Abstract
Motor imagery (MI) – the mental generation of both visual and kinesthetic movement properties – activates brain regions localized to the visual pathways, termed the dorsal and ventral stream. Particularly, MI is thought to rely on dorsal stream function, which underlies visual control of skilled actions. However, the role of the ventral stream, which underlies the transformation of visual inputs into conceptual representations, in MI is not well explored. To explore the role of the ventral stream in MI, participants (N = 18) engaged in two counterbalanced sessions of the hand laterality judgement task, requiring them to perform MI to determine if a left or right hand is presented on the screen. During session A, participants underwent active transcranial magnetic stimulation (TMS; non-invasive brain stimulation) delivered over the left occipito-temporal cortex (a key ventral stream region) at one of three distinct time points (250, 500, and 750ms after trial onset) across trials. During session B, participants received sham (placebo) TMS at the same three time points. A 2 (Condition: active, sham) x 2 (Hand: palm, back), x 4 (TMS onset: none, 250ms, 500ms, 750ms) ANOVA conducted on accuracy revealed only a main effect of Hand (p < 0.05). In line with previous literature, participants were less accurate when hand angles were palm-facing compared to back-facing; yet accuracy was consistent across Condition and TMS onset. Although we do not provide evidence that the ventral stream is involved in MI, findings from this study contribute to our understanding of neural processes required for MI.
