Differences in Brain Oscillation Patterns During Motor-Related Sensory Imagery Creation and Recall

Motor imagery (MI) engages higher cognitive functions such as memory, attention, and the transformation of sensory information in various ways, depending on the current goal. MI can be used to reproduce in the mind a possibly exact copy of an earlier motor experience (isomorphic motor imagery [IMI]) or to transform earlier experiences into new mental representations (transmorphic motor imagery [TMI]). Our study aimed to identify electroencephalographic (EEG) patterns of brain oscillations that can distinguish these two types of MI focused on differences in the frontal midline theta (FMΘ), central parietal beta (CPβ), and sensorimotor rhythms (SMR). Twenty subjects (14F; 18-25 years) participated in the study. Experimental stimuli were generated using a haptic interface to stimulate force feedback during hand clamping. The subjects had to squeeze the interface handle, memorizing the sensations associated with this movement. Then, they mentally reproduced the action they had just performed (IMI) or imagined stronger/weaker sensations (TMI). The study findings demonstrate significant differences in FMΘ and CPβ oscillation activity when comparing IMI and TMI. The IMI condition exhibits similar brain rhythm activity to working memory, probably due to its function of reproducing a previous motor experience. In contrast, oscillation patterns during TMI resemble introspective activity typical of multimodal sensory transformations. Additionally, we observed differences in the parietal delta and theta, in line with prior research on actual movement. Results may suggest that controlling movement kinematic parameters is critical when MI replicates sensory experiences, whereas creating new representations from experiences may require less stringent control.