Long-Term Effects of Non-Paretic Limb Training in Mice

Limb impairment following stroke greatly affects one\u27s quality of life and may lead to overreliance upon the good limb. Although functionally adaptive, this compensatory reliance is thought to limit recovery of the bad limb. Previous research has established that good limb training in mice impairs recovery of the bad limb following stroke in the short term. This study extends these findings by determining that good limb use following stroke severely retards, and may prevent, functional recovery in the long term. C57BL/6 mice underwent one week of shaping procedures followed by pre-operative training on the Pasta Matrix Reaching Task to establish the motor skill prior to stroke. Following pre-operative training, unilateral stroke was induced through intracortical infusions of a vasoconstricting peptide. Mice were divided into two groups for post-operative training: one receiving control procedures and the other receiving good limb training. Following post-operative training, functionality of the bad limb was assessed for 28 days. Throughout this rehabilitative training, control mice exhibited functional recovery while impairment persisted in good limb mice. These findings suggest permanent damage to neural activity following post-stroke behavioral compensation

Biochaos in cardiac rhythms

Biological rhythm is an essential characteristic of natural systems that can present regular or irregular dynamics, which can be associated with normal or pathological functioning. In this regard, nonlinear dynamics perspective is able to connect biorhythm with functioning characteristics. This paper investigates the heart dynamics by considering a mathematical model that is built from three coupled nonlinear oscillators. The main strategy is to investigate natural pacemaker behavior, establishing its influence on the electrical activity of the heart represented by electrocardiograms (ECGs). Different kinds of pacemaker behaviors are treated, dedicating special attention to chaotic rhythms

A three dimensional multiplane kinematic model for bilateral hind limb gait analysis in cats.

BACKGROUND:Kinematic gait analysis is an important noninvasive technique used for quantitative evaluation and description of locomotion and other movements in healthy and injured populations. Three dimensional (3D) kinematic analysis offers additional outcome measures including internal-external rotation not characterized using sagittal plane (2D) analysis techniques. METHODS:The objectives of this study were to 1) develop and evaluate a 3D hind limb multiplane kinematic model for gait analysis in cats using joint coordinate systems, 2) implement and compare two 3D stifle (knee) prediction techniques, and 3) compare flexion-extension determined using the multiplane model to a sagittal plane model. Walking gait was recorded in 3 female adult cats (age = 2.9 years, weight = 3.5 ± 0.2 kg). Kinematic outcomes included flexion-extension, internal-external rotation, and abduction-adduction of the hip, stifle, and tarsal (ankle) joints. RESULTS:Each multiplane stifle prediction technique yielded similar findings. Joint angles determined using markers placed on skin above bony landmarks in vivo were similar to joint angles determined using a feline hind limb skeleton in which markers were placed directly on landmarks ex vivo. Differences in hip, stifle, and tarsal joint flexion-extension were demonstrated when comparing the multiplane model to the sagittal plane model. CONCLUSIONS:This multiplane cat kinematic model can predict joint rotational kinematics as a tool that can quantify frontal, transverse, and sagittal plane motion. This model has multiple advantages given its ability to characterize joint internal-external rotation and abduction-adduction. A further, important benefit is greater accuracy in representing joint flexion-extension movements

Lateral stifle virtual marker (dark sphere) projection techniques.

<p>Tibia axis 1 (light arrow along the tibia) was defined as the vector of length equal to the fibula length originating at the lateral malleolus projected through the vector marker. The femoral axis was defined as the vector of length equal to the femur length originating at the greater trochanter projected towards the fibula vector endpoint. The lateral stifle virtual marker was defined as the midpoint of the line connecting the endpoints of tibia axis 1 and the femoral axis. Tibia axis 2 (dark arrow along the tibia) was defined as the vector of length equal to the fibular length originating at the lateral malleolus projected towards the lateral stifle virtual marker determined previously.</p

Mean flexion-extension for the hip, stifle, and tarsal joints for a representative limb from each cat using the multiplane and sagittal plane kinematic models during the step cycle for gait.

<p>Cat 1 corresponds to the cat in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197837#pone.0197837.g004" target="_blank">Fig 4</a> and Cat 2 corresponds to the cat in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197837#pone.0197837.g005" target="_blank">Fig 5</a>.</p

Mean stifle joint kinematics for a representative hind limb using both stifle prediction techniques during the step cycle for gait.

<p>Technique 1 corresponds to the unadjusted tibia axis, and technique 2 corresponds to the adjusted tibia axis. Flexion-extension angles correspond to the absolute angle between the segments while positive values indicate external rotation and abduction, and negative values correspond to internal rotation and adduction. The dashed horizontal lines indicate 0° (neutral) on external-internal rotation and abduction-adduction graphs.</p

Cat kinematics experimental setup overhead view.

<p>Ten infrared motion capture tracking cameras (numbered 1–10) surrounded the walkway, and 2 synced video cameras (indicated with A and B) were placed on opposite sides of the walkway to record sagittal plane movements. Camera locations relative to the motion capture space origin are indicated in the table, and the walkway length and width are shown. The walkway was 1.0 m above the ground, and the motion capture space origin was on the surface of the walkway.</p

Hip, stifle, and tarsal mean (solid line) ± SD (dotted line) kinematics for the <i>ex vivo</i> walking task using the transformed bony landmark marker set and the triad marker set.

<p>The horizontal dashed line indicates 0° on external-internal rotation and abduction-adduction graphs.</p

Hind limb specimen with bony landmark markers (gray circles) and marker triads (white circles at triangle vertices).

<p>Markers and marker triads are adhered along the pelvis and a single limb. The left hind limb was suspended to prevent obstruction of the right hind limb markers. The right hind limb was manipulated using the rigid extension (identified with a white arrow) attached to the metatarsal bones distal to the tarsus triad. Reflective markers can be seen at the stifle and anterior tibia, but these markers were not used in the current study.</p