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immobilization and brain, MOTOR cortical levels, Action observation…

- - - - Mu rythm
        
        EEG : event related synchronization (ERS) and desynchronization (ERD) of the sensorimotor alpha band, named as Mu rhythm, is associated with action performance, imagery and observation
        action observation modulates Mu oscillations also at more frontal and parietal areas
        Babiloni et al 2002 Naish et al 2014
      - alpha and beta rebounds
        
        The observation of all presented movements produced a desynchronization of alpha and beta rhythms in central and parietal regions, with a nadir around 700 ms, followed by a rebound
        Avanzini et al 2012
    - - Action observation and Action imitation
        Frontal preM, parietal, temporo occipital cortex
        
        AO : broca's area dorsal BA 45
        
        AI : broca's area ventral BA 44
  - - - single TMS during observation induced muscle specific MEPs faciltitation (enhancement of ctcspinal excitatbiliy)
        Fadiga et al 1995 Romani et al 2005 Alaerts et al 2009
      - decreased in SICI during Action observation
        Patuzzo et al 2003, Strafella et Paus 2000 Nuara et al 2023
        
        SICI modulation by AOT largely predicts AOT efficacy explining more than 60% of its variance
        
        predictive power of SICI almost doubled the MEPs one
        
        SICI modulations predicted specifically the contralateral hand improvementm contrary to the bilateral precitive capacity of MEPs
        
        Nuara et al 2023
      - goal-directed action
        Cattaneo et al 2009
        
        No-goal.
        MEPs of OP (opponens pollicis) incrreased followed the performed mvt (using of pliers and reverse pliers) ie during the thumb opposition
        
        Goal.
        MEPs of OP increased when the goal is reached, ie thumb extension when using the reverse plier
    - - we cannot always be certain that the modulation reported during observation reflects true muscle specificity, especially during reaching and grasping, squeezing, lifting compex tasks
        => one should record at least two separate muscles, during two distinct tasks, each muscle specific to one task
        the muscle recorded my EMG is of importance
        inducing and recording MEPs in a muscle with surface EMG cannot provide absolute specificity, especially when recorded muscles are next to eachother (for more specifity we would rather use intramuscular EMG)
        Naish et al 2014 2.2.1
      - at 200 ms : specific muscle enhancement
        this enhancement is muscle specific only if there is an effector-object interaction (there still is enhancement but without muscle specificity if the observation is about a static effector in front of an object)
        Lago and Fernandez-del-omo 2011
    - - H-reflex of FCR increased during observation of a wrist flexion (and H-reflex of ECR decrease at the same time)
        Borroni et al 2005
    - - we suggest that the mirror response comprises both a non-specific (at around 90 ms) and subsequent muscle-specific (from around 200ms) component
        Naish et al 2014
        
        at two early time points – 100 and 150 ms modulation was equivalent in FDI and ADM Cavallo et al 2013
        non-specific ctcspinal excitability at 90 ms
        Lepage et al 2010
    - - Motor resonance
        fMRI study on dancers. Greater activation of "mirror neurons areas" when dancers observed a mvt they have been trained to performed
        Calvo-Merino et al 2004
      - Motor learning by observing
        Mattar et al 2005
      - MEPs increase and SICI decreased are both significant predictors of motor improvements
        Nuara et al 2023
      - Even if the video during AO showed a right hand action, both hands showed a motor improvement. MEPS increase is a significant predictor of motor improvement in the untrained hand
        Rmq : no change in ISP compared to rest
        Nuara et al 2023
    - - M&M
        
        when MEPs increasings are defined towards a baseline condition, be careful with choice of the baseline
        While some studies have drawn conclusions based on differences between conditions, muscles, or participant groups, others base their conclusions on how excitability is modulated relative to a common baseline.
        Naish et al 2014 (3)
      - MEP (and H-reflex) of FDS increase during hand opening and decrease during grasp
        Montagna et al 2005
      - MEPs decrease during observation in the object present condition -even if the action is goal directed (cf grasping of an hidden object)-
        even if the same neurons fire during action exectuion
        Villiger et al 2011
        
        cf suppression of imitation ?
      - Viewing an object enhance MEPs in muscles that would be involed in acting
        Buccino et al 2009
      - MEP increase in the go condition, decrease in the no-go condition during go/no-go task
        Makin et al 2009
      - hyp . spinal excitability could be modulated by dysynaptic outputs, as evocated by Nuara et al 2023 :question:
      - hyp : ctc-striatal neurons that endowed a mirror mechanisms might be involved Nuara et al 2023 :question:
    - - Decreased H-reflex in FDS during finger closure (and increase during finger opening)
        Baldissera et al 2001
      - No changes in H-reflex during action observation (neither during MI)
        Pazzuro et al 2003
    - - M&M - timing between observation and MEPs assessment
        
        some of the studies does not provide the timing of MEPs assessment after observation (34/85)
        some of them assessed MEPs > 1000 ms after observation (35/51)
        16/51 assessed it < 1000 ms
        Naish et al 2014
        
        differential intrinsic temporal capacities for integrating goal-directed action information
        
        Longer timescales (> ± 10 s) were found in the posterior parietal and dorsal premotor compared to the ventral premotor (± 4 s) and anterior parietal (± 1.5 s) cortex.
        Aberbach-Goodman et al 2023
        
        The earliest visually-induced modulations of the amplitude of MEPs elicited by TMS over the primary motor cortex occur at around 75 ms
        Koch et al 2006
    - - Nuara et al 2023
        
        global facilitation of ctc spinal excitability (but 14/41 showed instead a decrease in MEPs)
        
        global decrease in SICI (but 13/41 showed instead an increase of SICI)
        
        only 1 overlap between the 14 MEP suppressors and 13 SICI enhancers
- - - - Clinical level
        
        after 16h immo
        less motor impairment in reach-to-grasp test if observation during immo
        De Marco et al 2021
        
        effets of AOT on rehab post hip fracture, hip or knee replacement (bias ++++++++) Bellelli et al 2010
      - after 10h immo
        no MEP decrease if AO
        Bassolino et al 2013
- - - - diminution of motor evoked potential (MEP) amplitude (TMS) Ngomo et al 2012
      - increased resting motor threshold (rMT) (TMS) Granert et al 2011, Burianova et al 2016, Karita et al 2017
      - The resting motor-evoked potential (MEP) recorded showed a significant decrease 3 h after initiation of immobilization.
        Both pinch power and integrated electromyogram were significantly reduced by immobilization,
        and then gradually returned to baseline after the cast was removed. => reversisble
        Karita et al 2017
  - - - decrease of the inhibitory influence in the ipsi-lateral hemisphere (single pulse TMS)
      - potentiation of these results if overuse of the non-immobilized arm
    - - short-latency intracortical inhibition (SICI) recruitment curves at lower conditioning pulse intensity has reduced Rozenkranz et al 2014
      - SICI increased from baseline Raffin and Siebner 2019
    - - intra-hemispheric coherence reduction in motor regions for theta (4–8 Hz) frequency band Brauns et al 2014
      - paralleled by increased coherence in other cortical regions in beta (12–30 Hz) frequency band Fortuna et al 2013
- - - - but no evidence of improved motor-skill acquisition after immobilization King et al 2022
- - - - if activation extent (i.e., number of activated voxels) in a region of interest during the pre- and posttest is compared, the conclusion is that CONTRA-M1 activation decreases following MI.
        Lacourse et al 2004
    - - If signal intensity differences between pre- and posttests are examined instead, the conclusion is that CONTRA-M1 activation increases following MI
        Lacourse et al 2004
    - - MI activates fronto-parietal, subcortical and cerebellar regions, including regions that are activated during actual execution
        
        M1 is not consistently activated during MI
        
        activations are modulated by type of MI and type of actions
        
        No difference between dominant and non-dominant hand
        
        meta analysis combining fMRI BOLD (whole brain analysis)+ PET studies
        Hétu et al 2013
        
        Kinesthetic MI consistently activated bilaterally the SMA, IPL, PcG, and CB (left lobule VII, right lobule VI), left IFG (including pars opercularis and triangularis), SMG, temporal pole, putamen, and anterior insula, and right rolandic operculum, angular gyrus, PreC and pallidum
        Hétu et al 2013
        
        LTJ : lateral task judgement (no instruction)
        Pure MI : instructions focusing on motorisc aspects of the mvt
        
        The LTJ consistently activated more right SPL, MfG, and PocG while Pure MI consistently activated more bilateral SMA and the left SMG
        Hétu et al 2013
        
        /!\ studies that investigate pure MA used whole brain analysis, whereas studies for LTJ focused on the area of the brain involved in varying the position of the hand
        
        Indeed, examining the 122 experiments (from 75 papers) considered in our study, only 22 (from 16 papers) reported primary motor cortex activation during MI (18%)
        Hétu et al 2013
        
        fMRI (BOLD) and PET : poor temporal specificity
        
        In fact, if any change in the primary motor cortex activity is actually produced during MI, it may be too rapidly suppressed for current fMRI/PET approaches to pick it up
        
        whole brain analysis : lack of sensitivity (can not pick up small changes)
        
        when fMRI + EMG to control the Ø of overt mvt (cf if MI + mvt : there is not MI anymore). electromagnetic noise due to the magnet can interfere with EMG recordings (if activation in M1 : could be activation of the muscles themselves)
- - - - descendant afferent inputs
        
        conditioned H-reflexes
        modulation of presynaptic circuitry through Ia interneuronal network
        
        cf primary afferent depolarization (PAD) of Ia sensory fibers by GABA-ergic action of interneurons
        reduces the neurotransmitter release in the Ia-to-alpha motoneuron synapse
        Rudomin et al 2009
        
        D1 presynaptic inhibition (PSI)
        
        MI induces decrease of PSI (plantar flexor muscles)
        Grosprêtre et al 2019
        
        Ia heteronymous facilitation
        
        MI induces increase of heteronymous facilitation (plantar flexor muscles)
        Grosprêtre et al 2019
        
        interneurons have lower activation threshold than motoneurones Daniele et al 2009 => interneurons could be more sensitive to minor cortical inputs such as generated by MI
        
        CMEP (cervicomedullary evoked potentials)
        transmedullary or transmastoid electrical or magnetic stimulation
        direct measurement of the pyramido-motoneuronal junction, not influenced by pre-syn inhibition Taylor et al 2006
        
        increase during MI
        Grosprêtre et al 2016
        
        H-reflex
        percutaneous electrical stimulation of the mixed nerve
        transmission between Ia afferences and alpha-motoneurons
        
        Hslope
        
        Hmax
        
        No change or even decrease in H-reflex amplitude after MI
        Aoyama & Kaneko 2011, Mouthon et al 2015 (No changes in Patuzzo et al 2003)
        
        Increase in H-reflex amplitude after MI
        Jeannerod 1995
      - intrinsic motor neuron excitability
        
        PICs (persistant inward currents)
        Heckman et al 2009
        
        PICs amplify and prolonge the effects of synaptic input (increase firing rate and prolonge the output of spinal motor neurons via Vdpt Na+ and slow and long lasting Ca2+ conductances, but only when the neuron is near or at the threshold)
        Gorassini et al 2002
  - - - single-pulse TMS
        paired-pulse TMS
        single supra-threshold TMS
        intra cortical inhibition (ICF, SICI, LICI)
        Kalmar et al 2018
        
        during MI : Increased amplitude of MEP (after single-pulse TMS) => facilitation of ctc spinal excitabiliy Ruffino et al 2017
        during MI : Decreased in SICI (after paired-pulse TMS)
        Stinear and Byblow 2004
    - - state (fatigue, train, rest, injured)
        time (planning, execution phases)
        task (strength, isometric contraction, precision)
        Kalmar et al 2018
        Contraction intensity
        Cowley et al 2008
        muscle specific
        Grosprêtre et al 2015
- - - - clinical level
        
        MI alone can induced long-lasting changes (up to 10 days) in accurracy but not in touch duration (TD), the inter-tapping interval (ITI), movement rate compared to ME (mvt execution)
        Bonassi et al 2020
        
        :question: Ø
      - :question: Ø
- - - - clinical level
        
        :question: Ø
      - significant increase in MEP amplitudes during the administration of AO-KI
        Bisio et al 2021
- - - - long-lasting changes in M1 (up to 2 weeks)
        
        increase in SICI for the vibrated muscle, decrease for the non-vibrated muscle
        Marconi et al 2008
        :warning: KI + voluntary contraction of the vibrated muscle at the same time
        
        No changes in RMT (??)
        Marconi et al 2008
        :warning: KI + voluntary contraction of the vibrated muscle at the same time
        
        reduction in the cortical map volume of the vibrated muscle, in concomitance with an increase in the map volume of the antagonist muscle
        Marconi et al 2008
        :warning: KI + voluntary contraction of the vibrated muscle at the same time
    - - during illusion
        
        the MEP was enhanced in the non-vibrated muscle (agonist muscle for KI of illusory flexion mvt)
        Kito et al 2006
      - aftereffect
        
        Def : transient perception of movement in the opposite direction
        
        In contrast, during aftereffects, the MEP in the non-vibrated muscle was selectively reduced with no changes in the vibrated muscle
        Kito et al 2006
        
        facilitation of musculature that is antagonistic to the site of the directly activated Ia afferent pathways
        Forner Cordero et al 2008
        
        can be consolidated (up to 30 min) if associated with :warning: repetitive TMS
        Perasso et al 2019
      - Clinical level
        
        the vividness of aftereffect is lower than that of illusion
        Kito et al 2006
        
        aftereffect
        
        When the vibratory stimulation is stopped, participants often continue to experience a kinesthetic sensation (kinesthetic aftereffect) in which the vibrated limb seems to return towards the original position, despite the fact that the limb still remains immobile.
        Kito et al 2006
      - No changes in H-reflex
        Marconi et al 2008
        :warning: KI + voluntary contraction of the vibrated muscle at the same time
- - - - clinical level
        
        (5-days immo), better amplitude of mvt in the treated (KI group) than in the no-vib group
        Roll et al 2012
      - 80Hz vib during 10h immo of right hand - RMT (TMS)
        
        partial decrease of left M1 excitability
        
        non change in right M1
        
        no change in IHI
        
        No-vib group :
        
        decrease in left M1 excitability (increease in right M1)
        
        decrease in IHI from L to R (increase in IHI from R to L)
        
        Avanzino et al 2014
    - - vibration patterns copying the responses of muscle spindle afferents previously recorded by microneurography during actual mvt
        Roll et al 2009
- - - - Scaphoid fractures
        incidences ranging from 1.5/100 000 up to 121/100 000 following the studies Jørgsholm et al 2020
        
        non-surgical treatment
        Immobilisation 8 weeks : >95% union Dias et al 2005
        
        recommend initial immobilization in a nonremovable short-arm thumb spica cast until evidence of callus formation on CT scan Mcveigh et al 2019
        Recommend 12 weeks of immobilization for the wrist only (not the thumb or elbow) for highest union rate on nondisplaced waist fractures
        Alshryda et al 2012
        
        most common in young men in the age group of 15 to 29 years, who have the highest incidence of non-union, take the longest time to unite, lose more time from work, and spend the longest time as outpatients Leslie et al 1981
      - 10% of fractures does not heal properly
        Einhorn et al 2015
        
        secundary displacement
        
        non-union
        
        delayed union
        
        Of the estimated 7.9 million fractures that occur annually in the US, approximately 5-10% have delayed or impaired healing
        Buza et al 2016
        
        of these 600 000 fractures with delayed healing nearly 100 000 progress to non union
        Buza et al 2016
      - depending on the fracture type
        
        cast to protect the rigid fixation (plate, screws, nails ...)
        
        Primary healing - rigid fixation
        Cottrell et al 2016
        
        2 types
        
        Gap healing
        
        gap filled with woven bone
        
        remodeling
        (cutting cones created by osteoclasts, trailed by osteoblasts that form new lamellar bone while reconstructing haversian canals and osteons)
        
        Contact healing
        (ex : bone fusion)
        
        remodeling only
        (cutting cones created by osteoclasts, trailed by osteoblasts that form new lamellar bone while reconstructing haversian canals and osteons)
        
        ø callus formation => intramedullar ossification only
        
        cast - orthopaedic treatment
        
        Secondary healing - limited motion that promotes callus formation (fibrous + cartilaginous tissue)
        Cottrell et al 2016
        
        Endochondral ossification
        
        formation of cartilage prior to ossification
        
        intramedullar ossification
        
        precursors differentiate into osteoblasts that lay down woven bone
        
        3 overlapping phases
        
        inflammatory
        
        reparative (Endochondral ossification + intramedullar ossification)
        
        remodeling
    - - immo theoretical advantages
        
        avoid gapping or rupture
        
        rupture of flexor tendon repair
        
        2010 - from 4 to 30%
        Momeni et al 2010
        
        Recent studies - range of 0% to 5% in zones 1 and 2 using a six-strand core suture combined with early active mobilization
        Chen et tang 2024, Sadek et al 2020
        
        most of the ruptures happen around 10 days after surgery Chen et Tang 2024
      - immo disadvantages
        
        prevent tendon glide
        
        increase adhesion formation
        
        tenolysis rate depends on strength of suture technique + rehab protocole
        
        zone 2 flexor digitorum profundus (FDP) with FDS tendon repairs using a four-strand technique and early passive motion exercises.
        28 out of 194 fingers (14.4%) required tenolysis.
        Civan et al 2020
        
        flexor tendon (FDP, FDS or both) repairs of zone 2 in 102 fingers using a six-strand core suture and early active motion protocol, noted tenolysis was needed in 5 (5%) fingers.
        Moriya et al 2019
        
        limit ROM
        Abdolrazaghi et al 2023
      - epidemio
        
        In the United States, nearly 1.5 million emergency room visits per year are due to flexor tendon injuries.
        De Jong et al 2014
        
        Tendon injuries have been found to be 20 times more frequent than scaphoid fractures
        Van tassel et al 2010, De jong et al 2014
  - - - 3 weeks short arm cast vs splint
        => better functional results with removable splint
        Plint et al 2006
  - - - immo theoretical advantages
        Logli et al 2018
        
        prevention of flexor tendon bowstringing
        
        prevention of nerve subluxation and prolapse into the healing wound
        
        reduction of immediate postoperative pain
        
        lower rates of wound-healing complications and symptom recurrence
        
        early post op period :
        
        pain alleviation
        
        stronger grip and pinch strength
        Zhang et al 2023**Logli et al 2018
      - disadvantages of immo
        Logli et al 2018
        
        unnecessary morbidity
        
        slow recovery
        
        increase time to return to work
      - epidemio
        
        prevalence of postoperative splint
        
        in 2012, ASSH survey, 707 answers, 46% of the surgeons sitll placed the wrist in a postoperative splint for 7 to 14 weeks
        Leinberry et al 2012
        
        incidence CTR
        
        most common surgical treatment of the upper extremity
        Adams et al 1994 and still more than 20 years after Fajardo et al 2012
        
        incidence of postoperative complications
        
        scar tenderness
        22–81% in the first 3 months
        up to 31% after more than 6 months postoperatively
        Sprangers et al 2024 (review)
        
        failure of treatment
        from 7 to 25% with re-operation rates from 1 to 12%
        Westenberg et al 2020, Sprangers et al 2024
    - - bone healing / union
    - - healing, avoid gapping and ruptures
  - - - good DASH / PRWE / EQ 5D
        functional outcomes
- - - - more cartilage tissue formation (cf patterns of osteogenic stem cells differentiation into chondrocytes and osteoblasts)
      - decreased angiogenesis
    - - According to the United States Food and Drug Administration (FDA), a nonunion is defined as a fracture that has not completely healed within 9 months of injury, with serial radiographs demonstrating no progression of healing during the final three months
        Buza et al 2016
      - Factors that influenced bone union
        patient status (smoking diabetus mellitus, nutritional state), fracture site, type of fracture, initial degree of bone loss, type of fixation, extent of soft tissue injury
        Castillo et al 2005
  - - - three overlapping steps: (1) inflammation, (2) proliferation, and (3) remodeling.
        Chartier et al 2021 Voleti et al 2012
        
        inflammation - 48h
        
        macrophage consume the necrotic tissue
        
        proliferative phase - 7 to 21 days
        
        macrophage and tenocyte-directed synthesis of collagen III
        
        remodeling - up to 12 months
        
        extra-C matrix alignement and collagen I synthesis replacing collagen III
      - In practice, the goal of treatment is to identify the minimum amount of motion to avoid scarring and tethering to nearby tissue while avoiding jeopardizing the repair site.
        
        prolonged tendon immobilization has been associated with significant repair strength, but increased risk of adhesion formation,
        Chartier et al 2021
        
        in vitro studies
        overloading or underloading has been shown to have detrimental effects on the tendon, resulting in a biologic response that is catabolic
        Gardner et al 2008
- - - - immobilization alone induced a reduction in MEP (AUC), but this reduction in corticospinal excitability of the immobilized muscle was prevented by concurrent training of the nonimmobilized finger. Moreover, the “training-only” group showed larger AUCs of the nontrained finger muscle compared with the nontrained, nonimmobilized finger muscle in the “immobilization-only” group
        Raffin et al 2019
    - - after 1 week finger immo
        
        transfer of the learned visuomotor tracking skill to the nontrained finger in the training-only group, however this transfer to nontrained finger DOES NOT HAPPEN when training is combined with 1 week immo (finger tracking performance)
        Raffin et al 2019
- - - - corticospinal coherence decreased => hyp : cf dim of inputs or outputs ?
        Lundbye-Jensen et al 2008
      - increase in H-reflex amplitudes without changes in MEP (both at rest and during static contraction)
        Lundbye-Jensen et al 2008 Clark et al 2010
    - - during rest : increased MEP (single pulse TMS)
        Clark et al 2008
      - during contraction : no changed in MEP + prolonged ctcspinal silent period (single pulse TMS)
        Clark et al 2008
    - - increased rMT, decreased MEPs (single pulse TMS) at rest- during immo-
        Facchini et al 2002 Raffin et al 2019
  - - - reduced activation in the finger areas of the contralateral S1 (fMRI) after 22,6 days of immo
        Lissek et al 2009
  - - - decreased in both somatosensory (and motor) MEP Huber et al 2006 (10h immo)
      - increased of SEP in premotor cortex and supplementary motor area (and not in M1) (after 10h immo) Okamoto et al 2022
  - - - These functional changes were associated with reduced grip strength, dexterity and tactile discrimination of the 72h immobilized hand, Weibull et al 2011
- - - - MVF improves motor skill tests performance (9 holes peg test, drawing, pick a stick etc) and it is even more effective than AO
        MVF + AO is less effective than AO (video) or MVF alone
        Bähr et al 2018
        Ball rotation task
        Nojima et al 2012
      - MVF performances are not influenced by hand dominance
        Rjosk et al 2016
      - MVF mechanisms rely more on cross-limb transfer than MNS
        3 groups, 2 balls rotation task, healthy volunteers
        
        Mirror vision : moving hand unseen, mirror : seen
        
        Active vision : moving hand seen, passive hand : unseen
        
        Passive vision : moving hand unseen, passive hand : seen
        
        one would expect to do not see any improvement in AV and PV group in passive hand if MVF relies only on MNS, except if MVF relies on cross-limb transfer
        results : improvements in the 3 groups.
        Reissig et al 2015
      - No study on MVF + immo
- - - - IN REHABILITATION
        Motor imagery practice
        
        Motor imagery modalities
        Ruffino et al 2017, Meugnot et al 2014
        
        visual imagery
        self-vizualisation of the movement
        
        predominately activates the visual association cortex, could supply the motor imagery if isn't working
        lire sakai et al 2021 10.1007/s00221-021-06136-2
        
        vividness of visual imagery questionnaire
        Marks et al 1973
        
        kinesthetic imagery
        "feel the movement"
        mentally percepts the muscle contractions
        
        effects of kinesthetic MI on immo induced impairments CORTICAL LEVEL
        
        effects of kinesthetic MI on immo induced impairments CTC SPINAL LEVEL
        
        effects of kinesthetic MI on immo induced impairments CLINICAL LEVEL
        
        3 more items...
        
        kinesthetic MI attenuated the loss of volontary neural activation and the prolongation of the cortical silent period after 4 weeks immo
        Clark et al 2014
        
        MI does not counteract the decreased of MEP induced by 7 days of immo Crews & Kamen 2006 or 10 hours or immo Bassolino et al 2014
        
        MI prevents immobilization-related changes in resting-state electroencephalographic (rsEEG) power after 12h immo
        Debarnot et al 2021
        
        the normal imbalance between C3 and C4 activation (in theta, beta and low-gamma frequencies) was maintained after 12 h of arm immobilization with MI practice, but not after immobilization alone.
        Debarnot et al 2021
        
        the amount of overall coherence within the sensors-network was reduced in both delta and alpha frequency bands after immobilization alone, compared to no immobilization or immobilization accompanied with MI practice.
        Debarnot et al 2021
        
        used more often than other modalities as it activates more the motor than the visual cortex Stinear et Byblow 2004
        
        haptic imagery (using cutaneous information to recreate the interaction with external objects)
        
        auditory imagery
        
        EEG - Inter trial phase locking consistency (ITPC) is mainly concentrated in μ, α, and γ bands in the process of motor imagery task guided by the auditory stimulus of task related verbs , while it is mainly concentrated in the β band under the independant nouns stimulation
        Li et al 2023
      - after long-term > 48h immo
        
        slow-down of the sensorymotor processes for images (ie MI) corresponding to both the immo (48h) and non-immo hand (mental rotation task => MI)
        Meugnot et Toussaint 2013, Meugnot et al 2016
      - after short-term < 24h immo
        
        slow-down of sensorymotor processes involved in images representing the immobilised hand only (mental rotation task => MI)
        Meugnot et Toussaint 2015
    - - faster resynchronization in the beta frequency band (i.e., beta rebound) only for MI of the constrained hand -> controlateral hemisphere (MEG of event-related desynchronization)
        Burianova et al 2016
    - - Immo 3-6 weeks /!\ to treat orthopedic injuries - lower MEP at the disuse stage during motor imagery (≠ at the recovery stage) Kaneko et al 2003
    - - cf reduction of sensorimotor stimuli during immo ? Huber et al 2006
- - - - SENSORY clinical level simultaneously improved tactile discrimination of the non-immobilised hand (72h immo).Weibull et al 2011
      - SENSORY cortical level Following unilateral immobilisation, cortical activation increased substantially during tactile stimulation of the non-immobilised hand (72h immo) Weibull et al 2011
    - - increase of iSP duration and area (ipsilateral silent period) = increase of IHI - interhemispheric inhibition, in proporition with motor task complexicity during both actual and mental mvt
        Gueugneau et al 2013
    - - increase of ISP duration and area, during both actual mvt and observation, no matter the task is transitive (object/goal-directed sucha as a grasp- or intransitive (no goal, ie finger tapping task)
        Gueugneau et al 2016
      - "tuned to the kinematics" => IHI of OP increase during the closing phase of the hand whereas no difference have been found during the hand opening Gueugneau et al 2016
      - No change in ISP between AO and rest Nuara et al 2023
        use of video clips instead of a live actor, as well as the absence of EMG-based dynamical TMS triggering, could have determined such divergences in results.
- - - - PMd
        (dorsal premotor cortex)
        (+)
        Gabitov et al 2015
        
        M1
        untrained
- - - - bilateral
        
        preM
        
        parietal
        
        subcortical structures (putamen, cerebellum)
    - - bilateral
        
        preM
        
        parietal
        
        occipital
        
        Ø subcortical structures
    - - bilateral
        
        preM
        
        sensorimotor
        
        subcortical structures (putamen, cerebellum, thalamus)
    - - MI
        
        MI training alone led to significant improvements in the overt performance of a fine motor skill with the hand.
        In both conditions (MI and action performance), there was an increase in the size and excitability of the cortical motor representation of the trained hand
        Pascal Leone 1995
      - AO
        
        Action observation training (AOT) sustains motor skill improvement.
        Nuara et al 2022