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FUNCTIONAL MRI in MOTOR IMAGERY JEFFREY S. ROSS, M.D. NEURORADIOLOGY CLEVELAND CLINIC FOUNDATION

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Presentation on theme: "FUNCTIONAL MRI in MOTOR IMAGERY JEFFREY S. ROSS, M.D. NEURORADIOLOGY CLEVELAND CLINIC FOUNDATION"— Presentation transcript:

1 FUNCTIONAL MRI in MOTOR IMAGERY JEFFREY S. ROSS, M.D. NEURORADIOLOGY CLEVELAND CLINIC FOUNDATION

2 FUNCTIONAL MRI BRAIN IS UNIQUEBRAIN IS UNIQUE –Strong relation between location and function MULTIPLE TECHNIQUES TO EVALUATE FUNCTIONMULTIPLE TECHNIQUES TO EVALUATE FUNCTION –Clinical cases (strokes, tumors, epilepsy, etc.) –Animal lesion studies –EEG, MEG, etc. –Direct intraoperative electrical stimulation –Functional imaging (PET, FMRI)

3 BASICS Change in local brain activity Change in local brain metabolism Change in local hemodynamics

4 BASICS IMAGE DURING 2 BEHAVIORAL STATESIMAGE DURING 2 BEHAVIORAL STATES –Control state –Activation state “DIFFERENCE” IMAGE SHOWS “ACTIVATED” BRAIN“DIFFERENCE” IMAGE SHOWS “ACTIVATED” BRAIN –Brain activated depends critically on design of task –Tasks carefully designed to isolate function of interest BLOOD FLOW USED AS ENDOGENOUS CONTRASTBLOOD FLOW USED AS ENDOGENOUS CONTRAST

5 BOLD FMRI basics BOLD: Blood Oxygenation Level DependentBOLD: Blood Oxygenation Level Dependent Signal changes based on blood O 2 level Signal changes based on blood O 2 level –Oxyhemoglobin (HbO 2 ) diamagnetic –Deoxyhemoglobin (Hb) weakly paramagnetic Paramagnetic substanceParamagnetic substance –Causes local magnetic field heterogeneity –Shortens T2, T2* relaxation times –Lowers signal in tissue

6 BOLD effect 2 100% O 2 Room air Rat brain at 9 tesla (Ogawa et al MRM 14:68, 1990)

7 BOLD EFFECT BLOOD O 2 LEVELBLOOD O 2 LEVEL –Blood flow –Tissue metabolism NEURAL ACTIVATIONNEURAL ACTIVATION –Increase in local blood flow greater than –Increase in local O 2 extraction –Increased capillary, venous HbO 2 –More HbO 2 causes increased signal SMALLSMALL DELAYED WITH RESPECT TO STIMULUS ONSETDELAYED WITH RESPECT TO STIMULUS ONSET LASTS A FEW SECONDSLASTS A FEW SECONDS FIELD STRENGTH DEPENDENTFIELD STRENGTH DEPENDENT

8 BOLD EFFECT RESTINGACTIVATED ARTERYCAPVEIN CBF CBVO 2 SAT

9 fMRI signal SIGNAL CHANGES OF 2-5%SIGNAL CHANGES OF 2-5% STRONGLY FIELD DEPENDENTSTRONGLY FIELD DEPENDENT LAG TIME FOR RESPONSE, AT LEAST 300 msec UP TO 4sLAG TIME FOR RESPONSE, AT LEAST 300 msec UP TO 4s 0 offonoffonoff

10 PROBLEMS IMAGE NOISEIMAGE NOISE MOTION SENSITIVEMOTION SENSITIVE –Head motion under 0.5 mm can ruin data SILENT REGIONSSILENT REGIONS –MAKE NOTHING OF WHAT YOU DON’T SEE ACTIVATED REGIONSACTIVATED REGIONS –ACTUAL CONTRIBUTION TO COGNITIVE TASK? ANATOMICAL ACCURACYANATOMICAL ACCURACY –LOCALIZATION OF EXTENT OF ACTIVATION –ASSUME ACTIVATION TAKES FORM OF DISCRETE LOCAL INCREASE IN FLOW

11 PROBLEMS PARADIGM DESIGNPARADIGM DESIGN –ASSUME BRAIN IN STABLE COGNITIVE STATE DURING MEASUREMENT –HOW OFTEN REPEATED –HOW EASY/HARD TO PERFORM –NATURAL OR TIGHTLY CONTROLLED –COGNITIVE DEMANDS –EMOTIONS MACROSCOPIC LANDMARKSMACROSCOPIC LANDMARKS –SEVERAL “SPACES” – TALAIRACH PRECISE TEMPORAL RELATIONSHIPPRECISE TEMPORAL RELATIONSHIP

12 Mapping the Sensori-motor Homunculus TONGUELIPHANDELBOW SHOULDERHIPKNEEANKLE

13 WORD GENERATION

14 MOTOR IMAGERY - Introduction Mental imagery involves rehearsing or practicing a task in the mind with no physical movementMental imagery involves rehearsing or practicing a task in the mind with no physical movement The technique is commonly utilized, and widely advocatedThe technique is commonly utilized, and widely advocated Physical foundation of imagery not well characterized for fast, complex, automatic motor movements such as the golf swingPhysical foundation of imagery not well characterized for fast, complex, automatic motor movements such as the golf swing

15 It's a great image for any golfer faced with a pressure shot. Replay an old "tape" from your memory bank, thinking of a past success rather than calling up a negative memory. You'll then have an excellent chance of duplicating the successful shot. LEADBETTER’S IMAGES GOLF DIGEST, MARCH 2001

16 Introduction This study evaluated motor imagery of the golf swing, of golfers of various handicaps, using fMRI to:This study evaluated motor imagery of the golf swing, of golfers of various handicaps, using fMRI to: 1) Assess whether areas of brain activation could be defined by this technique and;1) Assess whether areas of brain activation could be defined by this technique and; 2) To define any association between activated brain areas and golf skill.2) To define any association between activated brain areas and golf skill.

17 Materials and Methods Six golfers of various handicap levels (0,5,7,10,11,13) with evaluated with functional MRI during a control condition and during mental imagery of their golf swing.Six golfers of various handicap levels (0,5,7,10,11,13) with evaluated with functional MRI during a control condition and during mental imagery of their golf swing. Five of the six subjects were right handed, and play golf right handed.Five of the six subjects were right handed, and play golf right handed. The subject with a 5 handicap (hcp) was left handed, but plays golf right handed.The subject with a 5 handicap (hcp) was left handed, but plays golf right handed. 6 males, years of age, average age 39 years.6 males, years of age, average age 39 years.

18 Materials and Methods 1 st person perspective, as they would on a practice tee, with each swing mentally occurring every seconds. No preshot routine.1 st person perspective, as they would on a practice tee, with each swing mentally occurring every seconds. No preshot routine. Two control conditions were evaluated, “rest” and “wall”Two control conditions were evaluated, “rest” and “wall”

19 PARADIGMS RESTREST –subjects were told to project themselves into a restful state, such as sitting quietly on a beach, taking care not to move mentally (or physically) during the study WALLWALL –were told to imagine leaning against a wall with their hands outstretched and pushing against it

20 Materials and Methods Functional studies were performed on either a 1.5T whole body (Symphony, Siemens, Erlangen) or 3T head only (Allegra, Siemens, Erlangen) MRI systems.Functional studies were performed on either a 1.5T whole body (Symphony, Siemens, Erlangen) or 3T head only (Allegra, Siemens, Erlangen) MRI systems. On the 1.5T system, the body coil was used to transmit, with a receive-only head coil collecting the data.On the 1.5T system, the body coil was used to transmit, with a receive-only head coil collecting the data. A transmit/receive head coil was used to acquire the 3T functional studies.A transmit/receive head coil was used to acquire the 3T functional studies. Functional images : 2D multi-slice gradient echo EPI acquisition. Sixteen slice locations were collected every 3-4 sec with fat saturation.Functional images : 2D multi-slice gradient echo EPI acquisition. Sixteen slice locations were collected every 3-4 sec with fat saturation.

21 RESULTS Vermis, SMA, cerebellum and motor regions generally showed the greatest activationVermis, SMA, cerebellum and motor regions generally showed the greatest activation Little activation seen in cingulate gyrus, right temporal lobe, deep gray matter, and brainstemLittle activation seen in cingulate gyrus, right temporal lobe, deep gray matter, and brainstem Wall vs. golf paradigm showed generally diminished activation across all regions compared to the Rest vs. golfWall vs. golf paradigm showed generally diminished activation across all regions compared to the Rest vs. golf Decreased activation most extensively with the better playersDecreased activation most extensively with the better players

22 RESULTS Assuming a limit of 2% activation, 95% confidence intervals were generated. This showed with a 95% confidence that the following areas were activated greater than 2%Assuming a limit of 2% activation, 95% confidence intervals were generated. This showed with a 95% confidence that the following areas were activated greater than 2% –13 handicap: Brainstem, Left motor, Left sensory, Left SMA, Left temporal, Right cerebellum, Right SMA, Vermis –7 handicap: Left SMA –5 handicap: no areas –0 handicap: no areas

23 Percent area activation, 13 handicap averaged five series of “rest vs. golf”

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27 REST VS GOLF 13 HANDICAP

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29 CONCLUSIONS Demonstrated the feasibility of defining areas of brain activation during imagery of a complex, coordinated motor taskDemonstrated the feasibility of defining areas of brain activation during imagery of a complex, coordinated motor task Suggests increased activation with increasing handicapSuggests increased activation with increasing handicap

30 CONCLUSIONS Generally good agreement of golf swing imagery with brain activation areas defined in the literature including:Generally good agreement of golf swing imagery with brain activation areas defined in the literature including: –Primary motor control (motor cortex) –Imagery (parietal cortex) –Execution areas (premotor cortex of frontal lobe, lateral cerebellum, basal ganglia, vermis and medial cerebellar hemispheres) –Action planning areas (frontal and parietal cortex, SMA, lateral cerebellum) –Error detection (cingulate, cerebellum)

31 CONCLUSIONS Increased activation with high handicap players could potentially relate to two effects:Increased activation with high handicap players could potentially relate to two effects: –1) that increased activation reflects a failure to learn and become highly automatic or –2) that increased activation is essentially pathologic, and related to a loss of automaticity with compensatory increased brain activity. Development of automaticity is relative and can be dynamic and reversibleDevelopment of automaticity is relative and can be dynamic and reversible Classic example of this pathology is writer’s cramp (focal dystonia) where the severe functional disturbances can be explained in terms of a loss of automaticity and an increased need for controlled processingClassic example of this pathology is writer’s cramp (focal dystonia) where the severe functional disturbances can be explained in terms of a loss of automaticity and an increased need for controlled processing

32 Ross JS et al. The Minds Eye: Functional imaging of golf motor imagery. American Journal of Neuroradiology, 24: , June/July 2003.Ross JS et al. The Minds Eye: Functional imaging of golf motor imagery. American Journal of Neuroradiology, 24: , June/July


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