Correlation between Diffusion MRI metrics and

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Special thanks for all judo athletes from Clube Judo Total and Judo Clube Lisboa. Figure 2 – Group activation maps of the visual cortex obtained for the motor ...
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Authors: Catarina Correia1, Nuno Martins2, Margarida Ribeiro1, Hugo Ferreira3

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Introduction

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Affiliations: 1Escola Superior de Tecnologia da Saúde de Lisboa (ESTeSL), Instituto Politécnico de Lisboa, Lisboa, Portugal, 2Serviço de Radiologia, Hospital CUF Descobertas, Lisboa, Portugal, Lisboa, Portugal, 3Institute of Biophysics and Biomedical Engineering, Lisboa, Portugal

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In the second, a tactile sensory paradigm, 15s rest periods were alternated with 15s periods during which a kimono was passed by the subjects' right hands, simulating the touch during the kimono grip.

Fig.3.8 - Demonstração de técnica de judo no chão – Kami-shio-gatame (GladenBach, 2011)

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A 3D T1-weighted SPGR sequence was also run for depiction of brain anatomy. Images were analyzed using FEAT and MELODIC tools of FSL software. The first 2 volumes were excluded due to lack of signal steady-state. Individual subject and group analysis was done (using temporal concatenation). MELODIC components were selected based on their temporal similarity to the block-design used and on the identification of the networks of interest. Activation maps were then compared within and between groups (visually impaired and sighted) regarding activated areas, activation values and spatial extension.

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Results and Discussion

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Motor execution (left hand): kimono grip

Touch (right hand): kimono grip

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Motor imagery: judo techniques

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Motor execution (right hand): kimono grip

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Fig.3.7 - Demonstração de técnica de judo no chão – Hon-kesa-gatame (K. F., 2010).

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Three different block-design paradigms were tested. In the first, a motor execution paradigm, subjects were instructed to open and close the right and left hands alternately (15s each hand), simulating the kimono grip.

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Fig.3.6 - Demonstração de técnica de judo em pé – O-goshi (Silva, N.d)

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In the third, a motor imagery paradigm, 15s rest periods were alternated with 15s periods during which the names of different judo techniques (which translate different movement sequences) were pronounced: Osoto-gari; Uchi-mata; O-goshi; Hon-kesa-gatame; and Kami-shio-gatame. In this paradigm subjects were previously instructed to imagine executing the corresponding judo techniques. In every paradigm the first period was 20s long.

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Fig. 3.5 - Demonstração de técnica de judo em pé – Uchi-mata (Moreno, 2011).

Materials and Methods

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In spite of advances in the understanding of the brain of visually impaired individuals, there is lack of studies regarding blinded athletes, and in particular Judo athletes. Therefore, the main aim of this study was to assess brain responses in visual, auditory and motor areas in blind judo athletes and in sighted judo athletes when exposed to judo-related stimuli.

Twelve judo athletes (aged 19 to 52 years old), 6 visually impaired (2 early and 4 late totally blind) and 6 sighted, were studied by fMRI using a 1.5T MRI scanner (General Electric, Milwaukee, USA) and an 8-channel neurovascular coil. fMRI data was acquired using:

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Avaliação por fMRI do córtex visual, motor e auditivo através de estimulação sensoriomotora e sonora em desportistas invisuais e desportistas sem deficiência visual.

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Judo is one of the sports where visually impaired athletes can practice and compete in a almost identical manner as sighted athletes. In fact, visually impaired athletes may have some advantage over sighted athletes as they can "predict" the opponent's action faster by compensating the lack of vision with improved sensory modalities such as touch and hearing. Several neuroimaging studies have shown that, in visual impaired individuals, the occipital cortex is recruited in non-visual tasks such as Braille reading (Burton, 2002; Sadato, 2002); memory recovery (Amedi, 2003); sound localization (Gougoux, 2005); or other auditory functions (Arno, 2001). Additionally, other studies suggest that these individuals also have larger cortical representation of auditory and sensorymotor functions, as well as in voice perception (Gougoux, 2009).

Figure 1 – Typical activation maps for a) motor execution (right hand); c) touch; and d) motor imagery paradigms for a sighted judo athlete (FEAT/FSL).

Cluster 1 (3783 Vx; Zmax=4.41) Pre-central gyrus; BA3, 4 and 6 Cluster 2 (877 Vx; Zmax=3.63) Right Cerebellum

Cluster 1 (3039 Vx; Zmax=4.84) Right: Pre-central and Post-central gyrus; Middle frontal gyrus; BA3, 4 and 6; Cluster 2 (1045 Vx; Zmax=4.09) Right: Thalamus; Insula; Palidum; Putamen Cluster 3 (1045 Vx;Zmax=4.09) Left Cerebellum

Cluster 1 (2811 Vx; Zmax=4.82) Pre-central gyrus; BA3, 4 and 6

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Cluster 1 (925 Vx; Zmax=8.25) BA 13 and 40. Cluster 2 (703 Vx; Zmax=8.25) Left: Post-central gyrus.

Cluster 1 (1039 Vx; Zmax=6.48) BA 2, 4 and 40. Cluster 2 (680 Vx; Zmax=5.96) Pst-central gyrus.

Motor imagery

Cluster 1 (5418Vx; Zmax=8.25) Right: Post-central gyrus; Middle frontal gyrus; BA 6, 7, 21, 22 and 41;. Cluster 2 (4780 Vx; Zmax=4.09) Occipital cortex: BA 17 and 18. Cluster 3 (1045 Vx;Zmax=4.09) Left Cerebellum.

Cluster 1 (1513 Vx; Zmax=3.35) Pre-central gyrus; BA 21, 22, 41 and 42. Cluster 2 (1280 VX; Zmax=2.75) Superior and Middle temporal gyrus.

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Table 2 – Group activation clusters obtained for the tactile sensory and motor imagery paradigms. (FEAT/FSL). Vx= Voxels; BA= Brodmann area.

Figure 3 – Group activation maps of the visual cortex obtained for the tactile sensory paradigm: a) visually impaired and b) sighted judo athletes. (MELODIC/FSL temporal concatenation).

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Figure 4 – Group activation maps of the motor-, auditory- and visual cortex obtained for the motor imagery paradigm: a) visually impaired and b) sighted judo athletes. (MELODIC/FSL temporal concatenation).

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Cluster 1 (2958 Vx; Zmax=4.61) Left: Pre-central and Post-central gyrus; BA3, 4 and 6; Cluster 2 (729 Vx; Zmax=4.14) Right Cerebellum

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In both groups of volunteers (sighted and blind athletes) the visual cortex activation was observed when they received a verbal stimulus associated with a motor action. This suggests that vision loss does not lead to permanent inactivation of the visual cortex. Blindness leads to an adaptation of the visual cortex for analyzing information from other sense organs, particularly auditory and tactile (brain plasticity).

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Amedi, A. (2003) “Early ‘visual’ cortex activation correlates with superior verbal memory performance in the blind”, Nature Neuroscience, vol. 6, pp. 758–766; Arno, P. (2001), “Occipital activation by pattern recognition in the early blind using auditory substitution for vision”, Neuroimage, vol.13, pp. 632–645; Burton, H. (2002), “Adaptive Changes in Early and Late Blind: A fMRI Study of Braille Reading”, Journal of Neurophysiology, vol. 87, pp. 589-607; Gougoux, F. (2005), “A Functional Neuroimaging Study of Sound Localization: Visual Cortex Activity Predicts Performance in Early-Blind Individuals”, PLoS Bio, vol. 3, no. 2, pp. e27; Gougoux, F. (2009), “Voice perception in blind persons: A functional magnetic resonance imaging study”, Neuropsychology, vol. 47, pp. 2967–2974.

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Thus, this research contributes to understanding and development of studies in functional MRI geared to support the sport for athletes with a visual impairment; to guide clinical treatment decisions in cases of visual impairment; to improve training methodologies and effective communication between coaches and athletes with this handicap.

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Table 1 – Group activation clusters obtained for the motor execution paradigm. (FEAT/FSL). Vx= Voxels; BA= Brodmann area.

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Figure 2 – Group activation maps of the visual cortex obtained for the motor execution paradigm: a) visually impaired and b) sighted judo athletes. (MELODIC/FSL temporal concatenation).

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It was observed that both groups (visually impaired and sighted) showed similar regional activation maps Differences between groups also agree with the literature: typically higher activation values and larger within and between groups for all paradigms. Additionally, activation in the visual cortex was observed for activation volumes are observed in the visually impaired group. In particular, in the motor imagery paradigm, all paradigms as well. This suggests that the loss of vision does not lead to inactivation of the visual cortex motor-, auditory- and visually-related activations are more evident in the visually impaired judo athletes. but in fact it adapts to process other type of information in agreement with known literature (neural plasticity).

We thank the CUF Descobertas Hospital and its Radiologists and Radiographers, for supporting the realization of this study and for the many helpful comments. Special thanks for all judo athletes from Clube Judo Total and Judo Clube Lisboa.