title: The effector independent nature of motor imagery: Evidence from rTMS induced inhibition to the primary motor cortices.
abstract: Motor imagery (MI), the mental rehearsal of movement, facilitates learning by driving brain activation similar to that of physical practice (PP). However, a growing body of evidence suggests that learning via MI relies more on effector independent as opposed to effector dependent encoding. One approach to probing the nature of MI based learning is to study the primary motor cortex (MC), a brain region known to be critical to effector dependent encoding, but whose involvement in MI is debatable. The current study sought to inform on the nature of MI-based learning by examining the extent to which participants could learn via MI following inhibition of the MC using repetitive transcranial magnetic stimulation (TMS). Forty-seven participants completed an MI-based implicit sequence learning paradigm after receiving inhibitory TMS to the contralateral or ipsilateral MC (TMS groups), or with the coil angled away from the scalp (Sham). The extent to which participants learned was assessed via reaction time differences (dRT) and effect sizes between repeated and random sequences. Similar dRT values and moderate effect sizes were observed across all groups, providing evidence that inhibition of the MC did not disrupt MI-based learning. As the MC is critical to effector dependent encoding, the current findings suggest that MI-based learning does not rely on effector dependent encoding and unlike PP, is more effector independent in nature. Ultimately, these results inform on the nature of MI-based learning.
authors.affiliation: Laboratory for Brain Recovery and Function, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2; Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2. Electronic address: sarah.kraeutner@dal.ca.
authors.forename: Sarah N
authors.initials: SN
authors.lastname: Kraeutner
authors.affiliation: Laboratory for Brain Recovery and Function, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2; Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2. Electronic address: tony.ingram@dal.ca.
authors.forename: Tony G J
authors.initials: TGJ
authors.lastname: Ingram
authors.affiliation: Laboratory for Brain Recovery and Function, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2; Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2; School of Health and Human Performance, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2; School of Physiotherapy, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2. Electronic address: s.boe@dal.ca.
authors.forename: Shaun G
authors.initials: SG
authors.lastname: Boe
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D007266:Inhibition, Psychological; D007858:Learning / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: Implicit sequence learning; Motor imagery; Primary motor cortex; Skill acquisition; Transcranial magnetic stimulation