Coordinated Response Modulations Enable Flexible Use of Visual Information.

We use sensory information in remarkably flexible ways. We can generalize by ignoring task-irrelevant features, report different features of a stimulus, and use different actions to report a perceptual judgment. These forms of flexible behavior are associated with small modulations of the responses of sensory neurons. While the existence of these response modulations is indisputable, efforts to understand their function have been largely relegated to theory, where they have been posited to change information coding or enable downstream neurons to read out different visual and cognitive information using flexible weights. Here, we tested these ideas using a rich, flexible behavioral paradigm, multi-neuron, multi-area recordings in primary visual cortex (V1) and mid-level visual area V4. We discovered that those response modulations in V4 (but not V1) contain the ingredients necessary to enable flexible behavior, but not via those previously hypothesized mechanisms. Instead, we demonstrated that these response modulations are precisely coordinated across the population such that downstream neurons have ready access to the correct information to flexibly guide behavior without making changes to information coding or synapses. Our results suggest a novel computational role for task-dependent response modulations: they enable flexible behavior by changing the information that gets out of a sensory area, not by changing information coding within it.

Shoulder Pain Associated With Multiple Arteriovenous Malformations Successfully Treated With Embolization.

A 44-year-old male presented with left upper extremity and shoulder pain with worsening functional impairment after years of repetitive use, overtraining, and multiple injuries from weightlifting and mixed martial arts. Imaging showed no obvious injury or ligamentous deformity other than mild osteoarthritis (OA) of the left glenohumeral joint. Duplex ultrasonography (US) revealed four arteriovenous malformations (AVMs) surrounding the shoulder joint and left upper extremity. The vasculature was mapped via angiography through a transradial approach. Initial treatment included transarterial embolization of two AVMs off the axillary artery and branching anterior circumflex humeral artery. Secondary treatment included embolization of two lesions months later via direct puncture, one through a transvenous approach and the second through direct transmalformation cannulation, via the nidus, near the clavicle and posterior scapular lateral border. Treatment resulted in significant improvement in pain and range of motion. Follow-up assessments revealed improvement in overall symptoms, recovered function, and return to exercise and competitive mixed martial arts. This case highlights the value of duplex ultrasonography, embolization, and transarterial and transvenous approaches for the treatment of AVM-associated extremity or joint pain.

Embolization for the treatment of large, complex fibroids in an outpatient setting: A report of 2 cases.

Uterine leiomyomas are the most common benign pelvic tumors in premenopausal women, causing significant morbidity. Uterine fibroid embolization is a minimally invasive alternative to traditional open or laparoscopic surgeries for the management of symptomatic uterine leiomyoma. For large fibroids, hospitalization after treatment is often required. However, there are limited data on patients with large, complex uterine leiomyomas treated by embolization. This report of 2 cases describes 2 females with large, complex fibroids causing pain and decreased quality of life who were evaluated and treated with embolization in the outpatient setting. Each patient underwent transradial cannulation and uterine artery embolization under local anesthesia or conscious sedation and returned home without complication. For women wishing to preserve their uterus, uterine fibroid embolization is an effective nonsurgical alternative to hysterectomy and myomectomy in an outpatient setting. If standard protocols are followed, embolization by way of transradial artery catheterization is safe for the treatment of large, complex, symptomatic fibroids in the outpatient setting; however, additional studies with larger cohorts are warranted. Accessing the uterine arteries transradially reduces the risk of intra- and post-operative complications for patients, reduces their time spent in a hospital, and minimizes operating costs.