Variation among individuals is a prerequisite of evolution by natural selection. As such, identifying the origins of variation is a fundamental goal of biology. We investigated the link between gene interactions and variation in gene expression among individuals and species using the mammalian limb as a model system. We first built interaction networks for key genes regulating early (outgrowth;...

Natural behavior requires close but flexible coordination between attention, defined as selection for perception, and action. In recent years a distributed network including the lateral intraparietal area (LIP) has been implicated in visuospatial selection for attention and rapid eye movements (saccades), but the relation between the attentional and motor functions of this area remains unclear....

The Dynamic Similarity Hypothesis (DSH) suggests that when animals of different size walk at similar Froude numbers (equal ratios of inertial and gravitational forces) they will use similar size-corrected gaits. This application of similarity theory to animal biomechanics has contributed to fundamental insights in the mechanics and evolution of a diverse set of locomotor systems. However, despi...

Signal relay by guidance receptors at the axonal growth cone is a process essential for the assembly of a functional nervous system. We investigated the in vivo function of Src family kinases (SFKs) as growth cone guidance signaling intermediates in the context of spinal lateral motor column (LMC) motor axon projection toward the ventral or dorsal limb mesenchyme. Using in situ mRNA detection w...

Rupture of the cranial cruciate ligament (CCL) in stifle is one most common causes hind-limb lameness middle-aged and old dogs. The treatment choice involves surgical extra- or intra-capsular stabilization knee joint, increasingly preferred tibial osteotomy techniques. Postoperative rehabilitation affected limb an equally important part treatment. paper describes three cases rupture dogs method...

The default mode of the motor system is a coupling between limbs. However, in some movements, a decoupling is required and thus calls for selection and facilitation/inhibition processes. Here, we investigate the relative contribution of recruitment versus selection processes to the overall processing complexity. To this aim we proposed a new multilimb reaction-time task (MUL-RT). Simple, choice...

A key prediction made by theories of density-dependent competition is that resource overlap should increase the intensity of competition. By extension, we can predict that competition should lead to density-dependent natural selection. I studied natural selection on limb length and body size in a total of seven populations of Anolis sagrei over 3 years in the Bahamas. Experimental manipulations...

Corrective responses to limb disturbances are surprisingly complex, but the neural basis of these goal-directed responses is poorly understood. Here we show that somatosensory feedback is transmitted to many sensory and motor cortical regions within 25 ms of a mechanical disturbance applied to the monkey's arm. When limb feedback was salient to an ongoing motor action (task engagement), neurons...