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Seung-Jae Hyun, Ki-Jeong Kim, and Tae-Ahn Jahng

. The following parameters were evaluated ( Fig. 1 ): C0–1 angle (the angle between the McGregor line and the C1 arch line, measured using the Cobb method), C1–2 angle (the angle between the C1 arch line and the C2 lower endplate), C2–7 lordosis (the angle created by a line parallel to the inferior aspect of the C2 body and a line parallel to that of the C7 body, measured on neutral lateral radiographs), SVA COG (distance between the center of gravity of the head [COG] plumb line [PL] and the posterosuperior corner of the S1 endplate), SVA C2 (distance between the C

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Neal Conway, Noémie Wildschuetz, Tobias Moser, Lucia Bulubas, Nico Sollmann, Noriko Tanigawa, Bernhard Meyer, and Sandro M. Krieg

(if no MEP of the lower limbs could be induced at 130% of the rMT). Coil angulation was always perpendicular to the stimulated gyri. To minimize false negatives, we stimulated well beyond the areas appearing as positive for motor function. We considered a mapping point as positive for motor function when an EMG response > 50 mA was registered in 1 of the corresponding muscles upon its stimulation. All points were checked for artifacts after each mapping. Hotspot and Centers of Gravity Analysis We determined the hotspots (HSs) and the map centers of gravity (CoGs

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Mikkel V. Petersen, Torben E. Lund, Niels Sunde, Jesper Frandsen, Frederikke Rosendal, Niels Juul, and Karen Østergaard

readily exported (DICOM format) and loaded in standardized neuronavigation systems. This processing pipeline results in 2 STN maps representing HDP target regions, 1 using the DT-based and 1 using the CSD-based tractography method. To contrast the 2 STN target regions identified in the patients with PD, we extracted coordinates for the center of gravity and calculated the distance between the 2 points. To compare the target robustness across the 10 repeated scans, we again extracted the center of gravity and calculated the standard deviation of the 2 methods across the

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Martijn J. A. Malessy, Dick Bakker, Ad J. Dekker, J. Gert van Dijk, and Ralph T. W. M. Thomeer

in healthy volunteers revealed that the cortical map of the intercostal cortical area is localized in the midline, whereas that of the biceps muscle is located a few centimeters lateral from the midsagittal plane. The map coordinate system used in that study was the international 10–20 electrode system for electroencephalography examinations, which refers to skull landmarks. 12, 21, 33 At the end stage of reinnervation, the center of gravity of TMS maps of the reinnervated biceps muscle differed from that of the medial location of the intercostal muscles

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Wendy Guo, Bang-Bon Koo, Jae-Hun Kim, Rafeeque A. Bhadelia, Dae-Won Seo, Seung Bong Hong, Eun Yeon Joo, Seunghoon Lee, Jung-Il Lee, Kyung Rae Cho, and Young-Min Shon

target for ATN DBS, we determined the Euclidean distance between each active contact in patients and the reference point that represents the central location of the ATN (R28, regions drawn in yellow and orange in Fig. 2 ). The coordinates of the ATN surface from the DISTAL were averaged to obtain the overall center coordinate for each hemisphere. However, as active contacts were mostly localized within the anterior half of the ATN, the center of gravity of the anterior half of the ATN (orange portion of R28 in Fig. 2 ), defined as the anterior center (AC), must be a

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Jennifer Muller, Mahdi Alizadeh, Feroze B. Mohamed, Jonathan Riley, John J. Pearce, Benjamin Trieu, Tsao-Wei Liang, Victor Romo, Ashwini Sharan, and Chengyuan Wu

and mapped as a numerical value for both tracking methods. Using the manual parcellations of the basal ganglia structures, we created track density images to represent the number of sensorimotor pathways passing through a given ROI. Track Density Analysis In order to compare deterministic and probabilistic tracking solutions, the center of gravity (CoG) of the track density maps of both targeted regions (STN and GPi) was calculated for each patient. For deterministic tractography, the track density map was generated based on whole-brain streamline tractography using

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Martijn J. A. Malessy, Dick Bakker, Ad J. Dekker, J. Gert van Dijk, and Ralph T. W. M. Thomeer

Object

Recent progress in the understanding of cerebral plastic changes that occur after an intercostal nerve (ICN)–musculocutaneous nerve (MCN) transfer motivated a study with functional magnetic resonance (fMR) imaging to map reorganization in the primary motor cortex.

Methods

Eleven patients with traumatic root avulsions of the brachial plexus were studied. Nine patients underwent ICN–MCN transfer to restore biceps function and two patients were studied prior to surgery. The biceps muscle recovered well in seven patients who had undergone surgery and remained paralytic in the other two patients. Maps of neural activity within the motor cortex were generated for both arms in each patient by using fMR imaging, and the active pixels were counted. The motor task consisted of biceps muscle contraction. Patients with a paralytic biceps were asked to contract this muscle virtually. The location and intensity of motor activation of the seven surgically treated arms that required good biceps muscle function were compared with those of the four arms with a paralytic biceps and with activity obtained in the contralateral hemisphere regulating the control arms.

Activity could be induced in the seven surgically treated patients whose biceps muscles had regained function and was localized within the primary motor area. In contrast, activity could not be induced in the four patients whose biceps muscles were paralytic. Neither the number of active pixels nor the mean value of their activations differed between the seven arms with good biceps function and control arms. The weighted center of gravity of the distribution of activity also did not appear to differ.

Conclusions

Reactivation of the neural input activity for volitional biceps control after ICN–MCN transfer, as reflected on fMR images, is induced by successful biceps muscle reinnervation. In addition, the restored input activity does not differ from the normal activity regulating biceps contraction and, therefore, has MCN acceptor qualities. After ICN–MCN transfer, cerebral activity cannot reach the biceps muscle following the normal nervous system pathway. The presence of a common input response between corticospinal neurons of the ICN donor and the MCN acceptor seems crucial to obtain a functional result after transfer. It may even be the case that a common input response between donor and acceptor needs to be present in all types of nerve transfer to become functionally effective.

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Tobias A. Mattei, Brandon J. Bond, John W. Hafner Jr., Martin J. Morris, Jennifer Travis, Greg Hannah, Jim Webster, and Julian J. Lin

-powered vehicles with a weight typically between 300 and 600 lbs (135 and 270 kg), a high center of gravity, motorcycle-style handlebars for steering control, a seat designed to be straddled from atop a platform, and oversized, low-pressure knobby tires optimized for off-road, nonpaved terrain traversal. 21 With engine sizes ranging from approximately 50–750 cm 3 of displacement, ATVs are now capable of achieving speeds up to 75 mph (120 km/h). 22 In 1988, the US Department of Transportation and ATV manufacturers negotiated a 10-year consent decree in federal district court

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Adam J. Bartsch, Edward C. Benzel, Vincent J. Miele, Douglas R. Morr, and Vikas Prakash

H istorically , linear acceleration has been the main parameter by which to measure athletic head injury risk; however, combinations of linear and rotational impact dosage have been widely acknowledged as contributors to head injury. Current standard head injury metrics—the GSI 9 and HIC 35 —are based on resultant linear head center of gravity acceleration and cannot be used to quantify rotational injury risk. These injury metrics were developed from laboratory head impact studies conducted decades ago and were correlated to severe skull fracture and brain

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P. Sarat Chandra and Mohit Agarwal

correction using compression and extension technique with only a cable will suffice, as shown in the first row. So, following compression and extension, the center of gravity, abbreviated here as COG, align completely with each other after compression and extension. However, when the true joint becomes vertical, and the basilar invagination is very severe, as in this case, there is also a backward listhesis of C2 over O–C1, as shown in second row. Thus, just compression and extension movements do not align the center of gravities of O–C1 and C2 complexes. Here, we would