of uninformative results of the cluster permutation analysis, five time-windows for each directional condition were selected manually (in ms: 50–150, 150–250, 250–350, 350–450, 450–576).…”

Experiential traces first: Does holding a location in visuospatial working memory affect the processing of space-associated words?

“…For instance, Dudschig et al ( 2013 ) found that saccades are launched faster in an upward direction after reading words like “sun” or “cloud,” as compared to a downward direction whereas the opposite holds for words like “grass” or “root.” Additionally, Ostarek et al ( 2018 ) explored saccade trajectories instead of saccade launches and discovered that the processing of spatially associated words influenced vertical saccade trajectories towards directions congruent with the spatial associations of the words. Furthermore, studies involving participants performing hand movements (Dudschig et al, 2013 ) or using grip force sensors (Miklashevsky, 2022 ) while reading spatially associated words indicated the involvement of the motor system. This suggests that these words can effectively engage the motor system, simulating the presence of actual objects in space.…”