On the Assessment of Functional Connectivity in an Immersive Brain-Computer Interface During Motor Imagery

Neural Kinesthetic Contribution to Motor Imagery of Body Parts: Tongue, Hands, and Feet

“…Contrary to studies reported on somatotopic unilateral or bilateral forward (i.e., prefrontal and/or frontal) and backward (i.e., parietal) activations when participants were instructed to perform MI tasks of the right or left hand (Li et al, 2019 ; Alanis-Espinosa and Gutiérrez, 2020 ) and the left or right foot (Gu et al, 2020 ), the current investigation did not report somatotopic motor and/or somesthetic activations, i.e., motor and/or somesthetic representations of the upper and lower limbs. The inconsistencies between our results and the above-mentioned findings could be understood from a methodological point of view.…”

“…The inconsistencies between our results and the above-mentioned findings could be understood from a methodological point of view. First, the sample size importantly differs between the studies: only two subjects performed the motor hand imagery task via brain-computer interfaces (BCI) in the investigation of Alanis-Espinosa and Gutiérrez ( 2020 ), and 10 participants performed the feet imagery task in the Gu et al ( 2020 ). In the study of Li et al ( 2019 ), a conventional number of 40 participants was initially included but only the data of 22 subjects, totally unbalanced between male (21 subjects) and female (one subject), were analyzed.…”

“…Second, the studies differ with regard to their objectives. For instance, the aim of the Alanis-Espinosa and Gutiérrez ( 2020 ) study was to control the movement of a robotic hand using MI at the first and third-person perspective. For the other studies, the aim was to imagine moving different body parts according to a defined experimental design using various visual stimuli (Li et al, 2019 ; Gu et al, 2020 ).…”

“…Also, a specific MI paradigm was included in each study. More particularly, BCI was utilized to control an immersive telepresence system via MI (Alanis-Espinosa and Gutiérrez, 2020 ), but MI of the upper limbs (Li et al, 2019 ) and the lower limbs (Gu et al, 2020 ) was also performed. In the present study, a totally different procedure was employed where participants were instructed to complete a 4-class imagery task of the tongue and the upper and lower body limbs.…”

“…Neuroimaging studies in humans showed that when MI involves body parts and more particularly, hand movements, this typically initiates various areas associated with sensorimotor control areas including bilateral premotor, prefrontal supplementary motor, left posterior parietal area, and caudate nuclei (Gerardin et al, 2000 ). Recent brain network analysis has shown that frontal and parietal brain areas are also involved while performing MI of the right hand in third-person perspective (i.e., the subject was looking at a robotic hand movement) but not involved in the first-person perspective (i.e., the subject mentally controlled robot’s hand movement; Alanis-Espinosa and Gutiérrez, 2020 ). Moreover, in the prior mentioned study, prefrontal and sensorimotor brain areas demonstrated higher brain activity in first than in third-person perspective.…”