Why study mechanisms of brain stimulation therapies? To modulate the right neurons, in the right way, at the right time.

Clinical applications of vagus nerve stimulation (VNS) are burgeoning, but mechanistic work lags behind. In this issue of Neuron, Bowles and colleagues show that VNS timed with positive reinforcement improves motor learning and cortical function by a cholinergic mechanism.

Future of seizure prediction and intervention: closing the loop.

The ultimate goal of epilepsy therapies is to provide seizure control for all patients while eliminating side effects. Improved specificity of intervention through on-demand approaches may overcome many of the limitations of current intervention strategies. This article reviews the progress in seizure prediction and detection, potential new therapies to provide improved specificity, and devices to achieve these ends. Specifically, we discuss (1) potential signal modalities and algorithms for seizure detection and prediction, (2) closed-loop intervention approaches, and (3) hardware for implementing these algorithms and interventions. Seizure prediction and therapies maximize efficacy, whereas minimizing side effects through improved specificity may represent the future of epilepsy treatments.

A Miniature, Fiber-Coupled, Wireless, Deep-Brain Optogenetic Stimulator.

Controlled, wireless neuromodulation using miniature implantable devices is a long-sought goal in neuroscience. It will allow many studies and treatments that are otherwise impractical. Recent studies demonstrate advances in neuromodulation through optogenetics, but test animals are typically tethered, severely limiting experimental possibilities. Existing nontethered optical stimulators either deliver light through a cranial window limiting applications to superficial layers of the brain, are not widely accessible due to highly specialized fabrication techniques, or do not demonstrate robust and flexible control of the optical power emitted. To overcome these limitations, we have developed a novel, miniature, wireless, deep-brain, modular optical stimulator with controllable stimulation parameters for use in optogenetic experiments. We demonstrate its use in a behavioral experiment targeting a deep brain structure in freely behaving mice. To allow its rapid and widespread adoption, we developed this stimulator using commercially available components. The modular and accessible optogenetic stimulator presented advances the wireless toolset available for freely behaving animal experiments.

Image-guided musculoskeletal biopsies.

Image-guided musculoskeletal (MSK) biopsies are safe and effective procedures that yield diagnostic accuracies up to 97%. When performed in conjunction with a multidisciplinary team, they provide crucial information that will affect patient care and outcome. Computed tomography and ultrasound are the main modalities used to carry out MSK biopsies, and various needles and techniques are available to help the radiologist perform these procedures safely.

Magnetic resonance imaging appearance of partial latissimus dorsi muscle tendon tear.

There is still a paucity of information about the clinical presentation, treatment and imaging findings of latissimus muscle tears. Only one study has specifically described the magnetic resonance imaging (MRI) features of latissimus tendon tears. We describe a case of a high-grade tear in the latissimus muscle tendon in an active water skier with no significant prior medical history. MRI demonstrated at least a 50% tear of the latissimus tendon, manifesting as increased signal intensity on T2-weighted sequences and surrounding edema, as well as a diminutive tendon at the humeral insertion.

Evaluation of occult cervical spine fractures on radiographs and CT.

The aim of this study was to evaluate occult cervical spine fractures on radiographs and CT. We reviewed radiographs of 68 patients with cervical spine fractures at a level 1 trauma center. Twenty-six patients showed occult fractures on initial radiographs. Of seven odontoid fractures, two were diagnosed only after thinner repeat CT reconstructions. Five facet fractures were best seen on CT reconstructions. Three occult hangman's fractures were seen by CT. A C1 fracture was diagnosed on CT only. Two fractures through the C2 body were seen only by CT. Eight fractures were obscured by patient's shoulders, including five clay shoveler's fractures, a C6 facet fracture, a bilateral C6 pedicle fracture, and a C7-T1 fracture-dislocation. Odontoid, facet, and lower cervical spine fractures are most commonly occult on radiographs. CT, especially high-quality CT reconstructions for odontoid and facet fractures, can improve the diagnosis of cervical spine fracture.