Premotor Cortical Areas with Increased BOLD Responses with Both the Left- and the Right-Hand Map Overlaid on Coronal Slices of the MNI T1-Weighted Brain Template

<p>For the left hemisphere (L), significant activations ( <i>p</i> < 0.01, FWE-corrected) occurred in one cluster (443 voxels) with two maxima in precentral gyrus (#2 and #4; BA 6), in one single-peak cluster (153 voxels) in superior frontal gyrus (#3; BA 6), in one cluster (281 voxels) with two maxima in medial frontal gyrus (#5 and #6; BA 6), and in one small single-peak cluster (29 voxels) in left inferior frontal gyrus (#1; BA 44). In the right hemisphere (R), there was one cluster (303 voxels) with three maxima, one of which was located in the precentral gyrus outside the cluster delineated by left-hand-map > right-hand-map contrast (#7; BA 6). Solid black lines in the left and right hemisphere outline the clusters identified with the right-hand-map > left-hand-map and left-hand-map > right-hand-map contrasts, respectively (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040158#pbio-0040158-g004" target="_blank">Figure 4</a>C). Histograms give percent BOLD signal change relative to mean of session for the local maxima of identified clusters. Red and blue columns refer to left- and right-hand maps, respectively. Column height gives data averaged across participants and error bar ± 1SEM ( <i>n</i> = 16). Coordinates (X, Y, Z in MNI stereotaxic space) and <i>t</i>₍₃₀₎ values for the maxima are presented below each histogram. </p

The Bimanual Target-Chasing Task and Flexible Role Assignment of the Hands

<div><p>(A) Mappings between applied forces and cursor movements (top graph). With the left-hand map, the cursor moved horizontally in the direction of the longitudinal force applied by the left hand (solid purple arrows). A counter-clockwise twist force applied between the handles (as if unscrewing the lid of a jar) moved the cursor upward (solid green arrows). With the right-hand map the cursor moved in the opposite directions and thus in the direction of the forces of the right hand.</p> <p>(B and C) Performance under each mapping rule shown for a complete first session with 602 hits and from the last 100 hits of a second session. Superimposed thin lines show hit time and path index for each participant as a function of target number (data median-filtered over a ± 10-s period around each hit). Solid curve give medians across participants. Inserts in (C) exemplify cursor trajectories with a median path index of 4.6 and 1.4 across 10 target transitions. The targets, distributed about uniformly over the screen, were located 5.1 ± 2.1° (mean ± 1 SD) visual angle from its center, which corresponded to 2.2 ± 0.3 N force applied tangentially to the surfaces of the handles.</p> <p>(D and E) Hand-asymmetry indices computed for a sliding ± 10-s time window. Horizontal lines give the upper and lower 95% confidence limit of the index, postulating that hand selection would have occurred randomly. A significant positive and negative index indicates left and right-hand primarily acting, respectively.</p></div

Influence of Mapping Rule on Tool Movements during Performance with Left-Hand and Right-Hand Maps

<p>Superimposed time traces of longitudinal force and lateral tool movement (upper panels) and of twist force and rotational tool movement (lower panels) from a single participant during the last 20 s of target chasing in the first experiment; <i>r_LO</i> and <i>r_TW</i> indicate hand-asymmetry indices for longitudinal and twist forces. Bottom trace represents instances of target hits (spikes). For the last 20 s of runs by all participants and mapping rules, the slope coefficients of the linear regressions indicated that the tool moved 0.84 (0.28–1.23) mm/N longitudinal force and rotated 0.84 (0.36–1.42) °/N twist force (median and 25th–75th percentile). The corresponding values for the 30-s periods of target chasing for which fMRI data were analyzed (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040158#pbio-0040158-g005" target="_blank">Figure 5</a>A and <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040158#pbio-0040158-g005" target="_blank">5</a>B), where the wrists of the participants were strapped, were 0.28 (0.19–0.68) mm/N and 0.63 (0.42–1.04) °/N. </p

Comparisons of muscle strength between COPD and the reference group, mean of adjusted muscle strength during maximum isometric contraction.

Comparisons of muscle strength between COPD and the reference group, mean of adjusted muscle strength during maximum isometric contraction.</p

Basic characteristics of COPD and the reference group.

Basic characteristics of COPD and the reference group.</p

Flow chart over the recruitment of the study sample.

Notes: 1Post bronchodilator FEV1/VC 1% of predicted68 years old, living in Luleå, Boden or Piteå municipality. 2Individuals who denied participation or could not be located. 3 Individuals not fulfilling the additional inclusion criteria, including adequate vision to read 100 pt font size, ability to stand unassisted for at least 30 seconds, and to understand and process simple instructions. 4FEV1/VC 5n = 20 from OLIN COPD study, n = 2 from BAHRT study.</p

Comparisons of postural control between COPD and reference group: Mean of adjusted maximum amplitudes during static trials and limits of stability.

Comparisons of postural control between COPD and reference group: Mean of adjusted maximum amplitudes during static trials and limits of stability.</p

Coefficient plot of the OPLS-regression model with AP LoS (maximum anteroposterior amplitude in limits of stability test) as outcome, in the COPD group.

Notes: The direction of the coefficients represent positive or negative associations with increased sway amplitude. Variables have been centered and scaled for unit variance. Error bars (95% confidence interval) not including zero indicate significant coefficients. Abbreviations: FEV1% pred, Forced expiratory volume in 1 second, percent of predicted; L, Left; R, Right; JPS, Joint position sense, HGS, Hand grip strength, Hip ext, Hip extension; Hip abd, Hip abduction; Knee ext, Knee extension, Knee flx, Knee flexion; Ankle pla, Ankle plantar flexion; Ankle dor, Ankle dorsiflexion.</p

Comparisons of sensory measures and reaction time between COPD and the reference group.

Comparisons of sensory measures and reaction time between COPD and the reference group.</p

Coefficient plot of the OPLS-regression model with AP LoS (maximum anteroposterior amplitude in the limits of stability test) as outcome, in the reference group.

Notes: The direction of the coefficients represent positive or negative associations with increased sway amplitude. Variables have been centered and scaled for unit variance. Error bars (95% confidence interval) not including zero indicate significant coefficients. Abbreviations: FEV1% pred, Forced expiratory volume in 1 second, percent of predicted; L, Left; R, Right; JPS, Joint position sense, HGS, Hand grip strength, Hip ext, Hip extension; Hip abd, Hip abduction; Knee ext, Knee extension, Knee flx, Knee flexion; Ankle pla, Ankle plantar flexion; Ankle dor, Ankle dorsiflexion.</p