Migraine headache is uniquely exacerbated by light. Using psychophysical assessments in patients with normal eyesight we found that green light exacerbates migraine headache significantly less than white, blue, amber or red lights. To delineate mechanisms, we used electroretinography and visual evoked potential recording in patients, and multi-unit recording of dura- and light-sensitive thalamic neurons in rats to show that green activates cone-driven retinal pathways to a lesser extent than white, blue and red; that thalamic neurons are most responsive to blue and least responsive to green; and that cortical responses to green are significantly smaller than those generated by blue, amber and red lights. These findings suggest that patients' experience with colour and migraine photophobia could originate in cone-driven retinal pathways, fine-tuned in relay thalamic neurons outside the main visual pathway, and preserved by the cortex. Additionally, the findings provide substrate for the soothing effects of green light.

Small fiber neuropathy manifests in a variety of different diseases and often results in symptoms of burning pain, shooting pain, allodynia, and hyperesthesia. Diagnosis of small fiber neuropathy is determined primarily by the history and physical exam, but functional neurophysiologic testing and skin biopsy evaluation of intraepidermal nerve fiber density can provide diagnostic confirmation. Management of small fiber neuropathy depends on the underlying etiology with concurrent treatment of associated neuropathic pain. A variety of recent guidelines propose the use of antidepressants, anticonvulsants, opioids, topical therapies, and nonpharmacologic treatments as part of the overall management of neuropathic pain. Unfortunately, little data about the treatment of pain specifically in small fiber neuropathy exist because most studies combine mixed neuropathic pain syndromes in the analysis. Additional studies targeting the treatment of pain in small fiber neuropathy are needed to guide decision making.

The authors examined whether patients with schizophrenia learned sequential patterns in a probabilistic serial response time task in which pattern trials alternated with random ones. Patients showed faster and more accurate responses to pattern trials than to random trials, but controls showed greater sensitivity to patterns. The highest level of regularity learned in both groups was information about runs of 3 events. Pattern learning occurred largely outside of awareness, as participants could not describe patterns. Controls with higher memory spans learned the sequential pattern better than those with lower memory spans, suggesting that working memory influences implicit pattern learning. Pathology in motor sequencing systems and poor working memory may lead to deficits in learning sequence structure in schizophrenia.

Painful neuropathy is a common and often progressive complication of diabetes. Patients frequently report symptoms of tingling, burning, lancinating pain, hyperesthesia and allodynia. The natural history of the disease may vary from intermittent mild symptoms to severe chronic daily pain; the latter is often associated with diminished quality of life. There are a variety of pharmaceutical agents from different medicinal categories available for the symptomatic treatment of painful diabetic neuropathy, however selecting an agent is often challenging given the breadth of choices and lack of consistent guidelines. As a result, many patients remain untreated or undertreated. This article presents a practical clinical approach to the treatment of pain in diabetic neuropathy. Recommendations for first, second and third line medications are based on specific evidence for the treatment of painful diabetic neuropathy as well as safety, tolerability, drug interactions and cost. Additional topics of discussion include breakthrough pain, opioid use and topical therapies. This review does not comprehensively discuss all possible treatments for painful neuropathy, but provides a systematic approach designed to guide clinicians in tailoring therapies to the individual patient.