Smoothness discriminates physical from motor imagery practice of arm reaching movements

Abstract

Physical practice (PP) and motor imagery practice (MP) lead to the execution of fast and accurate arm movements. However, there is currently no information about the influence of MP on movement smoothness, nor about which performance parameters best discriminate these practices. In the current study, we assessed motor performances with an arm pointing task with constrained precision before and after PP (n= 15), MP (n= 15), or no practice (n= 15). We analyzed gains between Pre- and Post-Test for five performance parameters: movement duration, mean and maximal velocities, total displacements, and the number of velocity peaks characterizing movement smoothness. The results showed an improvement of performance after PP and MP for all parameters, except for total displacements. The gains for movement duration, and mean and maximal velocities were statistically higher after PP and MP than after no practice, and comparable between practices. However, motor gains for the number of velocity peaks were higher after PP than MP, suggesting that movements were smoother after PP than after MP. A discriminant analysis also identified the number of velocity peaks as the most relevant parameter that differentiated PP from MP. The current results provide evidence that PP and MP specifically modulate movement smoothness during arm reaching tasks. This difference may rely on online corrections through sensory feedback integration, available during PP but not during MP.

Motor imagery training is beneficial for motor memory of upper and lower limb tasks in very old adults

“…Firstly, at a functional level, motor imagery practice seems to induce positive changes within motor planning (Gentili et al, 2010; Taube et al, 2014). Indeed, via the activation of the neural network implicated in motor planning, motor imagery training could help to refine the internal representation of the considered action by the generation of sensorimotor predictions, leading to an improvement of motor command (Kilteni et al, 2018; Dahm and Rieger, 2019; Ruffino et al, 2022). Secondly, the modulation observed at both neural (Ruffino et al, 2017) and spinal (Grosprêtre et al, 2016) levels during motor imagery seems to reinforce the sensibility and the conductivity of synapses in corticospinal pathway (Avanzino et al, 2015), notably by increasing the effectiveness between pre- and post-synaptic neurons.…”

Optimizing the Benefits of Mental Practice on Motor Acquisition and Consolidation with Moderate-Intensity Exercise

“…The positive effects of PP on motor performance can be observed with different timescales, from a single practice session to several days or weeks of practice. Previous studies reported that a few minutes of practice is enough to improve motor performance on various tasks, such as pointing or sequential finger-tapping (Spampinato et al 2017;Ruffino et al 2022;Walker et al, 2003). This fast-learning process is defined as motor acquisition and is considered the first step in the development of new motor memories.…”