Actions become compulsive when they are no longer controlled by their consequences. Compulsivity can be assessed using the omission procedure in which animals are required to withhold a previously reinforced action to earn reward. The current study tested the hypothesis that inactivation of the dorsolateral striatum (DLS), a structure implicated in habitual behavior, can enhance sensitivity to ...

We recorded evoked potentials during performance of a reaction-time task, in which rats had to release a lever quickly in response to either a visual or an auditory stimulus for a food reward. We found two distinct peaks in their cortical evoked potentials. The first peak appeared at a fixed time after the stimulus, irrespective of the time it took the rat to release the lever. Its amplitude de...

The molecular motor protein myosin VI moves toward the minus-end of actin filaments with a step size of 30-36 nm. Such large step size either drastically limits the degree of complex formation between dimer subunits to leave enough length for the lever arms, or requires an extension of the lever arms' crystallographically observed structure. Recent experimental work proposed that myosin VI dime...

Obesity and overeating have become fundamental problems in modern society. This article studies the inhibition of food-seeking behavior, and how contextual cues can control it. Rats that had free food in the home cage nevertheless learned to lever press for sucrose or high-fat pellets in a distinctive context (a Skinner box). Lever pressing was then inhibited by extinction, in which lever press...

We present a case of ankylosis of the knee after knee arthroplasty due to heterotopic ossification in the ligaments. Treatment with resection of the collateral ligaments, reconstruction with a hinged implant and radiotherapy was successful.

Biomechanical and environmental constraints limit body movements and tool use actions. However, in the case of tool use, such constraints can often be overcome by adjusting a tool’s tool transformation to the requirements of the intended tool use action. The research presented here examined whether participants grasped a lever at different positions, thus modifying the lever’s tool transformati...

The purpose of this study was to (1) evaluate the mechanical efficiency (ME) of two commercially available lever-propulsion mechanisms for wheelchairs and (2) compare the ME of lever propulsion with hand rim propulsion within the same wheelchair. Of the two mechanisms, one contained a torsion spring while the other used a roller clutch design. We hypothesized that the torsion spring mechanism w...

Stereotaxic head fixation plays a necessary role in current physiological techniques, such as in vivo whole cell recording and two-photon laser-scanning microscopy, that are designed to elucidate the cortical involvement in animal behaviors. In rodents, however, head fixation often inhibits learning and performance of behavioral tasks. In particular, it has been considered inappropriate for hea...

We developed an algorithm, Lever, that systematically maps metazoan DNA regulatory motifs or motif combinations to sets of genes. Lever assesses whether the motifs are enriched in cis-regulatory modules (CRMs), predicted by our PhylCRM algorithm, in the noncoding sequences surrounding the genes. Lever analysis allows unbiased inference of functional annotations to regulatory motifs and candidat...

The power stroke pulling myosin along actin filaments during muscle contraction is achieved by a large rotation ( approximately 60 degrees ) of the myosin lever arm after ATP hydrolysis. Upon binding the next ATP, myosin dissociates from actin, but its ATPase site is still partially open and catalytically off. Myosin must then close and activate its ATPase site while returning the lever arm for...